Question

A CUBE connects an ITSP SIP trunk to CUCM. The provider sends RFC 2833 DTMF, but CUCM's SIP trunk is configured for out-of-band (SIP KPML/unsolicited NOTIFY), and calls otherwise complete with two-way audio. Digits pressed by PSTN callers into the CUCM auto-attendant are not recognized. The engineer wants CUBE to convert the DTMF signaling between the two legs while allowing media to bypass CUBE where possible. Which configuration approach correctly addresses this requirement?

Accepted Answer

Configure 'dtmf-relay rtp-nte' on the ITSP dial peer and 'dtmf-relay sip-kpml' (or sip-notify) on the CUCM dial peer, and configure the DTMF-affected leg for media flow-through so CUBE can perform interworking

Answer

Enable 'media flow-around' globally on both dial peers so CUBE passes RFC 2833 packets end-to-end unchanged, forcing CUCM to accept them

Answer

Configure 'dtmf-relay rtp-nte' on both the ITSP and CUCM dial peers so the method matches on each leg

Answer

Remove all 'dtmf-relay' commands so CUBE falls back to in-band DTMF tones carried transparently in the RTP stream