amed Telephony Event [NTE] Inband DTMF), SO Company P needs to configure its system in such a way that every digit passes without any error. Table 12-1 lists possible options of DTMF interworking between H.323 and SIP signaling. Table 12-1 DTMF Interworking Between H.323 and SIP H.323 H.245-Alphanumeric NOTIFY H.245-Signal NOTIFY RFC-2833 NOTIFY H.245-Alphanumeric RFC-2833 H.245-Signal RFC-2833 H.245-Alphanumeric H.245-Signal RFC-2833 RFC-2833 272 SIP Trunking In this specific case, it used H.245-Alphanumeric and RFC-2833 (the fourth row in Table 12-1), and it worked fine. Example 12-4 shows the dial-peer configuration at the H.323 side. The IP address is taken out for privacy purposes. Example 12-4 DTMF Configuration in H.323 dial-peer voice 3 voip description Dial-back - to CUCM - Company P destination pattern 91. session target ipv4 XX.XX.XX.XX dtmf-relay n245-alphanumeric codec g711ulaw ip qos dscp cs5 media no vad Example 12-5 shows the dial-peer configuration at the SIP side. The IP address is taken out for privacy purposes. Example 12-5 DTMF Configuration in SIP dial-peer voice 88532929 voip description Connected to Company Q's Server destination-pattern 88532929 session protocol sipv2 session target ipv4:xx.xx.xx.xx session transport udp dtmf-relay rtp-nte codec g711ulaw ip qos dscp cs5 media no vad Dial-Peer Configurations Example In the previous section, we showed the configuration of two dial-peers that establish the basic communications between Company P's CUCM and Company Q's conference serv- er. This conference server has a web conferencing feature where people can join a meeting through a web browser and then ask the conference server to dial-back to attendee's tele- phone number to establish the voice session. So, the call comes to CUBE from Company Q's conference sever over SIP, and then CUBE passes that call to Company P's CUCM to locate the final destination of the call. Chapter 12: Case Studies 273 Figure 12-5 shows the call flow between Company P's CUCM and Company Q's confer- ence server. He