Scenario#45: 7841 SIP phone in Registration loop

I was working on this customer issue last week where they added a new 7841 phone but it was not registering properly or should I say it was registering briefly before unregistering. Call Manager was 9.1.2.11900-12 which does not support 78XX phones so customer actually applied the device pack cmterm-devicepack9.1.2.12039-1.copĀ  so that they can add 78XX phones. Looking at the logs I found that it is registering with Pub and not Sub even though Sub was the Primary CCM in Call Manager group. At Pub I can see something like this: Pub: REGISTER sip:192.168.11.2 SIP/2.0 Via: SIP/2.0/TCP 172.18.52.91:51736;branch=z9hG4bK739dd207 From: <sip:49715220XXXXX@192.168.11.2>;tag=544a003629fd000a741be677-22e1dea8 … Continue reading Scenario#45: 7841 SIP phone in Registration loop

Scenario#41 – No Ringback tone from H323 Gateway going to SIP trunk

One of our customer reported an issue with ring back tone when calling their Contact center. I made a test call and observed that as a caller when you call their main Contact center number all you hear is dead silence and then when agent picks up the phone you could hear them talk. There was no ring back tone and no automated messages before an agent picks up the call. The call flow was something like this: PSTN > ISDN30 > H323 Dial-peer > SIP Trunk > 3rd-party Contact Center Equipment First I thought it could be the third-party … Continue reading Scenario#41 – No Ringback tone from H323 Gateway going to SIP trunk