<PAGE>
EXHIBIT 99.1
TO VOTE BY MAIL, PLEASE DETACH PROXY CARD HERE
--------------------------------------------------------------------------------
THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS
OF INTERFACE SYSTEMS, INC.
SPECIAL MEETING OF SHAREHOLDERS
SEPTEMBER 1, 2000
10:00 A.M. LOCAL TIME
R The undersigned hereby appoints the Board of Directors of Interface Systems,
E Inc. (the "Company") to act as proxy for the undersigned and to vote all
V shares of Common Stock of the Company that the undersigned is entitled to
O vote only at the Special Meeting of Shareholders, to be held on September 1,
C 2000, at 10:00 a.m., local time at Crowne Plaza Hotel, 610 Hilton Boulevard,
A Ann Arbor, Michigan and any and all adjournments thereof, as indicated on
B the reverse side of this proxy.
L
E This proxy is revocable and will be voted as directed, but if no instructions
P are specified, this proxy will be voted FOR each of the proposals listed. If
R any other business is presented at the Special Meeting, including whether or
O not to adjourn the meeting, this proxy will be voted by the Board of
X Directors in their best judgment. At the present time, the Board of
Y Directors knows of no other business to be presented at the Special Meeting.
(IMPORTANT--TO BE SIGNED AND DATED ON REVERSE SIDE)
----------------
SEE REVERSE SIDE
----------------
<PAGE>
INSTRUCTIONS FOR VOTING YOUR PROXY
Interface Systems, Inc. is now offering shareholders of record three
alternative ways of voting their proxies:
- BY TELEPHONE (using a touch-tone telephone)
- THROUGH THE INTERNET (using a browser)
- BY MAIL (traditional method)
Your telephone or Internet vote authorizes the named proxies to vote your
shares in the same manner as if you had returned your proxy card. We
encourage you to use these cost effective and convenient ways of voting, 24
hours a day, 7 days a week.
TELEPHONE VOTING Available only until 5:00 p.m., Eastern time on August 30, 2000
- This method of voting is available for residents of the U.S. and Canada
- On a touch-tone telephone, call TOLL FREE 1-877-816-0833 24 hours a
day, 7 days a week
- You will be asked to enter ONLY the CONTROL NUMBER shown below
- Have your proxy card ready, then follow the prerecorded instructions
- Your vote will be confirmed and cast as you directed
INTERNET VOTING Available only until 5:00 p.m., Eastern time on August 30, 2000
- Visit the Internet voting Website at http://proxy.georgeson.com
- Enter the COMPANY NUMBER AND CONTROL NUMBER shown below and follow the
instructions on your screen
- You will incur only your usual Internet charges
VOTING BY MAIL
- Simply mark, sign and date your proxy card and return it in the
enclosed postage-paid envelope
-------------- --------------
COMPANY NUMBER CONTROL NUMBER
-------------- --------------
If you are voting by telephone or the Internet,
please do not mail your proxy card
TO VOTE BY MAIL, PLEASE DETACH PROXY CARD HERE
--------------------------------------------------------------------------------
/X/ PLEASE MARK VOTES
AS IN THIS EXAMPLE
THIS PROXY, WHEN PROPERLY EXECUTED, WILL BE VOTED IN THE MANNER DIRECTED
BELOW. IF NO DIRECTION IS MADE, THIS PROXY WILL BE VOTED "FOR" EACH OF THE
PROPOSALS.
--------------------------------------------------------------------------------
THE BOARD OF DIRECTORS RECOMMENDS A VOTE "FOR" EACH OF THE PROPOSALS PRESENTED.
--------------------------------------------------------------------------------
1. The approval to adopt the Agreement and Plan of
Merger, dated as of June 28, 2000, by and among
Tumbleweed Communications Corp., Maize Acquisition
Sub, Inc., a direct wholly-owned subsidiary of
Tumbleweed, and the Company, pursuant to which
Maize Acquisition Sub will be merged with and into the
Company with the Company becoming a wholly-owned
subsidiary of Tumbleweed.
For Against Abstain
/ / / / / /
2. The approval to amend the Company's 1992 Stock
Option Plan to increase the number of shares
issuable under such plan by 900,000 shares from
1,100,000 to 2,000,000.
For Against Abstain
/ / / / / /
3. In their discretion, the proxies are authorized to vote
upon such other business as may properly come
before the meeting or any adjournment thereof.
The undersigned acknowledges receipt
from the Company prior to the
execution of this proxy of a Notice
of Special Meeting of Shareholders
and of a Proxy Statement dated August
3, 2000.
Date: ___________________________, 2000
_______________________________________
_______________________________________
SIGNATURE(S)
IMPORTANT: Please sign exactly as
your name(s) appear(s) on this card.
When signing as an attorney,
executor, administrator, trustee or
guardian, please give full title. If
shares are held jointly, each holder
may sign, but only one signature is
required.
