DTMF over Sip Trunk ?

[Kent Drugge]

CUCM CUC 11.5   I have a Sip Trunk connection to a Valcom paging unit. I can connect to the valcom unit ok, it answers and waits for me to dial additional digits, to call a specific device, ip speaker. This will work ok calling from an analog input, i.e. fxs/fxo. The issue is once I have a connection via Sip, I have not dtmf after the call connection. We use 7841 and 8851 phones everywhere for calling.

[j.huizinga]

You have to check what DTMF the paging unit supports and if this is negotiated correctly

You can also force MTP on the trunk, this can also solve DTMF issues

JH

[Mohammed al Baqari]

Use RTMT and look for real time call trace. Filter using your test call to
the paging and look at the ladder diagram for that call. You can hit any of
the messages. Depending if you are using early offer or delayed offer, look
at the SDP payload in INVITE/200OK/200OK-ACK. From there you can tell what
DTMF method is negotiated and if its supported by your paging unit.