I have an old MC3810 with 2 FXO ports connected to FCT's for mobile calls. This works fine. When we can this FCT, I am sending the call to the CM (6.1.3) that connects it to an IVR. This works fine.
What doesn't work is the DTMF tones. The are not recognized, the IVR is not interrupted to accept DTMF tones. I have enabled: dtmf-relay cisco-rtp
I don't have the choice: dtmf-relay h245-alphanumeric which I am sure works, since I did this on newer routers with FXO cards.
Is there some compatibility issue between MC3810 relay and CM 6.1.3?
DSPs in MC3810, are pretty old, that box is end of support/sale
The problem is you have the older VCM voice compression modules rather than the HCM High Density compression modules. Only the HCM's support the h245 dtmf relay command , it's something to do with DSP horsepower. The VCM can only do cisco-rtp.
Please upgrade to ISR, we dont support that anymore.