Cisco AS5300 Series Universal Gateways

Field Notice: Interoperability Issues With Microcom Modem Code 3.2.10

December 9, 1998

Products Affected



Problem Description

The V.8bis implementation in Microcom portware version 3.2.10 can cause interoperability problems with older/legacy modems.

Problem Symptoms

This defect is logged in bug ID CSCdj72032. If you are a registered CCO user and you have logged in, you can view bug details.

View CSCdj72032 (registered customers only)


The original V.8bis standard used tones that were hotter and longer in duration than the current standard. Older modems may incorrectly interpret the old V.8bis tones in 3.2.10 as negotiation tones used with older modem standards. This can cause these older modems to fail to connect.


Cisco recommends upgrading to version 3.3.20 or later, where the problem has been fixed.

Performing the show modem version command provides the version of portware running on the Microcom modems.

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods: