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Cisco MC3810 Multiservice Access Concentrators

Field Notice: *Expired* FN - 4228 - UVM to FTM/3810 Connections May Have Poor Voice Quality


Revised October 15, 2007

April 5, 1999

NOTICE:

THIS FIELD NOTICE HAS BEEN EXPIRED AND IS NO LONGER MAINTAINED OR UPDATED BY CISCO.

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE, WARRANTY OR SUPPORT. USE OF THE INFORMATION ON THIS FIELD NOTICE OR MATERIALS LINKED FROM THIS FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.


Products Affected

Product

Remarks

IGX-UVM

The IGX-8400 must be operating with switch software 9.1.07 or earlier.

MC3810

No remarks.

Problem Description

Poor voice quality may result on a G.729 or G.729ar8 permanent virtual circuit (PVC) between an IGX-UVM and an MC3810.

Problem Symptoms

The most noticeable symptom is observed at the MC3810 end of the connection where the voice signal is low quality due to the Zero Code Suppression (ZCS) density enforcement occurring in the UVM. The UVM end of the voice connection is unaffected and will demonstrate good voice fidelity.

Background

The IGX-UVM and MC3810 can interoperate via an IGX-FTM card in the IGX-8400. While several voice compression techniques are supported between the UVM and the MC3810, the G.729 and G.729ar8 types of compression are susceptible to this voice quality problem. The problem is caused by incorrectly setting ZCS on UVM connections terminating on an MC3810.

This defect has Cisco bug ID CSCdk50872. If you are a registered CCO user and you have logged in, you can view the bug details.

Workaround/Solution

Workaround

A temporary workaround can be implemented by configuring all voice connections for 32kBps compression instead of 8kBps G.729 or G.729A.

Solution

Upgrade IGX-8400 switch software to version 9.1.08 or later.

Switch software versions 9.1.08 or later may be downloaded from the CCO WAN Switches Software Center with your CCO user account at the URL below:

http://www.cisco.com/tacpage/sw-center/sw-wan.shtml

Select the "Cisco WAN Switching Upgrade Planner" link to find the latest software and firmware.

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:

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