News Release

Com21 to Develop MCNS/DOCSIS Cable Modems;

Product Roadmap Ensures Com21 Cable Modem Compatibility with Cisco Systems Cable Service Provider Solutions
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Nov 18, 1997



MILPITAS, Calif.-- Nov. 18, 1997 -- Com21, Inc. and Cisco Systems Inc. today announcedtheir intent to provide interoperable cable modem products based on the Multimedia CableNetwork System (MCNS) Data-Over-Cable Service Interface Specification (DOCSIS) industryprotocols.

Com21 is developing an MCNS/DOCSIS compliant cable modem to add to its existing ComUNITY Accesscable modem product line and is providing a seamless integration path for Com21 cable customerswho might also want to install and offer DOCSIS cable modems.

Cisco Systems has previously announced its intent to develop solutions with cable modem vendorsbased on DOCSIS. Compliance to the DOCSIS standard will ensure interoperability of equipmentthroughout system operators' infrastructures, including a range of consumer devices.

"Our cable modem system solution is designed to lower the overall cost of ownership for thecable operator. To maintain this focus and extend our core technology to DOCSIS compliantproducts, we needed to work closely with an internetworking partner such as Cisco," said PeterFenner, president of Com21.

The DOCSIS protocols were initially drafted by Multimedia Cable Network System (MCNS) PartnersLtd., an organization formed by four major cable operators -- Comcast Cable CommunicationsInc., Cox Communications, Tele-Communications Inc., and Time Warner Cable. The effort also issupported by Rogers Cablesystems Ltd., MediaOne and Cable Television Laboratories Inc.(CableLabs).

Since Com21 began volume production of its ComUNITY Access system this spring, it has shippedover 100 systems to over 24 countries worldwide, including Europe, North America, Latin Americaand Asia. Com21's ComUNITY Access cable modem system is comprised of the ComPORT cable modem,the ComCONTROLLER headend switch and NMAPS software.

The ComUNITY Access system provides end-to-end Ethernet data communications over cable TVnetworks. The ComUNITY architecture makes possible mixed media (voice, data, video)applications from the same cable modem platform. The Com21 system provides cable operators withopportunities in the residential, business, and SOHO (small office, home office) markets withsupport for virtual private networks (VPNs) and multiple Quality of Service classes.

Com21 and Cisco will be exhibiting at the Anaheim, Calif. Western Cable Show, Dec. 10-12, 1997.Com21 will be located at booth number 4732. Cisco will be located at booth number 4207.

Com2l

Com2l develops, manufactures and markets cable modem based high-speed communication systems.The ComUNITY Access system provides end-to-end Ethernet data communications over cable TVnetworks. The ComUNITY architecture makes possible mixed media (voice, data, video)applications from the same cable modem platform. Com21's systems serve residential, business,and SOHO (small office, home office) markets.

Cisco Systems

Cisco Systems, Inc. (NASDAQ: CSCO) is theworldwide leader in networking for the Internet. athttp://www.cisco.com.

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