[cisco-voip] frustrating FXO disconnect

[Robert Singleton]

I have a 2811 equipped with a 4FXO card in one particular location that 
suffers a symptom that no other location does.

Incoming calls on the gateway work great and can be transferred anywhere 
(ip phones, external gateways, etc) EXCEPT to Unity VM. Callers will be 
disconnected a few seconds into the greeting. Please note that the calls 
are being released and audio is cutting through, however, the call will 
be disconnected after about 10 seconds. This problem has existed since 
the branch was put on net, so I personally am pretty sure there is some 
minor configuration issue, but I have not found it.

In working with Cisco TAC, it seems to have been difficult to narrow the 
problem down to the proper technology. Since the word 'voicemail' was 
mentioned, I was connected with a Unity expert. However, only this 
specific location has this problem and only when the call is on this 
particular FXO gateway. In working with a gateway expert, the disconnect 
seems to be coming from Unity. I kanna win.

For political reasons, we are scheduling a complete replacement of all 
the equipment. You know, buying a new car because the old one is idling 
rough. Personally, I'd like to resolve this *before* replacing nay 
hardware because I don't think it's a hardware issue.

Equipment is as follows: 2811 running IOS 12.4(9)T7 with a PVDM2-16, a 
VIC2-4FXO and a WIC-1DSU-T1-V2. FXO ports are loop start, configured via 
MGCP. So far as I can determine, the configuration is identical (beyond 
unique site data such as IP addresses, dhcp pools, etc) to any of a 
dozen or more similar sites that do not suffer this symptom.

Any ideas?

Thanks,

Robert