There are four DTMF relay mechanisms that are supported on VoIP dial-peers: • H245-alphanumeric • H245-signal • SIP-Notify • Rtp-nte H.245 mechanisms are only available on H.323 dial-peers ...

The last blog entry covered DTMF relay. This blog entry will focus on Cisco IP Phone and Cisco SIP Trunk DTMF relay support. Cisco’s first generation of IP phones do not support RFC2833 DTMF-Relay.

“The cordless candlestick consists of three main components. The 90 year old candlestick phone itself, a Doro 850 2.4Ghz cordless telephone and a Pulse to DTMF converter by oldphoneworks.com.