Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations Mike Lewis on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!
Hearing tones while on a call
- Thread starter newglide
- Start date
reproducible? you can get a packet capture on the SBC from the webpage.
Otherwise, maybe recording tones? If not, I've seen some carriers/SIP ATAs that don't do RFC2833 DTMF (out of band) and leave the DTMF as audio in band. Other carriers refuse to have DSPs sniffing, so they never notice and just pass the tones through as is. If you could trace a call and hear the audio with the tones, perhaps you can see if the SDP of that call offer had a telephone-event 8000 or not - that's out of band DTMF. If its not in the SDP, definitely the issue. Even if telephone-event 8000 is there, doesn't mean the other thing 9 SIP proxies away isn't old and only doing in band DTMF.
Otherwise, maybe recording tones? If not, I've seen some carriers/SIP ATAs that don't do RFC2833 DTMF (out of band) and leave the DTMF as audio in band. Other carriers refuse to have DSPs sniffing, so they never notice and just pass the tones through as is. If you could trace a call and hear the audio with the tones, perhaps you can see if the SDP of that call offer had a telephone-event 8000 or not - that's out of band DTMF. If its not in the SDP, definitely the issue. Even if telephone-event 8000 is there, doesn't mean the other thing 9 SIP proxies away isn't old and only doing in band DTMF.
- Status
Similar threads
- Locked
- Question