Tumbleweed Communications Corp. To Acquire Interface Systems, Inc.

Interface's legacy data services and Tumbleweed's secure communications channel transform electronic statement delivery

REDWOOD CITY, CA and ANN ARBOR, MI - June 29, 2000 - Tumbleweed® Communications Corp. (Nasdaq:TMWD), a leading provider of advanced email solutions for business communications, and Interface Systems, Inc., (NASDAQ: INTF), a leading provider of Legacy-to-Internet (L2i) technology, today jointly announced that Tumbleweed has entered into a definitive agreement to acquire Interface. Together, Interface's industry-leading L2i™ suite of legacy data conversion products and services and Tumbleweed's secure channel for electronic bill and statement presentment provide the necessary technologies and services to transform electronic statement delivery and hasten its adoption.

Interface's industry-leading L2i products and services greatly simplify the process of transforming and using data found in legacy systems into electronic content that is easy to distribute and use online. The L2i products can automatically take information from mainframe print streams and intelligently convert it into formats such as pdf, HTML or XML for use online. Tumbleweed's solutions enable the secure exchange of this information between businesses and users via Tumbleweed Integrated Messaging Exchange™ (IME™), a platform and set of applications for creating secure communication channels between a business and its customers, partners, and suppliers.

"Tumbleweed studied the legacy data conversion market for several quarters, evaluating products, interviewing customers, and meeting management teams from a number of vendors," said Jeffrey C. Smith, president and CEO, Tumbleweed Communications Corp. "We concluded Interface was the leader in the legacy to Internet data conversion market. In fact, we integrated the products at a joint customer- Wachovia Securities Inc. - to validate the combination prior to executing the definitive agreement."

"Combining Tumbleweed IME with Interface's L2i products and services gives our customers a comprehensive end-to-end solution for electronic statement presentment: legacy data conversion, personalization, secure email delivery, archival and an automated inquiry/response loop. End users want to aggregate statements in their existing email boxes - banks, brokerages, telcos, utilities, and credit card companies want the same thing. These businesses don't want to simply post statements on web sites and wait for their customers and business partners to come to them; rather, they want to present those statements to their customers," continued Smith.

"Electronic Bill Payment and Presentment (EBPP) vendors have focused on payment and neglected the importance of presentment. Secure email is the key to solving the presentment problem," said Smith. "The combination of Tumbleweed IME and Interface L2i creates a vital communications channel between businesses and their customers that will take EBPP to a new level."

"Tumbleweed's secure communications platform is the ideal means to deliver information prepared by Interface's L2i products and services," said Robert Nero, president and chief executive officer of Interface Systems, Inc. "Many of our customers distribute confidential documents prepared by our platform inside their corporate firewalls, but the next major step forward involves sending those documents to customers and business partners via the Internet. Tumbleweed's secure communications platform satisfies one of our customers' key strategic growth requirements - a secure communications platform that reaches anyone on the Internet. We are delighted to become part of Tumbleweed and to offer our combined products and services to all of our customers."

"Statement presentment is a significant market opportunity for us. Interface's L2i technology will help us penetrate further into our target verticals to solidify our leadership position," said Smith. "Our primary business goal is to increase the amount of traffic that flows over our secure communications channel. Interface's diverse sources of legacy data and services can be automatically sent over Tumbleweed IME."

Upon the completion of the transaction, Interface will become a wholly owned subsidiary of Tumbleweed. Under the terms of the agreement, Interface shareholders will receive a fixed exchange ratio of 0.264 Tumbleweed common shares for each share of Interface common stock. In connection with the acquisition, the companies announced their intent to divest the Cleo solutions group.

The transaction, which is expected to close in the third quarter of 2000, is intended to be tax free to Interface shareholders and to be accounted for as a purchase. The boards of directors of both companies have approved the transaction. The completion of the transaction is subject to closing conditions and the approval of Interface shareholders.

About Interface Systems, Inc.
Interface Systems develops and markets Legacy-to-Internet software and services solutions under the L2i™ brand. The Company's products, which include MyCopy™, eBill Bridge™ and Document Server, enable large organizations to re-deploy information stored on legacy systems as the foundation for their strategic e-commerce or Internet-based applications. Interface's products, geared primarily toward the fast-growing customer statement delivery and online billing markets, offer rapid, cost-effective implementation without having to alter the legacy applications.

About Tumbleweed
Tumbleweed Communications Corp. is a leading provider of advanced email solutions for business communications. Our products and services enable businesses to create and manage secure online communication channels that leverage established email networks and enterprise applications. Tumbleweed Integrated Messaging Exchange is a platform and set of applications for creating secure communications channels between a business and its customers, partners, and suppliers. Tumbleweed Messaging Management System is a comprehensive solution that extends internal email systems to the Internet through centralized security, policy enforcement, filtering and archiving. Used together, Tumbleweed IME and Tumbleweed MMS automatically apply security policies and redirect sensitive email for secure, trackable delivery.

We urge investors and security holders to read the following documents, when they become available, regarding the merger described above, because they will contain important information:

• Interface Systems' definitive proxy statement relating to the special meeting of its shareholders to be held for the purpose of considering and voting upon the agreement and plan of merger; and


• Tumbleweed Communications' Registration Statement on Form S-4, containing such document and other information.

These documents and amendments or supplements to these documents will be filed with the United States Securities and Exchange Commission. When these and other documents are filed with the SEC, they may be obtained free of charge at the SEC's web site at www.sec.gov. You may also obtain for free each of these documents (when available) from Tumbleweed Communications by directing your request to Jennifer Ruddock in Investor Relations at 650-216-2129, or from Interface Systems by directing your request to Brian Brooks, CFO, at 734-769-5900 ext. 1747.

Except for the historical information contained herein, the matters discussed in this press release may constitute forward-looking statements that involve risks and uncertainties that could cause actual results to differ materially from those projected, particularly with respect to the security features of Tumbleweed's products and the activities of any third party. In some cases, forward-looking statements can be identified by terminology such as "may," "will," "should," "potential," "continue," "expects," "anticipates," "intends," "plans," "believes," "estimates," and similar expressions. For further cautions about the risks of investing in Tumbleweed, we refer you to the documents Tumbleweed files from time to time with the Securities and Exchange Commission, particularly Tumbleweed's Form 10-K filed March 30, 2001 and Form 10-Q filed November 13, 2001. Tumbleweed assumes no obligation to update information contained in this press release.