I recently networked an Axxess system with a 5000 system. The voicemail moved to the 5000 system and since then a call on a Loop start trunk on the Axxess has an intermittent problem dialing extensions or choices in the auto attendant. If the call comes in on a T-1 channel in the Axxess there is no problem.

Extend DTFMF timer to 120 at both ends.

Yep, I changed the DTMF digit duration/pause timer from 60 to 120 and that seems to have taken care of the problem. Thanks!