CME with SIP Provider - NO DTMF Relay

[gruiz]

I have a Call Manager Express router connected to a SIP provider. Calls go through; the only issue is that DTMF relay doesn't work. What is interesting is that if I have the 7960 IP phone on speakerphone while on a SIP call and I induce the tone through the speaker (using a cell phone) it works!!!. I also tried using different SIP provider and DTMF still doesn't work. I've tested this same configuration with a 2651XM and a 2821 running 12.3.8T6.

Below is the dial peer configuration. BTW, I’ve tried all the options of dtmf-relay.

dial-peer voice 150 voip

destination-pattern 1.T

session protocol sipv2

session target ipv4:192.168.1.13

session transport udp

dtmf-relay rtp-nte

[ebreniz]

To specify how an H.323 or Session Initiation Protocol (SIP) gateway relays dual tone multifrequency (DTMF) tones between telephony interfaces and an IP network, use the dtmf-relay command in dial-peer configuration mode. To remove all signalling options and send the DTMF tones as part of the audio stream, use the no form of this command.

dtmf-relay [cisco-rtp] [h245-alphanumeric] [h245-signal] [rtp-nte]

http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_feature_guide09186a0080087edb.html

[maharris]

A big issue here is that the ip phone does not actually put out dtmf tones when you push the keys, it puts out packets representing the tones - that is why it works when you play the tones through the speaker. We had this problem trying to send dtmf to an Avaya IP pbx, they had to load a special module to enable dtmf relay on their side, and we had it enabled on our side, and then it worked fine.

Mary Beth

[gruiz]

Upgrading to CME 3.2 (IOS 12.3(11)T) resolved the issue.

Check the links below regading DTMF and SCCP Phones.

http://www.cisco.com/en/US/partner/products/sw/iosswrel/ps5207/products_feature_guide_chapter09186a00802d2545.html

http://www.cisco.com/en/US/partner/products/sw/iosswrel/ps5207/products_feature_guide09186a00801ff0c2.html