Field Notice 12159: T-1s Associated with DS3XM-6 May Loopback in Testing

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Updated:November 4, 2003

Document ID:FN12159

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Revised January 18, 2002

April 13, 2000

Products Affected

Product	Comments
Cisco ONS 15454	Formerly Cerent 454

Problem Description

T-1s associated with a DS3XM-6 card may go into loopback during testing.

Background

This problem was discovered during testing in the Cerent lab.

Problem Symptoms

This problem occurs only when the DS3 associated with the port is provisioned for M23 line type, and the actual DS3 being inserted into the port is provisioned for C-bit line type. C-bit line parity is the loopback code for a T-1 when the associated DS3 is provisioned for M23 line type.

Inserting a C-bit framed DS3 into a Cerent 454 DS3XM-6 card that is provisioned for M23 DS3s, causes all of the T1s associated with the DS3 port to line (facility) loop up.

Workaround/Solution

The workaround for this problem is to provision the affected port out-of-service and then back in-service or provision the DS3XM port for C-bit parity. A fix has been found and is included in the Maintenance Software Revision 2.01.

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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