I have a customer that require codec payload of G729 with 40 byte/ms toward a particular voice gateway. The gateway is MGCP gateway. Under service parameter of the call manager i have found "Preferred G729 Millisecond Packet Size :" but the question is, if Preferred means that if i change this payload from default (20ms) to 40(ms) all call are affected but can work also with endpoint that support only G729 with 20 Byte/ms? or work with endpoint with only 40 byte? i have no found information about that and unfortunatly i can't try.
Any update is appreciate.