[cisco-voip] DTMF fun

[Rhodium]

Guess it's just me mis-interpreting your diagram so apologies:

PSTN --> MGCP GW --> CUCM --> H.323 GW --> PBX#1 --> PBX#2 --> VM

So you are seeing the digits get received on the GW which is good.

So now you have broken the fault down to between the GW and the VM box.

I presume you have an ISDN PRI interface connected to the first PABX? If you are using ISDN, DTMF tones are carried in band so you won't see it in the D-channel.

Next step is to debug the first PABX to see if it is getting everything in band, even if you call an extension on PABX2 from the PSTN and check whether there is noise or interference when the digits are pressed.

Also, you might want to look at your voice port configuration to see whether the compand type is correct, the echo-cancellation coverage, output attenuation, etc.

Might be worth to check those settings as well on the first PABX.

HTH

Jason