Hi, I have a Cisco 4300 Series ISR (CME 12.0) working without any problem with CP-7811 phones. However, we recently acquired some CP-6901 phones that we have not been able to make them work (the ISR assigns you an ip per dhcp, but they fail to register), when you connect them to the SW, after a few minutes you have a busy ringtone. We load the necessary packages according to the documentation.
I would appreciate if you can tell me what I can try.
Regards!
