DTMF recognition problem

I have a DTMF recognition problem on SIP with AMI for bridge calls:
When both peer dtmfmode set to same value like “rfc2833” AMI cant detect anything.
I put a tshark on server and I can see dtmf packets coming (like ; RTP EVENT Payload type=RTP Event, DTMF Nine 9) but seems asterisk miss them.
When the dtmfmode values for bridge call ends are different it is working fine .


Have you BRI, PRI or FXO?

Are external or internal?


All peers are softphones and ip-phones .


ok for phone but wich kind of line have you? Nornal Line (FXO), ISDN-Line (BRI) ore PRI?

Howevwer, you shoul check in your chan_dady.conf for dtmfmode.

Can you post your config file?


He may have an isolated system. Even if not, many, and probably most, uses use SIP and rely on an external provider to interface to the circuit switched network.

Have you try to’ set dtmfmode=inband in SIP.conf?

Set it in general and in single user config

Hi All,
Thanks for replies.
I am sure it is not a problem by phone I tested with two softphone on PCs and problem is same.
during my troubleshooting I found out when I set “TtKk” in Dial command this problem gone.
so the history is :
[color=#FF0000]1- When 2 peers (101 - 102) on same dtmfmode which using Dial(SIP/102) Asterisk wont capture DTMF.[/color]
[color=#00BF00]2- When 2 peers (101 - 102) on same dtmfmode which using Dial(SIP/102,TtKk) is ok.
3- When 2 peers (101 - 102) on diff dtmfmode which using Dial(SIP/102) or Dial(SIP/102,TtKk) is ok.[/color]