I found a peculiar problem when using "dtmf-relay rtp-nte" (that is pretty much an universal standard) from a CME box to a PRI gateway, only when calling AT&T teleconferencing service.
No digit is recognized, I believe the digits duration is 160 mS. Any other IVR number have been working ok since one year. I try dtmf-interworking and doesn't help.
I switched to sip-notify that I believe has a default digit duration of 250 ms and things worked ok that way.
I can't find a way to change digit duration with rtp-nte - there is ?
In CME, under ephone and ephone-template configuration, there is a
command to lengthen the dtmf duration from the default to 200ms
(max). The CLI command is nte-end-digit-delay.
Note that the max is 200ms.
You will also need the
CME-CUE-28(config)# voice service voip
CME-CUE-28(config-voi-serv)# dtmf-interworking rtp-nte
You need to configure both voice service dtmf-interworking rtp-nte and the
nte command on the ephone/ephone-template in question to produce the
necessary delay on the end packet.
Please note this command was introduced in 12.4(15) and rolled into 12.4(20).