This setup involves a T1 from an Avaya PBX connected to the Cisco CallManager Express (CME) router. Calls from the PBX to the Cisco CallManager Express phones work fine. However, when calls are forwarded to the Cisco Unity Express (CUE) voicemail, the Dual Tone Multifrequency (DTMF) tones do not work.
The third-party device (the Avaya PBX) sends the dtmf-relay command using h.245 signal that includes the duration of the digit. The Cisco CallManager Express gateway sends the digits to the Cisco Unity Express, but each digit is not considered finished unless another digit is received. This issue results in %SIP-3-DIGITEND: Missing digit end event messages.
The issue is addressed in Cisco bug ID CSCse47338.
In order to resolve this issue, perform these steps:
Upgrade to version 12.4.4XC4.
Enable this hidden Command Line Interface (CLI) command:
!--- Enter configuration commands, one per line. End with CTRL/Z.
3725(config)#voice service voip 3725(conf-voi-serv)#h323 3725(conf-serv-h323)#h245 signal update 3725(conf-serv-h323)#end