My Customer is with following problem: In Site A He have the CCM version 4.1.2 and Site B He have the CCM version 3.1.3. There is a communication by trunk site A to Site B. When the call is originate A for B it's Ok, the call is completed normally. When the call is originate B for A the phone ring but there is not audio, after 8 seconds the call dropped. I already verifyed codec, link, route pattern, version of gateway, but, didn't found the problem. Any ideia or suggestion?