I'm facing a problem. I have a cisco 3825 router SRST/K9 which is used as a voice gateway. But on SRST fallback mode, my IP Phone Cisco 7961 can not registered to the router. The ios version of this router is 12.3 and it does not recognize the IP Phone 7961 Please can you give the link of a version of the IOS on which the IP Phones 7961 can be registered on SRST mode ?
Thanks in advance.
PS: The CCM version is 4.1.3sr5b