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SRST does not work for Cisco IP Phone 7912

I'm running IOS 12.4(5) SPSERVICES on a Cisco 3825 (C3825-SPSERVICESK9-M) and have a cluster of two Cisco CallManager version 3.2.

When connectivity to the CallManager cluster is lost, IP Phones 7940 and 7960 successfuly enter fallback mode (SRST) but IP Phones 7912 do not. The Cisco 3825 is both the default-gateway of the IP Phones and the SRST-router.

I checked for bugs on the CCO and, although there are some SRST-related bugs with IP Phones 7912, none of them exactly match this problem.

Is there any limitation regarding SRST support for IP Phones 7912 on CallManager 3.2 or on IOS 12.4(5)?

Thanks in advance.


Cisco IOS Software, 3800 Software (C3825-SPSERVICESK9-M), Version 12.4(5), RELEASE SOFTWARE (fc3)

Technical Support:

Copyright (c) 1986-2005 by Cisco Systems, Inc.

Compiled Mon 31-Oct-05 21:03 by alnguyen

ROM: System Bootstrap, Version 12.3(11r)T2, RELEASE SOFTWARE (fc1)

System returned to ROM by power-on

System image file is "flash:c3825-spservicesk9-mz.124-5.bin"


interface Loopback0

ip address

h323-gateway voip bind srcaddr


interface GigabitEthernet0/0

ip address


max-conferences 24 gain -6

ip source-address port 2000

max-ephones 128

max-dn 256

time-zone 22

time-format 24


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Re: SRST does not work for Cisco IP Phone 7912

Try using

debug ephone register

to get more info


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