TELLABS INC
S-4, 1998-04-07
TELEPHONE & TELEGRAPH APPARATUS
Previous: COCA COLA BOTTLING CO CONSOLIDATED /DE/, DEF 14A, 1998-04-07
Next: GENENTECH INC, 10-K/A, 1998-04-07



<PAGE>   1
 
     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON APRIL 7, 1998
                                                     REGISTRATION NO. 333-
================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                      ------------------------------------
                                    Form S-4
            REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933
                      ------------------------------------
                                 TELLABS, INC.
             (Exact Name of Registrant as specified in its Charter)
 
<TABLE>
<S>                                <C>                                <C>
           DELAWARE                             3661                            36-3831568
(State or other jurisdiction of     (Primary Standard Industrial      (I.R.S. Employer Identification
        incorporation or             Classification Code Number)                   No.)
         organization)
</TABLE>
 
                              4951 INDIANA AVENUE
                           LISLE, ILLINOIS 60532-1698
                                 (630) 378-8800
              (Address, including zip code, and telephone number,
       including area code, of Registrant's principal executive offices)
                      ------------------------------------
                              CAROL COGHLAN GAVIN
                       VICE PRESIDENT AND GENERAL COUNSEL
                            TELLABS OPERATIONS, INC.
                              4951 INDIANA AVENUE
                           LISLE, ILLINOIS 60532-1698
                                 (630) 378-8800
           (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)
                      ------------------------------------
                                   Copies to:
 
<TABLE>
<S>                                                 <C>
                   IMAD I. QASIM                                    N. JEFFREY KLAUDER
                  SIDLEY & AUSTIN                               MORGAN, LEWIS & BOCKIUS LLP
             One First National Plaza                              2000 One Logan Square
              Chicago, Illinois 60603                        Philadelphia, Pennsylvania 19103
</TABLE>
 
    APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon as
practicable after the effective date of this Registration Statement which
relates to the merger (the "Merger") of Cardinal Merger Co., a wholly owned
subsidiary of Tellabs, Inc, with and into Coherent Communications Systems
Corporation pursuant to the Merger Agreement described herein.
 
    If the securities being registered on this form are being offered in
connection with the formation of a holding company and there is compliance with
General Instruction G, check the following box.  [ ]
 
                        CALCULATION OF REGISTRATION FEE
 
<TABLE>
<S>                                     <C>                 <C>                    <C>                    <C>
=============================================================================================================================
                                                               PROPOSED MAXIMUM       PROPOSED MAXIMUM
         TITLE OF EACH CLASS               AMOUNT TO BE         OFFERING PRICE           AGGREGATE             AMOUNT OF
    OF SECURITIES TO BE REGISTERED          REGISTERED             PER UNIT            OFFERING PRICE      REGISTRATION FEE
- -----------------------------------------------------------------------------------------------------------------------------
                                            11,722,949
  Common Stock, $.01 par value........       shares(1)          Not Applicable        $747,948,541(2)         $220,645(3)
=============================================================================================================================
</TABLE>
 
(1) Based on the maximum number of shares of Common Stock, $.01 par value per
    share, of Tellabs, Inc. to be delivered pursuant to Section 2.1 of the
    Merger Agreement (as defined herein), assuming the exercise of all currently
    outstanding options to purchase shares of Common Stock, $.01 par value per
    share, of Coherent Communications Systems Corporation ("Coherent Common
    Stock").
(2) Estimated solely for the purpose of calculating the registration fee
    required by Section 6(b) of the Securities Act of 1933, as amended (the
    "Securities Act"), and computed pursuant to Rule 457(f) under the Securities
    Act by multiplying the average of the high and low prices of shares of
    Coherent Common Stock on April 3, 1998, as reported on the Nasdaq Stock
    Market, by 16,281,873, the number of shares of Coherent Common Stock
    outstanding at the close of business on April 3, 1998, assuming the exercise
    of all then outstanding options to purchase shares of Coherent Common Stock.
(3) Pursuant to Rule 457(b) of the Securities Act, $130,561 of the registration
    fee was paid on March 16, 1998 in connection with the filing of preliminary
    proxy/prospectus materials.
                      ------------------------------------
    THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF
THE SECURITIES ACT OR UNTIL THIS REGISTRATION STATEMENT SHALL BECOME EFFECTIVE
ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(a), MAY
DETERMINE.
================================================================================
<PAGE>   2
 
[LOGO/COHERENT(TM)]
 
                                                                   April 7, 1998
 
Dear Stockholder:
 
     You are cordially invited to attend the Special Meeting of Stockholders of
Coherent Communications Systems Corporation ("Coherent") to be held on May 12,
1998 at Coherent's offices located at 48085 University Drive, Ashburn, Virginia
20147, at 11:00 A.M., local time (the "Coherent Special Meeting").
 
     The purpose of the Coherent Special Meeting is to consider a proposal to
approve and adopt the Agreement and Plan of Merger dated as of February 16, 1998
(the "Merger Agreement"), among Tellabs, Inc. ("Tellabs"), Cardinal Merger Co.,
a wholly owned subsidiary of Tellabs ("Sub"), and Coherent, pursuant to which
Sub will be merged with and into Coherent (the "Merger"), and Coherent will
become a wholly owned subsidiary of Tellabs.
 
     Subject to the terms and conditions of the Merger Agreement, each share of
Common Stock, $.01 par value per share, of Coherent ("Coherent Common Stock")
outstanding immediately prior to the effective time of the Merger will be
converted into .72 of a share of Common Stock, $.01 par value per share, of
Tellabs ("Tellabs Common Stock"). Cash will be paid in lieu of any fractional
share of Tellabs Common Stock.
 
     Your Board of Directors believes that the Merger Agreement and the Merger
are fair to and in the best interest of Coherent and its stockholders. Your
Board has unanimously approved the Merger Agreement and recommends that you vote
FOR its approval. Your Board has received a written opinion from Robert W. Baird
& Co. Incorporated that the consideration to be received by Coherent's
stockholders in the Merger is fair from a financial point of view. You are
encouraged to read the accompanying Proxy Statement/Prospectus, which provides
detailed information concerning the Merger and additional information regarding
Tellabs and Coherent.
 
     Your vote is important, regardless of the number of shares you own. In
order for the Merger Agreement to be approved and adopted, the affirmative vote
of the holders of a majority of the outstanding shares of Coherent Common Stock
entitled to vote thereon is required. Accordingly, on behalf of your Board of
Directors, I urge you to complete, date and sign the accompanying proxy and
return it promptly in the enclosed postage-paid envelope. This will not prevent
you from attending the Coherent Special Meeting or voting in person, but will
assure that your vote is counted if you are unable to attend the Coherent
Special Meeting. You may revoke your proxy at any time by filing a written
notice of revocation with, or by delivering a duly executed proxy bearing a
later date to, the Secretary of Coherent at Coherent's principal executive
offices prior to the Coherent Special Meeting or by attending the Coherent
Special Meeting and voting in person.
 
     On behalf of the Board of Directors, I thank you for your support and urge
you to vote FOR approval of the Merger Agreement.
 
                                          Sincerely,
 
                                          /s/ Daniel L. McGinnis
                                          Daniel L. McGinnis
                                          Chief Executive Officer
<PAGE>   3
 
                  COHERENT COMMUNICATIONS SYSTEMS CORPORATION
                             45085 UNIVERSITY DRIVE
                            ASHBURN, VIRGINIA 20174
                   NOTICE OF SPECIAL MEETING OF STOCKHOLDERS
                            TO BE HELD MAY 12, 1998
 
TO THE STOCKHOLDERS OF COHERENT COMMUNICATIONS SYSTEMS CORPORATION:
 
     NOTICE IS HEREBY GIVEN that a Special Meeting of Stockholders of Coherent
Communications Systems Corporation ("Coherent") will be held on May 12, 1998, at
Coherent's offices located at 48085 University Drive, Ashburn, Virginia 20147 at
11:00 A.M., local time (the "Coherent Special Meeting"), for the following
purposes:
 
     1. To consider and vote upon a proposal to approve and adopt the Agreement
and Plan of Merger dated as of February 16, 1998 (the "Merger Agreement"), among
Tellabs, Inc., a Delaware corporation ("Tellabs"), Cardinal Merger Co., a
Delaware corporation and a wholly owned subsidiary of Tellabs ("Sub"), and
Coherent, providing for the merger of Sub with and into Coherent, pursuant to
which (a) each outstanding share of Common Stock, $.01 par value per share, of
Coherent (other than any shares owned by Coherent or its subsidiaries, Tellabs,
Sub or any other wholly owned subsidiary of Tellabs, which will be canceled)
will be converted into .72 of a share of Common Stock, $.01 par value per share,
of Tellabs, and (b) Coherent will become a wholly owned subsidiary of Tellabs,
all as more fully described in the accompanying Proxy Statement/Prospectus.
 
     2. To transact such other business as properly may come before the Coherent
Special Meeting or any one or more adjournments thereof.
 
     Only stockholders of record at the close of business on April 3, 1998 are
entitled to notice of and to vote at the Coherent Special Meeting and at any and
all adjournments thereof.
 
     Your vote is important. Please complete the accompanying proxy and return
it promptly in the addressed envelope enclosed.
 
                                          By Order of the Board of Directors,
 
                                        /s/ James A. Ounsworth
                                          James A. Ounsworth
                                          Secretary
 
In order for the Merger Agreement to be approved and adopted, the affirmative
vote of the holders of a majority of the outstanding shares of Coherent Common
Stock entitled to vote thereon is required. Regardless of whether you plan to
attend the Coherent Special Meeting, please sign, date and return the enclosed
proxy card in the envelope provided. PLEASE DO NOT SEND STOCK CERTIFICATES FOR
YOUR SHARES AT THIS TIME.
<PAGE>   4
 
<TABLE>
<S>                                             <C>
                                                                  COHERENT
               TELLABS, INC.                                   COMMUNICATIONS
                                                            SYSTEMS CORPORATION
- --------------------------------------------    --------------------------------------------
                 PROSPECTUS                                   PROXY STATEMENT
- --------------------------------------------    --------------------------------------------
</TABLE>
 
     This Proxy Statement/Prospectus is being furnished to the holders of Common
Stock, $.01 par value per share ("Coherent Common Stock"), of Coherent
Communications Systems Corporation, a Delaware corporation ("Coherent"), in
connection with the solicitation of proxies by the Board of Directors of
Coherent (the "Coherent Board") for use at a Special Meeting of Stockholders of
Coherent to be held on May 12, 1998 at Coherent's offices located at 48085
University Drive, Ashburn, Virginia 20147 at 11:00 A.M., local time, and at any
and all adjournments thereof (the "Coherent Special Meeting").
 
     This Proxy Statement/Prospectus relates to the Agreement and Plan of Merger
dated as of February 16, 1998 (the "Merger Agreement"), among Tellabs, Inc., a
Delaware corporation ("Tellabs"), Cardinal Merger Co., a Delaware corporation
and a wholly owned subsidiary of Tellabs ("Sub"), and Coherent, which provides
for the merger of Sub with and into Coherent (the "Merger"), with Coherent
surviving as a wholly owned subsidiary of Tellabs. Subject to the terms and
conditions of the Merger Agreement, each share of Coherent Common Stock
outstanding immediately prior to the Effective Time (as defined herein) of the
Merger (other than any shares owned by Coherent or its subsidiaries, Tellabs,
Sub or any other wholly owned subsidiary of Tellabs, which will be canceled)
will be converted into .72 (the "Exchange Ratio") of a share of Common Stock,
$.01 par value per share ("Tellabs Common Stock"), of Tellabs. Cash will be paid
in lieu of any fractional share of Tellabs Common Stock.
 
     The consummation of the Merger is subject, among other things, to: (i) the
approval and adoption of the Merger Agreement by the requisite vote of holders
of Coherent Common Stock; and (ii) the receipt of certain regulatory approvals.
A conformed copy of the Merger Agreement is attached hereto as Annex I.
 
     This Proxy Statement/Prospectus also constitutes the Prospectus of Tellabs
filed as part of a Registration Statement on Form S-4 (the "Registration
Statement") with the Securities and Exchange Commission (the "SEC") under the
Securities Act of 1933, as amended (the "Securities Act"), relating to the
shares of Tellabs Common Stock to be delivered pursuant to the Merger Agreement.
 
     Shares of Tellabs Common Stock are listed for trading under the symbol
"TLAB" on the Nasdaq Stock Market ("Nasdaq"). Shares of Coherent Common Stock
are listed for trading under the symbol "CCSC" on Nasdaq. On February 13, 1998,
the last trading day prior to the execution of the Merger Agreement, the last
sale price of Tellabs Common Stock, as reported by Nasdaq, was $57 15/16 per
share and the last sale price of Coherent Common Stock, as reported by Nasdaq,
was $32 per share. On April 6, 1998, the last trading day prior to the date of
this Proxy Statement/Prospectus, the last sale price of Tellabs Common Stock, as
reported by Nasdaq, was $65 3/4 per share and the last sale price of Coherent
Common Stock, as reported by Nasdaq, was $45 9/16 per share.
 
     This Proxy Statement/Prospectus and the accompanying forms of proxy are
first being mailed to the stockholders of Coherent on or about April 8, 1998.
                      ------------------------------------
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
   EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE
     SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES
       COMMISSION PASSED UPON THE ACCURACY OR ADEQUACY OF THIS PROXY
         STATEMENT/PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS
                              A CRIMINAL OFFENSE.
                      ------------------------------------
 
          The date of this Proxy Statement/Prospectus is April 7, 1998
<PAGE>   5
 
                               TABLE OF CONTENTS
 
<TABLE>
<S>                                                           <C>
AVAILABLE INFORMATION.......................................    1
INCORPORATION OF DOCUMENTS BY REFERENCE.....................    1
SUMMARY.....................................................    3
  Tellabs...................................................    3
  Coherent..................................................    3
  Sub.......................................................    3
  Coherent Special Meeting..................................    3
     Purpose................................................    3
     Record Date............................................    4
     Required Vote..........................................    4
     Change of Vote.........................................    4
  The Merger and the Merger Agreement.......................    4
     General................................................    4
     Effective Time.........................................    4
     Recommendation of the Coherent Board...................    4
     Opinion of Coherent's Financial Advisor................    4
     Certain Federal Income Tax Consequences................    5
     Anticipated Accounting Treatment.......................    5
     Absence of Appraisal Rights............................    5
     Conditions to the Merger...............................    5
     Termination of the Merger Agreement....................    5
     Fees and Expenses......................................    5
     Interests of Certain Persons in the Merger.............    5
     Stockholder Agreements.................................    5
  Tellabs, Inc. Selected Consolidated Financial Data........    7
  Coherent Communications Systems Corporation Selected
     Consolidated Financial Data............................    8
  Comparative Per Share Data of Tellabs and Coherent........    9
  Market Prices.............................................   10
  Comparison of the Rights of Holders of Tellabs Common
     Stock and Coherent Common Stock........................   10
COHERENT SPECIAL MEETING....................................   11
  Purpose...................................................   11
  Record Date; Voting Rights................................   11
  Quorum....................................................   11
  Proxies...................................................   11
  Solicitation of Proxies...................................   12
  Required Vote.............................................   12
  Share Ownership of Management.............................   12
THE MERGER..................................................   12
  General...................................................   12
  Effective Time............................................   13
  Background of the Merger..................................   13
  Tellabs' Reasons for the Merger...........................   14
  Coherent's Reasons for the Merger; Recommendation of its
     Board of Directors.....................................   14
  Opinion of Coherent's Financial Advisor...................   16
  Certain Federal Income Tax Consequences...................   20
     Tax Opinions...........................................   20
     Real Estate Transfer Taxes.............................   21
</TABLE>
 
                                        i
<PAGE>   6
<TABLE>
<S>                                                           <C>
  Anticipated Accounting Treatment..........................   21
  Governmental and Regulatory Approvals.....................   22
  Percentage Ownership Interest of Coherent Stockholders
     after the Merger.......................................   22
  Absence of Appraisal Rights...............................   22
  Resales of Tellabs Common Stock...........................   23
TERMS OF THE MERGER AGREEMENT...............................   23
  The Merger................................................   23
  Conversion of Securities..................................   23
  Representations and Warranties............................   24
  Certain Covenants and Agreements..........................   25
     Conduct of Business of Coherent........................   25
     Conduct of Business of Tellabs.........................   26
     No Solicitation........................................   27
     Stock Plans and Options................................   28
     Indemnification; Directors' and Officers' Insurance....   28
  Conditions to Closing.....................................   29
     Conditions to Each Party's Obligation to Effect the
      Merger................................................   29
     Additional Conditions to Obligations of Tellabs and
      Sub...................................................   29
     Additional Conditions to Obligations of Coherent.......   30
  Termination...............................................   30
  Fees and Expenses.........................................   31
INTERESTS OF CERTAIN PERSONS IN THE MERGER..................   32
  Employment Agreements.....................................   32
  Severance Agreement.......................................   32
  Termination of Administrative Service Agreement...........   33
  Indemnification...........................................   33
STOCKHOLDER AGREEMENTS......................................   33
DESCRIPTION OF TELLABS COMMON STOCK.........................   34
  Capital Stock.............................................   34
  Dividend Rights...........................................   34
  Voting Rights.............................................   34
  Change of Control.........................................   35
     Charter and By-law Provisions..........................   35
     DGCL...................................................   36
  Liquidation Rights........................................   36
  Miscellaneous.............................................   36
COMPARISON OF THE RIGHTS OF HOLDERS OF TELLABS COMMON STOCK
  AND COHERENT COMMON STOCK.................................   36
  General...................................................   37
  Dividends.................................................   37
  Voting Rights.............................................   37
  Directors.................................................   37
     Number and Election of Directors.......................   37
     Classification.........................................   37
     Removal................................................   37
     Nominations............................................   38
     Liability of Directors.................................   38
  Call of Special Meetings..................................   38
  Action of Stockholders Without a Meeting..................   38
</TABLE>
 
                                       ii
<PAGE>   7
<TABLE>
<S>                                                           <C>
  Stockholder Proposals.....................................   38
  Amendment to Certificate of Incorporation.................   38
  Amendment to By-laws......................................   39
  Approval of Mergers and Asset Sales.......................   39
  Indemnification of Directors and Officers.................   39
  Anti-Takeover Provisions..................................   40
  Liquidation...............................................   40
  Miscellaneous.............................................   40
BUSINESS OF TELLABS.........................................   40
BUSINESS OF COHERENT........................................   41
EXPERTS.....................................................   42
LEGAL OPINIONS..............................................   42
ANNEXES TO THE PROXY STATEMENT/PROSPECTUS
  ANNEX I     AGREEMENT AND PLAN OF MERGER
  ANNEX II    SAFEGUARD STOCKHOLDER AGREEMENT
  ANNEX III   FORM OF STOCKHOLDER AGREEMENTS ENTERED INTO BY CERTAIN
              STOCKHOLDERS OF COHERENT
  ANNEX IV    OPINION OF ROBERT W. BAIRD & CO. INCORPORATED
</TABLE>
 
                                       iii
<PAGE>   8
 
                             AVAILABLE INFORMATION
 
     Tellabs and Coherent are subject to the informational requirements of the
Securities Exchange Act of 1934, as amended (the "Exchange Act"), and in
accordance therewith file reports, proxy statements and other information with
the SEC. Such reports, proxy and information statements and other information
may be inspected and copied at the public reference facilities maintained by the
SEC at Room 1024, Judiciary Plaza, 450 Fifth Street, N.W., Washington, D.C.
20549 and at the following Regional Offices of the SEC: Citicorp Center, 500
West Madison Street, Suite 1400, Chicago, Illinois 60661; The Curtis Center,
Suite 1005 E., 601 Walnut Street, Philadelphia, Pennsylvania 19106-3322; and 7
World Trade Center, Suite 1300, New York, New York 10048. Copies of such
materials relating to Tellabs and Coherent can be inspected at the offices of
Nasdaq, 1735 K Street, N.W., Washington, D.C. 20006. Copies may be obtained by
mail at prescribed rates from the Public Reference Section of the SEC at its
principal office at 450 Fifth Street, N.W., Washington, D.C. 20549. Such
materials also may be accessed electronically by means of the SEC's Web site at
http://www.sec.gov.
 
     This Proxy Statement/Prospectus does not contain all of the information set
forth in the Registration Statement, certain parts of which are omitted in
accordance with the rules and regulations of the SEC. Reference is made to the
Registration Statement and the Exhibits thereto for further information.
Statements contained or incorporated by reference herein concerning the
provisions of any agreement or other document filed as an Exhibit to the
Registration Statement or otherwise filed with the SEC are not necessarily
complete and reference is hereby made to the copy thereof so filed for more
detailed information, each such statement being qualified in its entirety by
such reference.
 
     THIS PROXY STATEMENT/PROSPECTUS INCORPORATES DOCUMENTS BY REFERENCE WHICH
ARE NOT PRESENTED HEREIN OR DELIVERED HEREWITH. COPIES OF SUCH DOCUMENTS (OTHER
THAN EXHIBITS THERETO WHICH ARE NOT SPECIFICALLY INCORPORATED BY REFERENCE
HEREIN) ARE AVAILABLE, WITHOUT CHARGE, TO ANY BENEFICIAL OWNER OF SHARES OF
COHERENT COMMON STOCK TO WHOM THIS PROXY STATEMENT/PROSPECTUS IS DELIVERED, UPON
WRITTEN OR ORAL REQUEST TO, IN THE CASE OF DOCUMENTS RELATING TO TELLABS,
SECRETARY, TELLABS, INC., 4951 INDIANA AVENUE, LISLE, ILLINOIS 60532-1698,
TELEPHONE NUMBER (630) 378-8800 AND, IN THE CASE OF DOCUMENTS RELATING TO
COHERENT, INVESTOR RELATIONS DEPARTMENT, COHERENT COMMUNICATIONS SYSTEMS
CORPORATION, 45085 UNIVERSITY DRIVE, ASHBURN, VIRGINIA 20147, TELEPHONE NUMBER
(703)729-6400. IN ORDER TO ENSURE TIMELY DELIVERY OF THE DOCUMENTS PRIOR TO THE
COHERENT SPECIAL MEETING, ANY REQUEST THEREFOR SHOULD BE MADE NOT LATER THAN
APRIL 28, 1998.
 
                    INCORPORATION OF DOCUMENTS BY REFERENCE
 
     The following documents heretofore filed with the SEC pursuant to the
Exchange Act are incorporated herein by reference:
 
          1. Tellabs' Annual Report on Form 10-K for the year ended January 2,
     1998 filed on March 20, 1998, as amended by the Form 10-K/A filed on March
     31, 1998;
 
          2. Tellabs' Current Report on Form 8-K reporting an event on February
     16, 1998; and
 
          3. Coherent's Annual Report on Form 10-K for the year ended December
     31, 1997 filed on March 31, 1998.
 
     All reports and other documents filed by either Tellabs or Coherent
pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to
the date of this Proxy Statement/Prospectus and prior to the date of the
Coherent Special Meeting shall be deemed to be incorporated by reference herein
and to be a part hereof from the dates of filing of such reports and documents.
Any statement contained in a document incorporated or deemed to be incorporated
by reference herein shall be deemed to be modified or superseded for purposes of
this Proxy Statement/Prospectus to the extent that a statement contained herein,
or in any other subsequently filed document which also is incorporated or deemed
to be incorporated by reference herein, modifies or supersedes such statement.
Any statement so modified or superseded shall not be deemed, except as so
modified or superseded, to constitute a part of this Proxy Statement/Prospectus.
 
                                        1
<PAGE>   9
 
     NO PERSON HAS BEEN AUTHORIZED TO GIVE ANY INFORMATION OR TO MAKE ANY
REPRESENTATIONS WITH RESPECT TO THE MATTERS DESCRIBED IN THIS PROXY
STATEMENT/PROSPECTUS OTHER THAN THOSE CONTAINED OR INCORPORATED BY REFERENCE
HEREIN, AND, IF GIVEN OR MADE, SUCH INFORMATION OR REPRESENTATIONS MUST NOT BE
RELIED UPON AS HAVING BEEN AUTHORIZED BY EITHER TELLABS OR COHERENT. THIS PROXY
STATEMENT/PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO SELL OR THE SOLICITATION OF
AN OFFER TO BUY ANY SECURITIES, NOR DOES IT CONSTITUTE THE SOLICITATION OF A
PROXY, IN ANY JURISDICTION TO OR FROM ANY PERSON TO WHOM IT IS UNLAWFUL TO MAKE
ANY SUCH OFFER OR SOLICITATION IN SUCH JURISDICTION. NEITHER THE DELIVERY OF
THIS PROXY STATEMENT/PROSPECTUS NOR ANY DISTRIBUTION OF SECURITIES HEREUNDER
SHALL, UNDER ANY CIRCUMSTANCES, CREATE ANY IMPLICATION THAT THERE HAS BEEN NO
CHANGE IN THE AFFAIRS OF TELLABS OR COHERENT SINCE THE DATE HEREOF OR THAT THE
INFORMATION CONTAINED HEREIN IS CORRECT AS OF ANY TIME SUBSEQUENT TO ITS DATE.
 
     CERTAIN INFORMATION CONTAINED OR INCORPORATED BY REFERENCE IN THIS PROXY
STATEMENT/PROSPECTUS IS FORWARD-LOOKING AND IS BASED ON VARIOUS ASSUMPTIONS.
THESE FORWARD-LOOKING STATEMENTS ARE BASED UPON TELLABS MANAGEMENT'S
EXPECTATIONS AND BELIEFS CONCERNING FUTURE EVENTS IMPACTING TELLABS. THERE CAN
BE NO ASSURANCE THAT SUCH EVENTS WILL OCCUR OR THAT THEIR EFFECTS ON TELLABS
WILL BE AS CURRENTLY EXPECTED. FOR A DESCRIPTION OF CERTAIN FACTORS THAT COULD
CAUSE TELLABS' FUTURE RESULTS TO DIFFER MATERIALLY FROM THOSE EXPRESSED IN ANY
SUCH FORWARD-LOOKING STATEMENTS, SEE THE DISCUSSION OF SUCH FACTORS CONTAINED IN
TELLABS' ANNUAL REPORT ON FORM 10-K FOR THE YEAR ENDED JANUARY 2, 1998 FILED ON
MARCH 20, 1998, AS AMENDED BY THE FORM 10-K/A FILED ON MARCH 31, 1998.
 
     All information contained in this Proxy Statement/Prospectus with respect
to Tellabs and Sub has been provided by Tellabs. All information contained in
this Proxy Statement/Prospectus with respect to Coherent has been provided by
Coherent. All information with respect to Robert W. Baird & Co. Incorporated
("Baird") has been provided by Baird.
 
                                        2
<PAGE>   10
 
                                    SUMMARY
 
     The following is a brief summary of certain information contained elsewhere
or incorporated by reference in this Proxy Statement/Prospectus. Reference is
made to, and this summary is qualified in its entirety by, the more detailed
information contained or incorporated by reference in this Proxy
Statement/Prospectus and the Annexes hereto.
 
        STOCKHOLDERS OF COHERENT ARE URGED TO CAREFULLY READ THIS PROXY
         STATEMENT/PROSPECTUS AND THE ANNEXES HERETO IN THEIR ENTIRETY.
 
TELLABS
 
     Tellabs designs, manufactures, markets and services voice and data
transport and network access systems that are used worldwide by public telephone
companies, long-distance carriers, alternate service providers, cellular and
other wireless service providers, cable operators, government agencies,
utilities and business end-users.
 
     Tellabs was incorporated in Delaware in 1992 in connection with the
reincorporation of its predecessor from an Illinois to a Delaware corporation.
Tellabs' predecessor corporation began operations in 1975 and became a public
company in 1980. Tellabs' principal executive offices are located at 4951
Indiana Avenue, Lisle, Illinois 60532-1698 and its telephone number is (630)
378-8800. For further information concerning Tellabs, see "-- Tellabs, Inc.
Selected Consolidated Financial Data," "BUSINESS OF TELLABS," "AVAILABLE
INFORMATION" and "INCORPORATION OF DOCUMENTS BY REFERENCE."
 
COHERENT
 
     Coherent develops, manufactures and markets voice quality enhancement
products for wireless (including digital cellular and personal communication
systems), satellite-based, cable communications systems and wireline
telecommunications systems throughout the world. Coherent's principal product
lines are transmission products and teleconference products.
 
     Coherent was incorporated in Delaware in 1990 and became a public company
in 1994. Before becoming a public company, Coherent was a 99.6% owned subsidiary
of Safeguard Scientifics, Inc. ("Safeguard"). Coherent's principal executive
offices are located at 45085 University Drive, Ashburn, Virginia 20174 and its
telephone number is (703) 729-6400. For further information concerning Coherent,
see "-- Coherent Communications Systems Corporation Selected Consolidated
Financial Data," "BUSINESS OF COHERENT," "AVAILABLE INFORMATION" and
"INCORPORATION OF DOCUMENTS BY REFERENCE."
 
SUB
 
     Sub was incorporated in Delaware on January 20, 1998 as a wholly owned
subsidiary of Tellabs solely for the purpose of consummating the Merger and the
other transactions contemplated by the Merger Agreement. Sub has minimal assets
and no business and has carried on no activities which are not directly related
to its formation and its execution of the Merger Agreement. Its principal
executive offices are located at 4951 Indiana Avenue, Lisle, Illinois 60532-1698
and its telephone number is (630) 378-8800.
 
COHERENT SPECIAL MEETING
 
     Purpose.  The Coherent Special Meeting will be held on May 12, 1998 at
Coherent's offices located at 48085 University Drive, Ashburn, Virginia 20147,
at 11:00 A.M., local time, to consider and vote upon a proposal to approve and
adopt the Merger Agreement, which provides for the merger of Sub with and into
Coherent, with Coherent surviving the Merger as a wholly owned subsidiary of
Tellabs. The stockholders of Coherent will also consider and take action upon
any other business which may properly be brought before the Coherent Special
Meeting. See "COHERENT SPECIAL MEETING -- Purpose."
 
                                        3
<PAGE>   11
 
     Record Date.  Only holders of record of Coherent Common Stock at the close
of business on April 3, 1998 (the "Record Date") are entitled to receive notice
of and to vote at the Coherent Special Meeting. At the close of business on the
Record Date, there were 15,543,854 shares of Coherent Common Stock outstanding,
each of which entitles the registered holder thereof to one vote. See "COHERENT
SPECIAL MEETING -- Record Date; Voting Rights." At the close of business on the
Record Date, directors and executive officers of Coherent beneficially owned and
had the right to vote an aggregate of 1,291,918 shares of Coherent Common Stock
(approximately 8.3% of the shares of Coherent Common Stock then outstanding).
See "COHERENT SPECIAL MEETING -- Share Ownership of Management" and "STOCKHOLDER
AGREEMENTS."
 
     Required Vote.  Approval and adoption of the Merger Agreement will require
the affirmative vote of the holders of a majority of the outstanding shares of
Coherent Common Stock entitled to vote thereon. Brokers who hold Coherent Common
Stock as nominees will not have discretionary authority to vote such shares in
the absence of instructions from the beneficial owners thereof. Broker non-votes
and abstentions have the effect of a vote against the approval and adoption of
the Merger Agreement. Stockholders of Coherent owning an aggregate of 6,031,136
shares of Coherent Common Stock (approximately 38.8% of the shares of Coherent
Common Stock then outstanding) at the close of business on the Record Date have
agreed pursuant to the Stockholder Agreements (as defined herein) to vote in
favor of approval and adoption of the Merger Agreement at the Coherent Special
Meeting. See "COHERENT SPECIAL MEETING -- Required Vote" and "STOCKHOLDER
AGREEMENTS."
 
     Change of Vote.  Coherent stockholders who have executed a proxy may revoke
the proxy at any time prior to its exercise at the Coherent Special Meeting by
filing a written notice of revocation with, or by delivering a duly executed
proxy bearing a later date to, the Secretary of Coherent at Coherent's principal
executive offices prior to the Coherent Special Meeting or by attending the
Coherent Special Meeting and voting in person. Accordingly, Coherent
stockholders who have executed and returned proxy cards in advance of the
Coherent Special Meeting may change their vote at any time prior to or at the
Coherent Special Meeting.
 
THE MERGER AND THE MERGER AGREEMENT
 
     General.  At the Effective Time of the Merger, Sub will be merged with and
into Coherent, with Coherent continuing as the surviving corporation (the
"Surviving Corporation") and as a wholly owned subsidiary of Tellabs, and the
separate corporate existence of Sub will cease. Subject to the terms and
conditions of the Merger Agreement, each share of Coherent Common Stock
outstanding immediately prior to the Effective Time (other than any shares owned
by Coherent or its subsidiaries, Tellabs, Sub or any other wholly owned
subsidiary of Tellabs, which will be canceled) will be converted into .72 of a
share of Tellabs Common Stock. Cash will be paid in lieu of any fractional share
of Tellabs Common Stock. See "TERMS OF THE MERGER AGREEMENT -- Conversion of
Securities."
 
     Effective Time.  The Merger will become effective (the "Effective Time")
upon the filing of the Certificate of Merger with the Secretary of State of the
State of Delaware. The filing of the Certificate of Merger will occur at or
concurrently with the closing of the Merger (the "Closing"). See "THE
MERGER -- Effective Time" and "TERMS OF THE MERGER AGREEMENT -- The Merger."
 
     Recommendation of the Coherent Board.  The Coherent Board believes that the
Merger Agreement and the Merger are fair to and in the best interests of
Coherent and its stockholders and has unanimously approved and adopted the
Merger Agreement and the transactions contemplated thereby. THE COHERENT BOARD
UNANIMOUSLY RECOMMENDS THAT THE STOCKHOLDERS OF COHERENT VOTE IN FAVOR OF
APPROVAL AND ADOPTION OF THE MERGER AGREEMENT. See "THE MERGER -- Coherent's
Reasons for the Merger; Recommendation of its Board of Directors."
 
     Opinion of Coherent's Financial Advisor.  On February 16, 1998, Baird,
financial advisor to Coherent in connection with the Merger, delivered its oral
opinion, later confirmed in writing, to the Coherent Board to the effect that,
as of such date, the Exchange Ratio was fair, from a financial point of view, to
the holders of Coherent Common Stock (other than Tellabs and its affiliates).
 
                                        4
<PAGE>   12
 
     The full text of the written opinion of Baird dated as of February 16,
1998, which sets forth the assumptions made, matters considered and limitations
on the review undertaken in connection with the opinion, is attached hereto as
Annex IV to this Proxy Statement/Prospectus and is incorporated herein by
reference. HOLDERS OF COHERENT COMMON STOCK ARE URGED TO, AND SHOULD, READ SUCH
OPINION IN ITS ENTIRETY. See "THE MERGER -- Coherent's Reasons for the Merger;
Recommendation of its Board of Directors" and "THE MERGER -- Opinion of
Coherent's Financial Advisor."
 
     Certain Federal Income Tax Consequences.  The Merger is intended to qualify
as a "reorganization" within the meaning of Section 368(a) of the Internal
Revenue Code of 1986, as amended (the "Code"). Accordingly, no gain or loss will
be recognized for United States federal income tax purposes by the stockholders
of Coherent upon the exchange of their Coherent Common Stock solely for shares
of Tellabs Common Stock pursuant to the Merger, except with respect to cash, if
any, received in lieu of fractional shares of Tellabs Common Stock. See "THE
MERGER -- Certain Federal Income Tax Consequences" and "TERMS OF THE MERGER
AGREEMENT -- Conditions to Closing."
 
     Anticipated Accounting Treatment.  The Merger will be accounted for as a
"pooling of interests" for accounting and financial reporting purposes. It is a
condition to the consummation of the Merger that (i) Coherent receive the
written opinion of KPMG Peat Marwick LLP ("KPMG") in which KPMG concurs with
Coherent's management's conclusion that Coherent is eligible to be a party to a
business combination accounted for as a pooling of interests in accordance with
generally accepted accounting procedures ("GAAP") and applicable published rules
and regulations of the SEC and (ii) Tellabs receive the written opinion of Ernst
& Young LLP ("Ernst & Young") that Ernst & Young concurs with Tellabs'
management's conclusion that Tellabs is eligible to be a party to a business
combination accounted for as a pooling of interests in accordance with GAAP and
applicable published rules and regulations of the SEC, and that the Merger will
qualify for pooling of interests accounting. See "THE MERGER -- Anticipated
Accounting Treatment" and "TERMS OF THE MERGER AGREEMENT -- Conditions to
Closing."
 
     Absence of Appraisal Rights.  Under the Delaware General Corporation Law,
as amended (the "DGCL"), the stockholders of Coherent are not entitled to
appraisal rights with respect to the approval and adoption of the Merger
Agreement. See "THE MERGER -- Absence of Appraisal Rights."
 
     Conditions to the Merger.  The respective obligations of Coherent and
Tellabs to effect the Merger are subject to waiver or satisfaction of various
conditions set forth in the Merger Agreement, including conditions relating to
the expiration of applicable waiting periods under the HSR Act (as defined
herein) and other material waiting periods under applicable foreign laws. See
"THE MERGER -- Governmental and Regulatory Approvals" and "TERMS OF THE MERGER
AGREEMENT -- Conditions to Closing."
 
     Termination of the Merger Agreement.  The Merger Agreement may be
terminated at any time prior to the Effective Time, whether before or after
approval by the stockholders of Coherent of the matters presented in connection
with the Merger, by Coherent or Tellabs upon the occurrence of certain events
set forth in the Merger Agreement. See "TERMS OF THE MERGER
AGREEMENT -- Termination."
 
     Fees and Expenses.  The Merger Agreement provides for the payment of a
termination fee by Coherent following a termination of the Merger Agreement
under certain circumstances. See "TERMS OF THE MERGER AGREEMENT -- Fees and
Expenses."
 
     Interests of Certain Persons in the Merger.  Certain persons, as members of
Coherent's management or the Coherent Board, have interests in the Merger in
addition to their interests as stockholders of Coherent. Pursuant to the Merger
Agreement, Coherent may, prior to the Effective Time, enter into employment
agreements with certain of its senior officers, which will be effective as of
the Effective Time. See "INTERESTS OF CERTAIN PERSONS IN THE MERGER."
 
     Stockholder Agreements.  Concurrently with the execution of the Merger
Agreement, in order to induce Tellabs to enter into the Merger Agreement,
Safeguard, the owner of 4,843,342 (approximately 31.2%) of the outstanding
shares of Coherent Common Stock as of the Record Date, and Daniel L. McGinnis,
Lawrence J. Gallick, Warren V. Musser, Charles A. Root, Charles M. Skibo and
Ernst Volgenau, who are all of the current directors of Coherent (together with
Safeguard, the "Stockholders") and who owned an aggregate of
 
                                        5
<PAGE>   13
 
1,160,920 (approximately 7.5%) of the outstanding shares of Coherent Common
Stock as of the Record Date, entered into stockholder agreements (the
"Stockholder Agreements") with Tellabs. Subsequent to the execution of the
Stockholder Agreements and prior to the Record Date, with the approval of
Tellabs, Mr. McGinnis transferred 8,958 shares of Coherent Common Stock held by
him to each of his three daughters (for a total of 26,874 shares of Coherent
Common Stock, approximately 0.2% of the outstanding shares of Coherent Common
Stock as of the Record Date), each of whom has agreed to be bound by the terms
and conditions of the Stockholder Agreement entered into by Mr. McGinnis.
 
     The Stockholder Agreements provide, among other things, that: (a) at the
special meeting of stockholders of Coherent to be held to consider the Merger
Agreement and the Merger (the "Stockholders Meeting") (or at any adjournment
thereof) or in any other circumstances upon which a vote, consent or other
approval with respect to the Merger or the Merger Agreement is sought, the
Stockholder shall vote (or cause to be voted) the shares of Coherent Common
Stock owned by such Stockholder as of the date of the Stockholder Agreement and
any other shares of capital stock of Coherent acquired by such Stockholder after
the date of the Stockholder Agreement and during the term of the Stockholder
Agreement (the "Subject Shares") in favor of the Merger, the adoption of the
Merger Agreement and the approval of the terms thereof and each of the other
transactions contemplated by the Merger Agreement; (b) at any meeting of
stockholders of Coherent or at any adjournment thereof or in any other
circumstances upon which the Stockholder's vote, consent or other approval is
sought, the Stockholder shall vote (or cause to be voted) the Subject Shares
against (i) any merger agreement or merger (other than the Merger Agreement and
the Merger), consolidation, combination, sale of substantial assets,
reorganization, recapitalization, dissolution, liquidation or winding up of or
by Coherent or any subsidiary thereof or any other Takeover Proposal (as defined
herein) or (ii) any amendment of the Coherent Charter (as defined herein) or the
Coherent By-laws (as defined herein) or other proposal or transaction involving
Coherent or any of its subsidiaries, which amendment or other proposal or
transaction would in any manner impede, frustrate, prevent or nullify the
Merger, the Merger Agreement or any of the other transactions contemplated by
the Merger Agreement or change in any manner the voting rights of any class of
capital stock of Coherent; and (c) the Stockholder will not (i) sell, transfer,
pledge, assign or otherwise dispose of (including by gift) (collectively,
"Transfer"), or enter into any contract, option or other arrangement (including
any profit-sharing arrangement) with respect to the Transfer of the Subject
Shares to any person or (ii) enter into any voting arrangement, whether by
proxy, voting agreement or otherwise, in relation to the Subject Shares, and
agrees not to commit or agree to take any of the foregoing actions. The
Stockholder Agreement between Tellabs and Safeguard (the "Safeguard Stockholder
Agreement") and the form of Stockholder Agreement entered into between Tellabs
and the other Stockholders are attached hereto as Annexes II and III,
respectively. See "STOCKHOLDER AGREEMENTS."
 
                                        6
<PAGE>   14
 
                                 TELLABS, INC.
 
                      SELECTED CONSOLIDATED FINANCIAL DATA
 
     The following table sets forth selected historical consolidated financial
data for Tellabs for each of the years ended January 2, 1998, December 27, 1996,
December 29, 1995, December 30, 1994, and December 31, 1993. Such data have been
derived from, and should be read in conjunction with, the audited Consolidated
Financial Statements and other financial information contained in Tellabs'
Annual Report on Form 10-K for the year ended January 2, 1998, as amended,
including the notes thereto, which are incorporated by reference herein. See
"AVAILABLE INFORMATION" and "INCORPORATION OF DOCUMENTS BY REFERENCE."
 
<TABLE>
<CAPTION>
                                            1997        1996       1995       1994       1993
                                         ----------   --------   --------   --------   --------
                                                 (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                                      <C>          <C>        <C>        <C>        <C>
Net sales.............................   $1,203,546   $868,975   $635,229   $494,153   $320,463
Gross profit..........................      758,003    519,243    363,835    270,003    164,255
Earnings before income taxes..........      399,529    175,282    162,825     97,824     35,801
Net earnings before cumulative
  effect..............................      263,689    117,965    115,606     72,389     30,467
Cumulative effect of accounting
  change..............................           --         --         --         --      1,500
Net earnings..........................      263,689    117,965    115,606     72,389     31,967
Earnings per share before cumulative
  effect of accounting change.........         1.46       0.66       0.66       0.42       0.18
Earnings per share before cumulative
  effect of accounting change,
  assuming dilution...................         1.42       0.64       0.63       0.40       0.17
Cumulative effect on earnings per
  share...............................           --         --         --         --       0.01
Cumulative effect on earnings per
  share, assuming dilution............           --         --         --         --       0.01
Earnings per share....................         1.46       0.66       0.66       0.42       0.19
Earnings per share, assuming
  dilution............................         1.42       0.64       0.63       0.40       0.18
Stockholders' equity..................      933,109    591,276    433,233    292,790    207,006
Total assets..........................    1,183,379    743,823    552,051    390,067    328,766
Net working capital...................      637,114    343,840    267,806    138,317     64,285
Long-term debt........................        2,850      2,850      2,850      2,850      2,850
</TABLE>
 
No cash dividends per common share were paid. Per share amounts are restated to
reflect stock splits in 1996, 1995 and 1994.
 
                                        7
<PAGE>   15
 
                  COHERENT COMMUNICATIONS SYSTEMS CORPORATION
 
                      SELECTED CONSOLIDATED FINANCIAL DATA
 
     The following table sets forth selected historical consolidated financial
data for Coherent for each of the last five years in the period ended December
31, 1997. Such data have been derived from, and should be read in conjunction
with, the audited Consolidated Financial Statements and other financial
information contained in Coherent's Annual Report on Form 10-K for the year
ended December 31, 1997, including the notes thereto, which are incorporated by
reference herein. See "AVAILABLE INFORMATION" and "INCORPORATION OF DOCUMENTS BY
REFERENCE."
 
<TABLE>
<CAPTION>
                                                       YEARS ENDED DECEMBER 31,
                                            -----------------------------------------------
                                             1997      1996      1995      1994      1993
                                            -------   -------   -------   -------   -------
                                                 (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                                       <C>       <C>       <C>       <C>       <C>     
Net Sales................................   $73,695   $54,431   $43,829   $30,516   $22,944
Gross Profit.............................    47,310    34,238    26,804    17,883    12,902
Net Income...............................    13,979     9,748     7,590     3,801       423(1)
Net income per common share
Basic....................................       .92       .65       .52       .27       .01
Diluted..................................       .90       .63       .49       .26       .01
Cash and short term investments..........    26,180    16,769     3,352     2,473       423
Net Working capital......................    38,356    25,652    15,993     9,694     4,044
Total assets.............................    55,467    37,558    28,616    17,278     9,306
Long-term debt including current
  portion................................        --        --     2,949     3,000       461
Total stockholders' equity...............    47,414    31,799    20,448    10,391     2,467
</TABLE>
 
- ---------------
 
(1) After a non-recurring goodwill write-off of $1.087 million.
 
                                        8
<PAGE>   16
 
COMPARATIVE PER SHARE DATA OF TELLABS AND COHERENT
 
     The following table sets forth selected per share data for Tellabs and
Coherent on a historical and unaudited pro forma combined basis. The unaudited
pro forma financial data assume that the Merger was consummated at the beginning
of the earliest period presented and gives effect to the Merger as a "pooling of
interests" in accordance with GAAP. Book value data for all pro forma
presentations are based upon the number of outstanding shares of Tellabs Common
Stock adjusted to include the maximum number of shares of Tellabs Common Stock
that could be issued in the Merger. The information set forth below should be
read in conjunction with the selected historical consolidated financial data of
Tellabs and Coherent, including the notes thereto, appearing elsewhere herein.
See "-- Tellabs, Inc. Selected Consolidated Financial Data" and "-- Coherent
Communications Systems Corporation Selected Consolidated Financial Data."
 
<TABLE>
<CAPTION>
                                                                       FISCAL YEAR(2)
                                                                -----------------------------
                                                                 1997      1996(3)    1995(3)
                                                                -------    -------    -------
<S>                                                             <C>        <C>        <C>
TELLABS HISTORICAL:
Income from continuing operations per share, assuming            1.42       0.64       0.63
  dilution..................................................
Cash dividends declared per share...........................       --         --         --
Book value per share........................................     5.14
COHERENT HISTORICAL:
Income from continuing operations per share, assuming            0.90       0.63       0.49
  dilution..................................................
Cash dividends declared per share...........................       --         --         --
Book value per share........................................     3.09
TELLABS UNAUDITED PRO FORMA COMBINED:(1)
Income from continuing operations per share, assuming            1.41       0.66       0.63
  dilution..................................................
Cash dividends declared per share...........................       --         --         --
Book value per share........................................     5.09
COHERENT EQUIVALENT:
Income from continuing operations per share, assuming            1.01       0.47       0.46
  dilution..................................................
Cash dividends declared per share...........................       --         --         --
Book value per share........................................     3.66
</TABLE>
 
- ---------------
 
(1) The unaudited pro forma income from continuing operations per share data for
     each of the years ended January 2, 1998, December 27, 1996 and December 29,
     1995, respectively, illustrates the results (under Tellabs' accounting
     policies) as if the Merger had occurred on the first day of each fiscal
     year. The pro forma per share data do not purport to represent what
     Tellabs' results of operations or financial position would have actually
     been or to project Tellabs' result of operations for any future period or
     financial position at any future date.
 
(2) For Tellabs, information is for the fiscal years ended January 2, 1998,
     December 27, 1996 and December 29, 1995. For Coherent, information is for
     the fiscal years ended December 31, 1997, December 31, 1996 and December
     31, 1995.
 
(3) Per share data of Tellabs have been restated to reflect a two for one stock
     split for the fiscal year ending December 29, 1995 and a two for one stock
     split for the fiscal year ending December 27, 1996.
 
                                        9
<PAGE>   17
 
MARKET PRICES
 
     Shares of Tellabs Common Stock are traded on Nasdaq under the symbol "TLAB"
and shares of Coherent Common Stock are traded on Nasdaq under the symbol
"CCSC". The following table sets forth for the fiscal periods indicated the
range of the high and low sale prices of Tellabs Common Stock and Coherent
Common Stock as reported on Nasdaq. Neither Tellabs nor Coherent has ever paid
cash dividends on their Common Stock and neither currently has plans to pay cash
dividends in the near future.
 
<TABLE>
<CAPTION>
                                                               TELLABS             COHERENT
                                                           COMMON STOCK(1)       COMMON STOCK
                                                           ---------------      --------------
                                                           HIGH       LOW       HIGH      LOW
                                                           -----      ----      ----      ----
<S>                                                        <C>        <C>       <C>       <C>
FISCAL 1996
  First Quarter........................................    26 3/8     15 1/4    25 3/4    17 1/4
  Second Quarter.......................................    34 3/4     23 5/8    28 1/4    18
  Third Quarter........................................    38 1/8     24 1/2    22        13 1/8
  Fourth Quarter.......................................    45 1/4     34 1/8    24        18
FISCAL 1997
  First Quarter........................................    46 1/8     32        23 3/4    16 1/2
  Second Quarter.......................................    58 5/8     33        25 1/4    15 3/8
  Third Quarter........................................    65         50 1/2    28 3/8    20 3/4
  Fourth Quarter.......................................    59 13/16   42 5/8    31 3/4    25 1/2
FISCAL 1998
  First Quarter........................................    69 1/2     44 1/2    48 1/2    21 7/8
  Second Quarter (through April 6, 1998)...............    68 3/8     65 1/4    47 1/4    45 1/4
</TABLE>
 
- ---------------
 
(1) Share prices have been restated to reflect a two for one stock split for the
    fiscal year ending December 27, 1996.
 
     Set forth below are the last reported sale price of Tellabs Common Stock
and Coherent Common Stock on February 13, 1998, the last trading day prior to
the public announcement of the execution of the Merger Agreement, and on April
6, 1998, the last trading day prior to the date of this Proxy
Statement/Prospectus, as reported on Nasdaq, and the equivalent pro forma sale
price of Coherent Common Stock on such dates, as determined by multiplying such
last reported sale price of Tellabs Common Stock by the Exchange Ratio of .72:
 
<TABLE>
<CAPTION>
                                                      FEBRUARY 13,    APRIL 6,
                                                          1998          1998
                                                      ------------    --------
<S>                                                   <C>             <C>
Tellabs Common Stock................................    57.9375         65.75
Coherent Common Stock...............................         32       45.5625
Coherent Equivalent.................................     41.715         47.34
</TABLE>
 
COMPARISON OF THE RIGHTS OF HOLDERS OF TELLABS COMMON STOCK AND COHERENT COMMON
STOCK
 
     See "COMPARISON OF THE RIGHTS OF HOLDERS OF TELLABS COMMON STOCK AND
COHERENT COMMON STOCK" for a summary of the material differences between the
rights of holders of Tellabs Common Stock and the rights of holders of Coherent
Common Stock.
 
                                       10
<PAGE>   18
 
                            COHERENT SPECIAL MEETING
 
     The Coherent Special Meeting will be held on May 12, 1998, at Coherent's
offices located at 48085 University Drive, Ashburn, Virginia 20147 at 11:00
A.M., local time.
 
PURPOSE
 
     At the Coherent Special Meeting, the stockholders of Coherent will consider
and vote upon a proposal to approve and adopt the Merger Agreement. The
stockholders of Coherent will also consider and take action upon any other
business which may properly be brought before the Coherent Special Meeting.
 
     The Coherent Board believes that the Merger is fair to and in the best
interests of Coherent and its stockholders and has unanimously approved and
adopted the Merger Agreement and the transactions contemplated thereby. THE
COHERENT BOARD UNANIMOUSLY RECOMMENDS THAT THE STOCKHOLDERS OF COHERENT VOTE IN
FAVOR OF APPROVAL AND ADOPTION OF THE MERGER AGREEMENT AT THE COHERENT SPECIAL
MEETING. See "THE MERGER -- Coherent's Reasons for the Merger; Recommendation of
its Board of Directors."
 
RECORD DATE; VOTING RIGHTS
 
     Only holders of record of Coherent Common Stock at the close of business on
the Record Date, April 3, 1998, are entitled to receive notice of and to vote at
the Coherent Special Meeting. At the close of business on the Record Date, there
were 15,543,854 shares of Coherent Common Stock outstanding, held by
approximately 294 record holders. Each share of Coherent Common Stock entitles
the record holder thereof to one vote.
 
QUORUM
 
     The holders of a majority of all of the shares of the stock entitled to
vote at the Coherent Special Meeting, present in person or by proxy, constitute
a quorum.
 
     Coherent Common Stock represented by proxies which are marked "abstain"
will be counted as shares present for purposes of determining the presence of a
quorum on all matters, as will shares that are represented by proxies that are
executed by any broker, fiduciary or other nominee on behalf of the beneficial
owner(s) thereof regardless of whether authority to vote is withheld by such
broker, fiduciary or nominee on one or more matters. In the event that a quorum
is not present at the Coherent Special Meeting, it is expected that such meeting
will be adjourned to solicit additional proxies.
 
PROXIES
 
     All shares of Coherent Common Stock represented by properly executed
proxies in the enclosed form which are received in time for the Coherent Special
Meeting and have not been revoked will be voted in accordance with the
instructions indicated by such proxies. If no instructions are indicated, such
shares will be voted FOR the adoption and approval of the Merger Agreement.
Brokers who hold Coherent Common Stock as nominees will not have discretionary
authority to vote such shares in the absence of instructions from the beneficial
owners thereof. Proxies which are marked "abstain" and broker non-votes will
have the effect of a vote AGAINST the adoption and approval of the Merger
Agreement.
 
     Coherent does not know of any matter not described in the Notice of
Coherent Special Meeting that is expected to come before the Coherent Special
Meeting. If, however, any other matters are properly presented for action at the
Coherent Special Meeting, proxies will be voted in the discretion of the
respective proxyholders, unless such authority is withheld.
 
     Any proxy in the enclosed form may be revoked by the stockholder executing
it at any time prior to its exercise by giving written notice thereof to the
Secretary of Coherent at Coherent's principal executive offices, by signing and
returning a later dated proxy or by voting in person at the Coherent Special
Meeting. Attendance at the Coherent Special Meeting will not in and of itself
constitute the revocation of a proxy.
 
                                       11
<PAGE>   19
 
SOLICITATION OF PROXIES
 
     Proxies are being solicited hereby by the Coherent Board on behalf of
Coherent. Pursuant to the Merger Agreement, the entire cost of proxy
solicitation for the Coherent Special Meeting, including the reasonable expenses
of brokers, fiduciaries and other nominees in forwarding solicitation material
to beneficial owners, will be borne by Coherent, provided, that Tellabs and
Coherent will share equally all printing expenses, filing fees in connection
with this Proxy Statement/Prospectus and the Registration Statement and filing
fees required to be paid by Tellabs under the Hart-Scott-Rodino Antitrust
Improvements Act of 1976, as amended (the "HSR Act"); except that the amount of
such fees and expenses to be paid by Coherent pursuant to the preceding proviso
shall not exceed $200,000. In addition to the use of the mail, solicitation may
be made by telephone or otherwise by officers and regular employees of Coherent.
Such officers and regular employees will not be additionally compensated for
such solicitation, but may be reimbursed for out-of-pocket expenses incurred in
connection therewith. If undertaken, the expense of such solicitation would be
nominal.
 
REQUIRED VOTE
 
     Approval and adoption of the Merger Agreement will require the affirmative
vote of the holders of a majority of the outstanding shares of Coherent Common
Stock entitled to vote thereon. Broker non-votes and abstentions will have the
effect of a vote against the Merger. Stockholders of Coherent owning an
aggregate of 6,031,136 shares of Coherent Common Stock (approximately 38.8% of
the shares of Coherent Common Stock then outstanding) at the close of business
on the Record Date have agreed pursuant to the Stockholder Agreements to vote in
favor of approval and adoption of the Merger Agreement at the Coherent Special
Meeting. See "STOCKHOLDER AGREEMENTS".
 
SHARE OWNERSHIP OF MANAGEMENT
 
     At the close of business on the Record Date, directors and executive
officers of Coherent beneficially owned and had the right to vote an aggregate
of 1,291,918 shares of the outstanding shares of Coherent Common Stock
(approximately 8.3% of the shares of Coherent Common Stock then outstanding).
 
     Safeguard and the other Stockholders (including transferees of shares of
Coherent Common Stock from Mr. McGinnis, who have agreed to be bound by the
terms and conditions of the Stockholder Agreements) beneficially owned and had
the right to vote an aggregate of 6,031,136 shares of Coherent Common Stock
(approximately 38.8% of the shares of Coherent Common Stock then outstanding) at
the close of business on the Record Date. Safeguard and the other Stockholders
(and Mr. McGinnis' transferees) have agreed pursuant to the Stockholder
Agreements, among other things, to vote (or cause to be voted) all of the shares
of Coherent Common Stock that they beneficially own and have the right to vote
to approve the Merger Agreement.
 
     As of the date of this Proxy Statement/Prospectus, all other directors and
executive officers of Coherent have indicated their intention to vote their
shares of Coherent Common Stock in favor of the Merger Agreement.
 
                                   THE MERGER
 
     The description of the Merger and the Merger Agreement contained in this
Proxy Statement/Prospectus is qualified in its entirety by reference to the
Merger Agreement, a conformed copy of which is attached hereto as Annex I and
incorporated herein by reference.
 
GENERAL
 
     At the Effective Time of the Merger, Sub will be merged with and into
Coherent, with Coherent continuing as the Surviving Corporation and as a wholly
owned subsidiary of Tellabs, and the separate corporate existence of Sub will
cease. Subject to the terms and conditions of the Merger Agreement, each share
of Coherent Common Stock outstanding immediately prior to the Effective Time
(other than shares owned by Coherent or its subsidiaries, Tellabs, Sub or any
other wholly owned subsidiary of Tellabs, which will be canceled) will be
converted into .72 of a share of Tellabs Common Stock. Cash will be paid in lieu
of
                                       12
<PAGE>   20
 
any fractional share of Tellabs Common Stock. See "TERMS OF THE MERGER
AGREEMENT -- Conversion of Securities."
 
EFFECTIVE TIME
 
     The Merger will become effective upon the filing of the Certificate of
Merger with the Secretary of State of the State of Delaware. The Certificate of
Merger will be filed at or concurrently with the Closing. See "TERMS OF THE
MERGER AGREEMENT -- The Merger."
 
BACKGROUND OF THE MERGER
 
     On December 5, 1997, Michael J. Birck, Tellabs' President and Chief
Executive Officer, telephoned Daniel L. McGinnis, Coherent's Chief Executive
Officer, to discuss a possible strategic combination of Coherent and Tellabs.
After this discussion, Mr. McGinnis consulted with Charles A. Root, Coherent's
Chairman, and certain other members of the Coherent Board and on December 8,
1997 telephoned Mr. Birck to arrange a meeting to pursue further discussions.
 
     At a meeting on December 15, 1997, Mr. McGinnis and Mr. Root met with Mr.
Birck and Brian J. Jackman, Executive Vice President of Tellabs. At that
meeting, the parties discussed the potential benefits of a strategic combination
of Tellabs and Coherent. At a December 16, 1997 meeting of the Coherent Board,
following a report from Mr. McGinnis and Mr. Root regarding the discussions with
Tellabs, the Coherent Board authorized management of Coherent to continue
discussions regarding a possible business combination.
 
     During the week of December 22, 1997, Mr. Birck and Mr. McGinnis had
further telephone conversations regarding the elements of a business combination
of Tellabs and Coherent and the process for moving forward with "due diligence"
examinations by each party of the other. On December 26, 1997, Mr. Birck sent a
letter to Mr. McGinnis summarizing his understanding of the status of the
discussions at that point, including that any combination between Tellabs and
Coherent would be structured as a tax free, stock-for-stock merger that would be
accounted for as a pooling of interests. On December 29, 1997, the parties
entered into a confidentiality agreement.
 
     On January 9, 1998, Coherent convened a telephonic meeting of its Board of
Directors. During that meeting the Coherent Board discussed the progress of and
timetable for the possible transaction with Tellabs. Prior to that meeting, the
members of the Coherent Board had been furnished with various SEC filings of
Tellabs. The Coherent directors discussed Tellabs and its business and the
potential benefits of a business combination of Tellabs and Coherent. In
addition, the Coherent Board approved the engagement of Baird to render its
opinion to the Coherent Board as to the fairness, from a financial point of
view, of the Exchange Ratio.
 
     On January 12, 1998, Tellabs' legal counsel distributed to Coherent and its
legal counsel a draft merger agreement. Beginning on January 16, 1998, certain
members of Tellabs' management, together with representatives of Goldman, Sachs
& Co., began a due diligence review of Coherent at Coherent's executive offices
and had a number of discussions with certain members of Coherent's management.
Beginning on January 19, 1998, certain members of Coherent's management,
together with its legal counsel, independent accountant and representatives of
Baird, conducted a due diligence examination of Tellabs at Tellabs' executive
offices. During the same period, the parties and their respective legal counsel
had a number of telephone communications regarding the draft merger documents.
 
     On January 19, 1998, Mr. McGinnis, together with representatives from
Baird, met with Mr. Birck and certain other members of Tellabs' management to
discuss the overall strategies of the two organizations and Tellabs' vision of
the business following a combination.
 
     On January 23, 1998, Coherent convened a regularly scheduled meeting of its
entire Board. At the meeting, Coherent management provided each member of the
Coherent Board with the then current draft merger agreement. Mr. McGinnis
presented a report to the Coherent Board regarding the findings of Coherent's
due diligence review of Tellabs and presented Coherent management's financial
and business analysis of the proposed transaction. Representatives of Baird also
reviewed with the Coherent Board a
 
                                       13
<PAGE>   21
 
preliminary financial analysis of Coherent, Tellabs and a possible merger with
Tellabs. Mr. McGinnis summarized for the Coherent Board his recent conversations
with Mr. Birck. Legal counsel to Coherent summarized the terms of the draft
merger agreement and reviewed with the Coherent Board certain issues raised by
the merger agreement. After the Board meeting, Mr. McGinnis telephoned Mr. Birck
to advise him of the results of the meeting of the Coherent Board.
 
     On January 29, 1998, Mr. Birck telephoned Mr. McGinnis to discuss moving
forward with the possible transaction. During the first two weeks of February,
1998, certain members of Coherent's management and Tellabs management, along
with their respective legal advisors, continued negotiations of the terms of a
possible transaction. On February 7, 1998, at a special meeting of the Coherent
Board, Coherent's management and counsel reviewed with the Coherent Board the
status of negotiations and identified the remaining issues to be resolved.
 
     On February 13, 1998, senior management of Coherent and Tellabs and their
respective legal counsels and representatives of Safeguard met to address the
remaining issues and review the draft merger documentation. Following the
meeting, revised drafts of the merger documentation were distributed to members
of the Coherent Board.
 
     On February 16, 1998, the Coherent Board convened a meeting by telephone
conference to review the Merger Agreement. At the meeting of the Coherent Board,
Mr. McGinnis reviewed with the Coherent directors the progress of the
negotiations and the benefits of the Merger to Coherent and its stockholders.
Legal counsel to Coherent reviewed with the Coherent Board the terms of the
final Merger Agreement. Baird reviewed with the Coherent Board its analysis of
Coherent, Tellabs and the financial terms of the Merger. At the meeting of the
Coherent Board, Baird rendered its oral opinion (which was subsequently
confirmed in writing) that, as of February 16, 1998, the Exchange Ratio was
fair, from a financial point of view, to the holders of Coherent Common Stock
(other than Tellabs and its affiliates). The Coherent Board then unanimously
approved the Merger Agreement and related agreements and determined to recommend
that the Coherent stockholders vote in favor of approval and adoption of the
Merger Agreement.
 
     On February 16, 1998, each of Tellabs, Sub and Coherent entered into the
Merger Agreement, and the other related agreements, including the Stockholder
Agreements, were also executed. Tellabs and Coherent then issued press releases
announcing the signing of the Merger Agreement.
 
TELLABS' REASONS FOR THE MERGER
 
     The Board of Directors of Tellabs (the "Tellabs Board") determined that the
Merger Agreement is in the best interest of Tellabs because it believed that,
among other things, the Merger would offer Tellabs a strategic advantage in
providing echo canceller and speech processing technology to customers around
the world, the Merger would augment Tellabs' existing research and development
thus enhancing Tellabs' ability to more quickly address new echo canceller and
speech processing opportunities and to explore new uses for existing echo
canceller and speech processing technology, and the Merger would combine
Tellabs' focus on the North American markets with Coherent's focus on the
international markets.
 
COHERENT'S REASONS FOR THE MERGER; RECOMMENDATION OF ITS BOARD OF DIRECTORS
 
     The Coherent Board unanimously approved the Merger Agreement and believes
that the terms of the Merger are fair to, and in the best interests of, the
stockholders of Coherent.
 
     In the course of its deliberations with respect to considering approval of
the Merger Agreement, the Coherent Board received the advice of management
regarding the Coherent and Tellabs businesses and the advice of management and
legal counsel regarding the terms and provisions of the Merger Agreement. In
addition, Baird rendered its opinion to the Coherent Board to the effect that,
as of February 16, 1998, the Exchange Ratio was fair, from a financial point of
view, to the holders of Coherent Common Stock (other than Tellabs and its
affiliates), and reviewed with the Coherent Board the financial analyses
conducted by Baird in connection with rendering such opinion. See "-- Opinion of
Coherent's Financial Advisor."
 
                                       14
<PAGE>   22
 
     The Coherent Board considered the reputation of Tellabs as a leading
provider of a wide range of voice and data transport and network access systems
and equipment. The Coherent Board also considered that the Merger would permit
Coherent stockholders to participate in the synergies and growth possibilities
made available to the combined company by the Merger, and discussed the
potential benefits to the combined company which could be obtained by marketing
Tellabs products and services to the international customers of Coherent's echo
canceller products and by making available to the combined company the
technology developed by Coherent in the area of echo cancellation. The Coherent
Board considered the importance of significant scale, scope and financial
resources to a company's ability to compete effectively in the changing global
telecommunications industry.
 
     The Coherent Board noted that after consummation of the Merger, the
Coherent stockholders would become, on a tax-free basis, stockholders in a
company that displayed superior historical revenue growth rates (a compounded
annual growth rate during the past three years in excess of 30%) and profit
margins (a gross profit margin of approximately 60%) which were comparable to
those of Coherent. The Coherent Board considered that the combined company, when
compared to Coherent on a stand-alone basis, would have a broader product line
than that of Coherent, a much larger revenue base (on a pro forma basis, the
1997 revenues of the combined company would have been approximately $1.3
billion, compared to $74 million for Coherent) and market capitalization and
trading volume (based on the last closing price for Coherent and Tellabs on
February 12, 1998, the combined company would have had a market capitalization
of approximately $10.8 billion, while Coherent's market capitalization was
approximately $477 million).
 
     In addition, the Coherent Board considered a number of other factors,
including without limitation:
 
(i)   an analysis of the financial performance, operations, assets, business
      condition and business prospects of Tellabs and Coherent;
 
(ii)  the terms of the Merger Agreement and the Stockholder Agreements;
 
(iii) the opinion rendered by Baird to the effect that, as of February 16, 1998,
      the Exchange Ratio was fair, from a financial point of view, to the
      holders of Coherent Common Stock (other than Tellabs and its affiliates);
 
(iv) the tax-free nature of the transaction that provides the ability for
     Coherent stockholders to defer recognition of taxable gains;
 
(v)  the current and historical market prices of the Common Stock of each of
     Coherent and Tellabs;
 
(vi) the likelihood of obtaining required regulatory approvals and satisfying
     the other conditions to consummation of the Merger;
 
(vii) the fact that Tellabs had indicated that it was willing to permit Coherent
      to enter into employment agreements with senior officers of Coherent to
      encourage the senior officers to remain in the employ of Coherent until
      the Merger is consummated and thereafter; and
 
(viii) the impact of the Merger on the customers and employees of Coherent.
 
     The foregoing discussion of the information and factors considered and
given weight by the Coherent Board is not intended to be exhaustive. In view of
the variety of factors considered in connection with its evaluation of the
Merger, the Coherent Board did not find it practicable to, and did not, quantify
or otherwise assign relative weights to the specific factors considered in
reaching its determination. In addition, individual members of the Coherent
Board may have given different weight to different factors.
 
     THE COHERENT BOARD BELIEVES THAT THE TERMS OF THE MERGER AGREEMENT ARE FAIR
TO, AND IN THE BEST INTERESTS OF, COHERENT AND ITS STOCKHOLDERS AND HAS
UNANIMOUSLY APPROVED AND ADOPTED THE MERGER AGREEMENT AND THE TRANSACTIONS
CONTEMPLATED THEREBY.
 
     THE COHERENT BOARD UNANIMOUSLY RECOMMENDS THAT STOCKHOLDERS OF COHERENT
VOTE "FOR" THE APPROVAL AND ADOPTION OF THE MERGER AGREEMENT.
 
                                       15
<PAGE>   23
 
OPINION OF COHERENT'S FINANCIAL ADVISOR
 
     The Coherent Board retained Baird to render its opinion as to the fairness
of the Exchange Ratio, from a financial point of view, to the holders of
Coherent Common Stock (other than Tellabs and its affiliates). On February 16,
1998, Baird rendered its opinion to the Coherent Board to the effect that, as of
such date, the Exchange Ratio was fair, from a financial point of view, to the
holders of Coherent Common Stock (other than Tellabs and its affiliates).
 
     THE FULL TEXT OF BAIRD'S OPINION, DATED FEBRUARY 16, 1998, WHICH SETS FORTH
THE ASSUMPTIONS MADE, GENERAL PROCEDURES FOLLOWED, MATTERS CONSIDERED AND
LIMITATIONS ON THE SCOPE OF REVIEW UNDERTAKEN BY BAIRD IN RENDERING ITS OPINION,
IS ATTACHED AS ANNEX IV TO THIS PROXY STATEMENT/PROSPECTUS AND IS INCORPORATED
HEREIN BY REFERENCE. BAIRD'S OPINION IS DIRECTED ONLY TO THE FAIRNESS, FROM A
FINANCIAL POINT OF VIEW, OF THE EXCHANGE RATIO TO THE HOLDERS OF COHERENT COMMON
STOCK (OTHER THAN TELLABS AND ITS AFFILIATES) AND DOES NOT CONSTITUTE A
RECOMMENDATION TO ANY COHERENT STOCKHOLDER AS TO HOW SUCH STOCKHOLDER SHOULD
VOTE WITH RESPECT TO THE MERGER AGREEMENT. THE SUMMARY OF BAIRD'S OPINION SET
FORTH BELOW IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO THE FULL TEXT OF SUCH
OPINION ATTACHED AS ANNEX IV. COHERENT STOCKHOLDERS ARE URGED TO READ THE
OPINION CAREFULLY IN ITS ENTIRETY.
 
     In conducting its investigation and analysis and in arriving at its
opinion, Baird has reviewed such information and has taken into account such
financial and economic factors as Baird deemed relevant under the circumstances.
In that connection, Baird, among other things: (i) reviewed certain internal
information, primarily financial in nature, including projections, concerning
the business and operations of Coherent and Tellabs furnished to Baird for
purposes of its analysis, as well as publicly available information including
but not limited to Coherent's and Tellabs' recent filings with the SEC and
equity analyst research reports prepared by various investment banking firms,
including Baird; (ii) reviewed the Merger Agreement in the form presented to the
Coherent Board; (iii) compared the historical market prices and trading activity
of Coherent Common Stock and Tellabs Common Stock with those of certain other
publicly traded companies Baird deemed relevant; (iv) compared the financial
position and operating results of Coherent and Tellabs with those of other
publicly traded companies Baird deemed relevant; and (v) compared the proposed
financial terms of the Merger with the financial terms of certain other business
combinations Baird deemed relevant. Baird held discussions with members of
Coherent's and Tellabs' respective senior managements concerning Coherent's and
Tellabs' historical and current financial condition and operating results, as
well as the future prospects of Coherent and Tellabs, respectively. Baird also
considered such other information, financial studies, analysis and
investigations and financial, economic and market criteria which Baird deemed
relevant for the preparation of its opinion. Baird was not asked to, and did
not, solicit third party indications of interest in acquiring all or any part of
Coherent. Coherent and Tellabs determined the Exchange Ratio in arms-length
negotiations. Coherent did not place any limitation upon Baird with respect to
the procedures followed or factors considered by Baird in rendering its opinion.
 
     In arriving at its opinion, Baird assumed and relied upon the accuracy and
completeness of all of the financial and other information that was publicly
available or provided to Baird by or on behalf of Coherent and Tellabs, and was
not engaged to independently verify any such information. Baird assumed, with
Coherent's consent, that (i) all material assets and liabilities (contingent or
otherwise, known or unknown) of Coherent and Tellabs are as set forth in their
respective financial statements and (ii) the Merger will be accounted for under
the pooling of interests method. Baird also assumed that the financial forecasts
examined by it were reasonably prepared on bases reflecting the best available
estimates and good faith judgments of Coherent's and Tellabs' respective senior
managements as to future performance of Coherent and Tellabs, respectively. In
conducting its review, Baird did not undertake nor obtain an independent
evaluation or appraisal of any of the assets or liabilities (contingent or
otherwise) of Coherent or Tellabs nor did it make a physical inspection of the
properties or facilities of Coherent or Tellabs. Baird's opinion necessarily was
based upon economic, monetary and market conditions as they existed and could be
evaluated on the date of its
 
                                       16
<PAGE>   24
 
opinion, and did not predict or take into account any changes which may occur,
or information which may become available, after the date of such opinion.
Furthermore, Baird expressed no opinion as to the price or trading range at
which any of Coherent's or Tellabs' securities (including Coherent Common Stock
and Tellabs Common Stock) will trade following the date of such opinion.
 
     The following is a summary of the material financial analyses performed by
Baird in connection with rendering its opinion.
 
     Analysis of the Coherent's Valuation Premiums.  Baird calculated the
"Implied Equity Value Per Share" from the Merger of Coherent Common Stock to be
$41.7150, obtained by multiplying the Exchange Ratio of 0.72 by the closing
price per share of Tellabs Common Stock of $57.9375 on February 13, 1998. Baird
compared the premium to holders of Coherent Common Stock represented by the
Implied Equity Value Per Share of $41.7150 to the closing prices for Coherent
Common Stock on February 13, 1998 (the last trading day prior to rendering its
opinion) and on the dates 30 days, 60 days, 90 days, 180 days and 52 weeks prior
thereto. Baird calculated that the Implied Equity Value Per Share represented
the following premiums to holders of Coherent Common Stock (i) a premium of
30.4% over the closing price of $32.00 for the Coherent Common Stock one trading
day prior to the rendering of its opinion; (ii) a premium of 81.4% over the
closing price of $23.00 for Coherent Common Stock 30 days prior thereto; and
(iii) a premium of 57.4% over the closing price of $26.50 for Coherent Common
Stock 60 days prior thereto; (iv) a premium of 40.8% over the closing price of
$29.63 for Coherent Common Stock 90 days prior thereto; (v) a premium of 99.9%
over the closing price of $20.87 for Coherent Common Stock 180 days prior
thereto; and (vi) a premium of 104.8% over the closing price of $20.37 for
Coherent Common Stock 52 weeks prior thereto.
 
     Analysis of Coherent Valuation Multiples.  Baird calculated the "Implied
Total Equity Value" and "Implied Enterprise Value" of Coherent as a result of
the Merger to be $673.75 million and $644.10 million, respectively. The Implied
Total Equity Value was obtained by multiplying the Implied Equity Value Per
Share by the total number of outstanding shares of Coherent Common Stock,
including shares issuable upon exercise of stock options outstanding as of
February 12, 1998, less net proceeds from the exercise of such stock options.
The Implied Enterprise Value was obtained by adding Coherent's outstanding total
debt and subtracting Coherent's cash and cash equivalents balances (as of
February 6, 1998 as provided to Baird by Coherent management) to the Implied
Total Equity Value. In performing its analysis, Baird used, among other items,
operating statistics for Coherent's twelve months ended December 31, 1997
("Actual 1997"), as provided by Coherent management. Baird calculated multiples
of the Implied Total Equity to Coherent's Actual 1997 net income and its
projected net income for calendar years 1998 and 1999 (based on Coherent
management's estimates) and multiples of Coherent's Implied Enterprise Value to
its Actual 1997 net sales, operating income before depreciation and
amortization, interest and taxes ("EBITDA") and its operating income before
interest and taxes ("EBIT"). The calculations resulted in multiples of the
Implied Total Equity Value to net income ("P/E Ratios") of 48.2x based on Actual
1997 results, 36.4x based on projected 1998 results and 26.8x based on projected
1999 results. The ratio of Implied Enterprise Value to Actual 1997 net sales was
8.7x, the ratio of Implied Enterprise Value to Actual 1997 EBITDA was 29.2x and
the ratio of Implied Enterprise Value to Actual 1997 EBIT was 32.2x.
 
     Analysis of Selected Publicly Traded Coherent Comparable Companies.  Baird
reviewed certain publicly available financial information as of the most
recently reported period and stock market information as of February 12, 1998,
for 33 publicly traded companies, which Baird deemed relevant. Such comparable
companies consisted predominantly of small to midcapitalization
telecommunications and related equipment providers. Such comparable companies,
as a group, had median market capitalizations and median latest twelve month
("LTM") net sales of approximately $778 million and $248 million, respectively.
For each comparable company, Baird compared historical and projected net income
and operating profitability to that of Coherent. Baird also reviewed the ratios
(the "P/E to Growth Ratio") of (i) 1998 P/E Ratios (based upon, with respect to
Coherent, projected 1998 net income as provided by Coherent management and, with
respect to the comparable companies, projected 1998 net income as reported by
published consensus equity analyst estimates for such companies) to (ii)
projected growth rate of net income (based upon, with respect to Coherent,
estimates provided by Coherent management and, with respect to the comparable
companies, published consensus equity analyst estimates). Baird noted that
Coherent's profitability, as indicated by
 
                                       17
<PAGE>   25
 
Actual 1997 gross profit, EBITDA, EBIT and net income margins exceeded the mean
and median LTM statistics for the selected comparable companies. For each
comparable company, Baird calculated multiples, as of February 12, 1998, of
Enterprise Value to LTM net sales, LTM EBITDA and LTM EBIT. Baird then compared
these multiples to the relevant Coherent multiples based on the Implied Equity
Price Per Share. An analysis of the multiples of Enterprise Value to Actual 1997
net sales, Actual 1997 EBITDA and Actual 1997 EBIT yielded 8.7x, 29.2x and
32.2x, respectively, for Coherent compared to medians of 2.9x, 17.3x and 18.5x,
respectively, for Coherent's comparable companies. For Coherent and each
comparable company, Baird also calculated P/E ratios based upon the Implied
Equity Value Per Share for Coherent and closing stock prices as of February 12,
1998, for the comparable companies and actual and projected net income
statistics for 1997, 1998 and 1999. An analysis of the P/E Ratios based on
Coherent's net income for Actual 1997 and projected 1998 and 1999 yielded 48.2x,
36.4x and 26.8x, respectively, compared to LTM 1997, projected 1998 and 1999
medians of 25.7x, 23.0x and 20.7x, respectively, for Coherent's comparable
companies. Baird also compared the P/E to Growth Ratio, based upon projected
1998 net income as provided by Coherent management to that of the comparable
companies. An analysis of Coherent's P/E to Growth Ratio based on projected 1998
net income yielded 1.2x as compared to a median P/E to Growth Ratio of 0.7x for
the comparable companies.
 
     Analysis of Selected Publicly Traded Tellabs Comparable Companies.  In
order to assess the relative public market valuation of the Tellabs Common Stock
to be used by Tellabs in exchange for Coherent Common Stock, Baird reviewed
certain publicly available financial information as of the most recently
reported period and stock market information as of February 12, 1998, for 31
publicly traded companies, which Baird deemed relevant. Such comparable
companies consisted of telecommunications equipment and related companies. Such
comparable companies, as a group, had median market capitalizations and LTM net
sales of approximately $1,016 million and $263 million, respectively. For each
comparable company, Baird compared historical and projected net income,
operating profitability and P/E to Growth Ratios to those of Tellabs. Baird
noted that Tellabs' profitability, as indicated by Actual 1997 gross profit,
EBITDA, EBIT and net income margins exceeded the mean and median LTM statistics
for the selected comparable companies. For each comparable company, Baird
calculated multiples as of February 12, 1998, of Enterprise Value to LTM net
sales, LTM EBITDA and LTM EBIT. Baird then compared these multiples to the
relevant Tellabs multiples based on Tellabs' closing share price of $57.9375 on
February 13, 1998, and Tellabs' Actual 1997 operating performance statistics, as
provided to Baird by Tellabs' management. An analysis of the multiples of
Enterprise Value to net sales, EBITDA and EBIT yielded 8.6x, 25.6x and 28.4x,
respectively, for Tellabs compared to median ratios of 3.1x, 17.2x and 19.1x,
respectively, for Tellabs' comparable companies. For Tellabs and each comparable
company, Baird also calculated P/E ratios based on the closing stock prices as
of February 13, 1998, for Tellabs and February 12, 1998, for the comparable
companies and Actual 1997 (for Tellabs) or LTM (for comparable companies)
earnings per share and estimated earnings per share for 1997, 1998 and 1999. An
analysis of the P/E Ratios based on earnings per share for Tellabs' Actual 1997
yielded 42.9x compared to a LTM 1997 median of 30.4x for Tellabs' comparable
companies. Baird also analyzed P/E Ratios based on projected earnings per share
for Tellabs, including a comparison of the P/E to Growth Ratio, based upon
projected 1998 net income as provided by Tellabs management to that of the
comparable companies. An analysis of Tellabs' P/E to Growth Ratio based on
projected 1998 net income yielded 1.0x as compared to a median P/E to Growth
Ratio of 0.7x for the comparable companies.
 
     Analysis of Selected Comparable Acquisition Transactions.  Baird reviewed
selected acquisition transactions, which Baird deemed relevant. Such
transactions were chosen based on a review of acquired companies which possessed
general business, operating and financial characteristics representative of
companies in the industry in which Coherent operates. Baird noted that none of
the selected transactions reviewed were identical to the Merger and that,
accordingly, the analysis of comparable transactions necessarily involves
complex consideration and judgments concerning differences in financial and
operating characteristics of Coherent and other factors that would affect the
acquisition value of comparable transactions. For each comparable transaction,
Baird calculated multiples of Enterprise Value to LTM net sales, LTM EBITDA and
LTM EBIT; calculated P/E Ratios based on LTM net income; and calculated the
premiums paid for the equity in these transactions over the public market value
of the equity at various times prior to the announcement of such transaction.
Baird then compared those multiples and premiums to the relevant Coherent
multiples and premiums. These calculations yielded multiples of Enterprise Value
to Actual 1997
                                       18
<PAGE>   26
 
net sales, Actual 1997 EBITDA and Actual 1997 EBIT of 8.7x, 29.2x and 32.2x,
respectively, for Coherent, compared to the LTM medians of 2.3x, 12.2x and
17.5x, respectively, for the comparable acquisition transactions. An analysis of
the P/E Ratios based on Actual 1997 earnings per share yielded 48.2x for
Coherent compared to a LTM median of 23.6x for the comparable transactions. An
analysis of the Implied Equity Value Per Share to the closing price of Coherent
Common Stock 1 day, 30 days and 90 days prior to the announcement date, compared
to the prices paid for the equity in such comparable acquisition transactions
relative to the market value of equity 1 day, 30 days and 90 days prior to the
announcement date of such transactions, yielded premiums of 30.4%, 81.4% and
40.8%, respectively, for Coherent, compared to median premiums of 9.4%, 18.3%
and 39.1%, respectively, for the comparable acquisition transactions.
 
     Contribution Analysis.  Baird analyzed Coherent's and Tellabs' relative
contribution to the combined company with respect to certain measurements,
including net sales, gross profit, EBIT and net income. As a result of the
Merger, Coherent stockholders will own approximately 5.9% of the outstanding
Tellabs Common Stock assuming an Exchange Ratio of 0.72. This compares to
Coherent's contribution, based on Actual 1997 and projected 1998 statistics for
the combined company, of approximately 5.8% of net sales, 5.9% of gross profit,
5.1% to 5.2% of EBIT and 5.2% to 5.3% of net income.
 
     Discounted Cash Flow Analysis.  Baird performed a discounted cash flow
analysis of Coherent on a stand-alone basis using management's projections for
calendar years 1998 through 2002 without taking into account any potential cost
savings and synergies which may be realized following the Merger. In such
analysis, Baird assumed terminal value multiples of 16.0x to 20.0x EBIT in the
year 2002 and discount rates of 23.0% to 27.0%. Such analysis produced implied
values of Coherent shares ranging from $26.86 to $44.16.
 
     In order to assess the relative public market valuation of the Tellabs
Common Stock to be used by Tellabs in exchange for Coherent Common Stock, Baird
performed a discounted cash flow analysis of Tellabs, on a stand alone basis,
based on assumptions provided by Tellabs' management for calendar years 1998
through 2002 without taking into account any potential cost savings and
synergies which may be realized following the Merger. In such analysis, Baird
assumed terminal value multiples of 15.0x to 17.0x EBIT in the year 2002 and
discount rates of 16.0% to 20.0%. Such analysis produced implied values of
Tellabs' shares ranging from $63.77 to $82.91.
 
     Pro Forma Merger Analysis.  Baird prepared pro forma analyses of the
financial impact of the Merger. In conducting its analysis, Baird relied upon
certain assumptions described above and projected earnings estimates for
Coherent (prepared by Coherent management) and Tellabs (prepared by Tellabs
management). Baird compared the earnings per share of Tellabs Common Stock, on a
stand-alone basis, to the earnings per share of the common stock of the combined
companies on a pro forma basis. The analysis (assuming no transaction-related
expenses, cost savings or synergies) indicated that the proposed transaction
would be modestly dilutive to Tellabs' stockholders on an earnings per share
basis in calendar years 1998 and 1999. The results of the pro forma merger
analysis are not necessarily indicative of future operating results or financial
position.
 
     Exchange Ratio Analysis.  Baird performed an analysis of the historical
trading ratio between Coherent Common Stock and Tellabs Common Stock based on
the closing market price per share of Coherent Common Stock relative to the
closing market price per share of Tellabs Common Stock for each trading day
during the calendar years of 1995, 1996 and 1997. This analysis yielded an
average annual historical trading ratio of 0.90x, 0.71x and 0.47x for 1995, 1996
and 1997, respectively.
 
     Leveraged Buyout Analysis.  Baird performed a leveraged buyout analysis in
order to assess the value financial acquirers could pay for Coherent Common
Stock based on certain assumed minimum debt and equity returns. Baird noted that
a large portion of Coherent's value under this methodology is derived from the
estimated terminal value for Coherent. Furthermore, Baird noted that to generate
the required returns estimated by Baird, this methodology required a significant
equity contribution when compared to the total Coherent equity value implied
from this analysis. Such analysis produced implied values of Coherent shares
ranging from $27.87 to $30.96.
 
                                       19
<PAGE>   27
 
     The foregoing summary does not purport to be a complete description of the
analyses performed by Baird. The preparation of a fairness opinion is a complex
process and is not susceptible to partial analyses or summary description. Baird
believes that its analyses must be considered as a whole, and that selecting
portions of such analyses without considering all analyses and factors, would
create an incomplete view of the processes underlying its opinion. Baird did not
attempt to assign specific weights to particular analyses. Any estimates
contained in Baird's analyses are not necessarily indicative of actual values,
which may be significantly more or less favorable than as set forth therein.
Estimates of values of companies do not purport to be appraisals or necessarily
to reflect the prices at which companies may actually be sold. Because such
estimates are inherently subject to uncertainty, Baird does not assume
responsibility for their accuracy.
 
     Baird, as part of its investment banking business, is engaged in the
evaluation of businesses and their securities in connection with mergers and
acquisitions, negotiated underwritings, competitive biddings, secondary
distributions of listed and unlisted securities, private placements, and
valuations for estate, corporate and other purposes. Coherent retained Baird
because of its experience and expertise in the valuation of businesses and their
securities in connection with mergers and acquisitions. In the ordinary course
of business, Baird may from time to time trade equity securities of Coherent and
Tellabs for its own account and for accounts of its customers and, accordingly,
may at any time hold a long or short position in such securities.
 
     Compensation.  Pursuant to an engagement letter agreement dated January 12,
1998, between Coherent and Baird, Coherent agreed to pay Baird a non-refundable
retainer fee of $50,000 and a fee of $325,000, payable upon delivery of its
opinion, regardless of the conclusions reached by Baird in such opinion.
Coherent has also agreed to reimburse Baird for its reasonable out-of-pocket
expenses. Coherent has also agreed to indemnify Baird, its affiliates and their
respective directors, officers, employees and agents and controlling persons
against certain liabilities relating to or arising out of its engagement,
including liabilities under the federal securities laws. In the past, Baird has
performed investment banking services for Safeguard, an affiliate of Coherent,
for which Baird has received customary compensation.
 
CERTAIN FEDERAL INCOME TAX CONSEQUENCES
 
     Tax Opinions.  It is a condition to the consummation of the Merger that
Coherent receive an opinion from its counsel, Morgan, Lewis & Bockius LLP, and
that Tellabs receive an opinion from its counsel, Sidley & Austin, each dated
the Effective Time, substantially to the effect that for federal income tax
purposes: (i) the Merger will constitute a "reorganization" within the meaning
of Section 368(a) of the Code, and Coherent, Sub and Tellabs will each be a
party to such reorganization within the meaning of Section 368(b) of the Code;
(ii) no gain or loss will be recognized by Tellabs, Sub or Coherent as a result
of the Merger; (iii) no gain or loss will be recognized by the stockholders of
Coherent upon the exchange of their Coherent Common Stock solely for shares of
Tellabs Common Stock pursuant to the Merger, except with respect to cash, if
any, received in lieu of fractional shares of Tellabs Common Stock; (iv) the
aggregate tax basis of the shares of Tellabs Common Stock received solely in
exchange for Coherent Common Stock pursuant to the Merger (including fractional
shares of Tellabs Common Stock for which cash is received) will be the same as
the aggregate tax basis of the Coherent Common Stock exchanged therefor; (v) the
holding period for shares of Tellabs Common Stock received in exchange for
Coherent Common Stock pursuant to the Merger will include the holding period of
such Coherent Common Stock exchanged therefor, provided such Coherent Common
Stock was held as a capital asset by the stockholder at the Effective Time; and
(vi) a stockholder of Coherent who receives cash in lieu of a fractional share
of Tellabs Common Stock will recognize gain or loss equal to the difference, if
any, between such stockholder's tax basis in such fractional share (as described
in (iv) above) and the amount of cash received. Each such opinion will be based
on current law (which may change, possibly retroactively) and various other
assumptions.
 
     Such opinions may not be applicable to, among other persons, stockholders
of Coherent who, for federal income tax purposes, are nonresident alien
individuals, foreign corporations, foreign partnerships, foreign trusts or
foreign estates, or who acquired their Coherent Common Stock pursuant to the
exercise of employee stock options or otherwise as compensation.
 
                                       20
<PAGE>   28
 
     In rendering such opinions, Morgan, Lewis & Bockius LLP and Sidley & Austin
will rely upon representations of Tellabs and representations of Coherent and
may rely upon representations of others.
 
     Real Estate Transfer Taxes.  Some states and localities, including the
State of New York, impose taxes on stockholders on certain indirect transfers
(including indirect transfers pursuant to corporate transactions such as the
Merger) of an interest in real property (including leases) located therein. Any
tax returns required to be filed in connection with such taxes will be filed by
Coherent on behalf of the stockholders of Coherent, and Coherent will pay any
taxes due thereon (the portion of any such payment attributable to each
stockholder of Coherent being referred to herein as a "Real Property Tax
Payment").
 
     Any Real Property Tax Payment should generally be treated for federal
income tax purposes as a deemed distribution by Coherent to each Coherent
stockholder which generally will be taxable to such stockholder as a dividend.
Any income taxes owing on account of such deemed distribution will be the
responsibility of the Coherent stockholders. Although there is no direct
authority on the question, there is a reasonable basis to conclude that, if
treated as a distribution from Coherent and taxed in the manner described above,
any Real Property Tax Payment should result in an increase of equal amount in
the tax basis of each shareholder's Coherent Common Stock and thereby result in
a corresponding increase in the tax basis of the shares of Tellabs Common Stock
received in the Merger.
 
     THE FOREGOING DISCUSSION IS INCLUDED FOR GENERAL INFORMATION AND IS BASED
ON CURRENT LAW. IN ADDITION, THE DISCUSSION DOES NOT ADDRESS ALL OF THE TAX
CONSEQUENCES THAT MAY BE RELEVANT TO PARTICULAR TAXPAYERS IN LIGHT OF THEIR
PERSONAL CIRCUMSTANCES OR TO TAXPAYERS SUBJECT TO SPECIAL TREATMENT UNDER THE
CODE (FOR EXAMPLE, INSURANCE COMPANIES, FINANCIAL INSTITUTIONS, DEALERS IN
SECURITIES AND TAX-EXEMPT ORGANIZATIONS). EACH STOCKHOLDER OF COHERENT SHOULD
CONSULT SUCH STOCKHOLDER'S OWN TAX ADVISOR AS TO THE SPECIFIC TAX CONSEQUENCES
TO SUCH STOCKHOLDER OF THE MERGER, INCLUDING THE APPLICATION AND EFFECT OF
FOREIGN, STATE, LOCAL AND OTHER TAX LAWS.
 
     EXCEPT WITH REGARD TO CERTAIN REAL ESTATE TRANSFER TAXES, NO INFORMATION IS
PROVIDED HEREIN WITH RESPECT TO THE TAX CONSEQUENCES, IF ANY, OF THE MERGER
UNDER APPLICABLE FOREIGN, STATE, LOCAL AND OTHER TAX LAWS. EXCEPT WITH REGARD TO
CERTAIN REAL ESTATE TRANSFER TAXES, THE FOREGOING DISCUSSION IS BASED UPON THE
PROVISIONS OF THE CODE, APPLICABLE TREASURY REGULATIONS THEREUNDER, INTERNAL
REVENUE SERVICE RULINGS AND JUDICIAL DECISIONS, AS IN EFFECT AS OF THE DATE
HEREOF. THERE CAN BE NO ASSURANCE THAT FUTURE LEGISLATIVE, ADMINISTRATIVE OR
JUDICIAL CHANGES OR INTERPRETATIONS WILL NOT AFFECT THE ACCURACY OF THE
STATEMENTS OR CONCLUSIONS SET FORTH HEREIN. ANY SUCH CHANGE COULD APPLY
RETROACTIVELY AND COULD AFFECT THE ACCURACY OF SUCH DISCUSSION. NO RULINGS HAVE
OR WILL BE SOUGHT FROM THE INTERNAL REVENUE SERVICE CONCERNING THE TAX
CONSEQUENCES OF THE MERGER.
 
ANTICIPATED ACCOUNTING TREATMENT
 
     The Merger will be accounted for as a "pooling of interests" for accounting
and financial reporting purposes. It is a condition to the consummation of the
Merger that (i) Coherent receive the written opinion of KPMG that KPMG concurs
with Coherent's management's conclusion that Coherent is eligible to be a party
to a business combination accounted for as a pooling of interests in accordance
with GAAP and applicable published rules and regulations of the SEC and (ii)
Tellabs receive the written opinion of Ernst & Young that Ernst & Young concurs
with Tellabs' management's conclusion that Tellabs is eligible to be a party to
a business combination accounted for as a pooling of interests in accordance
with GAAP and applicable published rules and regulations of the SEC, and that
the Merger will qualify for pooling of interests accounting.
 
                                       21
<PAGE>   29
 
     Pooling of interests accounting treatment requires the sharing of rights
and risks among the affiliates of each of the parties to a business combination
such that sales of stock by affiliates cannot occur in the period commencing 30
days prior to the consummation of the combination and ending on the date on
which the combined company publicly announces financial results covering at
least 30 days of combined operations. To ensure that such pooling requirements
are satisfied, each of Tellabs and Coherent has obtained the written agreements
from its respective affiliates relating to these trading restrictions, among
other things.
 
GOVERNMENTAL AND REGULATORY APPROVALS
 
     Filings with, notifications to and authorizations and approvals of various
governmental agencies, both domestic and foreign, with respect to the
transactions contemplated by the Merger Agreement, relating primarily to
antitrust and securities law issues, must be made and received prior to the
consummation of the Merger.
 
     The consummation of the Merger is conditioned upon the expiration or
termination of the applicable waiting period under the HSR Act. Under the HSR
Act and the regulations promulgated thereunder by the Federal Trade Commission
(the "FTC"), the Merger may not be consummated until notifications have been
given and certain information has been furnished to the FTC and the Antitrust
Division of the United States Department of Justice (the "Antitrust Division")
and the applicable waiting period has expired or been terminated.
 
     At any time before or after the Effective Time, notwithstanding that the
waiting period under the HSR Act has been terminated, the FTC or the Antitrust
Division could take such action under the antitrust laws as each deems necessary
or desirable in the public interest, including seeking to enjoin the
consummation of the Merger or seeking divestiture of assets of Tellabs or
Coherent. Similarly, at any time before or after the Effective Time, and
notwithstanding that the waiting period under the HSR Act has been terminated,
any state could take such action under the antitrust laws as it deems necessary
or desirable in the public interest and any foreign court, administrative
agency, commission or other governmental authority or instrumentality
("Governmental Entity") could take action under its antitrust or similar laws.
It is a condition to the consummation of the Merger Agreement that no such
action challenging or seeking to enjoin the consummation of the Merger by the
FTC, the Antitrust Division or any foreign Governmental Entity be instituted and
pending.
 
     The respective obligations of Tellabs and Coherent to consummate the Merger
are subject to the condition that no court of competent jurisdiction shall have
issued any temporary restraining order, preliminary or permanent injunction or
other order which is then in effect and restrains or prohibits consummation of
the Merger or any of the transactions contemplated by the Merger Agreement or
which prohibits or limits the ownership, operation or control by Coherent,
Tellabs or any of their respective subsidiaries of any portion of their
respective businesses or assets or compelling them to dispose of, grant rights
in respect of or hold separate any portion of their respective businesses or
assets. See "TERMS OF THE MERGER AGREEMENT -- Conditions to Closing."
 
PERCENTAGE OWNERSHIP INTEREST OF COHERENT STOCKHOLDERS AFTER THE MERGER
 
     Based on the number of shares of Tellabs Common Stock outstanding on the
Record Date and assuming the delivery of approximately 11,191,575 shares of
Tellabs Common Stock in connection with the Merger, upon consummation of the
Merger there will be approximately 192,963,257 shares of Tellabs Common Stock
outstanding at the Effective Time, of which the stockholders of Coherent will
own approximately 5.8%.
 
ABSENCE OF APPRAISAL RIGHTS
 
     Under the DGCL, the stockholders of Coherent are not entitled to appraisal
rights with respect to the approval and adoption of the Merger Agreement.
 
                                       22
<PAGE>   30
 
RESALES OF TELLABS COMMON STOCK
 
     All shares of Tellabs Common Stock delivered in the Merger will be freely
transferable, except that shares received by any person who may be deemed to be
an "Affiliate" (as that term is used in paragraphs (c) and (d) of Rule 145 under
the Securities Act, including, without limitation, directors and certain
executive officers) of Coherent for purposes of such Rule 145 may not be resold
except in transactions permitted by Rule 145 or as otherwise permitted under the
Securities Act.
 
     Coherent has caused each of its Affiliates to execute and deliver to
Tellabs a letter agreement, in the form attached to the Merger Agreement as an
exhibit thereto (the "Company Affiliate Letter"), providing that such person
will not sell, pledge, transfer or otherwise dispose of any Coherent Common
Stock or any shares of Tellabs Common Stock delivered to such person in
connection with the Merger, except pursuant to an effective registration
statement or in compliance with such Rule 145 or another exemption from the
registration requirements of the Securities Act. Coherent has agreed that, if
requested by Tellabs, it will provide Tellabs with such information as Tellabs
shall request for purposes of determining the Affiliates of Coherent and upon
the request of Tellabs it will use its reasonable best efforts to cause any
person who may in Tellabs' reasonable judgment be deemed an Affiliate of
Coherent to execute and deliver to Tellabs a Company Affiliate Letter.
 
                         TERMS OF THE MERGER AGREEMENT
 
     The following is a summary of certain provisions of the Merger Agreement, a
conformed copy of which is attached as Annex I to this Proxy
Statement/Prospectus and incorporated herein by reference. This summary is
qualified in its entirety by reference to the Merger Agreement. Stockholders of
Coherent are urged to read the Merger Agreement in its entirety for a more
complete description of the Merger. Capitalized terms not otherwise defined
herein shall have the meaning ascribed to such terms in the Merger Agreement.
 
THE MERGER
 
     The Merger Agreement provides that, subject to the provisions of the Merger
Agreement and in accordance with DGCL, at the Effective Time, Sub will be merged
with and into Coherent, with Coherent continuing as the Surviving Corporation
and becoming a wholly owned subsidiary of Tellabs. The Merger will become
effective at the time of filing of a Certificate of Merger with the Secretary of
State of the State of Delaware, which will occur at or concurrently with the
Closing.
 
CONVERSION OF SECURITIES
 
     As of the Effective Time, each issued and outstanding share of Coherent
Common Stock (other than any shares owned by Coherent or its subsidiaries,
Tellabs, Sub or any other wholly owned subsidiary of Tellabs, which will be
canceled) will be converted into the right to receive .72 of a share of Tellabs
Common Stock. If any holder of shares of Coherent Common Stock would be entitled
to receive a number of shares of Tellabs Common Stock that includes a fraction,
then, in lieu of such fractional share, such holder will be entitled to receive
cash in an amount equal to such fractional part of a share of Tellabs Common
Stock multiplied by the average of the last reported sale prices of Tellabs
Common Stock on Nasdaq on the ten trading days immediately preceding the
Effective Time.
 
     In the event of any reclassification, stock split or stock dividend with
respect to Tellabs Common Stock between the date of the Merger Agreement and the
Effective Time, appropriate adjustments, if any, shall be made by Tellabs to the
Exchange Ratio.
 
     As of the Effective Time, each issued and outstanding share of the capital
stock of Sub will be converted into and become one fully paid and nonassessable
share of common stock, $.01 par value, of the Surviving Corporation.
 
     Harris Trust and Savings Bank has been selected as exchange agent (the
"Exchange Agent") under the Merger Agreement. As soon as practicable after the
Effective Time, Tellabs shall deposit with the Exchange
 
                                       23
<PAGE>   31
 
Agent, for the benefit of holders of shares of Coherent Common Stock,
certificates representing the shares of Tellabs Common Stock issuable pursuant
to the Merger in accordance with the Merger Agreement. The Exchange Agent will
deliver the certificates representing shares of Tellabs Common Stock upon
surrender for exchange of the Coherent Certificates (as defined herein).
 
     As soon as reasonably practicable after the Effective Time, the Exchange
Agent will mail letters of transmittal and other transmittal forms, together
with exchange instructions, to each holder of record of a certificate or
certificates which immediately prior to the Effective Time represented
outstanding shares of Coherent Common Stock (the "Coherent Certificates"), for
use in effecting the surrender and exchange of Coherent Certificates for
certificates representing shares of Tellabs Common Stock (and cash in lieu of
any fractional shares) to which such holder has become entitled. After receipt
of such letters of transmittal and other transmittal forms, each holder of
Coherent Certificates will be able to surrender such certificates to the
Exchange Agent, and each such holder will receive in exchange therefor a
certificate representing the number of whole shares of Tellabs Common Stock (and
cash in lieu of any fractional shares) to which such holder is entitled. Such
transmittal forms will be accompanied by instructions specifying other details
of the exchange. COHERENT STOCKHOLDERS SHOULD NOT SEND IN THEIR CERTIFICATES
UNTIL THEY RECEIVE A LETTER OF TRANSMITTAL.
 
     After the Effective Time and until surrendered, each Coherent Certificate
will be deemed to represent only the right to receive upon surrender a
certificate representing shares of Tellabs Common Stock and cash in lieu of
fractional shares of Tellabs Common Stock. No dividends or other distributions
declared or made after the Effective Time with respect to Tellabs Common Stock
with a record date after the Effective Time shall be paid to the holder of any
unsurrendered Coherent Certificate with respect to the shares of Tellabs Common
Stock represented thereby, and no cash payment in lieu of fractional shares
shall be paid to any such holder until the holder of record of such Coherent
Certificate shall surrender such Coherent Certificate. Subject to the effect of
applicable laws, following surrender of any such Coherent Certificate, there
shall be paid to the record holder of the certificates representing whole shares
of Tellabs Common Stock issued in exchange therefor, without interest, (i) at
the time of such surrender, the amount of any cash payable in lieu of a
fractional shares of Tellabs Common Stock to which such holder is entitled and
the amount of dividends or other distributions with a record date after the
Effective Time previously paid with respect to such whole shares of Tellabs
Common Stock, and (ii) at the appropriate payment date, the amount of dividends
or other distributions with a record date after the Effective Time but prior to
surrender and a payment date subsequent to surrender payable with respect to
such whole shares of Tellabs Common Stock.
 
     Tellabs or the Exchange Agent shall be entitled to deduct and withhold from
the consideration otherwise payable pursuant to the Merger Agreement such
amounts as Tellabs or the Exchange Agent is required to deduct and withhold
under the Code, or any provision of state, local or foreign tax law, with
respect to the making of such payment. To the extent that amounts are so
withheld by Tellabs or the Exchange Agent, such withheld amounts shall be
treated for all purposes of the Merger Agreement as having been paid to the
person in respect of whom such deduction and withholding was made by Tellabs or
the Exchange Agent.
 
REPRESENTATIONS AND WARRANTIES
 
     The Merger Agreement contains representations and warranties by Coherent
relating to a number of matters, including: (i) the due organization, valid
existence and good standing of Coherent and its subsidiaries; (ii) subsidiaries
and joint ventures of Coherent; (iii) the capital structure of Coherent; (iv)
the authorization, execution, delivery and enforceability of the Merger
Agreement and related matters; (v) the absence of conflicts under Coherent's or
its subsidiaries' charters and bylaws or under any governmental order or law and
the absence of breaches of any material agreement binding upon Coherent or its
subsidiaries or their respective properties; (vi) the filing of documents and
financial statements by Coherent with the SEC and the accuracy of information
contained therein; (vii) the absence of certain liabilities; (viii) the absence
of certain changes or events in Coherent's business or condition; (ix) taxes,
tax returns, tax deficiencies and tax withholdings; (x) the possession of
leasehold interests in real properties; (xi) ownership and validity of
intellectual property rights; (xii) agreements, contracts and commitments;
(xiii) absence of certain litigation; (xiv) environmental matters; (xv) employee
benefit plans; (xvi) compliance with laws; (xvii) the ability to
 
                                       24
<PAGE>   32
 
account for the Merger as a pooling of interests; (xviii) affiliates of
Coherent; (xix) interested party transactions; (xx) the accuracy of information
supplied by Coherent for the Registration Statement and this Proxy
Statement/Prospectus; (xxi) the delivery of the opinion of Coherent's financial
advisor; (xxii) requirements for approval of the Merger Agreement by
stockholders of Coherent; (xxiii) the inapplicability of Section 203 of the DGCL
to the transactions contemplated by the Merger Agreement; (xxiv) the lack of any
"excess parachute payments" (as defined in the Code) with respect to amounts
received by employees, officers and directors of Coherent as a result of the
transactions contemplated by the Merger Agreement and (xxv) brokers and finders.
 
     The Merger Agreement contains representations and warranties by Tellabs and
Sub relating to a number of matters, including: (i) the due organization, valid
existence and good standing of Tellabs and its material subsidiaries; (ii)
subsidiaries of Tellabs; (iii) the capital structure of Tellabs; (iv) the
authorization, execution, delivery and enforceability of the Merger Agreement
and related matters; (v) the absence of conflicts under Tellabs' charter and
bylaws or under any governmental order or law and the absence of breaches of any
material agreement binding upon Tellabs or its properties; (vi) the filing of
documents and financial statements by Tellabs with the SEC and the accuracy of
information contained therein; (vii) the absence of certain liabilities; (viii)
the absence of certain changes or events in Tellabs' business or condition; (ix)
taxes, tax returns, tax deficiencies and tax withholdings; (x) the possession of
leasehold interests in real properties; (xi) ownership and validity of
intellectual property rights; (xii) agreements, contracts and commitments;
(xiii) absence of certain litigation; (xiv) environmental matters; (xv)
compliance with laws; (xvi) the ability to account for the Merger as a pooling
of interests; (xvii) affiliates of Tellabs; (xviii) the accuracy of information
supplied by Tellabs for the Registration Statement and Joint Proxy
Statement/Prospectus; (xix) voting requirements; and (xx) brokers and finders.
 
CERTAIN COVENANTS AND AGREEMENTS
 
     Conduct of Business of Coherent.  Coherent has agreed, for itself and its
Subsidiaries, that, during the period from the date of the Merger Agreement to
the Effective Time, it will carry on its businesses in the usual, regular and
ordinary course in substantially the same manner as previously conducted, pay
its debts and taxes when due subject to good faith disputes over such debts or
taxes, pay or perform other obligations when due, and use all reasonable best
efforts consistent with past practices and policies to preserve intact its
present business organizations, keep available the services of its present
officers and key employees and preserve its relationships with customers,
suppliers, distributors, licensors, licensees, and others having business
dealing with it. Coherent has also agreed that, without Tellabs prior written
consent, it will not (and will cause its Subsidiaries not to): (a) accelerate,
amend or change the period of exercisability of options or restricted stock
granted under Coherent's 1982 Stock Option Plan and 1993 Equity Compensation
Plan, as amended and restated (the "Coherent Option Plans") or authorize cash
payments in exchange for any options granted under any of such plans; (b)
transfer or license or otherwise extend, amend or modify any rights to its
intellectual property, other than licenses to customers in the ordinary course
of business consistent with past practices on a non-exclusive basis; (c) issue,
deliver, sell, pledge or otherwise encumber, or authorize or propose the
issuance, delivery, sale, pledge or encumbrance of, any shares of its capital
stock or securities convertible into shares of its capital stock, or any
subscriptions, rights, warrants, or options to acquire, or other agreements
obligating it to issue any such shares or other convertible securities, other
than the issuance of shares of Coherent Common Stock upon the exercise of stock
options to purchase shares of Coherent Common Stock ("Coherent Stock Options")
outstanding on the date of the Merger Agreement and except for the issuance of
Coherent Stock Options to purchase no more than 150,000 shares of Coherent
Common Stock in the aggregate in connection with the hiring of new employees or
the promotion of officers and employees other than Senior Officers of Coherent,
as described under "INTERESTS OF CERTAIN PERSONS IN THE MERGER," in each case in
the ordinary course of business, consistent with past practice; (d) take any
action to increase the compensation payable to its officers or employees, except
for regularly scheduled increases in salary or wages (not in excess of 10% in
the aggregate for each person) of employees (other than Senior Officers) in
accordance with past practices; grant additional severance or termination pay
to, or enter into employment or severance agreements with, directors or Senior
Officers; grant any severance or termination pay to, or enter into any
employment or severance agreement with any employee,
 
                                       25
<PAGE>   33
 
except in the ordinary course of business consistent with past practice (and not
in excess of $100,000 in the aggregate); enter into any collective bargaining
agreement; or establish, adopt, enter into any bonus, profit sharing, thrift,
compensation, stock option, restricted stock, pension, retirement, deferred
compensation, employment, termination, severance or other plan, trust fund,
policy or arrangement for the benefit of its directors, officers or employees or
amend any employee benefit plan; (e) revalue any of its assets, including
writing down the value of inventory or writing off notes or accounts receivable,
other than in the ordinary course of business pursuant to arm's length
transactions on commercially reasonable terms; (f) incur or commit to incur
capital expenditures in excess of $500,000 individually or $4,000,000 in the
aggregate; (g) make any material amendments to any OEM agreement or enter into
or make any amendments to any agreements pursuant to which any third party is
granted exclusive marketing, manufacturing or other rights with respect to any
product, process or technology, other than granting to specific customers
non-territorial exclusive rights to physical packaging and related interfaces
developed by Coherent for such customer's equipment; (h) amend in any respect
that, taken as a whole, is material and adverse to Coherent, or terminate any
material contract, agreement or license to which it is a party; (i) waive or
release any material right or claim (except in connection with amendments that
comply with clause (h) above) or pay, discharge or satisfy any material claims,
liabilities or obligations (absolute, accrued, asserted or unasserted,
contingent or otherwise), other than the payment, discharge or satisfaction, in
the ordinary course of business consistent with past practice or in accordance
with their terms, of liabilities reflected or reserved against in, or
contemplated by, its most recent financial statements (or notes thereto) filed
prior to the date of the Merger Agreement, or incurred in the ordinary course of
business consistent with past practice; (j) settle or compromise tax liabilities
in excess of $500,000 in the aggregate or prepare or file tax returns
inconsistent with past practice or, on any such return, take any position, make
any election, or adopt any method inconsistent with those taken in preparing or
filing similar returns in prior periods; (k) initiate any litigation or
arbitration proceeding except litigation involving Tellabs related to the Merger
Agreement and proceedings responsive to litigation filed by a third party; (l)
declare or pay any dividends on or make other distributions (other than
dividends or distributions by a direct or indirect wholly owned subsidiary of
Coherent to its parent) in respect of any of its respective capital stock, or
split, combine or reclassify any of its capital stock, or issue or authorize the
issuance of any other securities in respect of, in lieu of or in substitution
for shares of its capital stock, and not purchase or otherwise acquire, directly
or indirectly, any shares of its capital stock; (m) acquire or agree to acquire,
by merging or consolidating with, by purchasing any equity interest in or the
assets of, or by any other means, any business entity; (n) sell, lease, license,
mortgage, encumber or otherwise dispose of any of its properties or assets
except in the ordinary course of business; (o) incur indebtedness for money
borrowed (or guarantees thereof), issue or sell any debt securities (or warrants
or rights to acquire debt securities), guarantee debt securities of others,
enter into any "keep well" or similar agreement, or enter into any agreement
having the economic effect of the foregoing, or make any loans, advances or
capital contributions to, or investments in, any other person, other than to
Coherent or its wholly owned subsidiaries; (p) amend or propose to amend its
charter documents or bylaws; or (q) take any action that would make any of its
representations and warranties in the Merger Agreement untrue or incorrect in
any material respect or prevent it from performing, or cause it not to perform,
any of its obligations under the Merger Agreement. The parties have agreed that
Coherent may enter into employment agreements with its Senior Officers.
 
     Conduct of Business of Tellabs.  Pursuant to the Merger Agreement, Tellabs
has agreed that, during the period from the date of the Merger until April 16,
1998, except with the prior written consent of Coherent or as contemplated by
the Merger Agreement, each of Tellabs and its subsidiaries will not: (a) declare
or pay any dividends on or make other distributions in respect of any of its
respective capital stock, not effect certain other changes in its capitalization
or spend more than $50,000,000 to purchase or otherwise acquire, directly or
indirectly, any shares of its capital stock; (b) acquire or agree to acquire, by
merging or consolidating with, by purchasing any equity interest in or the
assets of, or by any other means, any business entity except for such
acquisitions involving purchase prices less than $500,000,000 in the aggregate;
(c) sell, lease, license, mortgage, encumber or otherwise dispose of any of its
properties or assets except in the ordinary course of business or to the extent
involving sale prices of less than $500,000,000 in the aggregate; (d) incur
indebtedness for money borrowed (or guarantees thereof), issue or sell any debt
securities (or warrants or rights to acquire debt securities), guarantee debt
securities of others, enter into any "keep well" or similar
 
                                       26
<PAGE>   34
 
agreement, or enter into any agreement having the economic effect of the
foregoing, or make any loans, advances or capital contributions to, or
investments in, any other person, other than Tellabs or its wholly owned
subsidiaries, except to the extent involving indebtedness or loans less than
$250,000,000 in the aggregate; (e) amend or propose to amend its charter
documents or bylaws; (f) take any action that would make any of its
representations and warranties in the Merger Agreement untrue or incorrect in
any material respect or prevent it from performing, or cause it not to perform,
any of its obligations under the Merger Agreement; or (g) issue or authorize the
issuance or delivery of, any shares of its capital stock or securities
convertible into shares of its capital stock, or subscriptions, rights, warrants
or options to acquire, or other agreements obligating it to issue any such
shares or other convertible securities, other than the issuance of Tellabs
Common Stock upon the exercise of stock options to purchase shares of Tellabs
Common Stock and issuances not involving in excess of 5% of the issued and
outstanding Tellabs Common Stock on the date of the Merger Agreement. The Merger
Agreement provides that nothing contained therein shall prohibit Tellabs from
adopting a stockholder rights plan or issuing securities pursuant thereto.
 
     Each of Tellabs and Coherent has also agreed to notify the other in writing
after becoming aware of any event or occurrence that would result in a material
breach of any of its covenants or agreements set forth in the Merger Agreement
or cause any of its representations as warranties to be untrue and which, if
uncured, could reasonably be expected to cause certain conditions to the
consummation of the Merger not to be satisfied.
 
     No Solicitation.  Coherent has agreed that, from the date of the Merger
Agreement to the earlier of the Effective Time or the termination of the Merger
Agreement, it will not, directly or indirectly, and will cause its officers,
directors, employees, representatives, agents and affiliates to not, (i)
solicit, initiate or encourage any inquiries or proposals that constitute, or
could reasonably be expected to lead to, a proposal or offer for a merger,
consolidation, sale or purchase of substantial assets or stock, tender or
exchange offer, or other business combination or change in control or similar
transaction involving Coherent or its subsidiaries, other than the transactions
contemplated or permitted by the Merger Agreement (any of the foregoing
inquiries or proposals being referred to as a "Takeover Proposal"), (ii) engage
in negotiations or discussions concerning, or provide any non-public information
to any person or entity relating to, any Takeover Proposal, or (iii) enter into
any agreement with respect to, agree to, approve or recommend any Takeover
Proposal. Notwithstanding the foregoing restriction, the Merger Agreement
permits Coherent and the Coherent Board to furnish non-public information or
enter into discussions or negotiations in connection with an unsolicited bona
fide written Takeover Proposal if and only to the extent that (1) such Takeover
Proposal would, if consummated, result in a transaction that would, in the
reasonable good faith judgment of the Coherent Board, after consultation with
its financial advisors, result in a transaction more favorable to its
stockholders from a financial point of view than the Merger (any such more
favorable Takeover Proposal being referred to as a "Superior Proposal") and, in
the reasonable good faith judgment of the Coherent Board, after consultation
with its financial advisors, the person or entity making such Superior Proposal
has the financial means to conclude such transaction, (2) the failure to take
such action would, in the reasonable good faith judgment of the Coherent Board,
on the basis of advice from its outside corporate counsel, be contrary to the
fiduciary duties of the Coherent Board to Coherent's stockholders under
applicable law, (3) prior to furnishing such non-public information or entering
into such discussions or negotiations, the Coherent Board receives an executed
confidentiality agreement with provisions no less favorable, with certain
limited exceptions, to Coherent than those contained in its December 29, 1997
Confidentiality and Non Disclosure Agreement with Tellabs and (4) Coherent shall
have complied with the provisions described in this paragraph. The Merger
Agreement also does not prevent Coherent from complying with Rules 14d-9 or
14e-2 promulgated under the Exchange Act with regard to a Takeover Proposal.
 
     Coherent must notify Tellabs orally and in writing within 24 hours after
receipt by Coherent (or its advisors) of any Takeover Proposal or any request
for non-public information or access to its properties, books or records by
anyone that informs Coherent it is considering a Takeover Proposal, including
the identity of the person making the Takeover Proposal and the terms and
conditions thereof. Coherent must notify Tellabs within 24 hours if the
financial terms of such Takeover Proposal are modified. In addition, Coherent
must notify Tellabs simultaneously with the delivery of notice to the Coherent
Board, and in any event at least 24 hours prior to (unless a longer period is
required by the Merger Agreement pursuant to the provisions
 
                                       27
<PAGE>   35
 
described in the next following paragraph) each meeting of the Coherent Board
held to consider taking definitive action with respect to withdrawing or
modifying, in a manner adverse to Tellabs, its recommendation to Coherent's
stockholders in favor of the Merger.
 
     Notwithstanding the foregoing, in the event that there exists a Superior
Proposal before the Coherent Board and in the reasonable good faith judgment of
Coherent, on the basis of the advice of its outside corporate counsel, the
failure to accept a Superior Proposal before the Coherent Board would be
contrary to the fiduciary duties of the Coherent Board to Coherent's
stockholders under applicable law, the Coherent Board may terminate the Merger
Agreement prior to the Stockholders Meeting (and, concurrent with such
termination, cause Coherent to enter into an acquisition agreement with respect
to such Superior Proposal), but only at a time that is (i) after the third day
following receipt by Tellabs of Coherent's written notice that the Coherent
Board is prepared to accept a Superior Proposal, specifying the material terms
and conditions thereof and the person making such proposal; (ii) after Coherent
pays the Termination Fee (as defined in " -- Fees and Expenses") to Tellabs in
full and in immediately available funds; and (iii) after Coherent and its
advisors have negotiated in good faith with Tellabs to make such changes to the
terms and conditions of the Merger Agreement as would enable Coherent to proceed
with the transactions contemplated thereby. From the date of the Merger
Agreement through the Effective Time, Coherent has agreed not to terminate,
amend, modify or waive any provision of any confidentiality or standstill
agreement (other than any entered into in the ordinary course of business not in
connection with any possible Takeover Proposal) to which it or any of its
subsidiaries is a party (other than any between Coherent and its Subsidiaries)
and to enforce, to the fullest extent permitted under applicable law, the
provisions of any such agreement, including by obtaining injunctions to prevent
any breaches of such agreements and to enforce specifically the terms and
provisions thereof.
 
     The Coherent Board shall be entitled to withdraw or modify its
recommendation to Coherent's stockholders in favor of approval and adoption of
the Merger Agreement and the Merger if (i) it has complied with the provisions
of the Merger Agreement described in this section and (ii) in the reasonable
good faith judgment of the Coherent Board, on the basis of the advice of
Coherent's outside corporate counsel, the making of, or the failure to withdraw
or modify, such recommendation would be contrary to the fiduciary duties of the
Coherent Board to Coherent's stockholders under applicable law.
 
     Stock Plans and Options.  Coherent has agreed to provide to each holder of
an outstanding Coherent Stock Option to purchase Coherent Common Stock under the
Coherent Stock Plans the notice (if any) required pursuant to such plans in
connection with the Merger. From and after the Effective Time, Tellabs has
agreed to assume each outstanding vested and unvested Coherent Stock Option, and
each such Coherent Stock Option will, pursuant to the terms of such option, be
deemed to constitute an option to acquire, on the same terms and conditions as
were applicable under such Coherent Stock Option, the same number of shares of
Tellabs Common Stock as the holder of such Coherent Stock Option would have been
entitled to receive in the Merger pursuant to the Merger Agreement had such
holder exercised such option in full immediately prior to the Effective Time
(rounded down to the nearest whole number), at a price per share (rounded up to
the nearest whole cent) equal to the quotient of (i) the exercise price per
share of Coherent Common Stock pursuant to such Coherent Stock Option divided by
(ii) the Exchange Ratio. All other terms of such Coherent Stock Options will
remain in effect.
 
     Coherent has agreed to take all actions necessary so that following the
Effective Time no holder of a Coherent Stock Option or any participant in any
employee benefit plan of Coherent will have any right thereunder to acquire
capital stock of Coherent, Sub, or the Surviving Corporation. Coherent has also
agreed to take all actions necessary so that, as of the Effective Time, none of
Sub, Coherent, the Surviving Corporation or any of their respective Subsidiaries
is or will be bound by any Coherent Stock Options, other options, warrants,
rights or agreements which would entitle any person, other than Tellabs, Sub or
its affiliates, to own any capital stock of Coherent, Sub, the Surviving
Corporation or any of their respective subsidiaries or to receive any payment in
respect thereof, except as otherwise provided in the Merger Agreement.
 
     Indemnification; Directors' and Officers' Insurance.  The parties have
agreed that all rights to indemnification for acts or omissions occurring prior
to the Effective Time now existing in favor of the current or former
 
                                       28
<PAGE>   36
 
directors or officers of Coherent provided in the Coherent Charter and Coherent
By-laws will survive the Merger and continue in full force and effect in
accordance with their terms for a period of not less than six years from the
Effective Time and to the extent the Surviving Corporation fails to perform its
obligations with respect thereto, Tellabs has agreed to perform such
obligations. Tellabs and the Surviving Corporation will cause to be maintained
for a period of not less than six years from the Effective Time Coherent's
current directors and officers insurance and indemnification policy to the
extent that is provides coverage for events occurring prior to the Effective
Time for all persons who are directors and officers of Coherent on the date of
the Merger Agreement. Notwithstanding the foregoing, the parties have agreed
that in no event shall the Surviving Corporation be required to pay a premium
for such insurance coverage in any one year in excess of $150,000, and if the
annual premiums of such insurance coverage exceed such amount or if such
existing directors' and officers' insurance and indemnification policy expires,
is terminated or canceled during such six-year period, the Surviving Corporation
shall be obligated to obtain a policy with the greatest coverage available for a
cost not exceeding $150,000.
 
CONDITIONS TO CLOSING
 
     Conditions to Each Party's Obligation to Effect the Merger.  The respective
obligations of each party to effect the Merger Agreement are subject to the
following conditions: (i) the Merger Agreement shall have been adopted and
approved by the requisite vote of holders of Coherent Common Stock pursuant to
the DGCL and the Coherent Charter; (ii) the waiting period applicable to the
consummation of the Merger under the HSR Act and any other material waiting
periods under applicable foreign laws shall have expired or been terminated and
no action by the Department of Justice, the FTC or any foreign Governmental
Entity challenging or seeking to enjoin the consummation of the Merger shall be
pending or have been instituted; (iii) the Registration Statement shall have
become effective under the Securities Act and shall not be the subject of any
stop order or proceedings seeking a stop order; (iv) there shall be no temporary
restraining order, preliminary or permanent injunction or other order issued by
any court of competent jurisdiction or other legal or regulatory restraint or
prohibition issued or in effect restraining or prohibiting the consummation of
the Merger or any of the transactions contemplated by the Merger Agreement or
prohibiting or limiting the ownership, operation or control by Coherent, Tellabs
or any of their respective subsidiaries of any portion of their respective
businesses or assets or compelling any of them to dispose of, grant rights in
respect of, or hold separate any portion of their respective businesses or
assets; nor shall any action have been taken or any statute, rule, regulation or
order have been enacted, entered or enforced or be deemed applicable to the
Merger which makes the consummation of the Merger illegal or prevents or
prohibits the Merger; (v) the shares of Tellabs Common Stock to be issued in the
Merger shall have been approved for quotation on Nasdaq; (vi) Coherent shall
have received the written opinion, dated as of the Effective Time, of KPMG that
KPMG concurs with management's conclusion that Coherent is eligible to be a
party to a business combination accounted for as a pooling of interests in
accordance with GAAP and applicable published rules and regulations of the SEC
and Tellabs shall have received the written opinion, dated as of the Effective
Time, of Ernst & Young that Ernst & Young concurs with management's conclusion
that Tellabs is eligible to be a party to a business combination accounted for
as a pooling of interests in accordance with GAAP and applicable published rules
and regulations of the SEC, and that the Merger will qualify for pooling of
interests accounting, each of such written opinions being in form and substance
reasonably satisfactory to Coherent and Tellabs.
 
     Additional Conditions to Obligations of Tellabs and Sub.  The obligations
of Tellabs and Sub to effect the Merger are subject to the satisfaction or
waiver of each of the following additional conditions, any of which may be
waived in writing exclusively by Tellabs and Sub: (i) each of the
representations and warranties of Coherent set forth in the Merger Agreement
that is qualified by materiality shall be true and correct at and as of the date
of the Closing (the "Closing Date") as if made at and as of the Closing Date and
each of such representations and warranties that is not so qualified shall be
true and correct in all material respects at and as of the Closing Date as if
made at and as of the Closing Date, in each case except as contemplated by the
Merger Agreement, and Tellabs shall have received a certificate signed on behalf
of Coherent by the chief executive officer or chief financial officer of
Coherent to such effect; (ii) Coherent shall have performed in all material
respects all obligations required to be performed by it under the Merger
Agreement at or prior to the
 
                                       29
<PAGE>   37
 
Closing Date, and Tellabs shall have received a certificate signed on behalf of
Coherent by the chief executive officer or chief financial officer of Coherent
to such effect; (iii) a Company Affiliate Letter shall have been executed and
delivered to Tellabs by or on behalf of each director and executive officer of
Coherent, and each such Company Affiliate Letter shall be in full force and
effect; (iv) no Material Adverse Effect with respect to Coherent shall have
occurred, and no fact or circumstance shall exist which could reasonably be
expected to result in a Material Adverse Effect with respect to Coherent;
provided that if the event resulting in such Material Adverse Effect was beyond
the control of Coherent, such event shall not be deemed to have occurred for
purpose of satisfying this condition unless Tellabs pays Coherent $2,000,000 in
immediately available funds (the term "Material Adverse Effect" is defined in
the Merger Agreement to mean, when used in connection with Tellabs or Coherent,
any change or effect that is materially adverse to the business, properties,
assets, condition (financial or otherwise), or results of operations of such
party and its subsidiaries taken as a whole but excluding (i) any change
resulting from general economic conditions or general industry conditions or
(ii) any change caused by the transactions contemplated by the Merger Agreement
and the public announcement thereof); (v) Tellabs shall have received an opinion
of its counsel, in form and substance reasonably satisfactory to Tellabs, dated
the Effective Time, substantially to the effect described under "The
Merger -- Certain Federal Income Tax Consequences"; and (vi) there shall not be
pending or threatened any suit, action or proceeding by any Governmental Entity
before any court or governmental authority, agency or tribunal, domestic or
foreign, seeking to restrain or prohibit the consummation of the Merger or any
of the other transactions contemplated by the Merger Agreement or seeking to
obtain from any of the parties any damages in connection therewith, seeking to
prohibit or limit the ownership, operation or control by Coherent, Tellabs or
any of their respective subsidiaries of any portion of the business or assets of
the respective parties, or to compel the parties to dispose of, grant rights in
respect of, or hold separate any portion of their respective businesses or
assets or which otherwise is reasonably likely to have a Material Adverse Effect
on Coherent.
 
     Additional Conditions to Obligations of Coherent.  The obligation of
Coherent to effect the Merger is subject to the satisfaction of each of the
following additional conditions, any of which may be waived, in writing,
exclusively by Coherent: (i) each of the representations and warranties of
Tellabs and Sub set forth in the Merger Agreement that is qualified by
materiality shall be true and correct at and as of the Closing Date and each of
such representations and warranties that is not so qualified shall be true and
correct in all material respects at and as of the Closing Date as if made at and
as of the Closing Date, in each case except as contemplated by the Merger
Agreement, and Coherent shall have received a certificate signed on behalf of
Tellabs by the chief executive officer or chief financial officer of Tellabs to
such effect; (ii) Tellabs and Sub shall have performed in all material respects
all obligations required to be performed by them under the Merger Agreement at
or prior to the Closing Date, and Coherent shall have received a certificate
signed on behalf of Tellabs by the chief executive officer or chief financial
officer of Tellabs to such effect; (iii) no Material Adverse Effect with respect
to Tellabs shall have occurred, and no fact or circumstance shall exist which
could reasonably be expected to result in a Material Adverse Effect with respect
to Tellabs; provided that, if the event resulting in such Material Adverse
Effect was beyond the control of Tellabs, such event shall not be deemed to have
occurred for purposes of satisfying this condition unless Coherent pays Tellabs
$2,000,000 in immediately available funds; (iv) Coherent shall have received an
opinion of its counsel, in form and substance reasonably satisfactory to
Coherent, dated the Effective Time, substantially to the effect described under
"The Merger -- Certain Federal Income Tax Consequences."
 
TERMINATION
 
     The Merger Agreement may be terminated at any time prior to the Effective
Time, whether before or after approval by the stockholders of Coherent of the
matters presented in connection with the Merger (a) by the mutual written
consent of Tellabs and Coherent; (b) by either Tellabs or Coherent if the Merger
shall not have been consummated by August 15, 1998 (provided, however, that the
right to terminate the Merger Agreement under this provision shall not be
available to any party whose failure to fulfill any obligation under the Merger
Agreement has been the cause of or resulted in the failure of the Merger to
occur on or before such date); (c) by either Tellabs or Coherent, if a court of
competent jurisdiction or other Governmental Entity shall have issued a final
order, decree or ruling, or taken any other action, having the effect of
permanently restraining, enjoining or otherwise prohibiting the Merger, and all
appeals of such order, decree,
 
                                       30
<PAGE>   38
 
ruling or action shall have been exhausted or the time for appeal of such order,
decree, ruling or action shall have expired (provided, however, that the right
to terminate the Merger Agreement under this clause (c) shall not be available
to any party to the Merger Agreement which has not complied with its obligations
under the Merger Agreement relating to compliance with legal requirements
imposed on such party with respect to the Merger); (d) by either Tellabs or
Coherent, if, at the Stockholders Meeting (including any adjournment or
postponement thereof), the requisite vote of the stockholders of Coherent in
favor of the Merger Agreement and approval of the Merger shall not have been
obtained, (provided, however, that the right to terminate the Merger Agreement
under this clause (d) shall not be available to Coherent if it has not complied
with certain of its obligations under the Merger Agreement, including those set
forth under "-- Certain Covenants and Agreements -- No Solicitation"); (e) by
Tellabs, if (i) the Coherent Board or any committee thereof shall have withdrawn
or modified its recommendation of the Merger Agreement or the Merger to
Coherent's stockholders in a manner adverse to Tellabs; (ii) an Alternative
Transaction involving Coherent shall have taken place or the Coherent Board or
any committee thereof shall have recommended such an Alternative Transaction (or
a proposal or offer therefor) to the stockholders of Coherent, or shall have
publicly announced its intention to recommend such an Alternative Transaction
(or proposal or offer therefor) or to engage in such a transaction or shall have
failed to recommend against such Takeover Proposal; or (iii) a tender offer or
exchange offer for any of the outstanding shares of Coherent Common Stock shall
have been commenced or a registration statement with respect thereto shall have
been filed (other than by Tellabs or an affiliate of Tellabs) and the Coherent
Board or any committee thereof shall have recommended that the stockholders of
Coherent tender their shares in such tender or exchange offer or publicly
announced its intention to take no position with respect to such tender or
exchange offer; or (f) by Tellabs, if a breach of any representation, warranty,
covenant or agreement on the part of Coherent set forth in the Merger Agreement
shall have occurred which, if uncured, would cause the conditions of Tellabs to
the consummation of the Merger not to be satisfied and such breach is either
incapable of being cured or shall not have been cured within 20 business days
following receipt by Coherent of written notice of such breach from Tellabs; (g)
by Coherent if a breach of any representation, warranty, covenant or agreement
on the part of Tellabs set forth in the Merger Agreement shall have occurred
which, if uncured, would cause the conditions of Coherent to the consummation of
the Merger not to be satisfied and such breach is either incapable of being
cured or shall not have been cured within 20 business days following receipt by
Tellabs of written notice of such breach from Coherent; or (h) by Coherent in
connection with a Superior Proposal, as described in "-- Certain Covenants and
Agreements -- No Solicitation;" provided, that it has complied with all
applicable requirements and has paid the Termination Fee.
 
FEES AND EXPENSES
 
     Except as described below, whether or not the Merger is consummated, all
fees and expenses incurred in connection with the Merger Agreement and the
transactions contemplated thereby shall be paid by the party incurring such
expenses; provided, that all fees and expenses, other than attorneys' and
accounting fees and expenses, incurred in connection with the printing and
filing of this Proxy Statement/Prospectus and any fees required to be paid by
Tellabs in connection with any required filings under the HSR Act shall be
shared equally by Tellabs and Coherent, except that the amount of fees and
expenses to be paid by Coherent pursuant to the preceding proviso shall be
limited to $200,000.
 
     If any Takeover Proposal is made between the date of the Merger Agreement
and the termination of the Merger Agreement and if the Merger Agreement is
terminated (i) by Tellabs following a breach by Coherent as described in clause
(f) of "-- Termination," or (ii) by Tellabs or Coherent as a result of the
failure to receive the requisite vote for adoption of the Merger Agreement and
approval of the Merger by the stockholders of Coherent at the Stockholders
Meeting, then if an Alternative Transaction involving Coherent shall take place
or Coherent shall enter into any letter of intent, agreement in principle,
acquisition agreement or other similar agreement with respect to an Alternative
Transaction (each, an "Acquisition Agreement") within 12 months of such
termination, then Coherent shall pay to Tellabs a termination fee in the amount
of $12,000,000 (the "Termination Fee") simultaneously with the earlier to occur
of such Alternative Transaction or execution of such Acquisition Agreement. If
the Merger Agreement is terminated by Tellabs under certain circumstances,
including that the Coherent Board shall have withdrawn or modified its
recommendation of the Merger Agreement, as set forth in clause (e) of
"-- Termination," then Coherent shall pay to Tellabs the
 
                                       31
<PAGE>   39
 
Termination Fee no later than one business day following such termination. If
the Merger Agreement is terminated by Coherent in connection with a Superior
Proposal as described in clause (h) of "-- Termination," then Coherent shall pay
to Tellabs the Termination Fee prior to, and as a condition to, effectiveness of
such termination. Any Termination Fee payable under the Merger Agreement shall
be paid in immediately available funds.
 
     For purposes of the Merger Agreement, "Alternative Transaction" involving
Coherent means (i) a transaction or series of transactions pursuant to which any
person or group (as such term is defined under the Exchange Act), other than
Tellabs or Sub, or any affiliate thereof (a "Third Party"), acquires (or would
acquire upon completion of such transaction or series of transactions) more than
35% of the equity securities of voting power of Coherent or any of its
subsidiaries, pursuant to a tender offer or exchange offer or otherwise, (ii) a
merger, consolidation, share exchange or other business combination involving
Coherent or any of its subsidiaries pursuant to which any Third Party acquires
ownership (or would acquire ownership upon consummation of such merger,
consolidation, share exchange or other business combination) of more than 35% of
the outstanding equity securities or voting power of Coherent or any of its
subsidiaries or of the entity surviving such merger or business combination or
resulting from such consolidation, (iii) any other transaction or series of
transactions pursuant to which any Third Party acquires (or would acquire upon
completion of such transaction or series of transactions) control of assets of
Coherent or any of its subsidiaries (including, for this purpose, outstanding
equity securities of subsidiaries of such party) having a fair market value
equal to more than 35% of the fair market value of all the consolidated assets
of Coherent immediately prior to such transaction or series of transactions, or
(iv) any transaction or series of transactions pursuant to which any Third Party
acquires (or would acquire upon completion of such transaction or series of
transactions) control of the Coherent Board or by which nominees of any Third
Party are (or would be) elected or appointed to a majority of the seats on the
Coherent Board.
 
                   INTERESTS OF CERTAIN PERSONS IN THE MERGER
 
     In considering the recommendation of the Coherent Board with respect to the
Merger Agreement, the stockholders of Coherent should be aware that certain
persons, as members of Coherent's management or the Coherent Board, have
interests in the Merger in addition to their interests as stockholders of
Coherent. The Coherent Board was aware of these interests and considered them,
among other things, in approving the Merger.
 
EMPLOYMENT AGREEMENTS
 
     In order to provide incentives to senior management to remain with Coherent
at least through the Closing of the Merger and the integration of the companies,
Coherent may, pursuant to the terms of the Merger Agreement, enter into
employment agreements, to be dated as of the Effective Time, with certain of its
existing officers (including Daniel L. McGinnis, Chief Executive Officer and a
director, David Powell, President and Chief Operating Officer, Melba G. Chan,
Vice President and Chief Financial Officer, and Miles Pratt, Vice President),
pursuant to which such officers would continue, after the Effective Time, to
serve in comparable positions. Such employment agreements will have a term of
one year and will provide for base salaries the same as those in effect with
respect to such officers on February 1, 1998 unless Tellabs otherwise agrees. In
addition, pursuant to such employment agreements, for the period from January 1,
1998 until the Effective Time bonuses for such officers will be calculated
pursuant to the terms of Coherent's current fiscal 1998 bonus plan and for the
period from the Effective Time through December 31, 1998 bonuses for such
officers will be calculated in a manner to provide such officers the same
potential compensation as would have been available under the current fiscal
1998 bonus plan.
 
SEVERANCE AGREEMENT
 
     Coherent is a party to a severance and non-competition agreement with Mr.
McGinnis that will continue in effect following the Effective Time. This
agreement provides for severance payments equal to one year of Mr. McGinnis'
base salary following the termination of his employment with Coherent for
reasons other than just cause or voluntary resignation. Pursuant to this
agreement, Mr. McGinnis has agreed to refrain from
 
                                       32
<PAGE>   40
 
competing with Coherent for one year after the termination of his employment,
and Coherent's severance payments are conditioned upon adherence to such
non-competition provisions. This agreement also provides that, for the period in
which severance payments are made, Mr. McGinnis will be covered under the
medical and health insurance plans which Coherent provides for its executives.
 
TERMINATION OF ADMINISTRATIVE SERVICE AGREEMENT
 
     Coherent and Safeguard are parties to an administrative services agreement
(the "Administrative Services Agreement"), pursuant to which Safeguard provides
Coherent with administrative support services for an annual fee (the "Services
Fee") that is paid monthly and is equal to one and one-half percent of
Coherent's net sales in each calendar year up to pre-determined maximum amounts.
In 1997, Coherent paid Safeguard a Service Fee of $660,000, the maximum amount
payable for such year. The maximum amount payable in 1998 is $480,000. The
Administrative Services Agreement has a term that currently extends through
December 31, 2001 and automatically renews for annual terms thereafter unless
either party provides notice to the other within 90 days prior to the end of the
then current term. Pursuant to the Merger Agreement, Coherent is obligated to
terminate the Administrative Services Agreement effective as of the Effective
Time (or such later date, up to 180 days following the Effective Time, as
requested by Tellabs), following which time Coherent will have no further
obligations thereunder other than the payment to Safeguard of a termination fee
equal to the Service Fee payable with respect to the period commencing on the
date of termination and ending on December 31, 1998. Charles A. Root and Warren
V. Musser, each directors of Coherent, are affiliated with Safeguard.
 
INDEMNIFICATION
 
     For six years after the Effective Time, Tellabs and Coherent have agreed
that the Surviving Corporation will maintain certain rights to indemnification
in favor of the current and former directors or officers of Coherent, and
Tellabs has agreed to perform such obligations to the extent the Surviving
Corporation fails to do so. Tellabs and Coherent have agreed to maintain
Coherent's existing directors' and officers' liability insurance policy or
provide a similar policy, subject to certain limitations. See "Indemnification;
Directors' and Officers' Insurance" under "TERMS OF THE MERGER
AGREEMENT -- Certain Covenants and Agreements."
 
                             STOCKHOLDER AGREEMENTS
 
     The following is a summary of certain provisions of the Safeguard
Stockholder Agreement and the form of Stockholder Agreement entered into between
Tellabs and the other Stockholders, conformed copies of which are attached
hereto as Annex II and Annex III, respectively, and incorporated herein by
reference. This summary is qualified in its entirety by reference to the
Stockholder Agreements. Stockholders of Coherent are urged to read the
Stockholder Agreements in their entirety.
 
     Concurrently with the execution of the Merger Agreement, in order to induce
Tellabs to enter into the Merger Agreement, Safeguard, the owner of 4,843,342
(approximately 31.2%) of the outstanding shares of Coherent Common Stock as of
the Record Date, and the other Stockholders, who are current directors of
Coherent and who collectively owned an aggregate of 1,160,920 (approximately
7.5%) of the outstanding shares of Coherent Common Stock as of the Record Date,
entered into Stockholder Agreements with Tellabs. Subsequent to the execution of
the Stockholder Agreements and prior to the Record Date, with the approval of
Tellabs, Mr. McGinnis transferred 8,958 shares of Coherent Common Stock held by
him to each of his three daughters (for a total of 26,874 shares of Coherent
Common Stock, approximately 0.2% of the outstanding shares of Coherent Common
Stock as of the Record Date), each of whom has agreed to be bound by the terms
and conditions of the Stockholder Agreement entered into by Mr. McGinnis.
 
     The Stockholder Agreements provide, among other things, that: (a) at the
Stockholders Meeting (or at any adjournment thereof) or in any other
circumstances upon which a vote, consent or other approval with respect to the
Merger or the Merger Agreement is sought, the Stockholder shall vote (or cause
to be voted) the Subject Shares in favor of the Merger, the adoption of the
Merger Agreement and the approval of the terms thereof and each of the other
transactions contemplated by the Merger Agreement; (b) at any meeting
 
                                       33
<PAGE>   41
 
of stockholders of Coherent or at any adjournment thereof or in any other
circumstances upon which the Stockholder's vote, consent or other approval is
sought, the Stockholder shall vote (or cause to be voted) the Subject Shares
against (i) any merger agreement or merger (other than the Merger Agreement and
the Merger), consolidation, combination, sale of substantial assets,
reorganization, recapitalization, dissolution, liquidation or winding up of or
by Coherent or any subsidiary thereof or any other Takeover Proposal or (ii) any
amendment of the Coherent Charter or the Coherent By-laws or other proposal or
transaction involving Coherent or any of its subsidiaries, which amendment or
other proposal or transaction would in any manner impede, frustrate, prevent or
nullify the Merger, the Merger Agreement or any of the other transactions
contemplated by the Merger Agreement or change in any manner the voting rights
of any class of capital stock of Coherent; and (c) the Stockholder will not (i)
Transfer, or enter into any contract, option or other arrangement (including any
profit-sharing arrangement) with respect to the Transfer of the Subject Shares
to any person or (ii) enter into any voting arrangement, whether by proxy,
voting agreement or otherwise, in relation to the Subject Shares, and agrees not
to commit or agree to take any of the foregoing actions. The Stockholder
Agreements bind the actions of the Stockholders only in their capacity as
Coherent stockholders.
 
                      DESCRIPTION OF TELLABS COMMON STOCK
 
     The statements set forth under this heading with respect to the DGCL,
Tellabs' Restated Certificate of Incorporation (the "Tellabs Charter") and
Tellabs' Amended and Restated By-laws (the "Tellabs By-laws") (copies of which
have been filed as Exhibits to the Registration Statement) are brief summaries
thereof and do not purport to be complete; such statements are subject to the
detailed provisions of the DGCL, the Tellabs Charter and the Tellabs By-laws.
See "AVAILABLE INFORMATION."
 
CAPITAL STOCK
 
     The authorized capital stock of Tellabs consists of 500,000,000 shares of
Tellabs Common Stock and 5,000,000 shares of Preferred Stock, $.01 par value
(the "Tellabs Preferred Stock"). At the close of business on February 16, 1998,
there were 181,771,682 shares of Tellabs Common Stock issued and outstanding and
no shares of Tellabs Preferred Stock issued or outstanding.
 
     The Tellabs Board is authorized by the Tellabs Charter to issue Tellabs
Preferred Stock in one or more series, from time to time, with such voting
powers, full or limited, or without voting powers, and with such designations,
preferences and relative, participating, optional or other special rights, and
qualifications, limitations or restrictions thereof, as may be stated in the
resolution or resolutions providing for the issuance of Tellabs Preferred Stock
adopted by the Tellabs Board. The issuance of shares of Tellabs Preferred Stock
would affect the relative rights of Tellabs Common Stock, depending upon the
exact terms, qualifications, limitations and relative rights and preferences, if
any, of the shares of Tellabs Preferred Stock as determined by the Tellabs Board
at the time of issuance.
 
DIVIDEND RIGHTS
 
     The holders of Tellabs Common Stock are entitled to receive ratably, from
funds legally available for the payment thereof, dividends when and as declared
by resolution of the Tellabs Board, subject to any preferential dividend rights
of the holders of any outstanding series of Tellabs Preferred Stock. Tellabs has
never paid cash dividends and currently has no plans to pay cash dividends in
the near future. See "SUMMARY -- Market Prices."
 
VOTING RIGHTS
 
     The holders of Tellabs Common Stock are entitled to one vote for each share
held on each matter submitted to a vote of stockholders and do not have
cumulative voting rights. Accordingly, holders of a majority of the shares of
Tellabs Common Stock entitled to vote in any election of directors may elect all
of the directors then standing for election. See "-- Change of Control" for
information regarding Tellabs' classified Board of Directors. All elections and
matters submitted to a vote of stockholders are decided by the
 
                                       34
<PAGE>   42
 
affirmative vote of a majority of the shares present (in person or by proxy) and
entitled to vote at a meeting at which a quorum is present, except as otherwise
required by the DGCL or the Tellabs Charter. The Tellabs Charter prohibits
action by holders of Tellabs Common Stock to be taken by written consent.
 
     Under Delaware law, the affirmative vote of a majority of the outstanding
shares is sufficient for amendments to the certificate of incorporation, unless
the certificate of incorporation specifies a higher percentage. Article Sixth of
the Tellabs Charter provides that the provisions of Article Fifth or Article
Sixth of the Tellabs Charter (Article Fifth relates to amendment of the Tellabs
By-laws and Article Sixth relates to the election of the Tellabs Board and
meetings of stockholders of Tellabs) may not be repealed or amended unless such
action is approved by the affirmative vote of the holders of 75% of the voting
power of the then outstanding shares of Tellabs. Article Fifth of the Tellabs
Charter provides that the Tellabs By-laws may be amended or repealed by the
Tellabs Board, or by the affirmative vote of the holders of 75% of the voting
power of the then outstanding shares of Tellabs.
 
CHANGE OF CONTROL
 
     The DGCL, the Tellabs Charter and the Tellabs By-laws contain provisions
that could discourage or make more difficult a change of control of Tellabs.
 
     Charter and By-law Provisions.  The Tellabs Charter and the Tellabs By-laws
provide that special meetings of stockholders may be called by the President or
by the President upon the written request of a majority of the Tellabs Board.
Stockholders of Tellabs are not entitled to request a special meeting.
 
     The Tellabs By-laws provide that nominations for the election of directors
may be made by the Tellabs Board or a committee appointed by the Tellabs Board
or by any stockholder entitled to vote in the election of directors generally.
However, any stockholder entitled to vote in the election of directors generally
may nominate one or more persons for election as directors at a meeting of
stockholders of Tellabs only if written notice of such stockholder's intent to
make such nomination or nominations has been given, either by personal delivery
or by mail, postage prepaid, to Tellabs not later than (i) with respect to an
election to be held at an annual meeting of stockholders, 120 days in advance of
the date of the proxy statement released to stockholders in connection with the
previous year's annual meeting of stockholders, and (ii) with respect to an
election to be held at a special meeting of stockholders for the election of
directors, at least 15 days before the date that the proxy statement in
connection with such meeting is to be mailed to the stockholders. Each such
notice must set forth: (a) the name and address of the stockholder who intends
to make the nomination and of the persons or persons to be nominated; (b) a
representation that the stockholder is a holder of record of Tellabs stock
entitled to vote at such meeting and intends to appear in person or by proxy at
the meeting to nominate the person or persons specified in the notice; (c) a
description of all arrangements or understandings between the stockholder and
each nominee and any other person or persons (naming such person or persons)
pursuant to which the nomination or nominations are to be made by the
stockholder; (d) such other information regarding each nominee proposed by such
stockholder as would be required to be included in a proxy statement filed
pursuant to the proxy rules of the SEC, had the nominee been nominated, or
intended to be nominated, by the Tellabs Board; and (e) the consent of each
nominee to serve as a director if so elected. The presiding officer at the
meeting may refuse to acknowledge the nomination of any person not made in
compliance with the foregoing procedure.
 
     Under the Tellabs Charter and the Tellabs By-laws, the Tellabs Board is
currently fixed at eight members. In addition, the Tellabs Board is divided into
three classes, as nearly equal in number as possible. At each annual meeting of
stockholders, directors elected to succeed those in the class whose terms then
expire are elected for three-year terms, so that the term of office of one class
of directors will expire each year. Vacancies which occur on the Tellabs Board
may be filled by the Tellabs Board and directors elected to fill a vacancy will
hold office for the remainder of the term of the class to which they have been
elected. If the number of directors is modified, any increase or decrease in
directorships would be apportioned among the classes so as to make all classes
as nearly equal in number as possible. These staggered terms for directors
extend the time required to elect a majority of directors from one to two years.
It would be impossible, assuming no resignations or removals of directors, for
the stockholders of Tellabs to change a majority of the
 
                                       35
<PAGE>   43
 
directors of Tellabs at any annual meeting should they consider such a change
desirable, unless Article Sixth of the Tellabs Charter is amended by action of
at least 75% of the voting power of the then outstanding shares of Tellabs. The
stockholders of Tellabs have the ability to remove directors only for cause, and
only by action of holders of 75% of the voting power of the then outstanding
shares of Tellabs.
 
     The Tellabs Charter provides that the Tellabs Board, when evaluating any
offer of another person to (a) make a tender or exchange offer for any equity
security of Tellabs, (b) merge or consolidate Tellabs with another corporation,
or (c) purchase or otherwise acquire all or substantially all of the properties
and assets of Tellabs, may in connection with the exercise of its judgment in
determining what is in the best interests of Tellabs and its stockholders, give
due consideration to all relevant factors, including without limitation the
social and economic effects on the employees, customers, suppliers and other
constituencies of Tellabs and its subsidiaries and in the communities in which
Tellabs and its subsidiaries operate or are located.
 
     DGCL.  Section 203 of the DGCL prohibits generally a public Delaware
corporation, including Tellabs, from engaging in a Business Combination (as
defined herein) with an Interested Stockholder (as defined herein) for a period
of three years after the date of the transaction in which an Interested
Stockholder became such, unless: (i) the board of directors of such corporation
approved, prior to the date such Interested Stockholder became such, either such
Business Combination or such transaction; (ii) upon consummation of such
transaction, such Interested Stockholder owns at least 85% of the voting shares
of such corporation (excluding specified shares); or (iii) such Business
Combination is approved by the board of directors of such corporation and
authorized by the affirmative vote (at an annual or special meeting and not by
written consent) of at least 66 2/3% of the outstanding voting shares of such
corporation (excluding shares held by such Interested Stockholder). For purposes
of Section 203 of the DGCL, a "Business Combination" includes: (i) mergers,
consolidations and sales or other dispositions of 10% or more of the assets of a
corporation to or with an Interested Stockholder; (ii) certain transactions
resulting in the issuance or transfer to an Interested Stockholder of any stock
of such corporation or its subsidiaries; and (iii) other transactions resulting
in a disproportionate financial benefit to an Interested Stockholder, where an
"Interested Stockholder" is a person who, together with its affiliates and
associates, owns (or within a three-year period did own) 15% or more of a
corporation's stock entitled to vote generally in the election of directors.
 
LIQUIDATION RIGHTS
 
     Upon the liquidation, dissolution or winding up of the affairs of Tellabs,
the holders of Tellabs Common Stock are entitled to share ratably in all assets
of Tellabs available for distribution to such holders after the payment of all
debts and other liabilities, subject to the prior rights of the holders of any
outstanding series of Tellabs Preferred Stock.
 
MISCELLANEOUS
 
     The holders of Tellabs Common Stock do not have preemptive, subscription,
redemption or conversion rights. The outstanding shares of Tellabs Common Stock
are, and the shares of Tellabs Common Stock to be delivered pursuant to the
Merger upon delivery will be, duly authorized, validly issued, fully paid and
nonassessable. The outstanding shares of Tellabs Common Stock are, and the
shares of Tellabs Common Stock to be delivered pursuant to the Merger upon
notice of issuance will be, listed on Nasdaq. Harris Trust and Savings Bank is
the transfer agent and registrar for Tellabs Common Stock.
 
                     COMPARISON OF THE RIGHTS OF HOLDERS OF
                 TELLABS COMMON STOCK AND COHERENT COMMON STOCK
 
     The statements set forth under this heading with respect to the DGCL,
Coherent's Certificate of Incorporation (the "Coherent Charter") and By-laws
(the "Coherent By-laws"), the Tellabs Charter and the Tellabs By-laws (copies of
which have been filed as Exhibits to the Registration Statement) are brief
summaries thereof and do not purport to be complete; such statements are subject
to the detailed provisions of the DGCL, the Coherent Charter, the Coherent
By-laws, the Tellabs Charter and the Tellabs By-laws. See "AVAILABLE
INFORMATION."
 
                                       36
<PAGE>   44
 
GENERAL
 
     The following summary compares certain rights of the holders of Coherent
Common Stock to the rights of the holders of Tellabs Common Stock. The rights of
holders of Coherent Common Stock are governed principally by the DGCL, the
Coherent Charter and the Coherent By-laws. Upon consummation of the Merger, such
stockholders will become holders of Tellabs Common Stock, and their rights will
be governed principally by the DGCL, the Tellabs Charter and the Tellabs
By-laws. In most respects, the rights of Tellabs stockholders are similar to
those of Coherent stockholders. The following summarizes the material
differences between the rights of holders of Coherent Common Stock and Tellabs
Common Stock.
 
DIVIDENDS
 
     Under the DGCL, a corporation may pay dividends out of surplus (defined as
the excess, if any, of net assets over capital) or, if no such surplus exists,
out of its net profits for the fiscal year in which such dividends are declared
and/or for its preceding fiscal year; provided, that dividends may not be paid
out of net profits if the capital of such corporation is less than the aggregate
amount of capital represented by the issued and outstanding stock of all classes
having a preference upon the distribution of assets.
 
     Neither Tellabs nor Coherent has ever paid cash dividends and currently
neither has plans to pay cash dividends in the near future. See "DESCRIPTION OF
TELLABS COMMON STOCK -- Dividend Rights" and "SUMMARY -- Market Prices."
 
VOTING RIGHTS
 
     Each share of Coherent Common Stock and each share of Tellabs Common Stock
is entitled to one vote on each matter submitted to a vote of stockholders.
Neither the holders of Coherent Common Stock nor the holders of Tellabs Common
Stock have cumulative voting rights in the election of directors.
 
     The Coherent directors are elected by the affirmative vote of the plurality
of the votes cast (in person or by proxy) in the election of directors at a
meeting of stockholders at which a quorum is present. The Tellabs directors are
elected by the affirmative vote of the majority of the shares present (in person
or by proxy) and entitled to vote in the election of directors at a meeting of
stockholders at which a quorum is present. For additional information regarding
the comparable voting rights of the holders of Tellabs Common Stock, see
"DESCRIPTION OF TELLABS COMMON STOCK -- Voting Rights."
 
DIRECTORS
 
     Number and Election of Directors.  Under the DGCL, the charter document or
by-laws of a corporation may specify the number of directors. The Coherent
Charter and the Coherent By-laws provide that the Coherent Board shall consist
of such number of directors as the Coherent Board shall designate, with the
number being three in the absence of any such designation. The current number of
directors has been designated by the Coherent Board to be seven. The number of
directors may be changed only by resolution of the Coherent Board. The Coherent
Board may fill vacancies and newly created directorships. Under the Tellabs
Charter and the Tellabs By-laws the number of directors on the Tellabs Board is
currently fixed at eight members. The size of the Tellabs Board may be changed
only by amending the Tellabs By-laws. The Tellabs Board may fill vacancies and
newly created directorships.
 
     Classification.  Directors on the Tellabs Board serve staggered terms of
office. The Tellabs Charter provides that the Tellabs Board shall be divided,
with respect to the terms of office for the individual directors, into three
classes, as nearly equal as possible, with each class to serve a staggered
three-year term. Directors on the Coherent Board do not serve staggered terms,
and are elected to one-year terms of office.
 
     Removal.  In the absence of express director removal provisions, the DGCL
provides that directors may be removed, with or without cause, by a majority
vote of the holders of the voting stock of a corporation entitled to vote at the
meeting at which the vote is taken, except that, with respect to a staggered
board, in the absence of contrary provisions in a corporation's certificate of
incorporation, stockholders may only remove a director for cause. The Tellabs
Charter expressly provides for the removal (only for cause) of any director or
 
                                       37
<PAGE>   45
 
directors on the Tellabs Board only by the affirmative vote of either the
holders of 75% of the voting power of the then outstanding shares of capital
stock of Tellabs entitled to vote in the election of directors or by a majority
of the Tellabs Board. The Coherent Charter does not contain any provisions
relating to removal of directors; therefore, such removal shall be governed by
the DGCL.
 
     Nominations.  Neither the Coherent By-laws nor the Coherent Charter contain
provisions relating to the nominations of directors. See "Charter and By-law
Provisions" under "DESCRIPTION OF TELLABS COMMON STOCK -- Change of Control" for
a description of the provisions of the Tellabs Charter and the Tellabs By-laws
relating to the nomination of directors.
 
     Liability of Directors.  The DGCL permits a corporation to limit the
personal liability of its directors, with specified exceptions. The DGCL permits
a corporation to include in its certificate of incorporation a provision
limiting or eliminating the liability of its directors to such corporation or
its stockholders for monetary damages arising from a breach of fiduciary duty,
except for: (i) a breach of the duty of loyalty to the corporation or its
stockholders; (ii) acts or omissions not in good faith or constituting
intentional misconduct or a knowing violation of law; (iii) a declaration of a
dividend or the authorization of the repurchase or redemption of stock in
violation of the DGCL; or (iv) any transaction from which the director derived
an improper personal benefit. Both the Coherent Charter and the Tellabs Charter
eliminate director liability to the maximum extent permitted by the DGCL.
 
CALL OF SPECIAL MEETINGS
 
     A special meeting of the stockholders of Coherent may be called by the
Coherent Board or the Chief Executive Officer of Coherent. Coherent stockholders
may not request a special meeting. Special meetings of stockholders of Tellabs
may be called only by the President of Tellabs or by the President of Tellabs
upon the written request of a majority of the Tellabs Board. Tellabs
stockholders may not request a special meeting.
 
ACTION OF STOCKHOLDERS WITHOUT A MEETING
 
     The DGCL permits the stockholders of a corporation to consent in writing to
any action without a meeting, unless the certificate of incorporation of such
corporation provides otherwise, provided such consent is signed by stockholders
having at least the minimum number of votes required to authorize such action at
a meeting of stockholders. The Coherent By-laws specifically allow the
stockholders of Coherent to take action without a meeting, without notice and
without a vote if written consents setting forth the action to be taken are
signed by the holders of outstanding stock having at least the minimum number of
votes that would be necessary to authorize the action at a meeting of
stockholders called for that purpose at which all shares entitled to vote
thereon were present and voted. The Tellabs Charter prohibits action by the
holders of Tellabs Common Stock to be taken by written consent.
 
STOCKHOLDER PROPOSALS
 
     The Coherent By-laws restrict business that may be transacted at a special
meeting of Coherent stockholders to the subjects stated in the notice of the
meeting. As described above, the Tellabs Charter restricts the manner in which
nominations for director may be made by stockholders. See "Charter and By-Law
Provisions" under "DESCRIPTION OF TELLABS COMMON STOCK -- Change of Control."
 
AMENDMENT TO CERTIFICATE OF INCORPORATION
 
     Under the DGCL, the certificate of incorporation of a corporation may be
amended by resolution of the board of directors and the affirmative vote of the
holders of a majority of the outstanding shares of stock entitled to vote
thereon. With respect to any amendment to the certificate of incorporation of a
corporation that would adversely affect a particular class or series of stock,
the DGCL requires the separate approval by the holders of the affected class or
series of stock, voting together as a single class. The Coherent Charter
provides that it may be amended in the manner prescribed by the DGCL. For a
description of the requirements related to the amendment of the Tellabs Charter,
see "DESCRIPTION OF TELLABS COMMON STOCK -- Voting Rights."
 
                                       38
<PAGE>   46
 
AMENDMENT TO BY-LAWS
 
     The Coherent By-laws may be amended or repealed by the affirmative vote of
a majority of the Coherent Board present at any meeting or by the stockholders
at any meeting. The Tellabs By-laws may be amended or replaced by the Tellabs
Board or by the affirmative vote of holders of at least 75% of the voting power
of the then outstanding shares of Tellabs capital stock entitled to vote in the
election of directors.
 
APPROVAL OF MERGERS AND ASSET SALES
 
     Under the DGCL, unless required by its certificate of incorporation
(neither the Coherent Charter nor the Tellabs Charter contain such a
requirement), no vote of the stockholders of a constituent corporation surviving
a merger is necessary to authorize such merger if: (i) the agreement of merger
does not in any way amend the certificate of incorporation of such constituent
corporation; (ii) each share of stock of such constituent corporation
outstanding immediately prior to such merger is to be an identical outstanding
or treasury share of the surviving corporation after such merger; (iii) either
no shares of Common Stock of the surviving corporation and no shares, securities
or obligations convertible into such Common Stock are to be issued under the
plan of merger, or the number of shares of Common Stock issued or so issuable
does not exceed 20% of the number thereof outstanding immediately prior to such
merger; and (iv) certain other conditions are satisfied. In addition, the DGCL
provides that a parent corporation that is the record holder of at least 90% of
the outstanding shares of each class of stock of a subsidiary may merge such
subsidiary into such parent corporation without the approval of such
subsidiary's stockholders or board of directors.
 
     The Tellabs Charter provides that the Tellabs Board, when evaluating any
offer of another person to (a) make a tender or exchange offer for any equity
security of Tellabs, (b) merge or consolidate Tellabs with another corporation,
or (c) purchase or otherwise acquire all or substantially all of the properties
and assets of Tellabs, may in connection with the exercise of its judgment in
determining what is in the best interests of Tellabs and its stockholders, give
due consideration to all relevant factors, including without limitation the
social and economic effects on the employees, customers, suppliers and other
constituencies of Tellabs and its subsidiaries and in the communities in which
Tellabs and its subsidiaries operate or are located. Neither the Coherent
Charter nor the Coherent By-laws contain a similar provision.
 
INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
     Section 145 of the DGCL permits a corporation to indemnify any person who
was or is a party or is threatened to be made a party to: (i) any action, suit
or proceeding, whether civil, criminal, administrative or investigative (other
than an action by or in the right of the corporation) against expenses
(including attorneys' fees), judgments, fines and reasonable settlement amounts
if such person acted in good faith and reasonably believed that his or her
actions were in or not opposed to the best interests of such corporation and,
with respect to any criminal proceeding, had no reasonable cause to believe that
his or her conduct was unlawful; or (ii) any derivative action or suit on behalf
of such corporation against expenses (including attorneys' fees) actually and
reasonably incurred in connection with the defense or settlement of such action
or suit, if such person acted in good faith and reasonably believed that his or
her actions were in or not opposed to the best interests of such corporation.
With respect to derivative suits and actions, in the event that a person is
adjudged to be liable to the corporation, the DGCL prohibits indemnification
unless, and then only to the extent that, either the Delaware Court of Chancery
or the court in which such derivative action or suit was brought determines that
such person is entitled to indemnification for those expenses which that court
deems proper. To the extent that a representative of a corporation has been
successful on the merits or otherwise in the defense of a third party or
derivative action, indemnification for actual and reasonable expenses incurred
is mandatory.
 
     The Coherent Charter provides for the indemnification of directors and
officers of Coherent to the maximum extent permitted by the DGCL. The Coherent
By-laws authorize the Coherent Board, from time to time, to indemnify employees
and agents of Coherent to the maximum extent permitted by the Coherent By-laws
with respect to the indemnification of officers and directors. The Coherent
By-laws provide for the advancement of certain expenses, provided that, if
required by the DGCL, the officer or director deliver to
 
                                       39
<PAGE>   47
 
Coherent an undertaking to reimburse all amounts so advanced to which the
officer or director is determined by a court not to be entitled.
 
     The Tellabs By-laws provide for indemnification of directors and officers
of Tellabs to the maximum extent permitted under the DGCL. The Tellabs By-laws
further provide for the advancement of certain expenses upon receipt of an
undertaking to repay such amount if it shall ultimately be determined that such
director or officer is not entitled to be indemnified by Tellabs.
 
ANTI-TAKEOVER PROVISIONS
 
     Section 203 of the DGCL prohibits generally a public Delaware corporation
from engaging in a Business Combination with an Interested Stockholder for a
period of three years after the date of the transaction in which an Interested
Stockholder became such, unless: (i) the board of directors of such corporation
approved, prior to the date such Interested Stockholder became such, either such
Business Combination or such transaction; (ii) upon consummation of such
transaction, such Interested Stockholder owns at least 85% of the voting shares
of such corporation (excluding specified shares); or (iii) such Business
Combination is approved by the board of directors of such corporation and
authorized by the affirmative vote (at an annual or special meeting and not by
written consent) of at least 66 2/3% of the outstanding voting shares of such
corporation (excluding shares held by such Interested Stockholder).
 
     The Coherent Charter provides that Section 203 of the DGCL shall not be
applicable to Coherent. Neither the Tellabs Charter nor Tellabs By-Laws contain
a similar provision. For information on the provisions of the DGCL with respect
to certain Business Combinations, see "DGCL" under "DESCRIPTION OF TELLABS
COMMON STOCK -- Change of Control."
 
LIQUIDATION
 
     The Coherent Charter does not address liquidation, dissolution or winding
up of Coherent. Upon the liquidation, dissolution or winding up of the affairs
of Tellabs, the holders Tellabs Common Stock are entitled to share ratably in
all remaining assets of Tellabs available for distribution to such holders,
subject to the prior rights of the holders of any outstanding series of Tellabs
Preferred Stock. See "DESCRIPTION OF TELLABS COMMON STOCK -- Liquidation
Rights."
 
MISCELLANEOUS
 
     Neither shares of Coherent Common Stock nor shares of Tellabs Common Stock
have preemptive, subscription, redemption or conversion rights.
 
                              BUSINESS OF TELLABS
 
     Tellabs designs, manufactures, markets and services voice and data
transport and network access systems that are used worldwide by public telephone
companies, long-distance carriers, alternate service providers, cellular and
other wireless service providers, cable operators, government agencies,
utilities and business end-users.
 
     Products provided by Tellabs include digital cross-connect systems, managed
digital networks, network access and wireless system products. Digital
cross-connect systems include Tellabs' TITAN (a registered trademark of Tellabs
Operations, Inc.) 5500 and 5300 series of digital cross-connect systems. Managed
digital networks include Tellabs' MartisDXX (a Finnish trademark of Tellabs Oy)
integrated access and transport system, statistical multiplexers, packet
switches, and T1 multiplexers, and network management systems. Network access
products include digital signal processing products such as echo cancelers and
T-coders; special service products such as voice frequency products; and local
access products such as the CABLESPAN (a registered trademark of Tellabs
Operations, Inc.) system.
 
     Tellabs' products are sold in both the domestic and international
marketplaces (under the Tellabs name and trademarks and under private labels)
through Tellabs' field sales force and selected distributors to a major
 
                                       40
<PAGE>   48
 
customer base. This base includes Regional Bell Operating Companies, independent
telephone companies, interexchange carriers, local telephone administrations,
local exchange carriers, original equipment manufacturers, cellular and other
wireless service companies, cable operators, alternate service providers, system
integrators, government agencies, and business end-users ranging from small
businesses to Fortune 500 companies.
 
     Tellabs was incorporated in Delaware in 1992 in connection with the
reincorporation of its predecessor corporation from an Illinois corporation to a
Delaware corporation. Tellabs' predecessor corporation began operations in 1975
and became a public company in 1980.
 
     Tellabs' principal executive offices are located at 4951 Indiana Avenue,
Lisle, Illinois 60532-1698 and its telephone number is (630) 378-8800. For
further information concerning Tellabs, see "SUMMARY -- Tellabs, Inc. Selected
Consolidated Financial Data," "AVAILABLE INFORMATION" and "INCORPORATION OF
DOCUMENTS BY REFERENCE."
 
                              BUSINESS OF COHERENT
 
     Coherent develops, manufactures and markets voice quality enhancement
products for wireless (including digital cellular and personal communication
systems), satellite-based, cable communication systems, and wireline
telecommunications systems throughout the world. Coherent is a worldwide leader
in state of the art voice enhancement technology, spanning transmission products
and conference products. Coherent's products utilize proprietary high speed
reduced instruction set computer microchips along with proprietary software to
enhance the quality of voice communications during a telephone call. Coherent's
products are compatible with domestic and foreign telecommunications systems.
 
     Coherent's transmission products include echo cancellation platforms and
associated network software such as stand-alone echo cancellers and integrated
echo cancellers that enhance voice quality in several ways, including
eliminating electrical and acoustic echoes inherent in telecommunications
systems. Coherent's transmission products are designed to support a variety of
speech enhancement functions in addition to echo cancellation. Sculptured
Sound(R) is designed to automatically optimize speech levels in a variety of
local, long distance and cellular networks. Enhanced Audio Plus(TM), Netreach(R)
and other software products may be incorporated into new transmission products
or marketed to existing transmission product customers of Coherent that desire
enhanced audio quality and functionality. Coherent sells its transmission
products to network operators and other end-users through its direct sales force
and third-party distributors, and also to other telecommunications equipment
manufacturers through its direct sales force. Coherent's products are used
globally by major wireless and wireline telecommunications companies and network
operators, including AT&T Wireless, British Telecom, Cable & Wireless, Cellular
One, Cisco System, Deutsche Telekom, France Telecom, KDD, Mercury, Nokia,
NORTEL, Telia, and Telmex, among the extensive list.
 
     Coherent's conference products include equipment and related software used
in teleconferencing and in video conferencing applications, such as distance
learning and business television. These products include the ConferenceMaster(R)
and Voicecrafter(TM) lines of audio systems. ConferenceMaster provides group
teleconferencing facilities for meeting rooms, and Voicecrafter provides
full-duplex, high quality audio for videoconference systems. Coherent utilizes
an indirect distribution strategy in marketing conference products to end-users
through a network of more than 100 independent dealers and distributors
throughout the world. Coherent also directly markets conference products to OEMs
and systems integrators, such as Intel, Lucent Technologies, AT&T, British
Telecom, CBCI Telecom and others.
 
     Coherent has been ISO-9001 registered since 1994. ISO-9001 is an
international quality standard relating to the design, manufacture and servicing
of products. In order to obtain registration to this standard, a company must
submit to regular independent audits of its processes and procedures. ISO-9001
ensures a higher standard of quality, and is required by many international
customers as a condition to commencing and maintaining a business relationship.
 
     Coherent was incorporated in Delaware in 1990 and became a public company
in 1994. Prior to becoming a public company, Coherent was a 99.6% owned
subsidiary of Safeguard. Coherent's principal executive
 
                                       41
<PAGE>   49
 
offices are located at 45085 University Drive, Ashburn, Virginia 20147, and its
telephone number is (703) 729-6400. For further information concerning Coherent,
see "SUMMARY -- Coherent Communications Systems Corporation Selected
Consolidated Financial Data," "AVAILABLE INFORMATION" and "INCORPORATION OF
DOCUMENTS BY REFERENCE."
 
                                    EXPERTS
 
     The consolidated financial statements of Tellabs at January 2, 1998 and for
the year then ended, incorporated by reference in Tellabs' Annual Report on Form
10-K for the year ended January 2, 1998, which is referred to and made a part of
this Proxy Statement/Prospectus and Registration Statement, were audited by
Ernst & Young, independent auditors, as set forth in their report thereon and
are incorporated by reference herein in reliance upon such firm as experts in
accounting and auditing.
 
     The financial statements incorporated by reference to the Annual Report on
Form 10-K of Tellabs for the periods ending on or prior to December 27, 1996
were audited by Grant Thornton LLP, independent auditors, as stated in their
reports, which are incorporated by reference herein, and have been so
incorporated in reliance upon the reports of such firm given upon their
authority as experts in accounting and auditing.
 
     The consolidated financial statements of Coherent as of December 31, 1997
and 1996 and for each of the years in the three-year period ended December 31,
1997, are incorporated by reference herein in reliance upon the report of KPMG,
independent certified public accountants, incorporated by reference herein, and
upon the authority of said firm as experts in accounting and auditing.
 
     Representatives of KPMG are expected to be present at the Coherent Special
Meeting, will have the opportunity to make a statement if they desire to do so
and will be available to respond to appropriate questions.
 
                                 LEGAL OPINIONS
 
     The validity of the shares of Tellabs Common Stock being offered hereby is
being passed for Tellabs by Carol Coghlan Gavin, Vice President and General
Counsel of Tellabs. Ms. Gavin is a stockholder of Tellabs and holds options to
purchase shares of Tellabs Common Stock.
 
     It is a condition to the consummation of the Merger that Sidley & Austin,
counsel to Tellabs, and Morgan, Lewis & Bockius LLP, counsel to Coherent, each
deliver opinions concerning certain federal income tax consequences of the
Merger, dated as of the Effective Time.
 
                                       42
<PAGE>   50
 
                                                                         Annex I
 
                          AGREEMENT AND PLAN OF MERGER
 
                                  BY AND AMONG
 
                                 TELLABS, INC.
                            A DELAWARE CORPORATION,
 
                              CARDINAL MERGER CO.
                    A DELAWARE CORPORATION AND WHOLLY OWNED
                          SUBSIDIARY OF TELLABS, INC.,
 
                                      AND
 
                  COHERENT COMMUNICATIONS SYSTEMS CORPORATION
                             A DELAWARE CORPORATION
 
                         DATED AS OF FEBRUARY 16, 1998
<PAGE>   51
 
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                                                         PAGE
                                                                                         -----
<S>            <C>             <C>                                                       <C>
ARTICLE I      THE MERGER.............................................................     I-1
               Section 1.1.    Merger.................................................     I-1
               Section 1.2.    Closing; Effective Time................................     I-2
               Section 1.3.    Effects of the Merger..................................     I-2
               Section 1.4.    Directors and Officers.................................     I-2
ARTICLE II     CONVERSION OF SECURITIES...............................................     I-2
               Section 2.1.    Conversion of Capital Stock............................     I-2
               Section 2.2.    Exchange of Certificates...............................     I-3
               Section 2.3.    No Dissenters Rights...................................     I-5
ARTICLE III    REPRESENTATIONS AND WARRANTIES OF THE COMPANY..........................     I-5
               Section 3.1.    Organization...........................................     I-5
               Section 3.2.    Company Subsidiaries and Joint Ventures................     I-5
               Section 3.3.    Company Capital Structure..............................     I-6
                               Authority; No Conflict; Required Filings and
               Section 3.4.    Consents...............................................     I-6
               Section 3.5.    SEC Filings; Financial Statements......................     I-7
               Section 3.6.    Absence of Undisclosed Liabilities.....................     I-8
               Section 3.7.    Absence of Certain Changes or Events...................     I-8
               Section 3.8.    Taxes..................................................     I-8
               Section 3.9.    Properties.............................................     I-9
               Section 3.10.   Intellectual Property..................................     I-9
               Section 3.11.   Agreements, Contracts and Commitments..................    I-10
               Section 3.12.   Litigation.............................................    I-10
               Section 3.13.   Environmental Matters..................................    I-10
               Section 3.14.   Employee Benefit Plans.................................    I-11
               Section 3.15.   Compliance with Laws...................................    I-12
               Section 3.16.   Pooling................................................    I-12
               Section 3.17.   Affiliates.............................................    I-12
               Section 3.18.   Interested Party Transactions..........................    I-12
               Section 3.19.   Registration Statement; Proxy Statement/Prospectus.....    I-12
               Section 3.20.   No Excess Parachute Payments...........................    I-13
               Section 3.21.   Opinion of Financial Advisor...........................    I-13
               Section 3.22.   Section 203 of the DGCL Not Applicable.................    I-13
               Section 3.23.   Voting Requirements....................................    I-13
               Section 3.24.   Brokers................................................    I-13
               Section 3.25.   Additional Disclosure..................................    I-13
ARTICLE IV     REPRESENTATIONS AND WARRANTIES OF PARENT AND SUB.......................    I-13
               Section 4.1.    Organization...........................................    I-13
               Section 4.2.    Parent Subsidiaries....................................    I-14
               Section 4.3.    Parent Capital Structure...............................    I-14
                               Authority; No Conflict; Required Filings and
               Section 4.4.    Consents...............................................    I-14
               Section 4.5.    SEC Filings; Financial Statements......................    I-15
               Section 4.6.    Absence of Undisclosed Liabilities.....................    I-15
               Section 4.7.    Absence of Certain Changes or Events...................    I-15
               Section 4.8.    Taxes..................................................    I-16
               Section 4.9.    Properties.............................................    I-16
               Section 4.10.   Intellectual Property..................................    I-17
</TABLE>
 
                                       I-i
<PAGE>   52
 
<TABLE>
<CAPTION>
                                                                                         PAGE
                                                                                         -----
<S>            <C>             <C>                                                       <C>
               Section 4.11.   Agreements, Contracts and Commitments..................    I-17
               Section 4.12.   Litigation.............................................    I-17
               Section 4.13.   Environmental Matters..................................    I-17
               Section 4.14.   Pooling................................................    I-18
               Section 4.15.   Affiliates.............................................    I-18
               Section 4.16.   Compliance with Laws...................................    I-18
               Section 4.17.   Registration Statement; Proxy Statement/Prospectus.....    I-18
               Section 4.18.   Interim Operations of Sub..............................    I-18
               Section 4.19.   Voting Requirements....................................    I-18
               Section 4.20.   Brokers................................................    I-18
ARTICLE V      CONDUCT OF BUSINESS....................................................    I-19
               Section 5.1.    Covenants of the Company...............................    I-19
               Section 5.2.    Covenants of Parent....................................    I-20
               Section 5.3.    Employment Agreements..................................    I-21
               Section 5.4.    Cooperation............................................    I-21
               Section 5.5.    Material Adverse Effect................................    I-22
ARTICLE VI     ADDITIONAL AGREEMENTS..................................................    I-22
               Section 6.1.    No Solicitation........................................    I-22
               Section 6.2.    Proxy Statement/Prospectus; Registration Statement.....    I-23
               Section 6.3.    Consents...............................................    I-23
               Section 6.4.    Current Nasdaq Quotation...............................    I-24
               Section 6.5.    Access to Information..................................    I-24
               Section 6.6.    Stockholders Meeting...................................    I-24
               Section 6.7.    Legal Conditions to Merger.............................    I-24
               Section 6.8.    Public Disclosure......................................    I-25
               Section 6.9     Tax-Free Reorganization................................    I-25
               Section 6.10    Pooling Accounting.....................................    I-25
               Section 6.11    Affiliate Letters......................................    I-25
               Section 6.12    Nasdaq Quotation.......................................    I-26
               Section 6.13    Stock Plans and Options................................    I-26
               Section 6.14    Indemnification........................................    I-26
               Section 6.15    Additional Agreements; Reasonable Efforts..............    I-26
               Section 6.16    Termination of Certain Agreements......................    I-27
               Section 6.17    Real Estate Transfer Taxes.............................    I-27
ARTICLE VII    CONDITIONS TO MERGER...................................................    I-27
                               Conditions to Each Party's Obligation to Effect the
               Section 7.1     Merger.................................................    I-27
                               Additional Conditions to Obligations of Parent and
               Section 7.2     Sub....................................................    I-28
               Section 7.3     Additional Conditions to Obligations of the Company....    I-29
ARTICLE VIII   TERMINATION AND AMENDMENT..............................................    I-30
               Section 8.1     Termination............................................    I-30
               Section 8.2     Effect of Termination..................................    I-31
               Section 8.3     Fees and Expenses......................................    I-31
               Section 8.4     Amendment..............................................    I-32
               Section 8.5     Extension; Waiver......................................    I-32
</TABLE>
 
                                      I-ii
<PAGE>   53
 
<TABLE>
<CAPTION>
                                                                                         PAGE
                                                                                         -----
<S>            <C>             <C>                                                       <C>
ARTICLE IX     MISCELLANEOUS..........................................................    I-33
                               Nonsurvival of Representations, Warranties and
               Section 9.1     Agreements.............................................    I-33
               Section 9.2     Notices................................................    I-33
               Section 9.3     Interpretation.........................................    I-33
               Section 9.4     Counterparts...........................................    I-33
               Section 9.5     Entire Agreement; No Third Party Beneficiaries.........    I-34
               Section 9.6     Governing Law..........................................    I-34
               Section 9.7     Assignment.............................................    I-34
EXHIBIT A -- Form of Company Affiliate Letter.........................................   I-A-1
EXHIBIT B -- Form of Parent Affiliate Letter..........................................   I-B-1
</TABLE>
 
                                      I-iii
<PAGE>   54
 
                             TABLE OF DEFINED TERMS
 
<TABLE>
<CAPTION>
                                                              SECTION
                                                              --------
<S>                                                           <C>
Agreement...................................................  Forepart
Acquisition Agreement.......................................    8.3(b)
Alternative Transaction.....................................    8.3(f)
Approval....................................................       6.7
Closing.....................................................       1.2
Closing Date................................................       1.2
Code........................................................  Recitals
Company.....................................................  Forepart
Company Affiliate Letter....................................      6.11
Company Auditors............................................      3.16
Company Balance Sheet.......................................    3.5(b)
Company Certificate.........................................    2.2(b)
Company Certificates........................................    2.2(b)
Company Common Stock........................................  Recitals
Company Employee Plans......................................   3.14(a)
Company Financial Statements................................    3.5(b)
Company Intellectual Property Rights........................   3.10(a)
Company Letter..............................................    3.2(a)
Company Material Contracts..................................      3.11
Company Preferred Stock.....................................    3.3(a)
Company SEC Reports.........................................    3.5(a)
Company Stock Plans.........................................    2.1(d)
Company Stock Options.......................................    3.3(b)
Company Tax Certificate.....................................       6.9
Confidentiality Agreement...................................    6.1(a)
Constituent Corporations....................................    1.3(a)
DGCL........................................................  Recitals
Effective Time..............................................       1.2
Environmental Permits.......................................   3.13(c)
ERISA.......................................................   3.14(a)
Exchange Act................................................    3.4(c)
Exchange Agent..............................................    2.2(a)
Exchange Fund...............................................    2.2(a)
Exchange Ratio..............................................    2.1(c)
GAAP........................................................    3.5(b)
Government Entity...........................................    3.4(c)
Hazardous Material..........................................   3.13(a)
Hazardous Materials Activities..............................   3.13(b)
HSR Act.....................................................    3.4(c)
Joint Venture...............................................    3.2(b)
Material Adverse Effect.....................................       5.5
Merger......................................................  Recitals
Parent......................................................  Forepart
Parent Affiliate Letter.....................................      6.11
Parent Auditors.............................................      4.14
Parent Balance Sheet........................................    4.5(b)
Parent Common Stock.........................................  Recitals
Parent Letter...............................................       4.2
Parent Material Contracts...................................      4.11
Parent Option Plans.........................................    4.3(a)
</TABLE>
 
                                      I-iv
<PAGE>   55
 
<TABLE>
<CAPTION>
                                                              SECTION
                                                              --------
<S>                                                           <C>
Parent Preferred Stock......................................    4.3(a)
Parent SEC Reports..........................................    4.5(a)
Parent Tax Certificate......................................       6.9
Proxy Statement.............................................      3.19
Registration Statement......................................      3.19
Returns.....................................................    3.8(b)
Rule 145....................................................      6.11
Safeguard...................................................      6.16
Services Agreement..........................................      6.16
SEC.........................................................    3.4(c)
Securities Act..............................................    3.4(c)
Senior Officers.............................................       5.3
Stockholders Meeting........................................      3.19
Sub.........................................................  Forepart
Subsidiary..................................................    3.2(b)
Superior Proposal...........................................    6.1(a)
Surviving Corporation.......................................    1.3(a)
Takeover Proposal...........................................    6.1(a)
Tax.........................................................    3.8(a)
Taxes.......................................................    3.8(a)
Termination Fee.............................................    8.3(b)
Third Party.................................................    8.3(f)
Transfer Taxes..............................................      6.17
1998 Bonus Plan.............................................   3.14(b)
</TABLE>
 
                                       I-v
<PAGE>   56
 
                          AGREEMENT AND PLAN OF MERGER
 
     AGREEMENT AND PLAN OF MERGER (this "Agreement"), dated as of February 16,
1998, by and among Tellabs, Inc., a Delaware corporation ("Parent"), Cardinal
Merger Co., a Delaware corporation and a wholly owned subsidiary of Parent
("Sub"), and Coherent Communications Systems Corporation, a Delaware corporation
(the "Company").
 
                                    RECITALS
 
     WHEREAS, Sub will merge with and into the Company (the "Merger"), pursuant
to the General Corporation Law of the State of Delaware, as amended (the "DGCL")
and upon the terms and subject to the conditions herein set forth, whereby each
issued and outstanding share of Common Stock, $.01 par value per share, of the
Company ("Company Common Stock"), not owned directly or indirectly by Parent or
the Company, will be converted into shares of Common Stock, $.01 par value per
share, of Parent ("Parent Common Stock");
 
     WHEREAS, as a result of the Merger, the Company will become a wholly owned
subsidiary of Parent and the stockholders of the Company will become
stockholders of Parent;
 
     WHEREAS, the Board of Directors of the Company has determined that the
Merger is consistent with and in furtherance of the long-term business strategy
of the Company and is fair to, and in the best interests of, the Company and its
stockholders, has approved and adopted this Agreement and the transactions
contemplated hereby and has recommended adoption of this Agreement by the
stockholders of the Company;
 
     WHEREAS, the Board of Directors of Parent has determined that the Merger is
consistent with and in furtherance of the long-term business strategy of Parent
and is in the best interests of Parent and its stockholders and has approved and
adopted this Agreement and the transactions contemplated hereby;
 
     WHEREAS, the Board of Directors of Sub has approved and adopted this
Agreement and Parent, as the sole stockholder of Sub, has adopted this
Agreement;
 
     WHEREAS, for federal income tax purposes, it is intended that the Merger
shall qualify as a reorganization within the meaning of Section 368(a) of the
Internal Revenue Code of 1986, as amended (the "Code");
 
     WHEREAS, for accounting purposes, it is intended that the Merger shall be
accounted for as a pooling of interests;
 
     WHEREAS, Parent, Sub and the Company desire to make certain
representations, warranties, covenants and agreements in connection with the
Merger and also to prescribe various conditions to the Merger; and
 
     WHEREAS, simultaneously with the execution and delivery of this Agreement,
certain stockholders of the Company, including each of the directors of the
Company, in order to induce Parent and Sub to enter into this Agreement, entered
into stockholder agreements with Parent, agreeing, among other things, to vote
in favor of this Agreement and the Merger and against any competing proposals.
 
     NOW, THEREFORE, in consideration of the foregoing and the respective
representations, warranties, covenants and agreements set forth below, the
parties agree as follows:
 
                                   ARTICLE I
                                   THE MERGER
 
     Section 1.1.  MERGER.  Subject to the provisions of this Agreement and in
accordance with the DGCL, Sub shall be merged with and into the Company. As a
result of the Merger, the outstanding shares of capital stock of Sub and the
Company shall be converted or canceled in the manner provided in Article II of
this Agreement, the separate corporate existence of Sub shall cease and the
Company shall be the surviving corporation in the Merger and shall succeed to
and assume all the rights and obligations of Sub in accordance with the DGCL.
 
                                       I-1
<PAGE>   57
 
     Section 1.2.  CLOSING; EFFECTIVE TIME.  The closing of the Merger (the
"Closing") will take place at 10:00 a.m., local time, on a date to be specified
by Parent and the Company, which shall be no later than the second business day
after satisfaction or waiver of the conditions set forth in Article VII (the
"Closing Date"), at the offices of Sidley & Austin, One First National Plaza,
Chicago, Illinois, unless another date or place is agreed to in writing by
Parent and the Company. At or concurrently with the Closing, the parties hereto
shall cause the Merger to become effective by filing a Certificate of Merger
with the Secretary of State of the State of Delaware, in accordance with the
relevant provisions of the DGCL (the time of such filing being the "Effective
Time") and shall make all other filings or recordings required under the DGCL.
 
     Section 1.3.  EFFECTS OF THE MERGER.  (a) At the Effective Time, (i) the
separate existence of Sub shall cease and Sub shall be merged with and into the
Company (Sub and the Company are sometimes referred to herein as the
"Constituent Corporations" and the Company after the Effective Time is sometimes
referred to herein as the "Surviving Corporation"), (ii) the Certificate of
Incorporation of the Company, as in effect immediately prior to the Effective
Time, shall be amended as of the Effective Time so that Article Fourth of such
Certificate of Incorporation reads in its entirety as follows: "The total number
of shares of all classes of stock which the Corporation shall have authority to
issue is 1,000 shares of Common Stock, $.01 par value per share" and, as so
amended, such Certificate of Incorporation shall be the Certificate of
Incorporation of the Surviving Corporation, and (iii) the Bylaws of Sub as in
effect immediately prior to the Effective Time shall be the Bylaws of the
Surviving Corporation.
 
     (b)  The Merger shall have the effects set forth in the DGCL.
 
     Section 1.4.  DIRECTORS AND OFFICERS.  The directors of Sub immediately
prior to the Effective Time and the directors of the Company listed in Item 1.4
of the Company Letter (as defined below) shall be the directors of the Surviving
Corporation until their resignation or removal or until their respective
successors have been elected and qualified. The officers of the Company
immediately prior to the Effective Time shall continue as officers of the
Surviving Corporation until their resignation or removal or until their
respective successors have been elected and qualified.
 
                                   ARTICLE II
 
                            CONVERSION OF SECURITIES
 
     Section 2.1.  CONVERSION OF CAPITAL STOCK.  As of the Effective Time, by
virtue of the Merger and without any action on the part of the holder of any
shares of Company Common Stock or capital stock of Sub:
 
          (a)  Capital Stock of Sub.  Each issued and outstanding share of the
     capital stock of Sub shall be converted into and become one fully paid and
     nonassessable share of Common Stock, $.01 par value per share, of the
     Surviving Corporation.
 
          (b)  Cancellation of Treasury Stock and Parent-Owned Stock.  Any
     shares of the Company Common Stock owned by the Company or by any
     Subsidiary (as defined in Section 3.2(b)) of the Company and each share of
     Company Common Stock owned by Parent, Sub or any other wholly owned
     Subsidiary of Parent shall be canceled and retired and shall cease to
     exist, and no stock of Parent or other consideration shall be delivered in
     exchange therefor.
 
          (c)  Exchange Ratio for Company Common Stock.  Subject to Section 2.2,
     each issued and outstanding share of Company Common Stock (other than
     shares to be canceled in accordance with Section 2.1(b)) shall be converted
     into the right to receive seventy-two hundredths (.72) (the "Exchange
     Ratio") of a fully paid and nonassessable share of Parent Common Stock. All
     such shares of the Company Common Stock, when so converted, shall no longer
     be outstanding and shall automatically be canceled and retired and shall
     cease to exist, and each holder of a certificate representing any such
     shares shall cease to have any rights with respect thereto, except the
     right to receive the shares of Parent Common Stock and any cash in lieu of
     fractional shares of Parent Common Stock to be issued or paid in
     consideration therefor upon the surrender of such certificate in accordance
     with Section 2.2, without interest.
 
                                       I-2
<PAGE>   58
 
          (d)  Company Stock Options.  At the Effective Time, all then
     outstanding options to purchase shares of Company Common Stock issued under
     the Company's 1982 Stock Option Plan and 1993 Equity Compensation Plan, as
     amended and restated (collectively, the "Company Stock Plans"), not
     exercised as of the Effective Time will be assumed by Parent in accordance
     with Section 6.13.
 
     Section 2.2.  EXCHANGE OF CERTIFICATES.  The procedures for exchanging
outstanding shares of Company Common Stock for Parent Common Stock upon
consummation of the Merger are as follows:
 
          (a)  Exchange Agent.  As soon as practicable after the Effective Time,
     Parent shall deposit with a bank or trust company designated by Parent and
     reasonably acceptable to the Company (the "Exchange Agent"), for the
     benefit of the holders of shares of Company Common Stock, for exchange in
     accordance with this Section 2.2, through the Exchange Agent, certificates
     representing the shares of Parent Common Stock (such shares of Parent
     Common Stock, together with any dividends or distributions with respect
     thereto, being hereinafter referred to as the "Exchange Fund") issuable
     pursuant to Section 2.1 in exchange for outstanding shares of Company
     Common Stock, which shares of Parent Common Stock shall be deemed to be
     issued at the Effective Time subject to the other provisions of this
     Section 2.2.
 
          (b)  Exchange Procedures.  As soon as reasonably practicable after the
     Effective Time, the Exchange Agent shall mail to each holder of record of a
     certificate or certificates which immediately prior to the Effective Time
     represented outstanding shares of Company Common Stock (each a "Company
     Certificate" and, collectively, the "Company Certificates") whose shares
     were converted pursuant to Section 2.1 into the right to receive shares of
     Parent Common Stock (i) a letter of transmittal (which shall specify that
     delivery shall be effected, and risk of loss and title to the Company
     Certificates shall pass, only upon delivery of the Company Certificates to
     the Exchange Agent and shall be in such form and have such other provisions
     as Parent may reasonably specify) and (ii) instructions for use in
     effecting the surrender of the Company Certificates in exchange for
     certificates representing shares of Parent Common Stock. Upon surrender of
     a Company Certificate for cancellation to the Exchange Agent or to such
     other agent or agents as may be appointed by Parent, together with such
     letter of transmittal, duly executed, and such other documents as may be
     reasonably required by the Exchange Agent or Parent, the holder of such
     Company Certificate shall be entitled to receive in exchange therefor a
     certificate representing that number of whole shares of Parent Common Stock
     which such holder has the right to receive pursuant to the provisions of
     this Article II, and the Company Certificate so surrendered shall forthwith
     be canceled. In the event of a transfer of ownership of Company Common
     Stock that is not registered in the transfer records of the Company, a
     certificate representing the proper number of shares of Parent Common Stock
     may be issued to a transferee if the Company Certificate representing such
     Company Common Stock is presented to the Exchange Agent, accompanied by all
     documents required to evidence and effect such transfer and by evidence
     that any applicable stock transfer taxes have been paid. Until surrendered
     as contemplated by this Section 2.2, each Company Certificate shall be
     deemed at any time after the Effective Time to represent only the right to
     receive upon such surrender the certificate representing shares of Parent
     Common Stock and cash in lieu of any fractional shares of Parent Common
     Stock as contemplated by this Section 2.2. Parent or the Exchange Agent
     shall be entitled to deduct and withhold from the consideration otherwise
     payable pursuant to this Agreement such amounts as Parent or the Exchange
     Agent are required to deduct and withhold under the Code, or any provision
     of state, local or foreign tax law, with respect to the making of such
     payment. To the extent that amounts are so withheld by Parent or the
     Exchange Agent, such withheld amounts shall be treated for all purposes of
     this Agreement as having been paid to the person in respect of whom such
     deduction and withholding was made by Parent or the Exchange Agent.
 
          (c)  Distributions with Respect to Unexchanged Shares.  No dividends
     or other distributions declared or made after the Effective Time with
     respect to Parent Common Stock with a record date after the Effective Time
     shall be paid to the holder of any unsurrendered Company Certificate with
     respect to the shares of Parent Common Stock represented thereby, and no
     cash payment in lieu of fractional shares shall be paid to any such holder
     pursuant to Section 2.2(e), until the holder of record of such Company
     Certificate shall surrender such Company Certificate. Subject to the effect
     of applicable laws, following surrender of any such Company Certificate,
     there shall be paid to the record holder of the certificates
 
                                       I-3
<PAGE>   59
 
     representing whole shares of Parent Common Stock issued in exchange
     therefor, without interest, (i) at the time of such surrender, the amount
     of any cash payable in lieu of a fractional share of Parent Common Stock to
     which such holder is entitled pursuant to Section 2.2(e)and the amount of
     dividends or other distributions with a record date after the Effective
     Time previously paid with respect to such whole shares of Parent Common
     Stock, and (ii) at the appropriate payment date, the amount of dividends or
     other distributions with a record date after the Effective Time but prior
     to surrender and a payment date subsequent to surrender payable with
     respect to such whole shares of Parent Common Stock.
 
          (d)  No Further Ownership Rights in Company Common Stock.  All shares
     of Parent Common Stock issued upon the surrender for exchange of shares of
     Company Common Stock in accordance with the terms hereof, including any
     cash paid pursuant to Sections 2.2(c) and 2.2(e), shall be deemed to have
     been issued in full satisfaction of all rights pertaining to such shares of
     Company Common Stock, and there shall be no further registration of
     transfers on the stock transfer books of the Surviving Corporation of the
     shares of Company Common Stock which were outstanding immediately prior to
     the Effective Time. If, after the Effective Time, Company Certificates are
     presented to the Surviving Corporation for any reason, they shall be
     canceled and exchanged as provided in this Section 2.2.
 
          (e)  No Fractional Shares.  No certificate or scrip representing
     fractional shares of Parent Common Stock shall be issued upon the surrender
     for exchange of the Company Certificates, and such fractional share
     interests will not entitle the owner thereof to vote or to any rights of a
     stockholder of Parent. Notwithstanding any other provision of this
     Agreement, each holder of shares of Company Common Stock exchanged in
     connection with the Merger who would otherwise have been entitled to
     receive a fraction of a share of Parent Common Stock (after taking into
     account all Company Certificates delivered by such holder) shall receive,
     in lieu thereof, cash (without interest) in an amount equal to such
     fractional part of a share of Parent Common Stock multiplied by the average
     of the last reported sale prices of Parent Common Stock on The Nasdaq
     National Market on the ten (10) trading days immediately preceding the
     Effective Time. Parent shall make available to the Exchange Agent the cash
     necessary for this purpose.
 
          (f)  Termination of Exchange Fund.  Any portion of the Exchange Fund
     which remains undistributed to the stockholders of the Company for one year
     after the Effective Time shall be delivered to Parent, upon demand, and any
     stockholders of the Company who have not previously complied with this
     Section 2.2 shall thereafter look only to Parent for payment of their claim
     for Parent Common Stock, cash in lieu of fractional shares of Parent Common
     Stock and dividends or distributions with respect to Parent Common Stock.
 
          (g)  No Liability.  Neither Parent nor the Company, nor any of their
     respective directors, officers, employees or agents, shall be liable to any
     holder of shares of Company Common Stock or Parent Common Stock, as the
     case may be, for such shares (or dividends or distributions with respect
     thereto) delivered to a public official pursuant to any applicable
     abandoned property, escheat or similar law.
 
          (h)  Adjustment of Exchange Ratio.  In the event of any
     reclassification, stock split or stock dividend with respect to Parent
     Common Stock between the date hereof and the Effective Time, appropriate
     adjustments, if any, shall be made by Parent to the Exchange Ratio, and all
     references to the Exchange Ratio in this Agreement shall be deemed to be to
     the Exchange Ratio as so adjusted.
 
          (i)  Further Assurances.  If, at any time after the Effective Time,
     the Surviving Corporation shall consider or be advised that any deeds,
     bills of sale, assignments or assurances or any other acts or things are
     necessary, desirable or proper (i) to vest, perfect or confirm, of record
     or otherwise, in the Surviving Corporation its right, title and interest
     in, to or under any of the rights, privileges, powers, franchises,
     properties or assets of either of the Constituent Corporations or (ii)
     otherwise to carry out the purposes of this Agreement, the Surviving
     Corporation and its proper officers and directors or their designees shall
     be authorized to execute and deliver, in the name and on behalf of either
     Constituent Corporation, all such deeds, bills of sale, assignments and
     assurances and to do, in the name and on behalf of either Constituent
     Corporation, all such other acts and things as may be necessary, desirable
     or proper to vest, perfect or confirm the Surviving Corporation's right,
     title and interest in, to and under any of the rights, privileges,
 
                                       I-4
<PAGE>   60
 
     powers, franchises, properties or assets of such Constituent Corporation
     and otherwise to carry out the purposes of this Agreement.
 
     Section 2.3.  NO DISSENTERS RIGHTS.  The holders of shares of Company
Common Stock shall not be entitled to appraisal rights with respect to the
Merger.
 
                                  ARTICLE III
 
                 REPRESENTATIONS AND WARRANTIES OF THE COMPANY
 
     The Company represents and warrants to Parent and Sub as follows:
 
     Section 3.1. ORGANIZATION.  The Company and each of its Subsidiaries (i) is
a corporation duly organized, validly existing and in good standing under the
laws of the jurisdiction of its incorporation, (ii) has all requisite corporate
power to own, lease and operate its property and to carry on its business as now
being conducted and as proposed to be conducted, and (iii) is duly qualified to
do business and is in good standing as a foreign corporation in each
jurisdiction in which the nature of its activities requires it to be so
qualified, except that, in the case of the clauses (i) and (ii), with respect to
Subsidiaries that in the aggregate do not constitute a "significant subsidiary"
within the meaning of Regulation S-X, Rule 1-02 (w), such representations are
being made to the best knowledge of the Company, and except, in the case of
clause (iii), where the failure to have such power or the failure to be so
qualified could not reasonably be expected to have a Material Adverse Effect on
the Company (as defined below).
 
     Section 3.2. COMPANY SUBSIDIARIES AND JOINT VENTURES. (a) Item 3.2 of the
letter from the Company to Parent and Sub dated and delivered as of the date
hereof (the "Company Letter"), which relates to this Agreement and is designated
therein as being the Company Letter sets forth a list of all Subsidiaries and
Joint Ventures (as defined below) of the Company, including the name of each
Subsidiary and Joint Venture and the jurisdiction in which such Subsidiary or
Joint Venture is organized. Except as set forth in Item 3.2 of the Company
Letter, there are no outstanding subscriptions, options, calls, contracts,
voting trusts, proxies or other commitments, understandings, restrictions,
arrangements, rights or warrants with respect to any such Subsidiary's capital
stock, including any right obligating any such Subsidiary to issue, deliver, or
sell additional shares of its capital stock, and no obligations, contingent or
otherwise, of the Company or any of its Subsidiaries to repurchase, redeem, or
otherwise acquire any shares of the capital stock of any Subsidiary of the
Company or make any investment (in the form of a loan, capital contribution or
otherwise) in any such Subsidiary or any other entity other than guarantees of
bank obligations of such Subsidiaries entered into in the ordinary course of
business. All of the outstanding shares of capital stock of each Subsidiary of
the Company are duly authorized, validly issued, fully paid and nonassessable,
and all such shares are owned by the Company or another Subsidiary of the
Company free and clear of all security interests, liens, claims, pledges,
agreements, limitations on the Company's voting rights, charges or other
encumbrances of any nature. Item 3.2 of the Company Letter sets forth the nature
and extent of the ownership and voting interests held by the Company in each
such Joint Venture. The Company has no obligation to make any capital
contributions, or otherwise provide assets or cash, to any Joint Venture. Except
as set forth in Item 3.2 of the Company Letter, neither the Company nor any of
its Subsidiaries directly or indirectly owns any material equity or similar
interest in, or any interest convertible into or exchangeable or exercisable for
any such equity or similar interest in, any corporation, limited liability
company, partnership, joint venture or other business association or entity.
 
          (b) As used in this Agreement, "Subsidiary" means, with respect to any
     party, any corporation, limited liability company, partnership, joint
     venture, or other business association or entity, at least a majority of
     the voting securities or economic interests of which is directly or
     indirectly owned or controlled by such party or by any one or more of its
     Subsidiaries. As used in this Agreement, "Joint Venture" means, with
     respect to any party, any corporation, limited liability company,
     partnership, joint venture or other entity in which (i) such party,
     directly or indirectly, owns or controls more than five percent (5%) and
     less than a majority of any class of the outstanding voting securities or
     economic interests, or (ii) such party or a Subsidiary of such party is a
     general partner.
 
                                       I-5
<PAGE>   61
 
     Section 3.3.  COMPANY CAPITAL STRUCTURE.  (a) The authorized capital stock
of the Company consists of 100,000,000 shares of Company Common Stock and
3,000,000 shares of Preferred Stock, $.01 par value per share ("Company
Preferred Stock"). As of February 12, 1998: (i) 15,519,944 shares of Company
Common Stock were issued and outstanding, all of which are validly issued, fully
paid and nonassessable; (ii) no shares of Company Preferred Stock were issued or
outstanding; (iii) no shares of Company Common Stock were held in the treasury
of the Company or by Subsidiaries of the Company; and (iv) 1,082,284 shares of
the Company Common Stock were reserved for issuance under Company Stock Plans
(including (A) 6,925 shares reserved for issuance under the 1982 Stock Option
Plan, of which 6,925 were subject to outstanding options and none of which were
reserved for future option grants and (B) 1,075,359 shares of Company Common
Stock reserved for issuance under the 1993 Equity Compensation Plan, as amended
and restated, 755,114 of which were subject to outstanding options and 320,245
of which were reserved for future option grants. Since February 12, 1998, (i) no
additional shares of capital stock have been reserved for issuance by the
Company and (ii) the only issuances of shares of capital stock of the Company
have been issuances of Company Common Stock upon the exercise of outstanding
Company Stock Options (as defined below) listed in Item 3.3 of the Company
Letter. All of the shares of Company Common Stock subject to issuance as
specified above, upon issuance pursuant to the terms and conditions specified in
the instruments pursuant to which they are issuable, shall be duly authorized,
validly issued, fully paid and nonassessable. Except as provided in Item 3.3 of
the Company Letter, there are no obligations, contingent or otherwise, of the
Company or any of its Subsidiaries to repurchase, redeem or otherwise acquire
any shares of Company Common Stock.
 
          (b) Except as set forth in this Section 3.3, there are no equity
     securities of any class of the Company or any of its Subsidiaries, or any
     security exchangeable into or exercisable for such equity securities,
     issued, reserved for issuance or outstanding. Except for the stock options
     issued pursuant to the Company Stock Plans (the "Company Stock Options") as
     set forth in this Section 3.3, there are no options, warrants, equity
     securities, calls, rights, commitments or agreements of any character to
     which the Company or any of its Subsidiaries is a party or by which it is
     bound obligating the Company or any of its Subsidiaries to issue, deliver
     or sell, or cause to be issued, delivered or sold, additional shares of
     capital stock of the Company or any of its Subsidiaries or any security or
     other instrument convertible into shares of capital stock of the Company or
     any of its Subsidiaries or obligating the Company or any of its
     Subsidiaries to grant, extend, accelerate the vesting of or enter into any
     such option, warrant, equity security, call, right, commitment or
     agreement, and, to the best knowledge of the Company, as of the date of
     this Agreement, there are no voting trusts, proxies or other agreements or
     understandings with respect to the shares of capital stock of the Company.
     Item 3.3 of the Company Letter sets forth for each of the Senior Officers
     (as defined below) by name, and for each other holder of options (i) the
     number of shares of Company Common Stock subject to each Company Stock
     Option held by such holder, (ii) the dates of grant of Company Stock
     Options to such holder, (iii) the vesting schedule for the Company Stock
     Options held by such holder, (iv) the exercise prices for the Company Stock
     Options held by such holder and (v) the expiration dates of Company Stock
     Options held by such holder. Item 3.3 of the Company Letter contains all
     forms of stock option agreements pursuant to which Company Stock Options
     have been issued.
 
     Section 3.4.  AUTHORITY; NO CONFLICT; REQUIRED FILINGS AND CONSENTS.  (a)
The Company has all requisite corporate power and authority to enter into this
Agreement and to consummate the transactions contemplated hereby. The execution
and delivery of this Agreement and the consummation of the transactions
contemplated hereby have been duly authorized by all necessary corporate and
stockholder action on the part of the Company, subject only to the adoption of
this Agreement and the approval of the Merger by the Company's stockholders
under the DGCL. This Agreement has been duly executed and delivered by the
Company and constitutes the valid and binding obligation of the Company,
enforceable in accordance with its terms, except as such enforceability may be
limited by bankruptcy, insolvency, reorganization, moratorium and other similar
laws affecting creditors' rights generally and general principles of equity,
regardless of whether asserted in a proceeding in equity or at law.
 
          (b) The execution and delivery of this Agreement by the Company does
     not, and the consummation of the transactions contemplated by this
     Agreement will not, (i) conflict with, or result in any violation or breach
     of, any provision of the Certificate of Incorporation or Bylaws of the
     Company or the comparable
 
                                       I-6
<PAGE>   62
 
     charter or organizational documents of any of its Subsidiaries (in each
     case as heretofore amended), (ii) result in any violation or breach of, or
     constitute (with or without notice or lapse of time, or both) a default (or
     give rise to a right of termination, cancellation or acceleration of any
     obligation or loss of any material benefit) under, any of the terms,
     conditions or provisions of any loan, credit agreement, note, bond,
     mortgage, indenture, lease, contract or other agreement, instrument or
     obligation to which the Company or any of its Subsidiaries is a party or by
     which any of them or any of their properties or assets may be bound, or
     (iii) subject to the consents, approvals, orders, authorizations, filings,
     declarations and registrations specified in Section 3.4(c), conflict with
     or violate any judgment, order, decree, statute, law, ordinance, rule or
     regulation or any permit, concession, franchise or license applicable to
     the Company or any of its Subsidiaries or any of their properties or
     assets, except in the case of clause (ii) and (iii) for any such
     violations, breaches, defaults, terminations, cancellations or
     accelerations which in the aggregate could not reasonably be expected to
     have a Material Adverse Effect on the Company and do not impair the ability
     of the Company to perform its obligations under this Agreement or prevent
     the consummation of any of the transactions contemplated hereby.
 
          (c)  No consent, approval, order or authorization of, or registration,
     declaration or filing with, any court, administrative agency, commission or
     other governmental authority or instrumentality ("Governmental Entity") is
     required by or with respect to the Company or any of its Subsidiaries in
     connection with the execution and delivery of this Agreement or the
     consummation of the transactions contemplated hereby, except for (i) the
     filing of pre-merger notification reports under the Hart-Scott-Rodino
     Antitrust Improvements Act of 1976, as amended (the "HSR Act"), and the
     expiration or early termination of the waiting period thereunder; (ii) the
     filing of the Registration Statement (as defined in Section 3.19) with the
     Securities and Exchange Commission (the "SEC") in accordance with the
     Securities Act of 1933, as amended (the "Securities Act"), and the entry of
     an order by the SEC permitting such registration statement to become
     effective; (iii) the filing of the Certificate of Merger with the Secretary
     of State of the State of Delaware in accordance with the DGCL; (iv) the
     filing of the Proxy Statement (as defined in Section 3.19) and related
     proxy materials with the SEC in accordance with the Securities Exchange Act
     of 1934, as amended (the "Exchange Act"); (v) such consents, approvals,
     orders, authorizations, filings, registrations, Returns (as defined in
     Section 3.8(b)) and declarations as may be required under applicable
     federal and state securities and Tax (as defined in Section 3.8(a)) laws
     and the laws of any foreign country; (vi) such other consents, orders,
     authorizations, filings, approvals, declarations and registrations which,
     individually or in the aggregate, if not obtained or made, could not
     reasonably be expected to have a Material Adverse Effect on the Company or
     impair the ability of the Company to perform its obligations under this
     Agreement.
 
     Section 3.5.  SEC FILINGS; FINANCIAL STATEMENTS.  (a) The Company has filed
and made available to Parent or its legal counsel all forms, reports and
documents required to be filed by the Company with the SEC (collectively, the
"Company SEC Reports") since January 1, 1995. The Company SEC Reports (i) at the
time filed, complied in all material respects with the applicable requirements
of the Securities Act and the Exchange Act, as the case may be, and (ii) did not
at the time they were filed (or if amended or superseded by a subsequent filing,
then on the date of such filing) contain any untrue statement of a material fact
or omit to state a material fact required to be stated in such Company SEC
Reports or necessary in order to make the statements in such the Company SEC
Reports, in the light of the circumstances under which they were made, not
misleading. None of the Company's Subsidiaries is required to file any forms,
reports or other documents with the SEC.
 
          (b)  Each of the consolidated financial statements (including, in each
     case, any related notes) contained in the Company SEC Reports, including
     any Company SEC Reports filed from the date of this Agreement until the
     Closing (collectively, the "Company Financial Statements"), complied or
     will comply in all material respects with the applicable published rules
     and regulations of the SEC with respect thereto, was or will be prepared in
     accordance with United States generally accepted accounting principles
     ("GAAP") applied on a consistent basis throughout the periods involved
     (except as may be indicated in the notes to such financial statements or,
     in the case of unaudited statements, as permitted by Form 10-Q or 8-K
     promulgated by the SEC), and fairly presented or will fairly present the
     consolidated financial position of the Company and its Subsidiaries as at
     the respective dates and the consolidated
 
                                       I-7
<PAGE>   63
 
     results of its operations and cash flows for the periods indicated, except
     that the unaudited interim financial statements were or are subject to
     normal and recurring year-end adjustments which were not or are not
     expected to be material in amount. The unaudited consolidated balance sheet
     of the Company as of September 30, 1997 is referred to herein as the
     "Company Balance Sheet."
 
     Section 3.6.  ABSENCE OF UNDISCLOSED LIABILITIES.  Except as disclosed in
Item 3.6 of the Company Letter or as otherwise disclosed in the Company SEC
Reports filed and publicly available prior to the date of this Agreement, the
Company and its Subsidiaries do not have any liabilities, either accrued or
contingent (whether or not required to be reflected in financial statements in
accordance with United States generally accepted accounting principles), and
whether due or to become due, which individually or in the aggregate could
reasonably be expected to have a Material Adverse Effect on the Company, other
than liabilities reflected in the Company Balance Sheet and normal or recurring
liabilities incurred since September 30, 1997 in the ordinary course of business
consistent with past practices which would not individually or in the aggregate
have a Material Adverse Effect on the Company.
 
     Section 3.7.  ABSENCE OF CERTAIN CHANGES OR EVENTS.  Since the date of the
Company Balance Sheet, the Company and its Subsidiaries have conducted their
businesses only in the ordinary course in a manner consistent with past practice
(except as disclosed in the Company SEC Reports filed and publicly available
prior to the date of this Agreement), and since such date there has not been:
(a) any Material Adverse Effect on the Company or any facts or circumstances
that could reasonably be expected to result in a Material Adverse Effect on the
Company; (b) any damage, destruction or loss (whether or not covered by
insurance) with respect to the Company or any of its Subsidiaries having a
Material Adverse Effect on the Company; (c) any material change by the Company
or any of its Subsidiaries in its accounting methods, principles or practices;
(d) any revaluation by the Company or any of its Subsidiaries of any of its
assets having a Material Adverse Effect on the Company, including writing down
the value of capitalized software or inventory or writing off notes or accounts
receivable other than in the ordinary course of business consistent with past
practice; or (e) except as disclosed in Item 3.7 of the Company Letter, any
other action or event that would have required the consent of Parent pursuant to
clauses (a), (c) or (g) of Section 5.1 of this Agreement had such action or
event occurred after the date of this Agreement.
 
     Section 3.8.  TAXES.  (a) For purposes of this Agreement, a "Tax" or,
collectively, "Taxes" means any and all federal, state, local and foreign taxes,
assessments and other governmental charges, duties, impositions and liabilities
of any kind whatsoever, including, without limitation, any of the foregoing
based upon or measured by gross receipts, income, profits, sales, use and
occupation, and value added, ad valorem, transfer, franchise, withholding,
payroll, recapture, employment, excise and property taxes (in all cases,
together with all interest, penalties and additions imposed with respect to such
amounts) and including any liability for taxes of a predecessor entity.
 
          (b)  Except as disclosed in Item 3.8 of the Company Letter, each of
     the Company and its Subsidiaries has prepared and timely filed (or will so
     file) all federal, state, local and foreign returns, estimates, information
     statements and reports ("Returns") required to be filed at or before the
     Effective Time relating to any and all Taxes concerning or attributable to
     the Company or any of its Subsidiaries or to their operations, and such
     Returns are true and correct in all material respects and have been
     completed in all material respects in accordance with applicable law.
 
          (c)  Except as disclosed in Item 3.8 of the Company Letter, each of
     the Company and its Subsidiaries as of the Effective Time will have paid
     all Taxes it is required to pay prior to the Effective Time.
 
          (d)  Except as disclosed in Item 3.8 of the Company Letter, there is
     no material Tax deficiency outstanding, proposed or assessed against the
     Company or any of its Subsidiaries that has not been paid in full or fully
     reflected as a liability on the Company Balance Sheet nor has the Company
     or any of its Subsidiaries executed any waiver of any statute of
     limitations on or extending the period for the assessment or collection of
     any material Tax.
 
          (e)  Except as disclosed in Item 3.8 of the Company Letter, neither
     the Company nor any of its Subsidiaries has any material liability for
     unpaid federal, state, local or foreign Taxes that has not been
 
                                       I-8
<PAGE>   64
 
     accrued for or reserved on the Company Balance Sheet, whether asserted or
     unasserted, contingent or otherwise.
 
          (f)  Except as disclosed in Item 3.8 of the Company Letter, the
     Returns referred to in clause (b) above, to the extent relating to federal
     and state income or franchise Taxes, have been examined by the appropriate
     taxing authority or the period for assessment of the Taxes in respect of
     which such Returns were required to be filed has expired.
 
          (g)  Except as disclosed in Item 3.8 of the Company Letter, there is
     no action, suit, investigation, audit, claim or assessment pending or
     proposed or threatened in writing with respect to Taxes of the Company or
     any of its Subsidiaries.
 
          (h)  Except as disclosed in Item 3.8 of the Company Letter, there are
     no liens for Taxes upon the assets of the Company or any of its
     Subsidiaries except liens relating to current Taxes not yet due.
 
          (i)  Except as disclosed in Item 3.8 of the Company Letter, all Taxes
     which the Company or any of its Subsidiaries are required by law to
     withhold or to collect for payment have been duly withheld and collected,
     and have been paid or accrued, reserved against and entered on the books of
     the Company.
 
          (j) Except as disclosed in Item 3.8 of the Company Letter, none of the
     Company or any of its Subsidiaries has been a member of any group of
     corporations filing Returns on a consolidated, combined, unitary or similar
     basis other than each such group of which it is currently a member.
 
          (k) Except as disclosed in Item 3.8 of the Company Letter, no
     transaction contemplated by this Agreement is subject to withholding under
     Section 1445 of the Code (relating to "FIRPTA").
 
          (l) Neither the Company nor any of its Subsidiaries, nor any of its
     other affiliates (i) has taken any action, agreed to take any action, or
     failed to take any action, or (ii) has knowledge of any fact or
     circumstance that (without regard to any action taken or agreed to be taken
     by Parent or any of its affiliates), in each case, the Company, such
     Subsidiary or such other affiliate has actual knowledge could reasonably be
     expected to cause the Merger to fail to qualify as a "reorganization"
     within the meaning of Section 368(a) of the Code.
 
     Section 3.9. PROPERTIES.  The Company and its Subsidiaries own or have
valid leasehold interests in all real property necessary for the conduct of
their businesses in all material respects as presently conducted. All material
leases to which the Company or any of its Subsidiaries is a party are in good
standing, valid and effective in accordance with their respective terms, and
neither the Company nor its Subsidiaries is in default under any of such leases,
except where the lack of such good standing, validity and effectiveness or the
existence of such default could not reasonably be expected to have a Material
Adverse Effect on the Company.
 
     Section 3.10. INTELLECTUAL PROPERTY.  (a) Except as disclosed in Item
3.10(a) of the Company Letter, the Company and its Subsidiaries own, or are
licensed or otherwise possess, legally enforceable rights to use, all patents,
trademarks, trade names, service marks, copyrights and mask works, any
applications for and registrations of such patents, trademarks, trade names,
service marks, copyrights and mask works, and all processes, formulae, methods,
schematics, technology, know how, computer software programs or applications and
tangible or intangible proprietary information or material that are necessary to
conduct the business of the Company and its Subsidiaries as currently conducted
or planned to be conducted by the Company and its Subsidiaries (the "Company
Intellectual Property Rights").
 
          (b) Except as disclosed in Item 3.10(b) of the Company Letter, neither
     the Company nor any of its Subsidiaries is, or will be as a result of the
     execution and delivery of this Agreement or the performance of its
     obligations under this Agreement, in breach of any material license,
     sublicense or other agreement relating to the Company Intellectual Property
     Rights or any material license, sublicense or other agreement pursuant to
     which the Company or any of its Subsidiaries is authorized to use any third
     party patents, trademarks or copyrights, including software, which are
     incorporated in or form a part of any product of the Company or any of its
     Subsidiaries that is material to the business of the Company and its
     Subsidiaries taken as a whole.
 
                                       I-9
<PAGE>   65
 
          (c)  Except as disclosed in Item 3.10(c) of the Company Letter, (i)
     all patents, registered trademarks, service marks and copyrights which are
     held by the Company or any of its Subsidiaries, and which are material to
     the business of the Company and its Subsidiaries, taken as a whole, are to
     the best knowledge of the Company valid and subsisting; (ii) the Company
     has not been sued in any suit, action or proceeding which involves a claim
     of infringement of any patents, trademarks, service marks, copyrights or
     violation of any trade secret or other proprietary right of any third
     party; and (iii) to the best knowledge of the Company the manufacturing,
     marketing, licensing or sale of the Company's products does not infringe
     any patent, trademark, service mark, copyright, trade secret or other
     proprietary right of any third party, which infringement, either
     individually or in the aggregate, could reasonably be expected to have a
     Material Adverse Effect on the Company.
 
          (d)  Item 3.10(d) of the Company Letter contains a list of (i) all
     registered United States, state and foreign trademarks, service marks,
     logos, trade dress and trade names and pending applications to register the
     foregoing, (ii) all United States and foreign patents and patent
     applications and (iii) all registered United States and foreign copyrights
     and pending applications to register the same, in each case owned by the
     Company and its Subsidiaries.
 
     Section 3.11.  AGREEMENTS, CONTRACTS AND COMMITMENTS.  Neither the Company
nor any of its Subsidiaries has breached, or received in writing any claim or
threat (for which there is a reasonable basis) that it has breached, any of the
terms or conditions of any material agreement, contract or commitment to which
it is a party or to which any of its assets and properties is subject ("Company
Material Contracts") in such a manner as would permit any other party to cancel,
modify the terms of or terminate the same or would permit any other party to
collect material damages from the Company or any of its Subsidiaries under any
Company Material Contract. Each Company Material Contract that has not expired
or been terminated is in full force and effect and is not subject to any
material default thereunder of which the Company is aware by any party obligated
to the Company or any of its Subsidiaries pursuant to such Company Material
Contract. All Company Material Contracts are filed as exhibits to the Company
SEC Reports or are listed in Item 3.11 of the Company Letter. Except as set
forth in Item 3.11 of the Company Letter, neither the Company nor any of its
Subsidiaries is a party to or bound by any non-competition agreement or any
other agreement or obligation which purports to limit in any material respect
the manner in which, or the localities in which, the Company or any such
Subsidiary is entitled to conduct all or any material portion of the business of
the Company and its Subsidiaries taken as whole.
 
     Section 3.12.  LITIGATION.  There is no action, suit or proceeding, claim,
arbitration or, to the knowledge of the Company, investigation against the
Company or any of its Subsidiaries pending or, to the knowledge of the Company,
threatened, or as to which the Company or any of its Subsidiaries has received
any written notice of assertion, which, if decided adversely to the Company or
such Subsidiary, could reasonably be expected to have a Material Adverse Effect
on the Company or impair the ability of the Company to consummate the
transactions contemplated by this Agreement, nor is there any judgment, decree,
injunction, rule or order of any Governmental Entity or arbitrator outstanding
against the Company or any of its Subsidiaries having or which, insofar as
reasonably can be foreseen, in the future would have any such effect.
 
     Section 3.13.  ENVIRONMENTAL MATTERS.  (a) Except as set forth in Item 3.13
of the Company Letter, the Company has no reason to believe (i) that any
underground storage tanks are present under any property that the Company or any
of its Subsidiaries has at any time owned, operated, occupied or leased or (ii)
that any amount of any substance that has been designated by any Governmental
Entity or by applicable federal, state or local law to be radioactive, toxic,
hazardous or otherwise a danger to health or the environment, including PCBs,
asbestos, petroleum, urea-formaldehyde and all substances listed as hazardous
substances pursuant to the Comprehensive Environmental Response, Compensation,
and Liability Act of 1980, as amended, or defined as a hazardous waste pursuant
to the United States Resource Conservation and Recovery Act of 1976, as amended,
and the regulations promulgated pursuant to said laws (a "Hazardous Material"),
is present, as a result of actions of the Company or any of its Subsidiaries or
actions of any third party or otherwise, in, on or under any property, including
the land and the improvements, ground water and surface water, that the Company
or any of its Subsidiaries has at any time owned, operated, occupied or leased,
where the presence of such underground storage tanks or Hazardous Material would
be reasonably likely to have a
 
                                      I-10
<PAGE>   66
 
Material Adverse Effect on the Company; provided that the handling or use of a
Hazardous Material in compliance with applicable standards or permits shall not
be included in this representation.
 
          (b)  At no time has the Company or any of its Subsidiaries
     transported, stored, used, manufactured, disposed of, released or exposed
     its employees or others to Hazardous Materials in violation of any law in
     effect on or before the Closing Date, nor has the Company or any of its
     Subsidiaries disposed of, transported, sold, or manufactured any product
     containing a Hazardous Material (collectively, "Hazardous Materials
     Activities") in violation of any rule, regulation, treaty or statute
     promulgated by any Governmental Entity to prohibit, regulate or control
     Hazardous Materials or any Hazardous Material Activity, which violation has
     had or is reasonably likely to have a Material Adverse Effect on the
     Company.
 
          (c)  The Company and its Subsidiaries currently hold all environmental
     approvals, permits, licenses, clearances and consents (the "Environmental
     Permits") necessary for the conduct of the Hazardous Material Activities
     and other businesses of the Company and its Subsidiaries as such activities
     and businesses are currently being conducted in all material respects.
 
          (d)  No action, proceeding, revocation proceeding, amendment
     procedure, writ, injunction or claim is pending or, to the knowledge of the
     Company, threatened concerning any Environmental Permit or any Hazardous
     Materials Activity of the Company or any of its Subsidiaries and the
     Company is not aware of any fact or circumstance which could (i) involve
     the Company or any of its Subsidiaries in any environmental litigation
     which, if decided adversely to the Company and its Subsidiaries, could have
     a Material Adverse Effect on the Company, or (ii) impose upon the Company
     or any of its Subsidiaries any environmental liability which would have a
     Material Adverse Effect on the Company
 
     Section 3.14.  EMPLOYEE BENEFIT PLANS.  (a) The Company has made available
to Parent all employee benefit plans (as defined in Section 3(3) of the Employee
Retirement Income Security Act of 1974, as amended ("ERISA")), all employment,
termination and consulting agreements, all bonus, stock option, stock
appreciation right, restricted stock, stock purchase, incentive, deferred
compensation, supplemental retirement, severance and other similar employee
benefit plans and agreements, and all unexpired severance plans and agreements,
written or otherwise, for the benefit of, or relating to, any current or former
employee of the Company or any of its Subsidiaries or any trade or business
(whether or not incorporated) or other organization that together with the
Company is treated as a single employer under Section 414 of the Code
(collectively, the "Company Employee Plans"). Neither the Company nor any of its
Subsidiaries, nor any trade or business (whether or not incorporated) or other
organization that together with the Company is treated as a single employer
under Section 414 of the Code maintains or has ever in the past maintained or
contributed to any employee benefit plan subject to Title IV of ERISA (including
a multiemployer plan as defined in Section 3(37) of ERISA). Item 3.14 of the
Company Letter contains a list of all of the Company Employee Plans.
 
          (b)  With respect to each Company Employee Plan, the Company has made
     available to Parent, a true and correct copy of (i) the most recent annual
     report (Form 5500) filed with the Internal Revenue Service if such Company
     Employee Plan is subject to such filing requirement, (ii) such Company
     Employee Plan, (iii) any trust agreement or group annuity contract relating
     to such Company Employee Plan and (iv) the most recent determination letter
     issued with respect to any Company Employee Plan which is intended to be
     qualified under Section 401(a) of the Code.
 
          (c)  With respect to the Company Employee Plans, no event has
     occurred, and to the knowledge of the Company there exists no condition or
     set of circumstances, in connection with which, individually or in the
     aggregate, the Company or any of its Subsidiaries could be subject to any
     material liability, including the loss of income Tax deductions under
     ERISA, the Code or any other applicable law.
 
          (d)  With respect to the Company Employee Plans, individually and in
     the aggregate, there are no material funded benefit obligations for which
     contributions have not been made or properly accrued and there are no
     material unfunded benefit obligations that have not been accounted for by
     reserves, or otherwise properly footnoted in accordance with United States
     generally accepted accounting principles, on the Company Financial
     Statements.
 
                                      I-11
<PAGE>   67
 
          (e)  Except as disclosed in Item 3.14 of the Company Letter, neither
     the Company nor any of its Subsidiaries is a party to any oral or written
     (i) union or collective bargaining agreement, (ii) agreement with any
     officer or other key employee of the Company or any of its Subsidiaries,
     the benefits of which are contingent, or the terms of which are materially
     altered, upon the occurrence of any of the transactions contemplated by
     this Agreement or upon such occurrence coupled with a subsequent event,
     (iii) agreement with any officer or key employee of the Company or any of
     its Subsidiaries providing any term of employment or compensation
     guarantee, or (iv) agreement or plan, including any Company Employee Plan,
     any of the benefits of which will be increased, or the vesting or
     exercisability of the benefits of which will be accelerated, by the
     occurrence of any of the transactions contemplated by this Agreement or the
     value of any of the benefits of which will be calculated on the basis of
     any of the transactions contemplated by this Agreement. Except as set forth
     in Item 3.14 of the Company Letter, Section 162 (m) of the Code does not
     limit the deductibility of any compensation payable to any officer of the
     Company, including compensation or benefits under any plan or agreement
     disclosed pursuant to the preceding sentence.
 
     Section 3.15.  COMPLIANCE WITH LAWS.  The Company and its Subsidiaries have
complied with, are not in violation of, and have not received any notices of
violations with respect to, any federal, state, local or foreign statute, law or
regulation with respect to the conduct of their business, or ownership or
operation of their business, except for failures to comply or violations which
could not reasonably be expected to have a Material Adverse Effect on the
Company or impair the ability of the Company to consummate the transactions
contemplated by this Agreement. There are no situations with respect to the
Company which involved or involve (i) the use of any corporate funds for
unlawful contributions, gifts, entertainment or other unlawful expenses related
to political activity, (ii) the making of any direct or indirect unlawful
payments to government officials or others from corporate funds or the
establishment or maintenance of any unlawful or unrecorded funds, (iii) the
violation of any of the provisions of The Foreign Corrupt Practices Act of 1977,
or any rules or regulations promulgated thereunder, or (iv) the receipt of any
illegal discounts or rebates or any other violation of the antitrust laws.
 
     Section 3.16.  POOLING.  Neither the Company nor any of its Subsidiaries,
nor, to the knowledge of the Company, any of its affiliates, has taken or agreed
to take any action that would prevent the Merger from being treated as a
"pooling of interests" for financial accounting purposes in accordance with GAAP
and applicable SEC regulations. The factual information to be provided by the
Company to KPMG Peat Marwick LLP (the "Company Auditors"), in connection with
their written opinion to be delivered pursuant to Section 7.1(f) will be correct
in all material respects and will be provided to Parent
 
     Section 3.17.  AFFILIATES.  Except for the persons listed on Item 3.17 of
the Company Letter, there are no persons who, to the knowledge of the Company,
may be deemed to be affiliates of the Company under Rule 1-02 of Regulation S-X
of the SEC.
 
     Section 3.18.  INTERESTED PARTY TRANSACTIONS.  Except as set forth in the
Company SEC Reports or by virtue of the Merger, since the date of the Company's
last proxy statement to its stockholders, no event has occurred that would be
required to be reported by the Company pursuant to paragraphs (a), (b) or (c) of
Item 404 of Regulation S-K promulgated by the SEC. Other than the Services
Agreement (as defined below) there are no agreements between the Company and any
of its affiliates which are not required to be listed in Item 3.14 of the
Company Letter. The loan agreement between the Company and Safeguard referenced
in the Company's Proxy Statement for its 1997 Annual Meeting of Stockholders has
terminated and is of no force or effect and there are no amounts outstanding
thereunder.
 
     Section 3.19.  REGISTRATION STATEMENT; PROXY STATEMENT/PROSPECTUS.  The
information supplied by the Company for inclusion in the registration statement
of Parent on Form S-4 pursuant to which shares of Parent Common Stock issued in
the Merger will be registered with the SEC (the "Registration Statement") shall
not contain, at the time the Registration Statement is declared effective by the
SEC, any untrue statement of a material fact or omit to state any material fact
required to be stated in the Registration Statement or necessary in order to
make the statements in the Registration Statement, in light of the circumstances
under which they were made, not misleading. The information supplied by the
Company for inclusion in the proxy statement/prospectus (the "Proxy Statement")
to be sent to the stockholders of the Company in connection with
 
                                      I-12
<PAGE>   68
 
the special meeting of the Company's stockholders to consider this Agreement and
the Merger (the "Stockholders Meeting") shall not, on the date the Proxy
Statement is first mailed to stockholders of the Company, at the time of the
Stockholders Meeting or at the Effective Time, contain any statement which, at
such time and in light of the circumstances under which it was made, is false or
misleading with respect to any material fact, or omit to state any material fact
necessary in order to make the statements made in the Proxy Statement not false
or misleading or omit to state any material fact necessary to correct any
statement in any earlier communication with respect to the solicitation of
proxies for the Stockholders Meeting which has become false or misleading. If at
any time prior to the Effective Time any event relating to the Company or any of
its affiliates should be discovered by the Company which should be set forth in
an amendment to the Registration Statement or a supplement to the Proxy
Statement, the Company shall promptly inform Parent.
 
     Section 3.20.  NO EXCESS PARACHUTE PAYMENTS.  Any amount that could be
received (whether in cash or property or the vesting of property) as a result of
any of the transactions contemplated by this Agreement by any employee, officer
or director of the Company or any of its affiliates who is a "disqualified
individual" (as such term is defined in Proposed Treasury Regulation Section
1.280G-1) under any employment, severance or termination agreement, other
compensation arrangement or Company Employee Plan currently in effect would not
be characterized as an "excess parachute payment" (as such term is defined in
Section 280G of the Code).
 
     Section 3.21.  OPINION OF FINANCIAL ADVISOR.  The financial advisor to the
Company, Robert W. Baird & Co., Inc., has delivered to the Company an opinion
dated as of the date of this Agreement to the effect that the Exchange Ratio is
fair from a financial point of view to the holders of the Company Common Stock
and a copy of such opinion has been made available to Parent.
 
     Section 3.22.  SECTION 203 OF THE DGCL NOT APPLICABLE.  The restrictions
contained in Section 203 of the DGCL applicable to a "business combination" (as
defined in Section 203) will not apply to the execution, delivery or performance
of this Agreement or the consummation of the Merger or the other transactions
contemplated hereby.
 
     Section 3.23.  VOTING REQUIREMENTS.  The affirmative vote of the holders of
a majority of the outstanding shares of Company Common Stock approving this
Agreement is the only vote of holders of any class or series of the Company's
capital stock necessary to approve this Agreement and the transactions
contemplated hereby.
 
     Section 3.24.  BROKERS.  No broker, investment banker, financial advisor or
other person, other than Robert W. Baird & Co., Inc., the fees and expenses of
which will be paid by the Company, is entitled to any broker's, finder's,
financial advisor's or other similar fee or commission in connection with the
transactions contemplated by this Agreement based upon arrangements made by or
on behalf of the Company. A true and complete copy of the Company's engagement
letter with Robert W. Baird & Co., Inc. has been made available to Parent.
 
     Section 3.25.  ADDITIONAL DISCLOSURE.  The information set forth in Item
3.25 of the Company Letter is complete and correct in all material respects as
of the date hereof and the Company will use its reasonable best efforts to cause
such information to continue to be so correct and complete as of the Closing
Date.
 
                                   ARTICLE IV
 
                REPRESENTATIONS AND WARRANTIES OF PARENT AND SUB
 
     Parent and Sub represent and warrant to the Company as follows:
 
     Section 4.1.  ORGANIZATION.  Parent and each of its material Subsidiaries
(i) is a corporation or other business entity duly organized, validly existing
and in good standing under the laws of the jurisdiction of its formation, (ii)
has all requisite corporate or similar power to own, lease and operate its
property and to carry on its business as now being conducted and as proposed to
be conducted, and (iii) is duly qualified to do business and is in good standing
as a foreign corporation or other business entity in each jurisdiction in which
the nature of its activities requires it to be so qualified, except where the
failure to have such power or the failure to be so qualified could not
reasonably be expected to have a Material Adverse Effect on Parent.
 
                                      I-13
<PAGE>   69
 
     Section 4.2.  PARENT SUBSIDIARIES.  Except as set forth in Item 4.2 of the
letter from Parent to the Company dated and delivered as of the date hereof (the
"Parent Letter"), which relates to this Agreement and is designated therein as
being the Parent Letter, there are no outstanding subscriptions, options, calls,
voting trusts, proxies or warrants with respect to any capital stock of any of
the material Subsidiaries of Parent, including any right obligating any such
material Subsidiary to issue, deliver, or sell additional shares of its capital
stock, in each case other than with Parent or one of its Subsidiaries. Except as
required by applicable law and except for director or qualifying shares, all of
the outstanding shares of capital stock of each material Subsidiary listed on
Item 4.2 of the Parent Letter are duly authorized, validly issued, fully paid
and nonassessable, and all such shares are owned by Parent or another Subsidiary
of Parent.
 
     Section 4.3.  PARENT CAPITAL STRUCTURE.  (a) The authorized capital stock
of Parent consists of 500,000,000 shares of Parent Common Stock and 5,000,000
shares of Preferred Stock, $.01 par value per share ("Parent Preferred Stock").
As of January 2, 1998: (i) 181,626,660 shares of Parent Common Stock were issued
and outstanding, all of which are validly issued, fully paid and nonassessable;
(ii) no shares of Parent Preferred Stock are issued or outstanding; (iii) no
shares of Parent Common Stock or Parent Preferred Stock were held in the
treasury of Parent or by Subsidiaries of Parent; and (iv) 10,903,494 shares of
Parent Common Stock were reserved for issuance pursuant to stock options granted
and outstanding under Parent's stock option plans (the "Parent Option Plans").
Between January 2, 1998 and the date hereof, (i) no additional shares of capital
stock have been reserved for issuance by Parent and (ii) the only issuances of
shares of capital stock of Parent Common Stock have been issuances of Parent
Common Stock upon the exercise of outstanding stock options. All shares of
Parent Common Stock subject to issuance as specified above, upon issuance
pursuant to the terms and conditions specified in the instruments pursuant to
which they are issuable, shall be duly authorized, validly issued, fully paid
and nonassessable. There are no obligations, contingent or otherwise, of Parent
or any of its Subsidiaries to repurchase, redeem or otherwise acquire any shares
of Parent Common Stock.
 
          (b)  Except as set forth in this Section 4.2 or as reserved for future
     grants of options under the Parent Option Plans, there are no equity
     securities of any class of Parent, or any security exchangeable into or
     exercisable for such equity securities, issued, reserved for issuance or
     outstanding.
 
     Section 4.4.  AUTHORITY; NO CONFLICT; REQUIRED FILINGS AND CONSENTS.  (a)
Parent has all requisite corporate power and authority to enter into this
Agreement and to consummate the transactions contemplated hereby. The execution
and delivery of this Agreement and the consummation of the transactions
contemplated hereby have been duly authorized by all necessary corporate action
on the part of Parent. This Agreement has been duly executed and delivered by
Parent and constitutes the valid and binding obligations of Parent, enforceable
in accordance with the terms hereof, except as such enforceability may be
limited by bankruptcy, insolvency, reorganization, moratorium and other similar
laws affecting creditors' rights generally and general principles of equity,
regardless of whether asserted in a proceeding in equity or at law.
 
          (b)  The execution and delivery of this Agreement by Parent and Sub do
     not, and the consummation of the transactions contemplated by this
     Agreement will not, (i) conflict with, or result in any violation or breach
     of, any provision of the Certificate of Incorporation or Bylaws of Parent
     or Sub (in each case as heretofore amended), (ii) result in any violation
     or breach of, or constitute (with or without notice or lapse of time, or
     both) a default (or give rise to a right of termination, cancellation or
     acceleration of any obligation or loss of any material benefit) under, any
     of the terms, conditions or provisions of any loan, credit agreement, note,
     bond, mortgage, indenture, lease, contract or other agreement, instrument
     or obligation to which Parent or any of its Subsidiaries is a party or by
     which any of them or any of their properties or assets may be bound, or
     (iii) subject to the consents, approvals, orders, authorizations, filings,
     declarations and registrations specified in Section 4.3(c), conflict with
     or violate any judgment, order, decree, statute, law, ordinance, rule or
     regulation or any permit, concession, franchise or license applicable to
     Parent or any of its Subsidiaries or any of their properties or assets,
     except in the case of clause (ii) and (iii) for any such violations,
     breaches, defaults, terminations, cancellations or accelerations which in
     the aggregate could not reasonably be expected to have a Material Adverse
     Effect on Parent and do not impair the ability of Parent to perform its
     obligations under this Agreement or prevent the consummation of any of the
     transactions contemplated hereby.
 
                                      I-14
<PAGE>   70
 
          (c)  No consent, approval, order or authorization of, or registration,
     declaration or filing with, any Governmental Entity is required by or with
     respect to Parent or any of its Subsidiaries in connection with the
     execution and delivery of this Agreement or the consummation of the
     transactions contemplated hereby, except for (i) the filing of pre-merger
     notification reports under the HSR Act and the expiration or early
     termination of the waiting period thereunder; (ii) the filing of the
     Registration Statement with the SEC in accordance with the Securities Act
     and the entry of an order by the SEC permitting the Registration Statement
     to become effective; (iii) the filing of the Certificate of Merger with the
     Secretary of State of the State of Delaware in accordance with the DGCL;
     (iv) the filing of the Proxy Statement and related proxy materials with the
     SEC in accordance with the Exchange Act; (v) such consents, approvals,
     orders, authorizations, filings, registrations, Returns, and declarations
     as may be required under applicable federal and state securities and Tax
     laws and the laws of any foreign country; and (vi) such other consents,
     approvals, orders, authorizations, filings, declarations and registrations
     which, in the aggregate, if not obtained or made, could not reasonably be
     expected to have a Material Adverse Effect on Parent or impair the ability
     of Parent to perform its obligations under this Agreement.
 
     Section 4.5.  SEC FILINGS; FINANCIAL STATEMENTS.  (a) Parent has filed and
made available to the Company or its legal counsel all forms, reports and
documents required to be filed by Parent with the SEC (collectively, the "Parent
SEC Reports") since January 1, 1995. The Parent SEC Reports (i) at the time
filed, complied in all material respects with the applicable requirements of the
Securities Act and the Exchange Act, as the case may be, and (ii) did not at the
time they were filed (or if amended or superseded by a subsequent filing, then
on the date of such filing) contain any untrue statement of a material fact or
omit to state a material fact required to be stated in such Parent SEC Reports
or necessary in order to make the statements in such Parent SEC Reports, in the
light of the circumstances under which they were made, not misleading. None of
Parent's Subsidiaries is required to file any forms, reports or other documents
with the SEC.
 
          (b)  Each of the consolidated financial statements (including, in each
     case, any related notes) contained in the Parent SEC Reports, including any
     Parent SEC Reports filed from the date of this Agreement until the Closing,
     complied or will comply in all material respects with the applicable
     published rules and regulations of the SEC with respect thereto, was or
     will be prepared in accordance with GAAP applied on a consistent basis
     throughout the periods involved (except as may be indicated in the notes to
     such financial statements or, in the case of unaudited statements, as
     permitted by Form 10-Q or 8-K promulgated by the SEC), and fairly presented
     or will fairly present the consolidated financial position of Parent and
     its Subsidiaries as at the respective dates and the consolidated results of
     its operations and cash flows for the periods indicated, except that the
     unaudited interim financial statements were or are subject to normal and
     recurring year-end adjustments which were not or are not expected to be
     material in amount. The unaudited consolidated balance sheet of Parent as
     of September 30, 1997 is referred to herein as the "Parent Balance Sheet."
 
     Section 4.6.  ABSENCE OF UNDISCLOSED LIABILITIES.  Except as disclosed in
Item 4.6 of the Parent Letter or as otherwise disclosed in the Parent SEC
Reports filed and publicly available prior to the date of this Agreement, Parent
and its Subsidiaries do not have any liabilities, either accrued or contingent
(whether or not required to be reflected in financial statements in accordance
with United States generally accepted accounting principles), and whether due or
to become due, which individually or in the aggregate could reasonably be
expected to have a Material Adverse Effect on Parent, other than (i) liabilities
reflected in the Parent Balance Sheet, and (ii) normal or recurring liabilities
incurred since September 30, 1997 in the ordinary course of business consistent
with past practices which would not individually or in the aggregate have a
Material Adverse Effect on Parent.
 
     Section 4.7.  ABSENCE OF CERTAIN CHANGES OR EVENTS.  Between the date of
the Parent Balance Sheet and the date hereof, Parent and its Subsidiaries have
conducted their businesses only in the ordinary course in a manner consistent
with past practice (except as disclosed in the Parent SEC Reports filed and
publicly available prior to the date of this Agreement). Except with respect to
the matters set forth in Item 4.6 of the Parent Letter, since the Parent Balance
Sheet Date there has not been: (a) any Material Adverse Effect on Parent or any
facts or circumstances that could reasonably be expected to result in a Material
Adverse Effect
 
                                      I-15
<PAGE>   71
 
on Parent; (b) any damage, destruction or loss (whether or not covered by
insurance) with respect to Parent or any of its Subsidiaries having a Material
Adverse Effect on Parent; (c) any material change by Parent or any of its
Subsidiaries in its accounting methods, principles or practices; or (d) any
revaluation by Parent or any of its Subsidiaries of any of its assets having a
Material Adverse Effect on Parent, including writing down the value of
capitalized software or inventory or writing off notes or accounts receivable
other than in the ordinary course of business consistent with past practice.
 
     Section 4.8.  TAXES.  (a) Except as disclosed in Item 4.8 of the Parent
Letter, each of Parent and its Subsidiaries has prepared and timely filed (or
will so file) all United States federal, state and local Returns required to be
filed at or before the Effective Time relating to any and all Taxes concerning
or attributable to Parent or any of its Subsidiaries or to their operations, and
such Returns are true and correct and have been completed in accordance with
applicable law, except where any such failure to prepare or file timely or any
such failure to be true and correct, or any such failure to be completed in
accordance with applicable law would not individually, or in the aggregate, have
a Material Adverse Effect on Parent.
 
          (b)  Except as disclosed in Item 4.8 of the Parent Letter, each of
     Parent and its Subsidiaries as of the Effective Time will have paid all
     Taxes it is required to pay prior to the Effective Time, except where any
     such failure to pay would not have a Material Adverse Effect on Parent.
 
          (c)  Except as disclosed in Item 4.8 of the Parent Letter, there is no
     material United States federal or state income Tax deficiency outstanding
     or assessed against Parent or any of its Subsidiaries that has not been
     paid in full or fully reflected as a liability on the Parent Balance Sheet
     nor has Parent or any of its Subsidiaries executed any waiver of any
     statute of limitations on or extending the period for the assessment or
     collection of any material United States federal or state income Tax.
 
          (d)  Except as disclosed in Item 4.8 of the Parent Letter, there is no
     action, suit, investigation, audit, claim or assessment pending or proposed
     or threatened in writing with respect to Taxes of Parent or any of its
     Subsidiaries that, if decided adversely to Parent, would have a Material
     Adverse Effect on Parent.
 
          (e)  Except as disclosed in Item 4.8 of the Parent Letter, there are
     no liens for Taxes upon the assets of Parent or any of its Subsidiaries
     except liens relating to current Taxes not yet due and except where such
     liens would not have a Material Adverse Effect on Parent.
 
          (f)  Except as disclosed in Item 4.8 of the Parent Letter, all Taxes
     which Parent or any of its Subsidiaries are required by law to withhold or
     to collect for payment have been duly withheld and collected, and have been
     paid or accrued, reserved against and entered on the books of Parent,
     except where any such failure to withhold or collect or such failure to pay
     or accrue, reserve against and enter would not individually, or in the
     aggregate, have a Material Adverse Effect on Parent.
 
          (g)  Except as disclosed in Item 4.8 of the Parent Letter, neither
     Parent nor any of its Subsidiaries has any material liability for unpaid
     federal, state, local or foreign Taxes that has not been accrued for or
     reserved on the Parent Balance Sheet, whether asserted or unasserted,
     contingent or otherwise, except where such liability would not have a
     Material Adverse Affect on Parent.
 
          (h)  Neither Parent nor any of its Subsidiaries, nor any of its other
     affiliates (i) has taken any action, agreed to take any action, or failed
     to take any action, or (ii) has knowledge of any fact or circumstance that
     (without regard to any action taken or agreed to be taken by the Company or
     any of its affiliates), in each case, Parent, such Subsidiary or such other
     affiliate has actual knowledge could reasonably be expected to cause the
     Merger to fail to qualify as a "reorganization" within the meaning of
     Section 368(a) of the Code.
 
     Section 4.9.  PROPERTIES.  Parent and its Subsidiaries own or have valid
leasehold interests in all real property necessary for the conduct of their
businesses in all material respects as presently conducted. All material leases
to which Parent or any of its Subsidiaries is a party are in good standing,
valid and effective in accordance with their respective terms, and neither
Parent nor its Subsidiaries is in default under any of such leases, except where
the lack of such good standing, validity and effectiveness or the existence of
such default could not reasonably be expected to have a Material Adverse Effect
on Parent.
 
                                      I-16
<PAGE>   72
 
     Section 4.10.  INTELLECTUAL PROPERTY.  Except with respect to the matters
set forth in Item 4.6 of the Parent Letter, Parent and its Subsidiaries own, or
are licensed or otherwise possess, legally enforceable rights to use, all
patents, trademarks, trade names, service marks, copyrights and mask works, any
applications for and registrations of such patents, trademarks, trade names,
service marks, copyrights and mask works, and all processes, formulae, methods,
schematics, technology, know how, computer software programs or applications and
tangible or intangible proprietary information or material that are necessary to
conduct the business of Parent and its Subsidiaries as currently conducted or
planned to be conducted by Parent and its Subsidiaries except where the failure
to have such ownership or possession could not reasonably be expected to have a
Material Adverse Effect on Parent.
 
     Section 4.11.  AGREEMENTS, CONTRACTS AND COMMITMENTS.  Neither Parent nor
any of its Subsidiaries has breached, or received in writing any claim or threat
(for which there is a reasonable basis) that it has breached, any of the terms
or conditions of any material agreement, contract or commitment to which it is a
party or to which any of its assets is subject ("Parent Material Contracts") in
such a manner as would permit any other party to cancel, modify the terms of or
terminate the same or would permit any other party to collect material damages
from Parent or any of its Subsidiaries under any Parent Material Contract. Each
Parent Material Contract that has not expired or been terminated is in full
force and effect and is not subject to any material default thereunder of which
Parent is aware by any party obligated to Parent or any of its Subsidiaries
pursuant to such Parent Material Contract.
 
     Section 4.12.  LITIGATION.  Except with respect to the matters set forth in
Item 4.6 of the Parent Letter, there is no action, suit or proceeding, claim,
arbitration or, to the knowledge of Parent, investigation against Parent or any
of its Subsidiaries pending or, to the knowledge of Parent, threatened, or as to
which Parent or any of its Subsidiaries has received any written notice of
assertion, which, if decided adversely to Parent or such Subsidiary, could
reasonably be expected to have a Material Adverse Effect on Parent or impair the
ability of Parent to consummate the transactions contemplated by this Agreement,
nor is there any judgment, decree, injunction, rule or order of any Governmental
Entity or arbitrator outstanding against Parent or any of its Subsidiaries
having or which, insofar as reasonably can be foreseen, in the future would have
any such effect.
 
     Section 4.13.  ENVIRONMENTAL MATTERS.  (a) Except as set forth in Item 4.13
of the Parent Letter, Parent has no reason to believe (i) that any underground
storage tanks are present under any property that Parent or any of its
Subsidiaries has at any time owned, operated, occupied or leased or (ii) that
any Hazardous Material is present, as a result of actions of Parent or any of
its Subsidiaries or actions of any third party or otherwise, in, on or under any
property, including the land and the improvements, ground water and surface
water, that Parent or any of its Subsidiaries has at any time owned, operated,
occupied or leased, where the presence of such underground storage tanks or
Hazardous Material would be reasonably likely to have a Material Adverse Effect
on Parent; provided that the handling and use of a Hazardous Material in
compliance with applicable standards or permits shall not be included in this
representation.
 
          (b)  At no time has Parent or any of its Subsidiaries transported,
     stored, used, manufactured, disposed of, released or exposed its employees
     or others to Hazardous Materials in violation of any law in effect on or
     before the Closing Date, nor has Parent or any of its Subsidiaries engaged
     in Hazardous Materials Activities in violation of any rule, regulation,
     treaty or statute promulgated by any Governmental Entity to prohibit,
     regulate or control Hazardous Materials or any Hazardous Materials
     Activity, which violation has had or is reasonably likely to have a
     Material Adverse Effect on Parent.
 
          (c)  Parent and its Subsidiaries currently hold all Environmental
     Permits necessary for the conduct of the Hazardous Materials Activities and
     other businesses of Parent and its Subsidiaries as such activities and
     businesses are currently being conducted.
 
          (d)  Parent is not aware of any fact or circumstance which could (i)
     involve Parent or any of its Subsidiaries in any environmental litigation
     which, if decided adversely to Parent and its Subsidiaries, could have a
     Material Adverse Effect on Parent, or (ii) impose upon Parent or any of its
     Subsidiaries any environmental liability which would have a Material
     Adverse Effect on Parent.
 
                                      I-17
<PAGE>   73
 
     Section 4.14.  POOLING.  Neither Parent nor any of its Subsidiaries, nor,
to the knowledge of Parent, any of its affiliates has taken or agreed to take
any action that would prevent the Merger from being treated as a "pooling of
interests" for financial accounting purposes in accordance with GAAP and
applicable SEC regulations. The factual information to be provided by Parent to
the Ernst & Young LLP, ("Parent Auditors") in connection with their written
opinion to be delivered pursuant to Section 7.1(f) will be correct in all
material respects.
 
     Section 4.15.  AFFILIATES.  Except for the persons listed on Item 4.15 of
the Parent Letter, there are no persons who, to the knowledge of Parent, may be
deemed to be affiliates of Parent under Rule 1-02 of Regulation S-X of the SEC.
 
     Section 4.16.  COMPLIANCE WITH LAWS.  Parent and its Subsidiaries have
complied with, are not in violation of, and have not received any notices of
violations with respect to, any federal, state, local or foreign statute, law or
regulation with respect to the conduct of their business, or ownership or
operation of their business, except for failures to comply or violations which
could not reasonably be expected to have a Material Adverse Effect on Parent or
impair the ability of Parent to consummate the transactions contemplated by this
Agreement. There are no situations with respect to Parent which involved or
involve (i) the use of any corporate funds for unlawful contributions, gifts,
entertainment or other unlawful expenses related to political activity, (ii) the
making of any direct or indirect unlawful payments to government officials or
others from corporate funds or the establishment or maintenance of any unlawful
or unrecorded funds, (iii) the violation of any of the provisions of The Foreign
Corrupt Practices Act of 1977, or any rules or regulations promulgated
thereunder, or (iv) the receipt of any illegal discounts or rebates or any other
violation of the antitrust laws.
 
     Section 4.17.  REGISTRATION STATEMENT; PROXY STATEMENT/PROSPECTUS.  The
information supplied by Parent for inclusion in the Registration Statement shall
not contain, at the time the Registration Statement is declared effective by the
SEC, any untrue statement of a material fact or omit to state any material fact
required to be stated in the Registration Statement or necessary in order to
make the statements in the Registration Statement, in light of the circumstances
under which they were made, not misleading. The information supplied by Parent
for inclusion in the Proxy Statement to be sent to the stockholders of the
Company in connection with the Stockholders Meeting shall not, on the date the
Proxy Statement is first mailed to stockholders of the Company, at the time of
the Stockholders Meeting or at the Effective Time, contain any statement which,
at such time and in light of the circumstances under which it was made, is false
or misleading with respect to any material fact, or omit to state any material
fact necessary in order to make the statements made in the Proxy Statement not
false or misleading or omit to state any material fact necessary to correct any
statement in any earlier communication with respect to the solicitation of
proxies for the Stockholders Meeting which has become false or misleading. If at
any time prior to the Effective Time any event relating to Parent or any of its
affiliates should be discovered by Parent which should be set forth in an
amendment to the Registration Statement or a supplement to the Proxy Statement,
Parent shall promptly inform the Company.
 
     Section 4.18.  INTERIM OPERATIONS OF SUB.  Sub was formed solely for the
purpose of engaging in the transactions contemplated by this Agreement, has
engaged in no other business activities, and has conducted its operations only
as contemplated by this Agreement.
 
     Section 4.19.  VOTING REQUIREMENTS.  No action by the stockholders of
Parent is required to approve this Agreement and the transactions contemplated
hereby.
 
     Section 4.20.  BROKERS.  No broker, investment banker, financial advisor or
other person, other than Goldman, Sachs & Co., the fees and expenses of which
will be paid by Parent, is entitled to any broker's, finder's, financial
advisor's or other similar fee or commission in connection with the transactions
contemplated by this Agreement based upon arrangements made by or on behalf of
Parent or Sub.
 
                                      I-18
<PAGE>   74
 
                                   ARTICLE V
 
                              CONDUCT OF BUSINESS
 
     Section 5.1.  COVENANTS OF THE COMPANY.  During the period from the date of
this Agreement to the Effective Time, the Company agrees as to itself and its
Subsidiaries (except to the extent that Parent shall otherwise consent in
writing), to carry on its business in the usual, regular and ordinary course in
substantially the same manner as previously conducted, to pay its debts and
Taxes when due subject to good faith disputes over such debts or Taxes, to pay
or perform its other obligations when due, and, to the extent consistent with
the foregoing, to use all reasonable best efforts consistent with past practices
and policies to (i) preserve intact its present business organization, (ii) keep
available the services of its present officers and key employees, and (iii)
preserve its relationships with customers, suppliers, distributors, licensors,
licensees and others having business dealings with it. The Company shall notify
Parent promptly after becoming aware of any event or occurrence that would
result in a material breach of any covenant or agreement of the Company set
forth in this Agreement or cause any representation or warranty of the Company
set forth in this Agreement to be untrue if made as of the date of, and giving
effect to, such event or occurrence, which if uncured, could reasonably be
expected to cause any condition set forth in Section 7.2(a) or 7.2(b) not to be
satisfied. Except as expressly contemplated by this Agreement, the Company shall
not (and shall not permit any of its Subsidiaries to), without the prior written
consent of Parent:
 
          (a) accelerate, amend or change the period of exercisability of
     options or restricted stock granted under any of the Company Stock Plans or
     authorize cash payments in exchange for any options granted under any of
     such plans;
 
          (b) transfer or license to any person or entity or otherwise extend,
     amend or modify any rights to the Company Intellectual Property Rights
     other than licenses to customers in the ordinary course of business
     consistent with past practices on a non-exclusive basis;
 
          (c) declare or pay any dividends on or make any other distributions
     (whether in cash, stock or property, other than dividends or distributions
     by a direct or indirect wholly owned subsidiary of the Company to its
     parent) in respect of any of its capital stock, or split, combine or
     reclassify any of its capital stock or issue or authorize the issuance of
     any other securities in respect of, in lieu of or in substitution for
     shares of its capital stock, or purchase or otherwise acquire, directly or
     indirectly, any shares of its capital stock;
 
          (d) issue, deliver, sell, pledge or otherwise encumber, or authorize
     or propose the issuance, delivery, sale, pledge or encumbrance of, any
     shares of its capital stock or securities convertible into shares of its
     capital stock, or subscriptions, rights, warrants or options to acquire, or
     other agreements or commitments of any character obligating it to issue any
     such shares or other convertible securities, other than the issuance of the
     Company Common Stock upon the exercise of Company Stock Options outstanding
     on the date of this Agreement and in accordance with their present terms,
     except for issuances of Company Stock Options pursuant to the Company Stock
     Plans relating to not more than one hundred fifty thousand (150,000) shares
     of Company Common Stock in the aggregate, in connection with the hiring of
     new employees or the promotion of officers and employees (other than Senior
     Officers), in each case in the ordinary course of business, consistent with
     past practice;
 
          (e) acquire or agree to acquire, by merging or consolidating with, by
     purchasing any equity interest in or the assets of, or by any other means,
     any business or any corporation, partnership, limited liability company or
     other business organization or division or any interest therein;
 
          (f) sell, lease, license, mortgage, encumber or otherwise dispose of
     any of its properties or assets, except for sales, leases or licenses of
     products or services in the ordinary course of business in accordance with
     past practices;
 
          (g) take any action to: (i) increase or agree to increase the
     compensation payable or to become payable to its officers or employees,
     except for regularly scheduled increases in salary or wages (not in excess
     of ten percent (10%) in the aggregate for each person) of employees (other
     than Senior Officers) in accordance with past practices, (ii) grant any
     severance or termination pay to, or enter into any
 
                                      I-19
<PAGE>   75
 
     employment or severance agreements with, directors or Senior Officers,
     (iii) grant any severance or termination pay to, or enter into any
     employment or severance agreement with, any other employees, except in the
     ordinary course of business consistent with past practice, provided that
     the aggregate of such payments shall not be in excess of one hundred
     thousand dollars ($100,000), (iv) enter into any collective bargaining
     agreement, or (v) establish, adopt or enter into any bonus, profit sharing,
     thrift, compensation, stock option, restricted stock, pension, retirement,
     deferred compensation, employment, termination, severance or other plan,
     trust, fund, policy or arrangement for the benefit of any directors,
     officers or employees or amend any Company Employee Plan;
 
          (h) revalue any of its assets, including writing down the value of
     inventory or writing off notes or accounts receivable, other than in the
     ordinary course of business pursuant to arm's length transactions on
     commercially reasonable terms;
 
          (i) (y) incur any indebtedness for borrowed money or guarantee any
     such indebtedness or issue or sell any debt securities or warrants or
     rights to acquire any debt securities or guarantee any debt securities of
     others, enter into any "keep well" or other agreement to maintain any
     financial statement condition of another person or enter into any
     arrangement having the economic effect of any of the foregoing, or (z) make
     any loans, advances or capital contributions to, or investments in, any
     other person, other than to the Company or any of its wholly owned
     Subsidiaries;
 
          (j) amend or propose to amend its Certificate of Incorporation or
     Bylaws or other comparable charter or organizational documents;
 
          (k) incur or commit to incur capital expenditures in excess of five
     hundred thousand dollars ($500,000) individually, or four million dollars
     ($4,000,000) in the aggregate;
 
          (l) make any material amendments to any OEM agreement or enter into or
     make any amendments to any agreements pursuant to which any third party is
     granted exclusive marketing, manufacturing or other rights with respect to
     any Company product, process or technology, other than granting to specific
     customers non-territorial exclusive rights to physical packaging and
     related interfaces developed by the Company for such customer's equipment;
 
          (m) amend in any respect that, taken as a whole, is material and
     adverse to the Company or terminate any material contract, agreement or
     license to which it is a party;
 
          (n) (y) waive or release any material right or claim (except in
     connection with amendments that comply with clause (m) immediately above),
     or (z) pay, discharge or satisfy any material claims, liabilities or
     obligations (absolute, accrued, asserted or unasserted, contingent or
     otherwise), other than the payment, discharge or satisfaction, in the
     ordinary course of business consistent with past practice or in accordance
     with their terms, of liabilities reflected or reserved against in, or
     contemplated by, the most recent Company Financial Statements (or the notes
     thereto) filed prior to the date hereof, or incurred in the ordinary course
     of business consistent with past practice;
 
          (o) settle or compromise Tax liabilities in excess of five hundred
     thousand dollars ($500,000) in the aggregate, or prepare or file any Return
     inconsistent with past practice or, on any such Return, take any position,
     make any election, or adopt any method that is inconsistent with positions
     taken, elections made or methods used in preparing or filing similar
     Returns in prior periods;
 
          (p) initiate any litigation or arbitration proceeding, other than
     litigation involving Parent relating to this Agreement and counterclaims or
     other proceedings responsive to litigation filed by a third party; or
 
          (q) take, or agree in writing or otherwise to take, any of the actions
     described in the foregoing clauses (a) through (p), or any action (other
     than actions of the type contemplated by clauses (a) through (p) above
     which are permitted thereby) which (i) would make any of the Company's
     representations or warranties in this Agreement, if made on and as of the
     date of such action or agreement, untrue or incorrect in any material
     respect, or (ii) could prevent it from performing, or cause it not to
     perform, its obligations under this Agreement.
 
     Section 5.2. COVENANTS OF PARENT.  Parent shall notify the Company promptly
after becoming aware of any event or occurrence that would result in a material
breach of any covenant or agreement of Parent set
 
                                      I-20
<PAGE>   76
 
forth in this Agreement or cause any representation or warranty of Parent set
forth in this Agreement to be untrue if made as of the date of, and giving
effect to, such event or occurrence, which if uncured, could reasonably be
expected to cause any condition set forth in Section 7.2(a) or 7.2(b) not to be
satisfied. Between the date hereof and April 16, 1998, except as expressly
contemplated by this Agreement, Parent shall not (and shall not permit any of
its Subsidiaries to), without the prior written consent of the Company:
 
          (a) declare or pay any dividends on or make any other distributions
     (whether in cash, stock or property, other than dividends or distributions
     by a direct or indirect wholly owned subsidiary of Parent to its parent) in
     respect of any of its capital stock, or split, combine or reclassify any of
     its capital stock or issue or authorize the issuance of any other
     securities in respect of, in lieu of or in substitution for shares of its
     capital stock, or spend more than $50,000,000 to purchase or otherwise
     acquire, directly or indirectly, any shares of its capital stock;
 
          (b) issue or authorize the issuance or delivery of, any shares of its
     capital stock or securities convertible into shares of its capital stock,
     or subscriptions, rights, warrants or options to acquire, or other
     agreements or commitments of any character obligating it to issue any such
     shares or other convertible securities, other than (i) the issuance of the
     Parent Common Stock upon the exercise of Parent stock options outstanding
     on the date of this Agreement and (ii) issuances not involving more than
     five percent (5%) of the currently issued and outstanding Parent Common
     Stock;
 
          (c) acquire or agree to acquire, by merging or consolidating with, by
     purchasing any equity interest in or the assets of, or by any other means,
     any business or any corporation, partnership, limited liability company or
     other business organization or division or any interest therein to the
     extent all such acquisitions together involve purchase prices in excess of
     five hundred million dollars ($500,000,000) in the aggregate, it being
     agreed that nothing in this Agreement shall prohibit Parent or any of its
     Subsidiaries from engaging in discussions or negotiations or from
     furnishing information in connection with any acquisitions or transactions;
 
          (d) sell, lease, license, mortgage, encumber or otherwise dispose of
     any of its properties or assets, except for sales, leases or licenses of
     products or services (i) in the ordinary course of business or (ii) to the
     extent involving sale prices of less than five hundred million dollars
     ($500,000,000) in the aggregate;
 
          (e) amend or propose to amend its Certificate of Incorporation or
     Bylaws or other comparable charter or organizational documents;
 
          (f) (x) incur any indebtedness for borrowed money or guarantee any
     such indebtedness or issue or sell any debt securities or warrants or
     rights to acquire any debt securities or guarantee any debt securities of
     others, enter into any "keep well" or other agreement to maintain any
     financial statement condition of another person or enter into any
     arrangement having the economic effect of any of the foregoing, or (y) make
     any loans, advances or capital contributions to, or investments in, any
     other person, other than to the Parent or any of its wholly owned
     Subsidiaries, to the extent involving in the case of all of the matters
     described in clauses (x) and (y) more than two hundred fifty million
     dollars ($250,000,000) in the aggregate; or
 
          (g) take, or agree in writing or otherwise to take, any of the actions
     described in the foregoing clauses (a) through (f), or any action (other
     than actions of the type contemplated by clauses (a) through (f) above
     which are permitted thereby) which (i) would make any of Parent's
     representations or warranties in this Agreement, if made on and as of the
     date of such action or agreement, untrue or incorrect in any material
     respect, or (ii) could prevent it from performing, or cause it not to
     perform, its obligations under this Agreement. Nothing contained in this
     Agreement shall prohibit Parent from adopting a stockholders rights plan or
     issuing securities pursuant thereto.
 
     Section 5.3. EMPLOYMENT AGREEMENTS.  The Company may enter into employment
agreements, effective as of the Effective Time, with the officers of the Company
listed in Item 5.3(a) of the Parent Letter (the "Senior Officers"), which
employment agreements shall be in the form attached as Item 5.3(b) of the Parent
Letter and shall be subject to the terms specified in Item 5.3(c) of the Parent
Letter.
 
     Section 5.4. COOPERATION.  Subject to compliance with applicable law, from
the date hereof until the Effective Time, (i) the Company shall confer on a
regular and frequent basis with one or more representatives
 
                                      I-21
<PAGE>   77
 
of Parent to report operational matters of materiality and the general status of
ongoing operations and (ii) each of Parent and the Company shall promptly
provide the other party or its counsel with copies of all filings made by the
Company with any Governmental Entity in connection with this Agreement, the
Merger and the other transactions contemplated hereby.
 
     Section 5.5. MATERIAL ADVERSE EFFECT.  For purposes of this Agreement,
"Material Adverse Effect" means, when used in connection with the Company or
Parent, any change or effect that is materially adverse to the business,
properties, assets, condition (financial or otherwise), or results of operations
of such party and its Subsidiaries taken as a whole but excluding (i) any change
resulting from general economic conditions or general industry conditions or
(ii) any change caused by the transactions contemplated by this Agreement and
the public announcement thereof.
 
                                   ARTICLE VI
                             ADDITIONAL AGREEMENTS
 
     Section 6.1.  NO SOLICITATION.  (a) The Company agrees that, from the date
of this Agreement until the earlier of the Effective Time or the termination of
this Agreement in accordance with Section 8.1, it shall not, directly or
indirectly, and shall cause its officers, directors, employees, representatives,
agents, and affiliates, to not (i) solicit, initiate, or encourage any inquiries
or proposals that constitute, or could reasonably be expected to lead to, a
proposal or offer for a merger, consolidation, sale or purchase of substantial
assets or stock, tender or exchange offer, or other business combination or
change in control or similar transaction involving the Company or any of its
Subsidiaries, other than the transactions contemplated or permitted by this
Agreement (any of the foregoing inquiries or proposals being referred to in this
Agreement as a "Takeover Proposal"), (ii) engage in negotiations or discussions
concerning, or provide any non-public information to any person or entity
relating to, any Takeover Proposal, or (iii) enter into any agreement with
respect to, agree to, approve or recommend any Takeover Proposal; provided,
however, that nothing contained in this Agreement shall prevent the Company or
its Board of Directors, directly or through representatives or agents on behalf
of the Board of Directors, from (A) furnishing non-public information to, or
entering into discussions or negotiations with, any person or entity in
connection with an unsolicited bona fide written Takeover Proposal by such
person or entity, if and only to the extent that (1) such Takeover Proposal
would, if consummated, result in a transaction that would, in the reasonable
good faith judgment of the Board of Directors of the Company, after consultation
with its financial advisors, result in a transaction more favorable to the
Company's stockholders from a financial point of view than the Merger (any such
more favorable Takeover Proposal being referred to in this Agreement as a
"Superior Proposal") and, in the reasonable good faith judgment of the Board of
Directors of the Company, after consultation with its financial advisors, the
person or entity making such Superior Proposal has the financial means to
conclude such transaction, (2) the failure to take such action would in the
reasonable good faith judgment of the Board of Directors of the Company, on the
basis of the advice of the outside corporate counsel of the Company, be contrary
to the fiduciary duties of the Board of Directors of the Company to the
Company's stockholders under applicable law; (3) prior to furnishing such
non-public information to, or entering into discussions or negotiations with,
such person or entity, such Board of Directors receives from such person or
entity an executed confidentiality agreement with provisions not less favorable
to the Company than those contained in the Confidentiality and Non Disclosure
Agreement dated December 29, 1997 between Parent and the Company, except for the
provision of Section 7 thereof (the "Confidentiality Agreement") and (4) the
Company shall have fully complied with this Section 6.1; or (B) complying with
Rule 14d-9 and Rule 14e-2 promulgated under the Exchange Act with regard to a
Takeover Proposal.
 
          (b)  The Company shall notify Parent no later than twenty-four (24)
     hours after receipt by the Company (or its advisors) of any Takeover
     Proposal or any request for nonpublic information in connection with a
     Takeover Proposal or for access to the properties, books or records of the
     Company by any person or entity that informs the Company that it is
     considering making, or has made, a Takeover Proposal. Such notice to Parent
     shall be made orally and in writing and shall indicate in reasonable detail
     the identity of the person or entity making the Takeover Proposal and the
     terms and conditions of such proposal, inquiry or contact. If the financial
     terms of such Takeover Proposal are modified, then the
 
                                      I-22
<PAGE>   78
 
     Company shall notify Parent of the terms and conditions of such
     modification within twenty-four (24) hours of the receipt of such
     modification. The Company shall also notify Parent simultaneously with the
     delivery of notice to the directors of the Company of, and in any event at
     least twenty-four (24) hours prior to (unless a longer period is required
     by Section 6.1(c)), each meeting of the Board of Directors at which the
     Company will consider taking definitive action with respect to withdrawing
     or modifying, in a manner adverse to Parent, its recommendation to the
     Company's stockholders in favor of approval of the Merger.
 
          (c)  Notwithstanding the foregoing, in the event that there exists a
     Superior Proposal before the Board of Directors of the Company and in the
     reasonable good faith judgment of the Company, on the basis of the advice
     of the outside corporate counsel of the Company, the failure to accept such
     Superior Proposal would be contrary to the fiduciary duties of the Board of
     Directors of the Company to the Company's stockholders under applicable
     law, the Board of Directors of the Company may pursuant to Section 8.1(h)
     (subject to this and the following sentences) terminate this Agreement
     prior to the Stockholders Meeting (and concurrently with such termination,
     cause the Company to enter into an acquisition agreement with respect to
     such Superior Proposal), but only at a time that is (i) after the third day
     following Parent's receipt of written notice advising Parent that the Board
     of Directors of the Company is prepared to accept a Superior Proposal,
     specifying the material terms and conditions of such Superior Proposal and
     identifying the person making such Superior Proposal; (ii) after the
     payment by the Company to Parent of the Termination Fee in full and in
     immediately available funds; and (iii) after the Company shall have, and
     shall have caused its financial and legal advisors to, negotiate in good
     faith with Parent to make such changes to the terms and conditions of this
     Agreement as would enable the Company to proceed with the transactions
     contemplated hereby.
 
          (d)  During the period from the date of this Agreement through the
     Effective Time, the Company shall not terminate, amend, modify or waive any
     provision of any confidentiality or standstill agreement (other than any
     entered into in the ordinary course of business not in connection with any
     possible Takeover Proposal) to which it or any of its Subsidiaries is a
     party (other than any between the Company and its Subsidiaries). During
     such period, the Company shall enforce, to the fullest extent permitted
     under applicable law, the provisions of any such agreement, including, but
     not limited to, by obtaining injunctions to prevent any breaches of such
     agreements and to enforce specifically the terms and provisions thereof in
     any court of the United States of America or of any state having
     jurisdiction.
 
     Section 6.2.  PROXY STATEMENT/PROSPECTUS; REGISTRATION STATEMENT.  (a) As
promptly as practicable after the execution of this Agreement, Parent and the
Company shall prepare and file with the SEC the Proxy Statement, and Parent
shall prepare and file with the SEC the Registration Statement, in which the
Proxy Statement will be included. Parent and the Company shall use all
reasonable best efforts to cause the Registration Statement to become effective
as soon after such filing as reasonably practicable. The Proxy Statement shall
include the recommendation of the Board of Directors of the Company to the
stockholders of the Company in favor of approval and adoption of this Agreement
and the Merger; provided, however, that such Board of Directors shall not be
required to make, and shall be entitled to withdraw or modify, such
recommendation if (i) the Company has complied with Section 6.1 and (ii) in the
reasonable good faith judgment of such Board of Directors, on the basis of the
advice of outside corporate counsel of the Company, the making of, or the
failure to withdraw or modify, such recommendation would be contrary to the
fiduciary duties of such Board of Directors to the Company's stockholders under
applicable law. The Board of Directors of the Company shall not rescind its
declaration that this Agreement and the Merger are advisable unless, in any such
case, each of the conditions set forth in clauses (i) and (ii) immediately above
is satisfied.
 
          (b)  Each of Parent and the Company shall make all necessary filings
     with respect to the Merger under the Securities Act and the Exchange Act
     and applicable state securities laws and the rules and regulations
     thereunder, and shall use its reasonable best efforts to obtain all permits
     and other authorizations required under applicable state securities laws
     for the issuance of the shares of Parent Common Stock pursuant to the
     Merger.
 
     Section 6.3.  CONSENTS.  Each of Parent and the Company shall use
reasonable best efforts to obtain all necessary consents, waivers and approvals
under its respective material agreements, contracts, licenses or
 
                                      I-23
<PAGE>   79
 
leases required for the consummation of the Merger and the other transactions
contemplated by this Agreement.
 
     Section 6.4.  CURRENT NASDAQ QUOTATION.  Parent shall continue the
quotation of Parent Common Stock, and the Company shall continue the quotation
of the Company Common Stock, on The Nasdaq National Market during the term of
this Agreement to the extent necessary so that appraisal rights will not be
available to stockholders of the Company under Section 262 of the DGCL.
 
     Section 6.5.  ACCESS TO INFORMATION.  Upon reasonable notice, the Company
shall (and shall cause each of its Subsidiaries to) afford to the officers,
employees, accountants, financial advisors, counsel and other representatives of
Parent, access, during normal business hours during the period prior to the
Effective Time, to all its properties, books, contracts, commitments, Returns,
and records and, during such period, the Company shall (and shall cause each of
its Subsidiaries to) furnish promptly to Parent (i) a copy of each report,
schedule, registration statement and other document filed or received by it
during such period pursuant to the requirements of federal securities laws and
(ii) all other information concerning its business, properties and personnel as
Parent may reasonably request; provided, however, that the Company's obligation
to provide information pursuant to this Section 6.5 shall be subject to Item 6.5
of the Company Letter. During the period prior to the Effective Time, Parent
shall provide the financial advisor of the Company identified in Section 3.24
and the Chief Executive Officer of the Company reasonable access to senior
executive officers of Parent, as appropriate, in connection with the
transactions contemplated by this Agreement. No information or knowledge
obtained in any investigation pursuant to this Section 6.5 shall affect or be
deemed to modify any representation or warranty contained in this Agreement or
the conditions to the obligations of the parties to consummate the Merger.
Unless otherwise required by law, Parent and the Company will hold, and will use
its reasonable best efforts to cause their respective officers, employees,
affiliates and representatives to hold, any nonpublic information received from
the other party to this Agreement, any of their respective Subsidiaries or any
of their respective representatives (other than information already in the
possession of such party at the time of receipt of such information from the
other party) in confidence until such time as such information becomes publicly
available (otherwise than through the wrongful act of any such person) and shall
use its reasonable best efforts to ensure that such officers, employees,
affiliates and representatives do not disclose such information to others
without the prior written consent of the Company or Parent, as the case may be.
In the event of termination of this Agreement for any reason, Parent and the
Company shall promptly return or destroy all documents containing nonpublic
information so obtained from the Company, Parent or any of their Subsidiaries
and any copies of such documents.
 
     Section 6.6.  STOCKHOLDERS MEETING.  (a) The Company shall call and hold
the Stockholders Meeting as promptly as practicable after the date hereof for
the purpose of voting upon the adoption of this Agreement and the approval of
the Merger. Subject to Section 6.1, the Company, through its Board of Directors,
shall recommend that the Company's stockholders vote in favor of the adoption of
this Agreement and the approval of the Merger (and shall not withdraw or modify
such recommendation) and shall otherwise use its best efforts to solicit from
its stockholders proxies in favor of such matters and to obtain the requisite
approval of the Company's stockholders; provided, however, that such Board of
Directors shall not be required to make, and shall be entitled to withdraw or
modify, such recommendation if (i) the Company has complied with Section 6.1 and
(ii) in the reasonable good faith judgment of such Board of Directors, on the
basis of advice of outside corporate counsel of the Company, the making of, or
the failure to withdraw or modify, such recommendation would be contrary to the
fiduciary duties of such Board of Directors to the Company's stockholders under
applicable law.
 
     Section 6.7.  LEGAL CONDITIONS TO MERGER.  (a) Each of Parent and the
Company shall take reasonable actions necessary to comply promptly with all
legal requirements which may be imposed on such party with respect to the Merger
(which actions shall include, without limitation, furnishing all information
required under the HSR Act and in connection with approvals of or filings with
any other Governmental Entity) and shall promptly cooperate with and, subject to
applicable law, furnish information to each other in connection with any such
requirements imposed upon either of them or any of their Subsidiaries in
connection with the Merger. Each of Parent and the Company shall, and shall
cause its Subsidiaries to take reasonable actions necessary to obtain (and shall
cooperate with each other in obtaining) any consent, authorization, order or
 
                                      I-24
<PAGE>   80
 
approval of, or any exemption by, any Governmental Entity or other third party,
required to be obtained or made by the Company, Parent or any of their
Subsidiaries for any of the conditions set forth in Article VII to be satisfied
(any of the foregoing, an "Approval") or the taking of any action required in
furtherance thereof or otherwise contemplated thereby or by this Agreement.
 
    (b)  Notwithstanding anything to the contrary contained in this Agreement,
  neither Parent nor the Company shall have any obligation to oppose, challenge
  or appeal any suit, action or proceeding by any Governmental Entity before any
  court or governmental authority, agency or tribunal, domestic or foreign or
  any order or ruling by any such body, (i) seeking to restrain or prohibit or
  restraining or prohibiting the consummation of the Merger or any of the other
  transactions contemplated by this Agreement, (ii) seeking to prohibit or limit
  or prohibiting or limiting the ownership, operation or control by the Company,
  Parent or any of their respective Subsidiaries of any portion of the business
  or assets of the Company, Parent or any of their respective Subsidiaries, or
  (iii) seeking to compel or compelling the Company, Parent or any of their
  respective Subsidiaries to dispose of, grant rights in respect of, or hold
  separate any portion of the business or assets of the Company, Parent or any
  of their respective Subsidiaries. Further, notwithstanding anything to the
  contrary contained in this Agreement, Parent shall have no obligation to
  dispose of, grant rights in respect of, or hold separate any portion of the
  business or assets of the Company, Parent or any of their respective
  Subsidiaries or to agree to any of the foregoing. Neither the Company nor any
  of its Subsidiaries shall take any of the actions described in preceding
  sentences of this Section 6.7(b) without the prior written consent of Parent.
 
     Section 6.8.  PUBLIC DISCLOSURE.  Except as otherwise required by
applicable law or the rules or regulations of any securities exchange or market
on which the securities of such party are listed or traded, no party or any of
its affiliates shall issue or cause the publication of any press release or
other public announcement or disclosure with respect to the transactions
contemplated by this Agreement without the consent of each other party, and in
any event, each party agrees that it shall give each other party reasonable
opportunity to review and comment upon any such release or announcement prior to
publication of the same.
 
     Section 6.9.  TAX-FREE REORGANIZATION.  Parent and the Company shall each
use its reasonable best efforts to cause the Merger to be treated as a
"reorganization" within the meaning of Section 368(a) of the Code, and to enable
its respective counsel to render the opinions contemplated by Sections 7.2(e)
and 7.3(d). Each party shall make (to the extent it can truthfully do so), and
shall use all reasonable best efforts to cause those of its respective
stockholders that counsel to the parties shall reasonably request to make, such
representations and certifications as counsel to the parties shall reasonably
request to enable them to render such opinions including, without limitation,
the representations of Parent contained in a certificate of Parent (the "Parent
Tax Certificate") substantially in the form of the Parent Tax Certificate
attached as Item 6.9 of the Parent Letter and representations of the Company
contained in a certificate of the Company (the "Company Tax Certificate")
substantially in the form of the Company Tax Certificate attached as Item 6.9 of
the Company Letter.
 
     Section 6.10.  POOLING ACCOUNTING.  Parent and the Company shall each use
its reasonable best efforts to cause the business combination to be effected by
the Merger to be accounted for as a pooling of interests. The Company shall use
its reasonable best efforts to cause its affiliates not to take any action that
would adversely affect the ability of Parent to account for the business
combination to be effected by the Merger as a pooling of interests.
 
     Section 6.11.  AFFILIATE LETTERS.  Between the date of this Agreement and
the Effective Time, the Company will use its reasonable best efforts to cause
each of the persons listed on Item 3.17 of the Company Letter to execute and
deliver to Parent an executed letter agreement, substantially in the form of
Exhibit A hereto (the "Company Affiliate Letter"), and Parent will use its
reasonable best efforts to cause each of the persons listed on Item 4.15 of the
Parent Letter to execute and deliver to Parent an executed letter agreement,
substantially in the form of Exhibit B hereto (the "Parent Affiliate Letter").
Between the date of this Agreement and the Effective Time, the Company shall, if
requested, promptly provide Parent such information and documents as Parent
shall reasonably request for purposes of determining the affiliates of the
Company and upon the request of Parent use its reasonable best efforts to cause
any person who may in the reasonable judgment of Parent be deemed an affiliate
of the Company to execute and deliver to Parent the
 
                                      I-25
<PAGE>   81
 
Company Affiliate Letter. Parent shall be entitled to place appropriate legends
on the certificates evidencing any Parent Common Stock to be received by
affiliates of the Company pursuant to this Agreement and to issue appropriate
stop transfer instructions to the transfer agent for the Parent Common Stock,
consistent with the terms of the Company Affiliate Letter.
 
     Section 6.12.  NASDAQ QUOTATION.  Parent shall use its reasonable best
efforts to cause the shares of Parent Common Stock to be issued in the Merger to
be approved for quotation on The Nasdaq National Market, subject to official
notice of issuance, prior to the Closing Date.
 
     Section 6.13.  STOCK PLANS AND OPTIONS.  (a) The Company shall provide to
each holder of an outstanding Company Stock Option to purchase the Company
Common Stock under the Company Stock Plans the notice (if any) required pursuant
to such plans in connection with the Merger.
 
    (b)  From and after the Effective Time, each outstanding Company Stock
  Option (including both vested and unvested Company Stock Options) shall be
  assumed by Parent and shall pursuant to the terms of such options, be deemed
  to constitute an option to acquire, on the same terms and conditions as were
  applicable under such Company Stock Option, the same number of shares of
  Parent Common Stock as the holder of such Company Stock Option would have been
  entitled to receive in the Merger pursuant to this Agreement had such holder
  exercised such option in full immediately prior to the Effective Time (rounded
  down to the nearest whole number), at a price per share (rounded up to the
  nearest whole cent) equal to the quotient of (i) the exercise price per share
  of Company Common Stock pursuant to such Company Stock Option divided by (ii)
  the Exchange Ratio. All other terms of such Company Stock Options shall remain
  in effect.
 
    (c)  The Company shall take all actions necessary so that following the
  Effective Time no holder of a Company Stock Option or any participant in any
  Company Benefit Plan shall have any right thereunder to acquire capital stock
  of the Company, Sub, or the Surviving Corporation. The Company shall take all
  actions necessary so that, as of the Effective Time, none of Sub, the Company,
  the Surviving Corporation or any of their respective Subsidiaries is or will
  be bound by any Company Stock Options, other options, warrants, rights or
  agreements which would entitle any person, other than Parent, Sub or its
  affiliates, to own any capital stock of the Company, Sub, the Surviving
  Corporation or any of their respective subsidiaries or to receive any payment
  in respect thereof, except as otherwise provided in Article I and Section
  6.13(b).
 
     Section 6.14.  INDEMNIFICATION.  All rights to indemnification for acts or
omissions occurring prior to the Effective Time now existing in favor of the
current or former directors or officers of the Company provided in the Company's
Certificate of Incorporation and Bylaws shall survive the Merger and shall
continue in full force and effect in accordance with their terms for a period of
not less than six (6) years from the Effective Time and to the extent the
Surviving Corporation fails to perform its obligations with respect thereto,
Parent shall perform such obligations. Parent and the Surviving Corporation will
cause to be maintained for a period of not less than six (6) years from the
Effective Time the Company's current directors and officers insurance and
indemnification policy (a copy of which has been provided to Parent) to the
extent that it provides coverage for events occurring prior to the Effective
Time for all persons who are directors and officers of the Company on the date
of this Agreement; provided, however, that in no event shall the Surviving
Corporation be required to pay a premium in any one year in excess of one
hundred fifty thousand dollars ($150,000), and provided, further, that if the
annual premiums of such insurance coverage exceed such amount or if such
existing directors' and officers' insurance and indemnification policy expires,
is terminated or canceled during such six-year period, the Surviving Corporation
shall be obligated to obtain a policy with the greatest coverage available for a
cost not exceeding one hundred fifty thousand dollars ($150,000).
 
     Section 6.15.  ADDITIONAL AGREEMENTS; REASONABLE EFFORTS.  Subject to the
terms and conditions of this Agreement, each of the parties agrees to use all
reasonable best efforts to take, or cause to be taken, all action and to do, or
cause to be done, all things necessary, proper or advisable under applicable
laws and regulations to consummate and make effective the transactions
contemplated by this Agreement, subject to the appropriate vote of the
stockholders of the Company described in Section 6.6, including cooperating
fully with the other party, providing information and making all necessary
filings under the HSR Act.
 
                                      I-26
<PAGE>   82
 
     Section 6.16.  TERMINATION OF CERTAIN AGREEMENTS.  The Company shall cause
the Administrative Services Agreement (the "Services Agreement"), dated as of
May 7, 1997 between the Company and Safeguard Scientifics, Inc. ("Safeguard "),
to be terminated effective as of the Effective Time (or such later time
thereafter as may be requested by Parent, not to exceed one hundred eighty (180)
days following the Effective Time) on terms that are reasonably satisfactory to
Parent, which terms shall include that the Company shall have no continuing
obligations under such agreement following such termination and that Safeguard
shall not be entitled to receive any consideration in connection with such
termination other than a termination fee equal to the Services Fee (as defined
in Section 3 of the Services Agreement) payable with respect to the period
commencing on the date of such termination and ending on December 31, 1998.
 
     Section 6.17.  REAL ESTATE TRANSFER TAXES.  Either the Company or the
Surviving Corporation shall pay all state or local real property transfer, gains
or similar Taxes, if any (collectively, the "Transfer Taxes"), attributable to
the transfer of the beneficial ownership of the Company's and its Subsidiaries'
real properties, and any penalties or interest with respect thereto, payable in
connection with the consummation of the Merger. The Company shall cooperate with
Parent in the filing of any returns with respect to the Transfer Taxes,
including supplying in a timely manner a complete list of all real property
interests held by the Company and its Subsidiaries and any information with
respect to such properties that is reasonably necessary to complete such
returns. The portion of the consideration allocable to the real properties of
the Company and its Subsidiaries shall be determined by Parent and the Company
in their reasonable discretion. The shareholders of the Company (who are
intended third-party beneficiaries of this Section 6.17) shall be deemed to have
agreed to be bound by the allocation established pursuant to this Section 6.17
in the preparation of any Return with respect to the Transfer Taxes.
 
                                  ARTICLE VII
 
                              CONDITIONS TO MERGER
 
     Section 7.1.  CONDITIONS TO EACH PARTY'S OBLIGATION TO EFFECT THE
MERGER.  The respective obligations of each party to this Agreement to effect
the Merger shall be subject to the satisfaction prior to the Closing Date of the
following conditions:
 
          (a)  Stockholder Approvals.  This Agreement and the Merger shall have
     been adopted and approved by the requisite vote of holders of the Company
     Common Stock pursuant to the DGCL and the Certificate of Incorporation of
     the Company.
 
          (b)  HSR Act.  The waiting period applicable to the consummation of
     the Merger under the HSR Act and any other material waiting periods under
     applicable foreign laws (if any) shall have expired or been terminated, and
     no action by the Department of Justice or Federal Trade Commission or any
     foreign Governmental Entity challenging or seeking to enjoin the
     consummation of the Merger shall have been instituted and be pending.
 
          (c)  Registration Statement.  The Registration Statement shall have
     become effective under the Securities Act and shall not be the subject of
     any stop order or proceedings seeking a stop order.
 
          (d)  No Injunctions or Restraints; Illegality.  No temporary
     restraining order, preliminary or permanent injunction or other order
     issued by any court of competent jurisdiction or other legal or regulatory
     restraint or prohibition shall have been issued and be in effect (i)
     restraining or prohibiting the consummation of the Merger or any of the
     transactions contemplated hereby or (ii) prohibiting or limiting the
     ownership, operation or control by the Company, Parent or any of their
     respective Subsidiaries of any portion of the business or assets of the
     Company, Parent or any of their respective Subsidiaries, or compelling the
     Company, Parent or any of their respective Subsidiaries to dispose of,
     grant rights in respect of, or hold separate any portion of the business or
     assets of the Company, Parent or any of their respective Subsidiaries; nor
     shall any action have been taken or any statute, rule, regulation or order
     have been enacted, entered or enforced or be deemed applicable to the
     Merger which makes the consummation of the Merger illegal or prevents or
     prohibits the Merger.
 
                                      I-27
<PAGE>   83
 
          (e)  Nasdaq.  The shares of Parent Common Stock to be issued in the
     Merger shall have been approved for quotation on The Nasdaq National
     Market.
 
          (f)  Pooling.  The Company shall have received the written opinion,
     dated as of the Effective Time, of the Company Auditors that the Company
     Auditors concur with management's conclusion that the Company is eligible
     to be a party to a business combination accounted for as a pooling of
     interests in accordance with GAAP and applicable published rules and
     regulations of the SEC. Parent shall have received the written opinion,
     dated as of the Effective Time, of the Parent Auditors that the Parent
     Auditors concur with management's conclusion that Parent is eligible to be
     a party to a business combination accounted for as a pooling of interests
     in accordance with GAAP and applicable published rules and regulations of
     the SEC, and that the Merger will qualify for pooling of interests
     accounting. Each of such written opinions will be in form and substance
     reasonably satisfactory to the Company and Parent.
 
     Section 7.2.  ADDITIONAL CONDITIONS TO OBLIGATIONS OF PARENT AND SUB.  The
obligations of Parent and Sub to effect the Merger are subject to the
satisfaction or waiver of each of the following conditions, any of which may be
waived in writing exclusively by Parent and Sub:
 
          (a)  Representations and Warranties.  Each of the representations and
     warranties of the Company set forth in this Agreement that is qualified by
     materiality shall be true and correct at and as of the Closing Date as if
     made at and as of the Closing Date and each of such representations and
     warranties that is not so qualified shall be true and correct in all
     material respects at and as of the Closing Date as if made at and as of the
     Closing Date, in each case except as contemplated by this Agreement, and
     Parent shall have received a certificate signed on behalf of the Company by
     the chief executive officer or chief financial officer of the Company to
     such effect.
 
          (b)  Performance of Obligations.  The Company shall have performed in
     all material respects all obligations required to be performed by it under
     this Agreement at or prior to the Closing Date, and Parent shall have
     received a certificate signed on behalf of the Company by the chief
     executive officer or chief financial officer of the Company to such effect.
 
          (c)  Certain Agreements.  A Company Affiliate Letter shall have been
     executed and delivered to Parent by or on behalf of each director and
     executive officer of the Company, and each such Company Affiliate Letter
     shall be in full force and effect.
 
          (d)  Absence of the Material Adverse Effect on the Company.  No
     Material Adverse Effect with respect to the Company shall have occurred,
     and no fact or circumstance shall exist which could reasonably be expected
     to result in a Material Adverse Effect with respect to the Company;
     provided, that if the event resulting in such Material Adverse Effect was
     beyond the control of the Company, such event shall not be deemed to have
     occurred for purposes of this Section 7.2(d) unless Parent pays the Company
     two million dollars ($2,000,000) in immediately available funds.
 
          (e)  Tax Opinion.  Parent shall have received an opinion of Sidley &
     Austin, in form and substance reasonably satisfactory to Parent, dated the
     Effective Time, substantially to the effect that, on the basis of facts,
     representations and assumptions set forth in such opinion that are
     consistent with the state of facts existing as of the Effective Time, for
     federal income tax purposes:
 
             (i)  the Merger will constitute a "reorganization" within the
        meaning of Section 368(a) of the Code, and the Company, Sub and Parent
        will each be a party to such reorganization within the meaning of
        Section 368(b) of the Code;
 
             (ii)  no gain or loss will be recognized by Parent, Sub or the
        Company as a result of the Merger;
 
             (iii)  no gain or loss will be recognized by the stockholders of
        the Company upon the exchange of their Company Common Stock solely for
        shares of Parent Common Stock pursuant to the Merger, except with
        respect to cash, if any, received in lieu of fractional shares of Parent
        Common Stock;
 
                                      I-28
<PAGE>   84
 
             (iv)  the aggregate tax basis of the shares of Parent Common Stock
        received solely in exchange for Company Common Stock pursuant to the
        Merger (including fractional shares of Parent Common Stock for which
        cash is received) will be the same as the aggregate tax basis of the
        Company Common Stock exchanged therefor;
 
             (v)  the holding period for shares of Parent Common Stock received
        solely in exchange for Company Common Stock pursuant to the Merger will
        include the holding period of the Company Common Stock exchanged
        therefor, provided such Company Common Stock was held as a capital asset
        by the stockholder at the Effective Time; and
 
             (vi)  a stockholder of the Company who receives cash in lieu of a
        fractional share of Parent Common Stock will recognize gain or loss
        equal to the difference, if any, between such stockholder's tax basis in
        such fractional share (as described in clause (iv) above) and the amount
        of cash received.
 
     In rendering such opinion, counsel may rely upon representations of Parent
(including, without limitation, representations contained in the Parent Tax
Certificate), representations of the Company (including, without limitation,
representations contained in the Company Tax Certificate) and representations by
others.
 
          (f)  No Litigation.  There shall not be pending or threatened any
     suit, action or proceeding by any Governmental Entity before any court or
     governmental authority, agency or tribunal, domestic or foreign, (i)
     seeking to restrain or prohibit the consummation of the Merger or any of
     the other transactions contemplated by this Agreement or seeking to obtain
     from the Company, Parent or Sub any damages in connection therewith, (ii)
     seeking to prohibit or limit the ownership, operation or control by the
     Company, Parent or any of their respective Subsidiaries of any portion of
     the business or assets of the Company, Parent or any of their respective
     Subsidiaries, or to compel the Company, Parent or any of their respective
     Subsidiaries to dispose of, grant rights in respect of, or hold separate
     any portion of the business or assets of the Company, Parent or any of
     their respective Subsidiaries, or (iii) which otherwise is reasonably
     likely to have a Material Adverse Effect on the Company.
 
     Section 7.3.  ADDITIONAL CONDITIONS TO OBLIGATIONS OF THE COMPANY.  The
obligation of the Company to effect the Merger is subject to the satisfaction of
each of the following conditions, any of which may be waived, in writing,
exclusively by the Company:
 
          (a)  Representations and Warranties.  Each of the representations and
     warranties of Parent and Sub set forth in this Agreement that is qualified
     by materiality shall be true and correct at and as of the Closing Date and
     each of such representations and warranties that is not so qualified shall
     be true and correct in all material respects at and as of the Closing Date
     as if made at and as of the Closing Date, in each case except as
     contemplated by this Agreement, and the Company shall have received a
     certificate signed on behalf of Parent by the chief executive officer or
     chief financial officer of Parent to such effect.
 
          (b)  Performance of Obligations.  Parent and Sub shall have performed
     in all material respects all obligations required to be performed by them
     under this Agreement at or prior to the Closing Date, and the Company shall
     have received a certificate signed on behalf of Parent by the chief
     executive officer or chief financial officer of Parent to such effect.
 
          (c)  Absence of the Material Adverse Effect on Parent.  No Material
     Adverse Effect with respect to Parent shall have occurred, and no fact or
     circumstance shall exist which could reasonably be expected to result in a
     Material Adverse Effect with respect to Parent; provided, that, if the
     event resulting in such Material Adverse Effect was beyond the control of
     Parent, such event shall not be deemed to have occurred for purposes of
     this Section 7.3(c) unless the Company pays the Parent two million dollars
     ($2,000,000) in immediately available funds.
 
          (d)  Tax Opinion.  The Company shall have received an opinion of
     Morgan, Lewis & Bockius LLP, in form and substance reasonably satisfactory
     to the Company, dated the Effective Time, substantially to the effect that,
     on the basis of facts, representations and assumptions set forth in such
     opinion that are consistent with the state of facts existing as of the
     Effective Time, for federal income tax purposes:
 
                                      I-29
<PAGE>   85
 
             (i)  the Merger will constitute a "reorganization" within the
        meaning of Section 368(a) of the Code, and the Company, Sub and Parent
        will each be a party to such reorganization within the meaning of
        Section 368(b) of the Code.
 
             (ii)  no gain or loss will be recognized by Parent, Sub or the
        Company as a result of the Merger;
 
             (iii)  no gain or loss will be recognized by the stockholders of
        the Company upon the exchange of their Company Common Stock solely for
        shares of Parent Common Stock pursuant to the Merger, except with
        respect to cash, if any, received in lieu of fractional shares of Parent
        Common Stock;
 
             (iv)  the aggregate tax basis of the shares of Parent Common Stock
        received solely in exchange for Company Common Stock pursuant to the
        Merger (including fractional shares of Parent Common Stock for which
        cash is received) will be the same as the aggregate tax basis of the
        Company Common Stock exchanged therefor;
 
             (v)  the holding period for shares of Parent Common Stock received
        solely in exchange for Company Common Stock pursuant to the Merger will
        include the holding period of the Company Common Stock exchanged
        therefor, provided such Company Common Stock was held as a capital asset
        by the stockholder at the Effective Time; and
 
             (vi)  a stockholder of the Company who receives cash in lieu of a
        fractional share of Parent Common Stock will recognize gain or loss
        equal to the difference, if any, between such stockholder's tax basis in
        such fractional share (as described in clause (iv) above) and the amount
        of cash received.
 
     In rendering such opinion, counsel may rely upon representations of Parent
(including, without limitation, representations contained in the Parent Tax
Certificate), representations of the Company (including, without limitation,
representations contained in the Company Tax Certificate) and representations by
others.
 
                                  ARTICLE VIII
 
                           TERMINATION AND AMENDMENT
 
     Section 8.1.  TERMINATION.  This Agreement may be terminated at any time
prior to the Effective Time (with respect to Sections 8.1(b) through 8.1(g), by
written notice by the terminating party to the other party), whether before or
after approval of the matters presented in connection with the Merger by the
stockholders of the Company:
 
          (a)  by mutual written consent of Parent and the Company; or
 
          (b)  by either Parent or the Company if the Merger shall not have been
     consummated by August 15, 1998 (provided, however, that the right to
     terminate this Agreement under this Section 8.1(b) shall not be available
     to any party whose failure to fulfill any obligation under this Agreement
     has been the cause of or resulted in the failure of the Merger to occur on
     or before such date); or
 
          (c)  by either Parent or the Company if a court of competent
     jurisdiction or other Governmental Entity shall have issued a final order,
     decree or ruling, or taken any other action, having the effect of
     permanently restraining, enjoining or otherwise prohibiting the Merger, and
     all appeals with respect to such order, decree, ruling or action have been
     exhausted or the time for appeal of such order, decree, ruling or action
     shall have expired (provided, however, that the right to terminate this
     Agreement under this Section 8.1(c) shall not be available to any party
     which has not complied with its obligations under Section 6.7); or
 
          (d)  by either Parent or the Company if, at the Stockholders Meeting
     (including any adjournment or postponement thereof), the requisite vote of
     the Company stockholders in favor of this Agreement and approval of the
     Merger shall not have been obtained (provided, however, that the right to
     terminate this Agreement under this Section 8.1(d) shall not be available
     to the Company if it has not complied with its
 
                                      I-30
<PAGE>   86
 
     obligations under Sections 6.1, 6.2 and 6.6, and no termination shall be
     effective by the Company if it has not complied with its obligations under
     Section 8.3, if applicable, of this Agreement); or
 
          (e)  by Parent if (i) the Board of Directors of the Company or any
     committee thereof shall have withdrawn or modified its recommendation of
     this Agreement or the Merger to the Company's stockholders in a manner
     adverse to Parent; (ii) an Alternative Transaction (as defined in Section
     8.3(f)) involving the Company shall have taken place or the Board of
     Directors of the Company or any committee thereof shall have recommended
     such an Alternative Transaction (or a proposal or offer therefor) to the
     stockholders of the Company or shall have publicly announced its intention
     to recommend such an Alternative Transaction (or a proposal or offer
     therefor) to the stockholders of the Company or to engage in an Alternative
     Transaction or shall have failed to recommend against such Takeover
     Proposal; or (iii) a tender offer or exchange offer for any of the
     outstanding shares of the Company Common Stock shall have been commenced or
     a registration statement with respect thereto shall have been filed (other
     than by Parent or an affiliate thereof) and the Board of Directors of the
     Company or any committee thereof shall have (A) recommended that the
     stockholders of the Company tender their shares in such tender or exchange
     offer or (B) publicly announced its intention to take no position with
     respect to such tender or exchange offer; or
 
          (f)  by Parent if a breach of any representation, warranty, covenant
     or agreement on the part of the Company set forth in this Agreement shall
     have occurred which if uncured would cause any condition set forth in
     Sections 7.2(a)or 7.2(b) not to be satisfied, and such breach is incapable
     of being cured or, if capable of being cured, shall not have been cured
     within twenty (20) business days following receipt by the Company of
     written notice of such breach from Parent; or
 
          (g)  by the Company if a breach of any representation, warranty,
     covenant or agreement on the part of Parent set forth in this Agreement
     shall have occurred which if uncured would cause any conditions set forth
     in Section 7.3(a) or 7.3(b) not to be satisfied, and such breach is
     incapable of being cured or, if capable of being cured, shall not have been
     cured within twenty (20) business days following receipt by Parent of
     written notice of such breach from the Company; or
 
          (h)  by the Company in accordance with Section 6.1(c); provided that
     in order for the termination of this Agreement pursuant to this paragraph
     (h) to be deemed effective, and as a condition thereto, the Company shall
     have complied with all provisions contained in Section 6.1, including the
     notice provisions therein, and with all the applicable requirements of
     Section 8.3, including the payment of the Termination Fee.
 
     Section 8.2.  EFFECT OF TERMINATION.  In the event of any termination of
this Agreement pursuant to Section 8.1, there shall be no liability or
obligation on the part of Parent, the Company, Sub, or any of their respective
officers, directors, stockholders or affiliates, except as set forth in Section
8.3. The foregoing limitations shall not apply, and the remedies provided by
Section 8.3 shall not be exclusive, to the extent that such termination results
from the willful breach by a party of any of its material representations,
warranties, covenants or agreements in this Agreement. The provisions of Section
8.3 of this Agreement shall remain in full force and effect and survive any
termination of this Agreement.
 
     Section 8.3.  FEES AND EXPENSES.
 
          (a)  Except as set forth in this Section 8.3, all fees and expenses
     incurred in connection with this Agreement and the transactions
     contemplated hereby shall be paid by the party incurring such expenses,
     whether or not the Merger is consummated; provided, however, that Parent
     and the Company shall share equally all fees and expenses, other than
     attorneys' and accounting fees and expenses, incurred in relation to the
     printing and filing of the Proxy Statement (including any related
     preliminary materials) and the Registration Statement (including financial
     statements and exhibits) and any amendments or supplements thereto and the
     fee(s) required to be paid by Parent in connection with the filing(s)
     required under the HSR Act and applicable foreign laws (if any) in
     connection with the transactions contemplated by this Agreement; provided,
     further, that the amount of fees and expenses to be paid by the Company
     pursuant to the immediately preceding proviso shall not exceed two hundred
     thousand dollars ($200,000).
 
                                      I-31
<PAGE>   87
 
          (b)  If any Takeover Proposal is made between the date hereof and the
     termination of this Agreement, and this Agreement is terminated (i) by
     Parent pursuant to Section 8.1(f), or (ii) by Parent or the Company
     pursuant to Section 8.1(d) as a result of the failure to receive the
     requisite vote for adoption of this Agreement and approval of the Merger by
     the stockholders of the Company at the Stockholders Meeting, then if an
     Alternative Transaction involving the Company shall take place or the
     Company shall enter into any letter of intent, agreement in principle,
     acquisition agreement or other similar agreement with respect to an
     Alternative Transaction (each, an "Acquisition Agreement") within twelve
     (12) months of such termination, then the Company shall pay to Parent a
     termination fee in the amount of twelve million dollars ($12,000,000) (the
     "Termination Fee") simultaneously with the earlier to occur of such
     Alternative Transaction or execution of such Acquisition Agreement.
 
          (c)  If this Agreement is terminated by Parent pursuant to Section
     8.1(e), then the Company shall pay to Parent the Termination Fee no later
     than one business day following such termination.
 
          (d)  If this Agreement is terminated by the Company pursuant to
     Section 8.1(h), then the Company shall pay to Parent the Termination Fee
     prior to, and as a condition to, effectiveness of such termination.
 
          (e) Any Termination Fee payable under this Section 8.3 shall be paid
     in immediately available funds.
 
          (f) As used in this Agreement, an "Alternative Transaction" involving
     the Company means (i) a transaction or series of transactions pursuant to
     which any person or group (as such term is defined under the Exchange Act),
     other than Parent or Sub, or any affiliate thereof (a "Third Party"),
     acquires (or would acquire upon completion of such transaction or series of
     transactions) more than thirty-five percent (35%) of the equity securities
     or voting power of the Company or any of its Subsidiaries, pursuant to a
     tender offer or exchange offer or otherwise, (ii) a merger, consolidation,
     share exchange or other business combination involving the Company or any
     of its Subsidiaries pursuant to which any Third Party acquires ownership
     (or would acquire ownership upon consummation of such merger,
     consolidation, share exchange or other business combination) of more than
     thirty-five percent (35%) of the outstanding equity securities or voting
     power of the Company or any of its Subsidiaries or of the entity surviving
     such merger or business combination or resulting from such consolidation,
     (iii) any other transaction or series of transactions pursuant to which any
     Third Party acquires (or would acquire upon completion of such transaction
     or series of transactions) control of assets of the Company or any of its
     Subsidiaries (including, for this purpose, outstanding equity securities of
     Subsidiaries of such party) having a fair market value equal to more than
     thirty-five percent (35%) of the fair market value of all the consolidated
     assets of the Company immediately prior to such transaction or series of
     transactions, or (iv) any transaction or series of transactions pursuant to
     which any Third Party acquires (or would acquire upon completion of such
     transaction or series of transactions) control of the Board of Directors of
     the Company or by which nominees of any Third Party are (or would be)
     elected or appointed to a majority of the seats on the Board of Directors
     of the Company.
 
     Section 8.4. AMENDMENT.  This Agreement may be amended by the parties
hereto, by action taken or authorized by their respective Boards of Directors,
at any time before or after approval of the matters presented in connection with
the Merger by the stockholders of the Company, but, after any such approval, no
amendment shall be made which by law requires further approval by such
stockholders without such further approval. This Agreement may not be amended
except by an instrument in writing signed on behalf of each of the parties
hereto.
 
     Section 8.5. EXTENSION; WAIVER.  At any time prior to the Effective Time,
the parties hereto, by action taken or authorized by their respective Boards of
Directors, may, to the extent legally allowed, (i) extend the time for the
performance of any of the obligations or other acts of the other parties hereto,
(ii) waive any inaccuracies in the representations and warranties contained
herein or in any document delivered pursuant hereto, and (iii) waive compliance
with any of the agreements or conditions contained herein. Any agreement on the
part of a party hereto to any such extension or waiver shall be valid only if
set forth in a written instrument signed on behalf of such party.
 
                                      I-32
<PAGE>   88
 
                                   ARTICLE IX
 
                                 MISCELLANEOUS
 
     Section 9.1. NONSURVIVAL OF REPRESENTATIONS, WARRANTIES AND
AGREEMENTS.  None of the representations, warranties and agreements in this
Agreement or in any instrument delivered pursuant to this Agreement shall
survive the Closing and the Effective Time, except for the agreements contained
in Section 6.14 (Indemnification), this Article IX, the Company Affiliate
Letters delivered pursuant to Sections 3.17 and 6.11, the Parent Tax
Certificate, the Company Tax Certificate and any other agreement contemplated by
this Agreement which, by its terms, does not terminate until a later date.
 
     Section 9.2. NOTICES.  All notices and other communications hereunder shall
be in writing and shall be deemed given if delivered personally, telecopied
(which is confirmed) or mailed by registered or certified mail (return receipt
requested) to the parties at the following addresses (or at such other address
for a party as shall be specified by like notice):
 
          (a) if to Parent or Sub, to:
 
          Tellabs, Inc.
          4951 Indiana Avenue
          Lisle, Illinois 60532
          Attention: General Counsel
          Facsimile No.: (630) 512-7293
 
          with a copy to:
 
          Sidley & Austin
          One First National Plaza
          Chicago, Illinois 60603
          Attention: Thomas A. Cole and
                     Imad I. Qasim
          Facsimile No.: (312) 853-7036
 
          (b) if to the Company, to:
 
           Coherent Communications Systems Corporation
           45085 University Drive
           Ashburn, Virginia 20147
           Attention: Daniel L. McGinnis
                      Chief Executive Officer
           Facsimile No.: (703) 729-3345
 
           with a copy to:
 
           Morgan Lewis & Bockius LLP
           2000 One Logan Square
           Philadelphia, PA 19103
           Attention: N. Jeffrey Klauder
           Facsimile No.: (215) 963-5299
 
     Section 9.3. INTERPRETATION.  When a reference is made in this Agreement to
an Article or a Section, such reference shall be to an Article or a Section of
this Agreement unless otherwise indicated. The table of contents and headings
contained in this Agreement are for reference purposes only and shall not affect
in any way the meaning or interpretation of this Agreement. Whenever the words
"include," "includes" or "including" are used in this Agreement they shall be
deemed to be followed by the words "without limitation."
 
     Section 9.4. COUNTERPARTS.  This Agreement may be executed in two or more
counterparts, all of which shall be considered one and the same agreement and
shall become effective when two or more counterparts have been signed by each of
the parties and delivered to the other parties, it being understood that all
parties need not sign the same counterpart.
 
                                      I-33
<PAGE>   89
 
     Section 9.5. ENTIRE AGREEMENT; NO THIRD PARTY BENEFICIARIES.  This
Agreement (including the documents and the instruments referred to herein) and
the Confidentiality Agreement (other than Section 7 thereof) constitute the
entire agreement and supersede all prior agreements and understandings, both
written and oral, among the parties with respect to the subject matter hereof.
Except as provided in Section 6.14 and Section 6.17, this Agreement is not
intended to confer upon any person other than the parties hereto any rights or
remedies hereunder.
 
     Section 9.6. GOVERNING LAW.  This Agreement shall be governed and
construed, and any controversy arising out of or otherwise relating to the
Agreement shall be determined, in accordance with the internal laws of the State
of Delaware without regard to conflicts of law rules thereof. Each party hereto
consents and submits to the exclusive jurisdiction of the courts of the State of
Delaware and the courts of the United States located in such state for the
adjudication of any action, suit, proceeding, claim or dispute arising out of or
otherwise relating to this Agreement.
 
     Section 9.7.  ASSIGNMENT.  Neither this Agreement nor any of the rights,
interests or obligations hereunder shall be assigned by any of the parties
hereto (whether by operation of law or otherwise) without the prior written
consent of the other parties, and any attempted assignment thereof without such
consent shall be null and void. Subject to the preceding sentence, this
Agreement will be binding upon, inure to the benefit of and be enforceable by
the parties and their respective successors and assigns.
 
     IN WITNESS WHEREOF, Parent, Sub and the Company have caused this Agreement
to be signed by their respective officers thereunto duly authorized as of the
date first written above.
 
                                          TELLABS, INC.
 
                                          By:   /s/ MICHAEL J. BIRCK
                                          Name: Michael J. Birck
                                          Title: President and Chief Executive
                                          Officer
 
                                          CARDINAL MERGER CO.
 
                                          By:   /s/ MICHAEL J. BIRCK
                                          Name: Michael J. Birck
                                          Title: President
 
                                          COHERENT COMMUNICATIONS SYSTEMS
                                          CORPORATION
 
                                          By:   /s/ DANIEL L. MCGINNIS
                                          Name: Daniel L. McGinnis
                                          Title: Chief Executive Officer
 
                                      I-34
<PAGE>   90
 
                                   EXHIBIT A
 
                       Affiliate Letter for Affiliates of
                  Coherent Communications Systems Corporation
 
February     , 1998
 
Tellabs, Inc.
4951 Indiana Avenue
Lisle, Illinois 60532
 
Ladies and Gentlemen:
 
     I have been advised that as of the date of this letter I may be deemed to
be an "affiliate" of Coherent Communications Systems Corporation, a Delaware
corporation (the "Company"), as the term "affiliate" is (i) defined for purposes
of paragraphs (c) and (d) of Rule 145 of the rules and regulations (the "Rules
and Regulations") of the Securities and Exchange Commission (the "Commission")
under the Securities Act of 1933, as amended (the "Act"), and/or (ii) used in
and for purposes of Accounting Series Releases 130 and 135, as amended, of the
Commission. Pursuant to the terms of the Agreement and Plan of Merger dated as
of February 16, 1998 (the "Merger Agreement") among Tellabs, Inc., a Delaware
corporation ("Parent"), Cardinal Merger Co., a Delaware corporation and a wholly
owned subsidiary of Parent ("Sub"), and the Company, Sub will be merged with and
into the Company (the "Merger"), with the Company surviving as a wholly-owned
subsidiary of Parent. Capitalized terms used in this letter without definition
shall have the meanings assigned to them in the Merger Agreement.
 
     As a result of the Merger, I may receive shares of common stock, par value
$.01 per share, of Parent (the "Parent Shares") in exchange for shares of the
Company's Common Stock, par value $.01 per share (the "Company Shares") owned by
me or purchasable upon exercise of stock options.
 
     1.  I represent and warrant to, and covenant with, Parent as follows:
 
          A.  I shall not make any sale, transfer or other disposition of any
     Parent Shares in violation of the Act or the Rules and Regulations.
 
          B.  I have carefully read this letter and the Merger Agreement and
     have discussed the requirements of such documents and other applicable
     limitations upon my ability to sell, transfer or otherwise dispose of the
     Parent Shares, to the extent I felt necessary, with my counsel.
 
          C.  I have been advised that the issuance of the Parent Shares to me
     pursuant to the Merger has been or will be registered with the Commission
     under the Act on a Registration Statement on Form S-4. However, I have also
     been advised that, because at the time the Merger is submitted for a vote
     of the stockholders of the Company, (a) I may be deemed to be an
     "affiliate" of the Company and (b) the sale, transfer or other distribution
     by me of the Parent Shares has not been registered under the Act, I may not
     sell, transfer or otherwise dispose of the Parent Shares issued to me in
     the Merger unless (i) such sale, transfer or other disposition is made in
     conformity with the volume limitations and other conditions of Rule 145
     promulgated by the Commission under the Act, (ii) such sale, transfer or
     other disposition has been registered under the Act or (iii) in the opinion
     of counsel reasonably acceptable to Parent, such sale, transfer or other
     disposition is otherwise exempt from registration under the Act.
 
          D.  I understand that Parent is under no obligation to register the
     sale, transfer or other disposition of any Parent Shares by me or on my
     behalf under the Act or to take any other action necessary in order to make
     compliance with an exemption from such registration available.
 
          E.  I will not, during the 30 days prior to the Effective Time, sell,
     transfer or otherwise dispose of or reduce my risk (as contemplated by SEC
     Accounting Series Release No. 135) with respect to the Company Shares or
     shares of the capital stock of Parent that I may hold and, furthermore,
     that I will not sell, transfer or otherwise dispose of or reduce my risk
     (as contemplated by SEC Accounting Series Release No. 135) with respect to
     the Parent Shares received by me in the Merger or any other shares of the
     capital stock of Parent until after such time as results covering at least
     30 days of combined operations of the Company and Parent have been
     published by Parent, in the form of a quarterly earnings
 
                                      I-A-1
<PAGE>   91
 
     report, an effective registration statement filed with the Commission, a
     report to the Commission on Form 10-K, 10-Q, or 8-K, or any other public
     filing or announcement which includes the combined results of operations.
     Notwithstanding the foregoing, I understand that during the aforementioned
     period, subject to providing written notice to and obtaining the consent of
     Parent, which such consent shall not be unreasonably withheld, I will not
     be prohibited from de minimis dispositions and charitable contributions or
     bona fide gifts of the Parent Shares which, in each case, will not
     disqualify the accounting for the Merger as a pooling of interests.
 
     2.  Execution of this letter should not be considered an admission on my
part that I am an "affiliate" of the Company as described in the first paragraph
of this letter, nor as a waiver of any rights I may have to object to any claim
that I am such an affiliate on or after the date of this letter.
 
     3.  I understand that the Parent may cause to be placed on the certificates
of the Parent Shares issued to me, or any substitutions therefor, a legend
stating in substance:
 
          "The shares represented by this certificate were issued pursuant to a
     business combination which is being accounted for as a pooling of interests
     in a transaction to which Rule 145, promulgated under the Securities Act of
     1933, as amended, applies. The shares have been acquired by the holder not
     with a view to, or for resale in connection with, any distribution thereof
     within the meaning of the Securities Act of 1933, as amended. The shares
     may not be sold, pledged or otherwise transferred nor may any owner reduce
     the owner's risk relative thereto in any other way (i) until such time as
     Tellabs, Inc. shall have published financial results covering at least 30
     days of combined operations after [Closing Date] and (ii) except in
     accordance with an exemption from the registration requirement of the
     Securities Act of 1933, as amended."
 
                                          Very truly yours,
 
                                          Name:
 
Agreed and accepted this      day
of February, 1998, by
TELLABS, INC.
 
By:
    Name:
    Title:
 
                                      I-A-2
<PAGE>   92
 
                                   EXHIBIT B
 
                       Affiliate Letter for Affiliates of
                                 Tellabs, Inc.
 
February     , 1998
 
Tellabs, Inc.
4951 Indiana Avenue
Lisle, Illinois 60532
 
Ladies and Gentlemen:
 
     I have been advised that as of the date of this letter I may be deemed to
be an "affiliate" of Tellabs, Inc., a Delaware corporation ("Parent"), as the
term "affiliate" is used in and for purposes of Accounting Series Releases 130
and 135, as amended, of the Securities and Exchange Commission ("Commission").
Pursuant to the terms of the Agreement and Plan of Merger dated as of February
16, 1998 (the "Merger Agreement") among Parent, Cardinal Merger Co., a Delaware
corporation and a wholly-owned subsidiary of Parent ("Sub"), and Coherent
Communications Systems Corporation, a Delaware corporation (the "Company"), Sub
will be merged (the "Merger") with and into the Company, with the Company
surviving as a wholly-owned subsidiary of Parent. Capitalized terms not defined
herein have the meaning specified in the Merger Agreement.
 
     I will not, during the 30 days prior to the Effective Time, sell, transfer
or otherwise dispose of or reduce my risk (as contemplated by SEC Accounting
Series Release No. 135) with respect to the shares that I may hold of the
capital stock of Parent, including any purchasable upon exercise of stock
options ("Parent Shares"). Furthermore, I will not sell, transfer or otherwise
dispose of or reduce my risk (as contemplated by SEC Accounting Series Release
No. 135) with respect to any shares of the capital stock of Parent until after
such time as results covering at least 30 days of combined operations of the
Company and Parent have been published by Parent, in the form of a quarterly
earnings report, an effective registration statement filed with the Commission,
a report to the Commission on Form 10-K, 10-Q, or 8-K, or any other public
filing or announcement which includes the combined results of operations.
Notwithstanding the foregoing, I understand that during the aforementioned
period, subject to providing written notice to and obtaining the consent of
Parent, which such consent shall not be unreasonably withheld, I will not be
prohibited from de minimis dispositions and charitable contributions or bona
fide gifts of the Parent Shares which, in each case, will not disqualify the
accounting for the Merger as a pooling of interests.
 
                                          Very truly yours,
 
                                          Name:
 
Agreed and accepted this      day
of February, 1998, by
 
TELLABS, INC.
 
By:
    Name:
    Title:
 
                                      I-B-1
<PAGE>   93
 
                                                                        ANNEX II
 
                        SAFEGUARD STOCKHOLDER AGREEMENT
 
     STOCKHOLDER AGREEMENT, dated as of February 16, 1998 (this "Agreement") by
the undersigned stockholder (the "Stockholder") of Coherent Communications
Systems Corporation, a Delaware corporation (the "Company"), for the benefit of
Tellabs, Inc., a Delaware corporation ("Parent").
 
     WHEREAS, Parent, Cardinal Merger Co., a Delaware corporation and a
wholly-owned subsidiary of Parent ("Sub"), and the Company are entering into an
Agreement and Plan of Merger, dated as of February 16, 1998 (the "Merger
Agreement"), whereby, upon the terms and subject to the conditions set forth in
the Merger Agreement, each issued and outstanding share of the Common Stock, par
value $.01 per share, of the Company ("Company Common Stock") not owned directly
or indirectly by Parent or the Company, will be converted into shares of Common
Stock, par value $.01 per share, of Parent ("Parent Common Stock");
 
     WHEREAS, stockholder owns 4,843,342 shares of Company Common Stock (such
shares of Company Common Stock, together with any other shares of capital stock
of the Company acquired by such Stockholder after the date hereof and during the
term of this Agreement, being collectively referred to herein as the "Subject
Shares"); and
 
     WHEREAS, as a condition to its willingness to enter into the Merger
Agreement, Parent has required that the Stockholder agree, and in order to
induce Parent to enter into the Merger Agreement the Stockholder has agreed, to
enter into this Agreement.
 
     NOW, THEREFORE, in consideration of the promises and the mutual covenants
and agreements set forth herein, the Stockholder agrees as follows:
 
     1.  CAPITALIZED TERMS.  Capitalized terms used in this Agreement that are
not defined herein shall have such meanings as set forth in the Merger
Agreement.
 
     2.  COVENANTS OF STOCKHOLDER.  Until the termination of this Agreement in
accordance with Section 5, Stockholder agrees as follows:
 
          (a)  At the Stockholders Meeting (or at any adjournment thereof) or in
     any other circumstances upon which a vote, consent or other approval with
     respect to the Merger or the Merger Agreement is sought, the Stockholder
     shall vote (or cause to be voted) the Subject Shares in favor of the
     Merger, the adoption of the Merger Agreement and the approval of the terms
     thereof and each of the other transactions contemplated by the Merger
     Agreement.
 
          (b)  At any meeting of stockholders of the Company or at any
     adjournment thereof or in any other circumstances upon which the
     Stockholder's vote, consent or other approval is sought, the Stockholder
     shall vote (or cause to be voted) the Subject Shares against (i) any merger
     agreement or merger (other than the Merger Agreement and the Merger),
     consolidation, combination, sale of substantial assets, reorganization,
     recapitalization, dissolution, liquidation or winding up of or by the
     Company or any subsidiary thereof or any other Takeover Proposal or (ii)
     any amendment of the Company's Certificate of Incorporation or Bylaws or
     other proposal or transaction involving the Company or any of its
     subsidiaries, which amendment or other proposal or transaction would in any
     manner impede, frustrate, prevent or nullify the Merger, the Merger
     Agreement or any of the other transactions contemplated by the Merger
     Agreement or change in any manner the voting rights of any class of capital
     stock of the Company. The Stockholder further agrees not to commit or agree
     to take any action inconsistent with the foregoing.
 
          (c) The Stockholder agrees not to (i) sell, transfer, pledge, assign
     or otherwise dispose of (including by gift) (collectively, "Transfer"), or
     enter into any contract, option or other arrangement (including any
     profit-sharing arrangement) with respect to the Transfer of the Subject
     Shares to any person or (ii) enter into any voting arrangement, whether by
     proxy, voting agreement or otherwise, in relation to the Subject Shares,
     and agrees not to commit or agree to take any of the foregoing actions.
 
          (d) The Stockholder shall not, nor shall the Stockholder permit any
     affiliate, director, officer, employee, investment banker, attorney or
     other advisor or representative of the Stockholder to,
 
                                      II-1
<PAGE>   94
 
     (i) directly or indirectly solicit, initiate or encourage the submission
     of, any Takeover Proposal or (ii) directly or indirectly participate in any
     discussions or negotiations regarding, or furnish to any person any
     information with respect to, or take any other action to facilitate any
     inquiries or the making of any proposal that constitutes or may reasonably
     be expected to lead to, any Takeover Proposal.
 
          (e) The Stockholder shall use all reasonable efforts to take, or cause
     to be taken, all actions, and to do, or cause to be done, and to assist and
     cooperate with Parent in doing, all things necessary, proper or advisable
     to consummate and make effective, in the most expeditious manner
     practicable, the Merger and the other transactions contemplated by the
     Merger Agreement.
 
     Stockholder makes the covenants and agreements contained in this Section 2
solely in Stockholder's capacity as a stockholder of the Company and nothing
contained in this Agreement shall limit the ability of Stockholder, to the
extent Stockholder is a director of the Company, to discharge Stockholder's
fiduciary duties as a director of the Company under applicable law.
 
     3. THE SUBJECT SHARES.  The Stockholder represents and warrants to Parent
that (i) the Stockholder is the record and beneficial owner of, and has good and
marketable title to, the Subject Shares, (ii) the Stockholder does not own, of
record or beneficially, any shares of capital stock of the Company other than
the Subject Shares and (iii) the Stockholder has the sole right to vote, and the
sole power of disposition with respect to, the Subject Shares, and none of the
Subject Shares is subject to any voting trust, proxy or other agreement,
arrangement or restriction with respect to the voting or disposition of such
Subject Shares, except as contemplated by this Agreement.
 
     4.  AFFILIATES LETTER.  Stockholder agrees to execute and deliver on a
timely basis an Affiliate Letter in the form of Exhibit A to the Merger
Agreement, when and if requested by Parent.
 
     5.  TERMINATION.  The obligations of the Stockholder hereunder shall
terminate upon the earlier of the termination of the Merger Agreement pursuant
to Section 8.1 thereof or the Effective Time; provided, however, that if the
Merger Agreement is terminated pursuant to Sections 8.1(d), 8.1(e) or 8.1(f) of
the Merger Agreement, this Agreement shall not terminate until 60 days following
the termination of the Merger Agreement.
 
     6.  FURTHER ASSURANCES.  Stockholder will, from time to time, execute and
deliver, or cause to be executed and delivered, such additional or further
consents, documents and other instruments as Parent may reasonably request for
the purpose of effectively carrying out the transactions contemplated by this
Agreement.
 
     7.  SUCCESSORS, ASSIGNS AND TRANSFEREES BOUND.  Any successor, assignee or
transferee (including a successor, assignee or transferee as a result of the
death of the Stockholder, such as an executor or heir) shall be bound by the
terms hereof, and the Stockholder shall take any and all actions necessary to
obtain the written confirmation from such successor, assignee or transferee that
it is bound by the terms hereof.
 
     8.  REMEDIES.  The Stockholder acknowledges that money damages would be
both incalculable and an insufficient remedy for any breach of this Agreement by
it, and that any such breach would cause Parent irreparable harm. Accordingly,
the Stockholder agrees that in the event of any breach or threatened breach of
this Agreement, Parent, in addition to any other remedies at law or in equity it
may have, shall be entitled, without the requirement of posting a bond or other
security, to equitable relief, including injunctive relief and specific
performance.
 
     9.  SEVERABILITY.  The invalidity or unenforceability of any provision of
this Agreement in any jurisdiction shall not affect the validity or
enforceability of any other provision of this Agreement in such jurisdiction, or
the validity or enforceability of any provision of this Agreement in any other
jurisdiction. If in the opinion of Parent's independent accountants, any
provision hereof would cause the Merger to be ineligible for "pooling of
interest" accounting treatment, it shall be deemed to be ineffective and
inapplicable.
 
     10.  AMENDMENT.  This Agreement may be amended only by means of a written
instrument executed and delivered by both the Stockholder and Parent.
 
                                      II-2
<PAGE>   95
 
     11.  GOVERNING LAW.  This Agreement shall be governed by, and construed in
accordance in accordance with, the laws of the State of Delaware, regardless of
the laws that might otherwise govern under applicable principles of conflicts of
laws thereof.
 
     12.  COUNTERPARTS.  For the convenience of the parties, this Agreement may
be executed in one or more counterparts, each of which shall be deemed an
original, but all of which together shall constitute one and the same
instrument.
 
     13.  TERMINATION OF LOAN AGREEMENT.  The loan agreement between the
Stockholder and the Company referenced in the Company's Proxy Statement for its
1997 Annual Meeting of Stockholders has been terminated and is of no force or
effect and no amounts are owing to the Stockholder or the Company thereunder.
 
     14.  TERMINATION OF ADMINISTRATIVE SERVICES AGREEMENT.  The Stockholder
agrees to take all necessary action to cause the Administrative Services
Agreement dated as of May 7, 1997 between the Company and the Stockholder (the
"Services Agreement") to be terminated effective immediately before the
Effective Time (or such later time thereafter as may be requested by Parent, not
to exceed one hundred eighty (180) days following the Effective Time) on terms
that are reasonably satisfactory to Parent, which terms shall include that the
Company shall have no continuing obligations under the such agreements following
such termination and that the Stockholder shall not be entitled to receive any
consideration in connection with such termination other than a termination fee,
payable by the Company at the time of such termination, equal to the Services
Fee (as defined in Section 3 of the Services Agreement) payable with respect to
the period commencing on the date of such termination and ending on December 31,
1998. The Stockholder represents to Parent that a true and complete copy of such
agreement has been delivered to Parent and that all amounts due to Stockholder
from the Company thereunder up to and including January 1, 1998 have been paid
in full.
 
                                          SAFEGUARD SCIENTIFICS, INC.
 
                                          By:   /s/ JAMES A. OUNSWORTH
                                             Name: James A. Ounsworth
                                             Title: Senior Vice President,
                                                    General Counsel and
                                                    Secretary
 
Accepted and Agreed to
as of the date noted above:
 
TELLABS, INC.
 
By:    /s/ MICHAEL J. BIRCK
   Name: Michael J. Birck
   Title: President and Chief
          Executive Officer
 
                                      II-3
<PAGE>   96
 
                                                                       ANNEX III
 
                         FORM OF STOCKHOLDER AGREEMENT
 
     STOCKHOLDER AGREEMENT, dated as of February 16, 1998 (this "Agreement") by
the undersigned stockholder (the "Stockholder") of Coherent Communications
Systems Corporation, a Delaware corporation (the "Company"), for the benefit of
Tellabs, Inc., a Delaware corporation ("Parent").
 
     WHEREAS, Parent, Cardinal Merger Co., a Delaware corporation and a
wholly-owned subsidiary of Parent ("Sub"), and the Company are entering into an
Agreement and Plan of Merger, dated as of February 16, 1998 (the "Merger
Agreement"), whereby, upon the terms and subject to the conditions set forth in
the Merger Agreement, each issued and outstanding share of the Common Stock, par
value $.01 per share, of the Company ("Company Common Stock") not owned directly
or indirectly by Parent or the Company, will be converted into shares of Common
Stock, par value $.01 per share, of Parent ("Parent Common Stock");
 
     WHEREAS, stockholder owns           shares of Company Common Stock (such
shares of Company Common Stock, together with any other shares of capital stock
of the Company acquired by such Stockholder after the date hereof and during the
term of this Agreement, being collectively referred to herein as the "Subject
Shares"); and
 
     WHEREAS, as a condition to its willingness to enter into the Merger
Agreement, Parent has required that the Stockholder agree, and in order to
induce Parent to enter into the Merger Agreement the Stockholder has agreed, to
enter into this Agreement.
 
     NOW, THEREFORE, in consideration of the promises and the mutual covenants
and agreements set forth herein, the Stockholder agrees as follows:
 
     1.  CAPITALIZED TERMS.  Capitalized terms used in this Agreement that are
not defined herein shall have such meanings as set forth in the Merger
Agreement.
 
     2.  COVENANTS OF STOCKHOLDER.  Until the termination of this Agreement in
accordance with Section 5, Stockholder agrees as follows:
 
          (a)  At the Stockholders Meeting (or at any adjournment thereof) or in
     any other circumstances upon which a vote, consent or other approval with
     respect to the Merger or the Merger Agreement is sought, the Stockholder
     shall vote (or cause to be voted) the Subject Shares in favor of the
     Merger, the adoption of the Merger Agreement and the approval of the terms
     thereof and each of the other transactions contemplated by the Merger
     Agreement.
 
          (b)  At any meeting of stockholders of the Company or at any
     adjournment thereof or in any other circumstances upon which the
     Stockholder's vote, consent or other approval is sought, the Stockholder
     shall vote (or cause to be voted) the Subject Shares against (i) any merger
     agreement or merger (other than the Merger Agreement and the Merger),
     consolidation, combination, sale of substantial assets, reorganization,
     recapitalization, dissolution, liquidation or winding up of or by the
     Company or any subsidiary thereof or any other Takeover Proposal or (ii)
     any amendment of the Company's Certificate of Incorporation or Bylaws or
     other proposal or transaction involving the Company or any of its
     subsidiaries, which amendment or other proposal or transaction would in any
     manner impede, frustrate, prevent or nullify the Merger, the Merger
     Agreement or any of the other transactions contemplated by the Merger
     Agreement or change in any manner the voting rights of any class of capital
     stock of the Company. The Stockholder further agrees not to commit or agree
     to take any action inconsistent with the foregoing.
 
          (c) The Stockholder agrees not to (i) sell, transfer, pledge, assign
     or otherwise dispose of (including by gift) (collectively, "Transfer"), or
     enter into any contract, option or other arrangement (including any
     profit-sharing arrangement) with respect to the Transfer of the Subject
     Shares to any person or (ii) enter into any voting arrangement, whether by
     proxy, voting agreement or otherwise, in relation to the Subject Shares,
     and agrees not to commit or agree to take any of the foregoing actions.
 
          (d) The Stockholder shall not, nor shall the Stockholder permit any
     affiliate, director, officer, employee, investment banker, attorney or
     other advisor or representative of the Stockholder to,
 
                                      III-1
<PAGE>   97
 
     (i) directly or indirectly solicit, initiate or encourage the submission
     of, any Takeover Proposal or (ii) directly or indirectly participate in any
     discussions or negotiations regarding, or furnish to any person any
     information with respect to, or take any other action to facilitate any
     inquiries or the making of any proposal that constitutes or may reasonably
     be expected to lead to, any Takeover Proposal.
 
          (e) The Stockholder shall use all reasonable efforts to take, or cause
     to be taken, all actions, and to do, or cause to be done, and to assist and
     cooperate with Parent in doing, all things necessary, proper or advisable
     to consummate and make effective, in the most expeditious manner
     practicable, the Merger and the other transactions contemplated by the
     Merger Agreement.
 
     Stockholder makes the covenants and agreements contained in this Agreement
solely in Stockholder's capacity as a stockholder of the Company and nothing
contained in this Agreement shall limit the ability of Stockholder, to the
extent Stockholder is a director of the Company, to discharge Stockholder's
fiduciary duties as a director of the Company under applicable law.
 
     7. THE SUBJECT SHARES.  The Stockholder represents and warrants to Parent
that (i) the Stockholder is the record and beneficial owner of, and has good and
marketable title to, the Subject Shares, (ii) the Stockholder does not own, of
record or beneficially, any shares of capital stock of the Company other than
the Subject Shares and (iii) the Stockholder has the sole right to vote, and the
sole power of disposition with respect to, the Subject Shares, and none of the
Subject Shares is subject to any voting trust, proxy or other agreement,
arrangement or restriction with respect to the voting or disposition of such
Subject Shares, except as contemplated by this Agreement.
 
     4.  AFFILIATES LETTER.  Stockholder agrees to execute and deliver on a
timely basis an Affiliate Letter in the form of Exhibit A to the Merger
Agreement, when and if requested by Parent.
 
     5.  TERMINATION.  The obligations of the Stockholder hereunder shall
terminate upon the earlier of the termination of the Merger Agreement pursuant
to Section 8.1 thereof or the Effective Time; provided, however, that if the
Merger Agreement is terminated pursuant to Sections 8.1(d), 8.1(e) or 8.1(f) of
the Merger Agreement, this Agreement shall not terminate until 60 days following
the termination of the Merger Agreement.
 
     6.  FURTHER ASSURANCES.  Stockholder will, from time to time, execute and
deliver, or cause to be executed and delivered, such additional or further
consents, documents and other instruments as Parent may reasonably request for
the purpose of effectively carrying out the transactions contemplated by this
Agreement.
 
     7.  SUCCESSORS, ASSIGNS AND TRANSFEREES BOUND.  Any successor, assignee or
transferee (including a successor, assignee or transferee as a result of the
death of the Stockholder, such as an executor or heir) shall be bound by the
terms hereof, and the Stockholder shall take any and all actions necessary to
obtain the written confirmation from such successor, assignee or transferee that
it is bound by the terms hereof.
 
     8.  REMEDIES.  The Stockholder acknowledges that money damages would be
both incalculable and an insufficient remedy for any breach of this Agreement by
it, and that any such breach would cause Parent irreparable harm. Accordingly,
the Stockholder agrees that in the event of any breach or threatened breach of
this Agreement, Parent, in addition to any other remedies at law or in equity it
may have, shall be entitled, without the requirement of posting a bond or other
security, to equitable relief, including injunctive relief and specific
performance.
 
     9.  SEVERABILITY.  The invalidity or unenforceability of any provision of
this Agreement in any jurisdiction shall not affect the validity or
enforceability of any other provision of this Agreement in such jurisdiction, or
the validity or enforceability of any provision of this Agreement in any other
jurisdiction. If in the opinion of Parent's independent accountants, any
provision hereof would cause the Merger to be ineligible for "pooling of
interest" accounting treatment, it shall be deemed to be ineffective and
inapplicable.
 
     10.  AMENDMENT.  This Agreement may be amended only by means of a written
instrument executed and delivered by both the Stockholder and Parent.
 
                                      III-2
<PAGE>   98
 
     11.  GOVERNING LAW.  This Agreement shall be governed by, and construed in
accordance in accordance with, the laws of the State of Delaware, regardless of
the laws that might otherwise govern under applicable principles of conflicts of
laws thereof.
 
     12.  COUNTERPARTS.  For the convenience of the parties, this Agreement may
be executed in one or more counterparts, each of which shall be deemed an
original, but all of which together shall constitute one and the same
instrument.
 
                                          Name:
 
Accepted and Agreed to
as of the date noted above:
 
TELLABS, INC.
 
By:
    Name:
    Title:
 
                                      III-3
<PAGE>   99
 
                                                                        ANNEX IV
 
                                                         [BAIRD LETTERHEAD/LOGO]
 
                                                               February 16, 1998
 
Board of Directors
Coherent Communications Systems Corporation
45085 University Drive
Ashburn, VA 20147-2745
 
Gentlemen:
 
     Coherent Communications Systems Corporation (the "Company") proposes to
enter into an Agreement and Plan of Merger (the "Agreement") with Tellabs, Inc.
("Parent") and Cardinal Merger Co., a wholly owned subsidiary of Parent ("Sub").
Pursuant to the Agreement, at the Effective Time (as defined in the Agreement),
Sub will be merged with and into the Company (the "Merger") and each issued and
outstanding share of common stock, par value $.01 per share ("Company Common
Stock"), of the Company (other than shares owned by the Company, Parent or Sub,
or any of their respective direct or indirect wholly owned subsidiaries) will be
converted solely into the right to receive 0.72 of one share of common stock,
par value $.01 per share ("Parent Common Stock"), of Parent (the "Exchange
Ratio").
 
     You have requested our opinion as to the fairness, from a financial point
of view, of the Exchange Ratio to the holders of Company Common Stock (other
than Parent and its affiliates).
 
     Robert W. Baird & Co. Incorporated ("Baird"), as part of its investment
banking business, is engaged in the evaluation of businesses and their
securities in connection with mergers and acquisitions, negotiated
underwritings, competitive biddings, secondary distributions of listed and
unlisted securities, private placements, and valuations for estate, corporate
and other purposes.
 
     In conducting our investigation and analysis and in arriving at our opinion
herein, we have reviewed such information and taken into account such financial
and economic factors as we have deemed relevant under the circumstances. In that
connection, we have, among other things: (i) reviewed certain internal
information, primarily financial in nature, including projections, concerning
the business and operations of the Company and the Parent furnished to us for
purposes of our analysis, as well as publicly available information including
but not limited to the Company's and the Parent's recent filings with the
Securities and Exchange Commission (the "SEC") and equity analyst research
reports prepared by various investment banking firms including Baird; (ii)
reviewed the February 16, 1998 Agreement in the form presented to the Company's
Board of Directors; (iii) compared the historical market prices and trading
activity of the Company Common Stock and Parent Common Stock with those of
certain other publicly traded companies we deemed relevant; (iv) compared the
financial position and operating results of the Company and Parent with those of
other publicly traded companies we deemed relevant; and (v) compared the
proposed financial terms of the Merger with the financial terms of certain other
business combinations we deemed relevant. We have held discussions with members
of the Company's and Parent's respective senior managements concerning the
Company's and Parent's historical and current financial condition and operating
results, as well as the future prospects of the Company and Parent,
respectively. We have not been requested to, and did not, solicit third party
indications of interest in acquiring all or any part of the Company. We have
also considered such other information, financial studies, analysis and
investigations and financial, economic and market criteria which we deemed
relevant for the preparation of this opinion.
 
     In arriving at our opinion, we have assumed and relied upon the accuracy
and completeness of all of the financial and other information that was publicly
available or provided us by or on behalf of the Company and the Parent, and have
not been engaged to independently verify any such information. We have assumed,
with your consent, (i) that all material assets and liabilities (contingent or
otherwise, known or unknown) of the
                                      IV-1
<PAGE>   100
 
Company and the Parent are as set forth in their respective financial statements
and (ii) the Merger will be accounted for under the pooling-of-interests method.
We have also assumed that the financial forecasts examined by us were reasonably
prepared on bases reflecting the best available estimates and good faith
judgments of the Company's and Parent's respective senior managements as to
future performance of the Company and Parent, respectively. In conducting our
review, we have not undertaken nor obtained an independent evaluation or
appraisal of any of the assets or liabilities (contingent or otherwise) of the
Company and Parent nor have we made a physical inspection of the properties or
facilities of the Company or Parent. Our opinion necessarily is based upon
economic, monetary and market conditions as they exist and can be evaluated on
the date hereof, and does not predict or take into account any changes which may
occur, or information which may become available, after the date hereof.
Furthermore, we express no opinion as to the price or trading range at which any
of the Company's or Parent's securities (including the Company Common Stock and
Parent Common Stock) will trade following the date hereof.
 
     Our opinion has been prepared at the request and solely for the information
of the Board of Directors of the Company, and shall not be used for any other
purpose or disclosed to any other party without the prior written consent of
Baird; provided, however, that this letter may be reproduced in full in the
Proxy Statement/Prospectus, to be provided to the Company's stockholders in
connection with the Merger. This opinion does not address the relative merits of
the Merger and any other potential transactions or business strategies
considered by the Company's Board of Directors, and does not constitute a
recommendation to any shareholder of the Company as to how any such shareholder
should vote with respect to the Merger. In the past, Baird has performed
investment banking services for Safeguard Scientifics, Inc., an affiliate of the
Company, for which Baird has received its customary compensation. Baird will
receive a fee for rendering this opinion.
 
     In the ordinary course of our business, we may from time to time trade the
securities of the Company or Parent for our own account or the accounts of our
customers and, accordingly, may at any time hold long or short positions in such
securities.
 
     Based upon and subject to the foregoing, we are of the opinion that, as of
the date hereof, the Exchange Ratio is fair, from a financial point of view, to
the holders of Company Common Stock (other than Parent and its affiliates).
 
Very truly yours,
 
ROBERT W. BAIRD & CO. INCORPORATED
 
                                      IV-2
<PAGE>   101
 
                                    PART II
 
                     INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 20.  INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
     The Tellabs By-Laws provide, among other things, that each person who was
or is made a party or is threatened to be made a party to or is involved in any
action, suit or proceeding, whether civil, criminal, administrative or
investigative, by reason of the fact that he or she is or was a director or
officer of Tellabs, or is or was serving at the request of Tellabs as a
director, officer, employee, fiduciary or agent of another corporation or of a
partnership, joint venture, trust or other enterprise, shall be indemnified and
held harmless by Tellabs as provided in the Tellabs By-Laws and to the fullest
extent which it is empowered to do so by the DGCL against all expense, liability
and loss (including attorneys' fees) actually and reasonably incurred by such
person in connection with such action, suit or proceeding, and such
indemnification shall inure to the benefit of his or her heirs, executors and
administrators; provided, however, that, subject to certain conditions, Tellabs
shall indemnify any such person seeking indemnification in connection with an
action, suit or proceeding, whether civil, criminal, administrative or
investigative, initiated by such person only if such action, suit or proceeding
was authorized by the Tellabs Board. The right to indemnification under the
Tellabs By-Laws is a contract right and, subject to certain conditions, includes
the right to be paid by Tellabs the expenses incurred in defending any such
action, suit or proceeding in advance of its final disposition. The Tellabs
By-Laws further provide that the indemnification and payment of expenses
incurred provided therein shall not be deemed exclusive of any other rights to
which those seeking indemnification may be entitled.
 
     Section 145 of the DGCL authorizes indemnification by Tellabs of directors
and officers under the circumstances provided in the provisions of the Tellabs
By-Laws described above, and requires such indemnification for expenses actually
and reasonably incurred to the extent a director or officer is successful in the
defense of any action, or any claim, issue or matter therein.
 
     Tellabs has purchased insurance which purports to insure Tellabs against
certain costs of indemnification which may be incurred by it pursuant to the
Tellabs By-Laws and to insure the officers and directors of Tellabs, and of its
subsidiary companies, against certain liabilities incurred by them in the
discharge of their functions as such officers and directors except for
liabilities resulting from their own malfeasance.
 
ITEM 21.  EXHIBITS AND FINANCIAL STATEMENT SCHEDULES
 
     (a)  The following is a list of Exhibits included as part of this
Registration Statement. Tellabs agrees to furnish supplementally a copy of any
omitted schedule to the SEC upon request. Items marked with an asterisk are
filed herewith.
 
<TABLE>
<S>         <C>
   2.1  --   Agreement and Plan of Merger dated as of February 16, 1998
             among Tellabs, Inc., Cardinal Merger Co. and Coherent
             Communications Systems Corporation (included as Annex I to
             the Proxy Statement/Prospectus).
   4.1  --   Restated Certificate of Incorporation of Tellabs, Inc.,
             dated June 24, 1992, is hereby incorporated by reference to
             Exhibit No. 3.1 of Tellabs' Quarterly Report on Form 10-Q
             for the quarter ended June 30, 1995.
   4.2  --   Amended and Restated By-Laws of Tellabs, Inc., as amended
             January 27, 1993, are hereby incorporated by reference to
             Exhibit No. 3.2 to Tellabs' Annual Report on Form 10-K for
             the year ended January 1, 1993.
   4.3  --   The instruments defining the rights of holders of long-term
             debt securities of Tellabs and its subsidiaries are omitted
             pursuant to Item 601(b)(4)(iii)(A) of Regulation S-K.
             Tellabs hereby agrees to furnish copies of these instruments
             to the SEC upon request.
  *5.1  --   Opinion of Carol Coghlan Gavin, Vice President and General
             Counsel of Tellabs, as to the legality of the securities
             being registered.
  *8.1  --   Opinion of Sidley & Austin, as to certain United States
             federal income tax consequences of the Merger.
</TABLE>
 
                                    Part II-1
<PAGE>   102
 
<TABLE>
<C>        <S>        <C>
     *8.2  --         Opinion of Morgan, Lewis & Bockius LLP, as to certain United States federal income tax
                      consequences of the Merger.
    *23.1  --         Consent of Ernst & Young LLP
    *23.2  --         Consent of KPMG Peat Marwick LLP
    *23.3  --         Consent of Grant Thornton LLP
     23.4  --         Consent of Carol Coghlan Gavin (included in Exhibit 5.1 to this Registration Statement).
     23.5  --         Consent of Sidley & Austin (included in Exhibit 8.1 to this Registration Statement).
     23.6  --         Consent of Morgan, Lewis & Bockius LLP (included in Exhibit 8.2 to this Registration
                      Statement).
    *24.1  --         Powers of Attorney.
    *99.1  --         Form of proxy card to be mailed to holders of Coherent Common Stock.
</TABLE>
 
     (b)  Not applicable.
 
     (c)  The opinion of Robert W. Baird & Co. Incorporated is included as Annex
IV to the Proxy Statement/Prospectus.
 
ITEM 22.  UNDERTAKINGS.
 
     (a)  The undersigned Registrant hereby undertakes: (1) to file, during any
period in which offers or sales are being made, a post-effective amendment to
this registration statement:
 
    (i)  To include any prospectus required by Section 10(a)(3) of the
  Securities Act of 1933.
 
    (ii)  To reflect in the prospectus any facts or events arising after the
  effective date of the registration statement (or the most recent
  post-effective amendment thereof) which, individually or in the aggregate,
  represent a fundamental change in the information set forth in the
  registration statement. Notwithstanding the foregoing, any increase or
  decrease in volume of securities offered (if the total dollar amount of
  securities offered would not exceed that which was registered) and any
  deviation from the low or high end of the estimated offering range may be
  reflected in the form of prospectus filed with the SEC pursuant to Rule 424(b)
  if, in the aggregate, the changes in volume and price represent no more than a
  20 percent change in the maximum aggregate offering price set forth in the
  "Calculation of Registration Fee" table in the effective registration
  statement.
 
    (iii)  To include any material information with respect to the plan of
  distribution not previously disclosed in the registration statement or any
  material change to such information in the registration statement.
 
             (2)  That, for the purpose of determining any liability under the
        Securities Act of 1933, each such post-effective amendment shall be
        deemed to be a new registration statement relating to the securities
        offered therein, and the offering of such securities at that time shall
        be deemed to be the initial bona fide offering thereof.
 
             (3)  To remove from registration by means of a post-effective
        amendment any of the securities being registered which remain unsold at
        the termination of the offering.
 
     (b)  The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
Registrant's annual report pursuant to section 13(a) or section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in the
registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at the time shall be deemed to be the initial bona fide offering thereof.
 
     (c)  (1) The undersigned Registrant hereby undertakes as follows: that
prior to any public reoffering of the securities registered hereunder through
use of a prospectus which is a part of this registration statement, by any
person or party who is deemed to be an underwriter within the meaning of Rule
145(c), the issuer
 
                                    Part II-2
<PAGE>   103
 
undertakes that such reoffering prospectus will contain the information called
for by the applicable registration form with respect to reofferings by persons
who may be deemed underwriters, in addition to the information called for by the
other Items of the applicable form.
 
             (2)  The Registrant undertakes that every prospectus (i) that is
        filed pursuant to the paragraph immediately preceding, or (ii) that
        purports to meet the requirements of section 10(a)(3) of the Securities
        Act and is used in connection with an offering of securities subject to
        Rule 415, will be filed as a part of an amendment to the registration
        statement and will not be used until such amendment is effective, and
        that, for purposes of determining any liability under the Securities Act
        of 1933, each such post-effective amendment shall be deemed to be a new
        registration statement relating to the securities offered therein, and
        the offering of such securities at that time shall be deemed to be the
        initial bona fide offering thereof.
 
     (d)  Insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to directors, officers and controlling
persons of the Registrant pursuant to the foregoing provisions, or otherwise,
the Registrant has been advised that in the opinion of the Securities and
Exchange Commission such indemnification is against public policy as expressed
in the Securities Act and is, therefore, unenforceable. In the event that a
claim for indemnification against such liabilities (other than the payment by
the Registrant of expenses incurred or paid by a director, officer or
controlling person of the Registrant in the successful defense of any action,
suit or proceeding) is asserted by such director, officer or controlling person
in connection with the securities being registered, the Registrant will, unless
in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the
Securities Act and will be governed by the final adjudication of such issue.
 
     (e)  The undersigned Registrant hereby undertakes to respond to requests
for information that is incorporated by reference into the prospectus pursuant
to Items 4, 10(b), 11, or 13 of this Form S-4, within one business day of
receipt of such request, and to send the incorporated documents by first class
mail or other equally prompt means. This includes information contained in
documents filed subsequent to the effective date of the registration statement
through the date of responding to the request.
 
     (f)  The undersigned Registrant hereby undertakes to supply by means of a
post-effective amendment all information concerning a transaction, and the
company being acquired involved therein, that was not the subject of and
included in the registration statement when it became effective.
 
                                    Part II-3
<PAGE>   104
 
                                   SIGNATURES
 
     Pursuant to the requirements of the Securities Act of 1933, as amended, the
Registrant has duly caused this Registration Statement to be signed on its
behalf by the undersigned, thereunto duly authorized, in the City of Lisle,
State of Illinois, on April 7, 1998.
 
                                          TELLABS, INC.
 
                                          BY:     /s/ MICHAEL J. BIRCK
                                                      Michael J. Birck
                                               President and Chief Executive
                                                           Officer
 
     Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed below by the following persons in
the capacities and on the dates indicated.
 
<TABLE>
<CAPTION>
                   SIGNATURE                                     CAPACITY                     DATE
                   ---------                                     --------                     ----
<S>                                              <C>                                     <C>
              /s/ MICHAEL J. BIRCK                President, Chief Executive Officer      April 7, 1998
- ------------------------------------------------  and Director
                Michael J. Birck                  (Principal Executive Officer)
 
                       *                          Executive Vice President and Director   April 7, 1998
- ------------------------------------------------  (Principal Financial Officer)
               Peter A. Guglielmi
 
                       *                          Controller                              April 7, 1998
- ------------------------------------------------  (Principal Accounting Officer)
                J. Peter Johnson
 
                       *                          Director                                April 7, 1998
- ------------------------------------------------
             John D. Foulkes, Ph.D.
 
                       *                          Director                                April 7, 1998
- ------------------------------------------------
                Brian J. Jackman
 
                       *                          Director                                April 7, 1998
- ------------------------------------------------
             Frederick A. Krehbiel
 
                       *                          Director                                April 7, 1998
- ------------------------------------------------
         Stephanie Pace Marshall, Ph.D.
 
                       *                          Director                                April 7, 1998
- ------------------------------------------------
               William F. Souders
 
                       *                          Director                                April 7, 1998
- ------------------------------------------------
                Jan H. Suwinski
 
           *By: /s/ MICHAEL J. BIRCK
  -------------------------------------------
                Michael J. Birck
              As Attorney-in-Fact
</TABLE>
 
                                    Part II-4
<PAGE>   105
 
                               INDEX TO EXHIBITS
 
<TABLE>
<CAPTION>
EXHIBIT                                                                  PAGE
  NO.                             DESCRIPTION                           NUMBER
- -------                           -----------                           ------
<S>      <C>                                                           <C>
  2.1     Agreement and Plan of Merger dated as of February 16, 1998
          among Tellabs, Inc., Cardinal Merger Co. and Coherent
          Communications Systems Corporation (included as Annex I to
          the Proxy Statement/Prospectus).............................
  4.1     Restated Certificate of Incorporation of Tellabs, Inc.,
          dated June 24, 1992, is hereby incorporated by reference to
          Exhibit No. 3.1 of Tellabs' Quarterly Report on Form 10-Q
          for the quarter ended June 30, 1995.........................
  4.2     Amended and Restated By-Laws of Tellabs, Inc., as amended
          January 27, 1993, are hereby incorporated by reference to
          Exhibit No. 3.2 to Tellabs' Annual Report on Form 10-K for
          the year ended January 1, 1993..............................
  4.3     The instruments defining the rights of holders of long-term
          debt securities of Tellabs and its subsidiaries are omitted
          pursuant to Item 601(b)(4)(iii)(A) of Regulation S-K.
          Tellabs hereby agrees to furnish copies of these instruments
          to the SEC upon request.....................................
 *5.1     Opinion of Carol Coghlan Gavin, Vice President and General
          Counsel of Tellabs, as to the legality of the securities
          being registered............................................
 *8.1     Opinion of Sidley & Austin, as to certain United States
          federal income tax consequences of the Merger...............
 *8.2     Opinion of Morgan, Lewis & Bockius LLP, as to certain United
          States federal income tax consequences of the Merger........
*23.1     Consent of Ernst & Young LLP................................
*23.2     Consent of KPMG Peat Marwick LLP............................
*23.3     Consent of Grant Thornton LLP...............................
 23.4     Consent of Carol Coghlan Gavin (included in Exhibit 5.1 to
          this Registration Statement)................................
 23.5     Consent of Sidley & Austin (included in Exhibit 8.1 to this
          Registration Statement).....................................
 23.6     Consent of Morgan, Lewis & Bockius LLP (included in Exhibit
          8.2 to this Registration Statement).........................
*24.1     Powers of Attorney..........................................
*99.1     Form of proxy card to be mailed to holders of Coherent
          Common Stock................................................
</TABLE>
 
                                    Part II-5

<PAGE>   1
                                                                   EXHIBIT 5.1
                           [Tellabs, Inc. Letterhead]



                                  April 7, 1998





Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, D.C. 20549

            Re:   11,722,949 Shares of Common Stock,
                  $.01 par value per share, of Tellabs, Inc.

Ladies and Gentlemen:

            I am General Counsel of Tellabs, Inc., a Delaware corporation (the
"Company"), and, in such capacity, I am familiar with the proceedings to date
in connection with the preparation and filing with the Securities and
Exchange Commission under the Securities Act of 1933, as amended (the
"Securities Act"), of the Company's registration statement on Form S-4 (the
"Registration Statement") relating to the registration of 11,722,949 shares of
Common Stock, $.01 par value, of the Company (the "New Shares") pursuant to the
terms of the Agreement and Plan of Merger dated as of February 16, 1998  among
the Company, Cardinal Merger Co., a Delaware corporation and a wholly owned
subsidiary of the Company ("Sub"), and Coherent Communications Systems
Corporation, a Delaware corporation ("Coherent"), which provides for the merger
(the "Merger") of Sub with and into Coherent, with Coherent surviving as a
wholly owned subsidiary of the Company.

            Based on the foregoing, I am of the opinion that:

            1. The Company is duly incorporated and validly existing under the
laws of the State of Delaware.

            2. The New Shares will be legally issued, fully paid and
non-assessable when (i) the Registration Statement, as finally amended, shall
have become effective under the Securities Act; and (ii) the Merger shall have
become effective under the General Corporation Law of the State of Delaware.
<PAGE>   2
            The foregoing opinions are limited to the federal laws of the United
States of America and the General Corporation Law of the State of Delaware. I
express no opinion as to the application of the securities or blue sky laws of
the various states to the sale of the New Shares.

            I hereby consent to the filing of this opinion as an Exhibit to the
Registration Statement and to all references to my name included in or made a
part of the Registration Statement.

                                Very truly yours,

                             /s/ CAROL COGHLAN GAVIN

<PAGE>   1
                       [Letterhead of Sidley & Austin]



                                 April 7, 1998                     EXHIBIT 8.1



Tellabs, Inc.
4951 Indiana Avenue
Lisle, Illinois 60532


Ladies and Gentlemen:

            We refer to the Agreement and Plan of Merger dated as of February
16, 1998 (the "Agreement") among Tellabs, Inc., a Delaware corporation
("Parent"), Cardinal Merger Co., a Delaware corporation and wholly owned
subsidiary of Parent ("Sub"), and Coherent Communications Systems Corporation, a
Delaware corporation (the "Company"), which provides for the merger (the
"Merger") of Sub with and into the Company on the terms and conditions therein
set forth, the time at which the Merger becomes effective being hereinafter
referred to as the "Effective Time." Capitalized terms used but not defined
herein have the meanings specified in the Agreement.

            As provided in the Agreement, at the Effective Time, by reason of
the Merger: (i) all outstanding shares of Company Common Stock then owned by the
Company or by any Subsidiary of the Company and each share of Company Capital
Stock owned by Parent, Sub or any other wholly owned Subsidiary of Parent shall
be canceled and retired and shall cease to exist, and no stock of Parent or
other consideration shall be delivered in exchange therefor; (ii) each then
issued and outstanding share of capital stock of Sub shall be converted into and
become one fully paid and nonassessable share of Common Stock, $.01 par value
per share, of the Surviving Corporation; and (iii) each issued and outstanding
share of Company Common Stock (other than shares canceled as described above)
shall be converted into the right to receive seventy-two hundredths (.72) of a
fully paid and nonassessable share of Parent Common Stock. Cash will be paid in
lieu of fractional shares of Parent Common Stock.

            The Merger and the Agreement are more fully described in the
Parent's Registration Statement on Form S-4 (the "Registration Statement")
relating to the registration of
<PAGE>   2

Tellabs, Inc.
April 7, 1998
Page 2


shares of Parent Common Stock to which this opinion is an exhibit, which is
being filed by Parent with the Securities and Exchange Commission pursuant to
the Securities Act of 1933, as amended. The Registration Statement includes the
Proxy Statement/Prospectus (the "Prospectus") of Parent and the Company.

            In rendering the opinions expressed below, we have relied upon the
accuracy of the facts, information and representations and the completeness of
the covenants contained in the Agreement, the Prospectus and such other
documents as we have deemed relevant and necessary. Such opinions are
conditioned, among other things, not only upon such accuracy and completeness as
of the date hereof, but also the continuing accuracy and completeness thereof as
of the Effective Time. Moreover, we have assumed the absence of any change to
any of such instruments between the date hereof and the Effective Time.

            We have assumed the authenticity of all documents submitted to us as
originals, the genuineness of all signatures, the legal capacity of all natural
persons and the conformity with original documents of all copies submitted to us
for our examination. We have further assumed that: (i) the transactions related
to the Merger or contemplated by the Agreement will be consummated (A) in
accordance with the Agreement and (B) as described in the Prospectus; (ii) the
Merger will qualify as a statutory merger under the laws of the State of
Delaware; and (iii) as of the date hereof, and as of the Effective Time (as if
made as of the Effective Time), the written statements made by executives of
Parent and the Company contained in the Parent Tax Certificate and the Company
Tax Certificate, respectively, will be accurate in all respects.

            In rendering the opinions expressed below, we have considered the
applicable provisions of the Internal Revenue Code of 1986, as amended (the
"Code"), Regulations promulgated thereunder by the United States Treasury
Department (the "Regulations"), pertinent judicial authorities, rulings of the
Internal Revenue Service and such other authorities as we have considered
relevant. It should be noted that the Code, the Regulations and such judicial
decisions, administrative interpretations and other authorities are subject to
change at any time and, in some circumstances, with retroactive effect; and any
such change could affect the opinions stated herein. Furthermore, the opinions
expressed below might not be applicable to Company stockholders who, for federal
income tax purposes, are nonresident alien individuals, foreign corporations,
foreign partnerships, foreign trusts or foreign estates, or who acquired their
Company Common Stock pursuant to the exercise of employee stock options or
otherwise as compensation.

            Based upon and subject to the foregoing, it is our opinion, as
counsel for Parent, that for federal income tax purposes:
<PAGE>   3

Tellabs, Inc.
April 7, 1998
Page 3


                  (i) the Merger will constitute a "reorganization" within the
      meaning of Section 368(a) of the Code, and the Company, Sub and Parent
      will each be a party to such reorganization within the meaning of Section
      368(b) of the Code;

                  (ii) no gain or loss will be recognized by Parent, Sub or the
      Company as a result of the Merger;

                  (iii) no gain or loss will be recognized by the stockholders
      of the Company upon the exchange of their Company Common Stock solely for
      shares of Parent Common Stock pursuant to the Merger, except with respect
      to cash, if any, received in lieu of fractional shares of Parent Common
      Stock;

                  (iv) the aggregate tax basis of the shares of Parent Common
      Stock received solely in exchange for Company Common Stock pursuant to the
      Merger (including fractional shares of Parent Common Stock for which cash
      is received) will be the same as the aggregate tax basis of the Company
      Common Stock exchanged therefor;

                  (v) the holding period for shares of Parent Common Stock
      received solely in exchange for Company Common Stock pursuant to the
      Merger will include the holding period of the Company Common Stock
      exchanged therefor, provided such Company Common Stock was held as a
      capital asset by the stockholder at the Effective Time; and

                  (vi) a stockholder of the Company who receives cash in lieu of
      a fractional share of Parent Common Stock will recognize gain or loss
      equal to the difference, if any, between such stockholder's tax basis in
      such fractional share (as described in clause (iv) above) and the amount
      of cash received.

            Except as expressly set forth in paragraphs (i) through (vi),
inclusive, you have not requested, and we do not herein express, any opinion
concerning the tax consequences of, or any other matters related to, the Merger.

            We assume no obligation to update or supplement this letter to
reflect any facts or circumstances which may hereafter come to our attention
with respect to the opinions expressed above, including any changes in
applicable law which may hereafter occur.

            This opinion is provided to you only, and without our prior consent,
may not be relied upon, used, circulated, quoted or otherwise referred to in any
manner by any person, firm, governmental authority or entity whatsoever other
than reliance thereon by you. Notwithstanding
<PAGE>   4

Tellabs, Inc.
April 7, 1998
Page 4

the prior sentence, we hereby consent to the filing of this letter as an exhibit
to the Registration Statement and to all references to our firm included in or
made part of the Registration Statement.


                                Very truly yours,

                                /s/ Sidley & Austin

<PAGE>   1
                                                                EXHIBIT 8.2


                   [Letterhead of Morgan, Lewis & Bockius LLP]

April 7, 1998


COHERENT COMMUNICATIONS SYSTEMS CORPORATION
45085 University Drive
Ashburn, Virginia 20174


Re:      Certain Federal Income Tax Consequences of the Triangular Merger of
         Coherent with Tellabs

Ladies and Gentlemen:

Pursuant to the Agreement and Plan of Merger dated as of February 16, 1998 (the
"Agreement"), among Tellabs, Inc., a Delaware corporation ("Parent"), Cardinal
Merger Co., a Delaware corporation and a direct wholly-owned subsidiary of
Parent ("Sub"), and Coherent Communications Systems Corporation, a Delaware
corporation (the "Company"), Sub will merge with and into the Company (the
"Merger"). Capitalized terms not otherwise defined in this opinion have the
meanings ascribed to such terms in the Agreement or the other documents referred
to in the Agreement.

We have acted as legal counsel to the Company in connection with the Merger and
you have requested our opinion regarding certain federal income tax consequences
of the Merger. As such, and for the purpose of rendering this opinion, we have
examined and are relying upon (without any independent investigation or review
thereof) the truth and accuracy, at all relevant times, of the statements,
covenants, representations and warranties contained in the following documents:

         1.       The Agreement;

         2.       Such other instruments and documents related to the formation,
                  organization and operation of the Company, Parent, and Sub and
                  to the consummation of the Merger as we have deemed necessary
                  or appropriate.






<PAGE>   2


Coherent Communications
April 7, 1998
Page 2



In preparing our opinion, as set forth below, we have reviewed such other
documents relating to the Merger and such federal income tax authority as we
deemed relevant under the circumstances. For purposes of this opinion, we have
assumed, with your permission and without independent investigation, that (i)
original documents (including signatures) are authentic, documents submitted to
us as copies conform to the original documents, and there has been (or will be
by the date of the Merger) due execution and delivery of all documents where due
execution and delivery are prerequisites to the effectiveness of those documents
and (ii) the Merger will be effective under the laws of the State of Delaware.

Furthermore, as to certain facts material to our opinion that we did not
independently establish or verify, we have relied upon the accuracy of
statements and representations of officers of each of the Company and Parent
contained in the Company Tax Certificate and the Parent Tax Certificate
(collectively, the "Certifications").

                                    OPINIONS
                                    --------
Based upon the foregoing, it is our opinion that for federal income tax purposes
the Merger will constitute a "reorganization" within the meaning of Section
368(a) of the Code and the Company, Parent, and Sub will each be a party to the
reorganization within the meaning of Section 368(b) of the Code. It is also our
opinion that (i) no gain or loss will be recognized by the Company, Parent, or
Sub as a result of the Merger; (ii) no gain or loss will be recognized by the
stockholders of the Company upon the exchange of their Company Common Stock
solely for shares of Parent Common Stock pursuant to the Merger, except with
respect to cash, if any, received in lieu of fractional shares of Parent Common
Stock; (iii) the aggregate tax basis of the shares of Parent Common Stock
received solely in exchange for Company Common Stock pursuant to the Merger
(including fractional shares of Parent Common Stock for which cash is received)
will be the same as the aggregate tax basis of the Company Common Stock
exchanged therefor; (iv) the holding period for shares of Parent Common Stock
received solely in exchange for Company Common Stock pursuant to the Merger will
include the holding period of the Company Common Stock exchanged therefor,
provided such Company Common Stock was held as a capital asset by the
stockholder at the Effective Time; and (v) a stockholder of the Company who
receives cash in lieu of a fractional share of Parent Common Stock will
recognize gain or loss equal to the difference, if any, between such
stockholder's tax basis in such fractional share (as described in clause (iii)
above) and amount of cash received.


                                      * * *


<PAGE>   3

Coherent Communications
April 7, 1998
Page 3


Our opinions set forth herein are based upon existing law, regulations,
administrative pronouncements and judicial decisions, all as in effect as of
today's date. All such authorities are subject to change, either prospectively
or retroactively. No assurance can be provided as to the effect of any such
change on our opinions. If any of the facts, assumptions or Certifications on
which our opinions are based is incorrect, please advise us so that we may
consider the effect, if any, on our opinions.

The opinions set forth herein have no binding effect on the United States
Internal Revenue Service or the courts. Accordingly, no assurance can be given
that, if the matter were contested, a court would agree with the opinions set
forth above.

We hereby consent to the use of this opinion as Exhibit 8.2 to the Registration
Statement and to the reference to this firm under the captions "LEGAL OPINIONS,"
"SUMMARY" and "CERTAIN FEDERAL INCOME CONSEQUENCES OF THE MERGER." In giving
such consent, we do not thereby admit that we are acting within the category of
persons whose consent is required under Section 7 of the Act or the rules or
regulations of the Securities and Exchange Commission thereunder.



Very truly yours,

/s/ MORGAN, LEWIS & BOCKIUS LLP




<PAGE>   1
                                                                  EXHIBIT 23.1

                        Consent of Independent Auditors

We consent to the reference to our firm under the caption "Experts" in the Proxy
Statement/Prospectus and Registration Statement (Form S-4) of Tellabs, Inc. for
the registration of 11,722,949 shares of its common stock and to the
incorporation by reference therein of our reports dated January 26, 1998, with
respect to the consolidated financial statements of Tellabs, Inc., incorporated
by reference in its Annual Report (Form 10-K) for the year ended January 2, 1998
and the related financial statement schedules included therein, filed with the
Securities and Exchange Commission.


ERNST & YOUNG LLP
Chicago, Illinois
April 6, 1998

<PAGE>   1
                                                                EXHIBIT 23.2


The Board of Directors
Coherent Communications Systems Corporation



We consent to the incorporation by reference in this Registration Statement on
Form S-4 of Tellabs, Inc. of our report dated January 23, 1998, with respect to
the consolidated balance sheets of Coherent Communications Systems Corporation
and subsidiaries as of December 31, 1997 and 1996, and the related consolidated
statements of income, stockholders' equity and cash flows for each of the years
in the three-year period ended December 31, 1997, which report appears in the
December 31, 1997 annual report on Form 10-K of Coherent Communications Systems
Corporation, and to the reference to our firm under the heading "Experts" in the
Proxy Statement/Prospectus.

                                                     KPMG Peat Marwick LLP



McLean, VA.
April 7, 1998








<PAGE>   1
                                                                  EXHIBIT 23.3


              CONSENT OF INDEPENDENT CERTIFIED PUBLIC ACCOUNTANTS


We have issued our report dated January 15, 1997, accompanying the consolidated
financial statements of Tellabs, Inc. and Subsidiaries as of December 27, 1996
and for the two years then ended incorporated by reference in this Registration
Statement on Form S-4. We consent to the use of the aforementioned report, and
to the use of our name as it appears under the caption "Experts".




GRANT THORNTON LLP
Chicago, Illinois
April 6, 1998

<PAGE>   1
                                                              EXHIBIT 24.1

                                POWER OF ATTORNEY

                  KNOW ALL MEN BY THESE PRESENTS, that the undersigned, a
Director and/or Officer of Tellabs, Inc., a Delaware corporation (the
"Company"), does hereby constitute and appoint Michael J. Birck and Carol
Coghlan Gavin, and each of them, with full power to act alone, his true and
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him and in his name, place and stead, in any and all
capacities, to sign on behalf of the undersigned a Registration Statement on
Form S-4 under the Securities Act of 1933, as amended (the "Securities Act"),
with respect to the registration under the Securities Act of the shares of
Common Stock, $.01 par value per share, of the Company to be issued pursuant to
the terms of the Agreement and Plan of Merger dated as of February 16, 1998
among the Company, Cardinal Merger Co., a Delaware corporation and a
wholly-owned subsidiary of the Company ("Sub"), and Coherent Communications
Systems Corporation, a Delaware corporation ("Coherent"), which provides for the
merger of Sub with and into Coherent, with Coherent surviving as a wholly-owned
subsidiary of the Company; and to execute any and all amendments to such
Registration Statement, whether filed prior or subsequent to the time such
Registration Statement becomes effective, including amendments filed on Form
S-8, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite and
necessary to be done, as fully to all intents and purposes as the undersigned
might or could do in person, hereby ratifying and confirming all that said
attorneys-in-fact and agents or any one of them, or such person's substitute or
their substitutes, lawfully do or cause to be done by virtue hereof.

                  IN WITNESS WHEREOF, I have hereunto set my hand this 7th day
of April, 1998.


                                                     /s/  PETER A. GUGLIELMI
                                                     --------------------------
                                                     Peter A. Guglielmi



<PAGE>   2
                                                                  EXHIBIT 24.1

                              POWER OF ATTORNEY

            KNOW ALL MEN BY THESE PRESENTS, that the undersigned, a Director
and/or Officer of Tellabs, Inc., a Delaware corporation (the "Company"), does
hereby constitute and appoint Michael J. Birck and Carol Coghlan Gavin, and each
of them, with full power to act alone, his true and lawful attorney-in-fact and
agent, with full power of substitution and resubstitution, for him and in his
name, place and stead, in any and all capacities, to sign on behalf of the
undersigned a Registration Statement on Form S-4 under the Securities Act of
1933, as amended (the "Securities Act"), with respect to the registration under
the Securities Act of the shares of Common Stock, $.01 par value per share, of
the Company to be issued pursuant to the terms of the Agreement and Plan of
Merger dated as of February 16, 1998 among the Company, Cardinal Merger Co., a
Delaware corporation and a wholly-owned subsidiary of the Company ("Sub"), and
Coherent Communications Systems Corporation, a Delaware corporation
("Coherent"), which provides for the merger of Sub with and into Coherent, with
Coherent surviving as a wholly-owned subsidiary of the Company; and to execute
any and all amendments to such Registration Statement, whether filed prior or
subsequent to the time such Registration Statement becomes effective, including
amendments filed on Form S-8, granting unto said attorneys-in-fact and agents,
and each of them, full power and authority to do and perform each and every act
and thing requisite and necessary to be done, as fully to all intents and
purposes as the undersigned might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any one of them, or
such person's substitute or their substitutes, lawfully do or cause to be done
by virtue hereof.

            IN WITNESS WHEREOF, I have hereunto set my hand this 7th day of
April, 1998.


                                    /s/  J. PETER JOHNSON
                                    ---------------------
                                    J. Peter Johnson
<PAGE>   3
                                                                  EXHIBIT 24.1

                              POWER OF ATTORNEY

            KNOW ALL MEN BY THESE PRESENTS, that the undersigned, a Director
and/or Officer of Tellabs, Inc., a Delaware corporation (the "Company"), does
hereby constitute and appoint Michael J. Birck and Carol Coghlan Gavin, and each
of them, with full power to act alone, his true and lawful attorney-in-fact and
agent, with full power of substitution and resubstitution, for him and in his
name, place and stead, in any and all capacities, to sign on behalf of the
undersigned a Registration Statement on Form S-4 under the Securities Act of
1933, as amended (the "Securities Act"), with respect to the registration under
the Securities Act of the shares of Common Stock, $.01 par value per share, of
the Company to be issued pursuant to the terms of the Agreement and Plan of
Merger dated as of February 16, 1998 among the Company, Cardinal Merger Co., a
Delaware corporation and a wholly-owned subsidiary of the Company ("Sub"), and
Coherent Communications Systems Corporation, a Delaware corporation
("Coherent"), which provides for the merger of Sub with and into Coherent, with
Coherent surviving as a wholly-owned subsidiary of the Company; and to execute
any and all amendments to such Registration Statement, whether filed prior or
subsequent to the time such Registration Statement becomes effective, including
amendments filed on Form S-8, granting unto said attorneys-in-fact and agents,
and each of them, full power and authority to do and perform each and every act
and thing requisite and necessary to be done, as fully to all intents and
purposes as the undersigned might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any one of them, or
such person's substitute or their substitutes, lawfully do or cause to be done
by virtue hereof.

            IN WITNESS WHEREOF, I have hereunto set my hand this 7th day of
April, 1998.


                           /s/ JOHN D. FOULKES, PH.D.
                           --------------------------
                             John D. Foulkes, Ph.D.
<PAGE>   4
                                                                  EXHIBIT 24.1

                              POWER OF ATTORNEY

            KNOW ALL MEN BY THESE PRESENTS, that the undersigned, a Director
and/or Officer of Tellabs, Inc., a Delaware corporation (the "Company"), does
hereby constitute and appoint Michael J. Birck and Carol Coghlan Gavin, and each
of them, with full power to act alone, his true and lawful attorney-in-fact and
agent, with full power of substitution and resubstitution, for him and in his
name, place and stead, in any and all capacities, to sign on behalf of the
undersigned a Registration Statement on Form S-4 under the Securities Act of
1933, as amended (the "Securities Act"), with respect to the registration under
the Securities Act of the shares of Common Stock, $.01 par value per share, of
the Company to be issued pursuant to the terms of the Agreement and Plan of
Merger dated as of February 16, 1998 among the Company, Cardinal Merger Co., a
Delaware corporation and a wholly-owned subsidiary of the Company ("Sub"), and
Coherent Communications Systems Corporation, a Delaware corporation
("Coherent"), which provides for the merger of Sub with and into Coherent, with
Coherent surviving as a wholly-owned subsidiary of the Company; and to execute
any and all amendments to such Registration Statement, whether filed prior or
subsequent to the time such Registration Statement becomes effective, including
amendments filed on Form S-8, granting unto said attorneys-in-fact and agents,
and each of them, full power and authority to do and perform each and every act
and thing requisite and necessary to be done, as fully to all intents and
purposes as the undersigned might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any one of them, or
such person's substitute or their substitutes, lawfully do or cause to be done
by virtue hereof.

            IN WITNESS WHEREOF, I have hereunto set my hand this 7th day of
April, 1998.


                                    /s/  BRIAN J. JACKMAN
                                    ---------------------
                                    Brian J. Jackman
<PAGE>   5
                                                                  EXHIBIT 24.1

                              POWER OF ATTORNEY

            KNOW ALL MEN BY THESE PRESENTS, that the undersigned, a Director
and/or Officer of Tellabs, Inc., a Delaware corporation (the "Company"), does
hereby constitute and appoint Michael J. Birck and Carol Coghlan Gavin, and each
of them, with full power to act alone, his true and lawful attorney-in-fact and
agent, with full power of substitution and resubstitution, for him and in his
name, place and stead, in any and all capacities, to sign on behalf of the
undersigned a Registration Statement on Form S-4 under the Securities Act of
1933, as amended (the "Securities Act"), with respect to the registration under
the Securities Act of the shares of Common Stock, $.01 par value per share, of
the Company to be issued pursuant to the terms of the Agreement and Plan of
Merger dated as of February 16, 1998 among the Company, Cardinal Merger Co., a
Delaware corporation and a wholly-owned subsidiary of the Company ("Sub"), and
Coherent Communications Systems Corporation, a Delaware corporation
("Coherent"), which provides for the merger of Sub with and into Coherent, with
Coherent surviving as a wholly-owned subsidiary of the Company; and to execute
any and all amendments to such Registration Statement, whether filed prior or
subsequent to the time such Registration Statement becomes effective, including
amendments filed on Form S-8, granting unto said attorneys-in-fact and agents,
and each of them, full power and authority to do and perform each and every act
and thing requisite and necessary to be done, as fully to all intents and
purposes as the undersigned might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any one of them, or
such person's substitute or their substitutes, lawfully do or cause to be done
by virtue hereof.

            IN WITNESS WHEREOF, I have hereunto set my hand this 7th day of
April, 1998.


                            /s/ FREDERICK A. KREHBIEL
                            -------------------------
                            Frederick A. Krehbiel
<PAGE>   6
                                                                  EXHIBIT 24.1

                              POWER OF ATTORNEY

            KNOW ALL MEN BY THESE PRESENTS, that the undersigned, a Director
and/or Officer of Tellabs, Inc., a Delaware corporation (the "Company"), does
hereby constitute and appoint Michael J. Birck and Carol Coghlan Gavin, and each
of them, with full power to act alone, her true and lawful attorney-in-fact and
agent, with full power of substitution and resubstitution, for her and in her
name, place and stead, in any and all capacities, to sign on behalf of the
undersigned a Registration Statement on Form S-4 under the Securities Act of
1933, as amended (the "Securities Act"), with respect to the registration under
the Securities Act of the shares of Common Stock, $.01 par value per share, of
the Company to be issued pursuant to the terms of the Agreement and Plan of
Merger dated as of February 16, 1998 among the Company, Cardinal Merger Co., a
Delaware corporation and a wholly-owned subsidiary of the Company ("Sub"), and
Coherent Communications Systems Corporation, a Delaware corporation
("Coherent"), which provides for the merger of Sub with and into Coherent, with
Coherent surviving as a wholly-owned subsidiary of the Company; and to execute
any and all amendments to such Registration Statement, whether filed prior or
subsequent to the time such Registration Statement becomes effective, including
amendments filed on Form S-8, granting unto said attorneys-in-fact and agents,
and each of them, full power and authority to do and perform each and every act
and thing requisite and necessary to be done, as fully to all intents and
purposes as the undersigned might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any one of them, or
such person's substitute or their substitutes, lawfully do or cause to be done
by virtue hereof.

            IN WITNESS WHEREOF, I have hereunto set my hand this 7th day of
April, 1998.


                       /s/ STEPHANIE PACE MARSHALL, PH.D.
                       ----------------------------------
                       Stephanie Pace Marshall, Ph.D.
<PAGE>   7
                                                                  EXHIBIT 24.1

                              POWER OF ATTORNEY

            KNOW ALL MEN BY THESE PRESENTS, that the undersigned, a Director
and/or Officer of Tellabs, Inc., a Delaware corporation (the "Company"), does
hereby constitute and appoint Michael J. Birck and Carol Coghlan Gavin, and each
of them, with full power to act alone, his true and lawful attorney-in-fact and
agent, with full power of substitution and resubstitution, for him and in his
name, place and stead, in any and all capacities, to sign on behalf of the
undersigned a Registration Statement on Form S-4 under the Securities Act of
1933, as amended (the "Securities Act"), with respect to the registration under
the Securities Act of the shares of Common Stock, $.01 par value per share, of
the Company to be issued pursuant to the terms of the Agreement and Plan of
Merger dated as of February 16, 1998 among the Company, Cardinal Merger Co., a
Delaware corporation and a wholly-owned subsidiary of the Company ("Sub"), and
Coherent Communications Systems Corporation, a Delaware corporation
("Coherent"), which provides for the merger of Sub with and into Coherent, with
Coherent surviving as a wholly-owned subsidiary of the Company; and to execute
any and all amendments to such Registration Statement, whether filed prior or
subsequent to the time such Registration Statement becomes effective, including
amendments filed on Form S-8, granting unto said attorneys-in-fact and agents,
and each of them, full power and authority to do and perform each and every act
and thing requisite and necessary to be done, as fully to all intents and
purposes as the undersigned might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any one of them, or
such person's substitute or their substitutes, lawfully do or cause to be done
by virtue hereof.

            IN WITNESS WHEREOF, I have hereunto set my hand this 7th day of
April, 1998.


                                    /s/  WILLIAM F. SOUDERS
                                    -----------------------
                                    William F. Souders
<PAGE>   8
                                                                  EXHIBIT 24.1

                              POWER OF ATTORNEY

            KNOW ALL MEN BY THESE PRESENTS, that the undersigned, a Director
and/or Officer of Tellabs, Inc., a Delaware corporation (the "Company"), does
hereby constitute and appoint Michael J. Birck and Carol Coghlan Gavin, and each
of them, with full power to act alone, his true and lawful attorney-in-fact and
agent, with full power of substitution and resubstitution, for him and in his
name, place and stead, in any and all capacities, to sign on behalf of the
undersigned a Registration Statement on Form S-4 under the Securities Act of
1933, as amended (the "Securities Act"), with respect to the registration under
the Securities Act of the shares of Common Stock, $.01 par value per share, of
the Company to be issued pursuant to the terms of the Agreement and Plan of
Merger dated as of February 16, 1998 among the Company, Cardinal Merger Co., a
Delaware corporation and a wholly-owned subsidiary of the Company ("Sub"), and
Coherent Communications Systems Corporation, a Delaware corporation
("Coherent"), which provides for the merger of Sub with and into Coherent, with
Coherent surviving as a wholly-owned subsidiary of the Company; and to execute
any and all amendments to such Registration Statement, whether filed prior or
subsequent to the time such Registration Statement becomes effective, including
amendments filed on Form S-8, granting unto said attorneys-in-fact and agents,
and each of them, full power and authority to do and perform each and every act
and thing requisite and necessary to be done, as fully to all intents and
purposes as the undersigned might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents or any one of them, or
such person's substitute or their substitutes, lawfully do or cause to be done
by virtue hereof.

            IN WITNESS WHEREOF, I have hereunto set my hand this 7th day of
April, 1998.


                                    /s/  JAN H. SUWINSKI
                                    --------------------
                                    Jan H. Suwinski


<PAGE>   1
 
                                                                    EXHIBIT 99.1
 
                  COHERENT COMMUNICATIONS SYSTEMS CORPORATION
                   PROXY SOLICITED BY THE BOARD OF DIRECTORS
                        FOR SPECIAL MEETING MAY 12, 1998
 
     The undersigned stockholder of Coherent Communications Systems Corporation,
a Delaware corporation (the "Company"), hereby appoint(s) Daniel L. McGinnis,
David L. Powell and Melba G. Chan, and each of them, as proxies for the
undersigned, with full power of substitution, for and in the name, place and
stead of the undersigned, to attend the Special Meeting of Stockholders of the
Company to be held at the Company's offices located at 48085 University Drive,
Ashburn, Virginia 20147 on May 12, 1998 at 11:00 A.M., local time, and any
adjournment(s) thereof, and to cast on behalf of the undersigned the number of
votes the undersigned would be entitled to vote if personally present as set
forth herein and otherwise to represent the undersigned at the meeting with all
powers possessed by the undersigned if personally present at the meeting. The
undersigned acknowledges receipt of the Notice of the Special Meeting of
Stockholders and the accompanying Proxy Statement and releases any proxy
heretofore given with respect to such meeting.
 
     THIS PROXY, WHEN PROPERLY EXECUTED, WILL BE VOTED IN THE MANNER DIRECTED
HEREIN BY THE UNDERSIGNED STOCKHOLDER. IF NO DIRECTION IS MADE, THIS PROXY WILL
BE VOTED FOR APPROVAL OF THE MERGER AGREEMENT AS SET FORTH IN PARAGRAPH 1 ON THE
REVERSE SIDE.
<PAGE>   2
 
                  COHERENT COMMUNICATIONS SYSTEMS CORPORATION
 
                           PROXY FOR SPECIAL MEETING
 
     The proxy is revocable at any time before it is exercised and the
undersigned reserve(s) the right to attend the meeting and vote in person.
 
                                    PROPOSAL
 
     The Board of Directors recommends a vote "FOR" the listed proposal.
 
     1. PROPOSAL FOR APPROVAL OF THE AGREEMENT AND PLAN OF MERGER dated as of
February 16, 1998 by and among Tellabs, Inc., Cardinal Merger Co. and Coherent
Communications Systems Corporation.
             [ ] FOR             [ ] AGAINST             [ ] ABSTAIN
 
     2. In their discretion, the proxies are authorized to vote upon such other
business as may properly come before the meeting.
 
The undersigned hereby ratifies and confirms all that said attorneys and
proxies, or any one or more of them or their substitute or substitutes, may
lawfully do or cause to be done by virtue hereof and any prior proxies are
hereby revoked.
 
                                          Dated:  , 1998
 
                                          Signature
 
                                          Signature
 
                                          Your signature should be as your name
                                          appears hereon. When signed in a
                                          fiduciary or representative capacity
                                          please show your full title as such.
                                          For joint accounts each joint owner
                                          should sign.
                                          PLEASE DATE, SIGN AND RETURN IN THE
                                          ENCLOSED POSTMARKED ENVELOPE PROMPTLY.
 
                                        2


© 2022 IncJournal is not affiliated with or endorsed by the U.S. Securities and Exchange Commission