Cisco 3600 Series Multiservice Platforms

Cisco 3600 NM-4B-U and NM-8B-U Problems

April 15, 1997

Problem Description

The NM-4B-U and NM-8B-U (ISDN BRI Network Modules for the Cisco 3600 with integrated NT-1) have a problem in the ISDN "dying gasp" circuit that leads to the following symptoms:

  • Not all the BRI ports come up after a reload. If you unplug, and then plug the ports in individually, they will come up.

  • If you issue the clear interface command on one port, other ports on the network module will also be cleared.

All NM-4B-U and NM-8B-U Network Modules built prior to March 31, 1997 are subject to this problem. The network module revisions subject to the problem, and the network module revisions are listed in Table 1.

Table 1: Network Module Revisions


Problem Part Number

Fixed Part Number







Issue the show diag command to see the network module part number:

BRI (U) port adapter, 0 ports
        Port adapter is analyzed 
        Port adapter insertion time unknown
        Hardware revision 0.0           Board revision UNKNOWN
        Serial number     0             Part number    800-01239-03
        Test history      0x0           RMA number     00-00-00
        EEPROM format version 0
        EEPROM contents (hex):
          0x20: 00 23 00 00 00 00 00 00 50 04 D7 03 00 00 00 00
          0x30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Problem Resolution

There are two ways to resolve this problem. Either fix alone is sufficient to fix the problem

  • Install a version of Cisco IOS with the fix for CSCdj04625 (registered customers only) .

  • Install a NM-4B-U or NM-8B-U with the "Fixed Part Number" shown in Table 1.

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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