ADTRAN, Inc. and Compatible Systems Corporation Enter Into Technology Licensing Agreement.

HUNTSVILLE, Ala.--(BUSINESS WIRE)--Feb. 4, 1997--ADTRAN, Inc. (NASDAQ:ADTN) and COMPATIBLE SYSTEMS CORPORATION of Boulder, Colorado, announced today that the two companies have signed a technology licensing agreement.

"The agreement paves the way for the companies to work together on a variety of WAN development projects," said Danny Windham, Vice President of CPE Marketing for ADTRAN. "Compatible Systems will provide access to elements of its routing technology and will in turn have access to ADTRAN technology for wide area networking."

This is an opportunity for ADTRAN to integrate field-proven technology in the form of additional protocol support into various products. The first to benefit from this agreement will be ADTRAN's family of ISDN LAN adapters.

"Compatible Systems and ADTRAN have maintained a working relationship for some time," said Matt McConnell, President and CEO of Compatible Systems. "It was a logical progression to move to the next level. With our extensive routing experience and ADTRAN's expertise in wide area communications, we can only expect great success for both companies as the relationship matures."

"The agreement is a great move for both of our organizations," said McConnell. "For us, the agreement is another validation of our technology and our standing in the internetworking marketplace."

ADTRAN product introductions incorporating the Compatible technology will follow in the second half of 1997.

COMPATIBLE SYSTEMS CORPORATION

Compatible Systems Corporation designs, manufactures, and markets products for Internet access, ISP sites, Tunneling/private WANs and local Ethernet interconnection. With more than a decade of internetworking experience, Compatible Systems products play vital roles in thousands of networks worldwide. For more information, contact Compatible Systems Corporation at [phone] or [phone]. The company's FAX number is [phone]. The company can be reached by e-mail at [e-mail] or on the World Wide Web server at http://www.compatible.com .

ADTRAN, Inc.

ADTRAN was established in 1985 to design, develop and manufacture advanced transmission products for high-speed digital communications. Today ADTRAN is a primary provider of DDS, ISDN, T1/FT1 and HDSL digital loop products to Regional Bell Operating Companies and many well-known OEMs. The broad selection of customer premises products offered by ADTRAN includes a complete line of DSU/CSUs, a variety of ISDN extension and network terminating products and flexible T1 multiplexers. For more information regarding ADTRAN and its products, call 1-800-326-3700, fax [phone] or E-mail: [e-mail]. ADTRAN may be found on the Internet at http://www.adtran.com .

CONTACT: ADTRAN, Inc., Huntsville

Stacy Thomas, 205/971-8488

[e-mail]