Cisco Port Adapters

Field Notice: T3 Port Adapters May Not Provide a Two-Second Delay Before Bringing Down the T3 Controller

October 05, 2004

Products Affected


7202 - PA-2T3+

7204 - PA-2T3+

7204 - PA-MC-2T3+

7204 - PA-T3+

7206 - PA-2T3+

7206 - PA-MC-2T3+

7206 - PA-T3+

7500 - PA-2T3+

7500 - PA-MC-2T3+

7500 - PA-T3+

7505 - PA-2T3+

7505 - PA-MC-2T3+

7505 - PA-T3+

7507 - PA-2T3+

7507 - PA-MC-2T3+

7507 - PA-T3+

7513 - PA-2T3+

7513 - PA-MC-2T3+

7513 - PA-T3+

7576 - PA-MC-2T3+

Problem Description

The port adapters listed in the Products Affected section above, bring the T3 controller down immediately after receiving one of the following alarms on the wire: LOS or AIS.


Based on the ANSI T1.231 specification a T3 controller should not react to an alarm (LOF, LOS, AIS) unless the alarm persists for 2 +/-0.5 seconds. The T3 Port Adapters (PAs) listed above in the Products Affected section do not adhere to the failure declaration specification threshold.

Problem Symptoms

Since the T3 PAs listed above in the Products Affected section do not adhere to the two second holddown timer before reacting to an alarm as defined in the ANSI T1.231 specification, the controllers will go down immediately and come back up a few seconds later. This will result in loss of data and interference with user traffic.





Upgrade IOS to a version that resolves the failure. Please view the Bug ID provided below for the respective PAs that correct the failure.

Port Adapter










IOS releases with fix for the PA-T3+ and PA-2T3+:

12.2(26.09)S 12.1(23.02)E 12.0(29.03)S 12.3(11.01)T 012.003(011.001) 12.2(24.08)S03

IOS releases with fix for PA-MC-T3+, PA-MC-2T3+:

12.1(23.01)E 12.0(29.01)S 12.3(09.07)T 12.2(24.08)S 12.2(24a) 012.003(009.007) 012.002(024.008) 12.2(19c)


To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.



CSCee49862 (registered customers only)

PA-MC-2T3+ does not adhere to ANSI T1.231 standard

CSCee70591 (registered customers only)

PA-2T3+ does not adhere to the ANSI T1.231 standard

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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