I am currently attempting a SIP integration between an existing NEC Electra Elite IPK II PBX system and a new Cisco CME/UE implementation using a Cisco 2821 Integrated Services Router.
So far, I've been able to successfully follow the setup documentation to get all the voice calling up and running with great success (for those who may be new to this like I am, here is the guide I used for the NEC components-- http://www.connect-comm.com/NEC_SIPTrunkConnections.pdf). The NEC is the primary system in the picture so all calls from the Cisco side are sent through the NEC system and routed out accordingly.
The issue I have, however, is that touch tone (DTMF) services aren't working properly. All DTMF going TO the Cisco system work perfectly. All DTMF going FROM the Cisco system result in two conditions depending on dtmf-relay and dtmf-interworking settings on the Cisco configuration and DTMF Relay Mode on the NEC Programming Data section 84-13...
All Cisco modes with NEC DTMF Relay Mode set to Disabled produce a clicking sound on the non-Cisco side, so you know it's getting the signals, just not processing them properly. Furthermore, all Cisco modes with NEC DTMF Relay mode set to RFC2833 produce the same clicking EXCEPT for Cisco dtmf-relay rtp-nte, which DOES trigger the first touch tone... except the tone hangs and never stops until the call is disconnected, and no follow-up tones are triggered (although a packet scan reveals they are being sent and received).
If anyone here has worked on this system combination or experienced similar situations, I'd appreciate any advice and suggestions. I have attached my config file stripped of any accounts/passwords.