I have one branch oficce (Region A), in headquarter (Region B) i have one Cisco 2821 (in Region B) connected to PSTN With one E1 and i have also one BRI connected to an interface GSM . From Region A to Region B i choose G.729. And inside Region A and B choose G.711.
An ip phone in branch office(region A) can make calls to PSTN trough cisco 2821 in Region B but couldn't make calls to interface GSM in same 2821 router. I don't understand why this happens.
Should i have to configure transcoder or MTP in 2821?
If yes in CCM what i should configure transcoder ios enanhced or MTP hardware?
And in CCM H.323 gateway should i choose require MTP?