Callers are getting DTMF tones wile they are talking

I have a few locations that are getting a DTMF tone wile they are on a call. This is been happening more frequently on some PBXs. Any suggestions on fix !

What type of trunk, phones, etc

If the connection starts with inband DTMF, but then switches to a non-inband scheme, it could be “talk off”. You haven’t even told us enough to be sure that non-inband DTMF is even possible. Asterisk provides a DTMF logging option, which will allow you to work out which side of the PABX is experiencing the problem.

Talk-off means a DTMF decoder has misidentified speech as DTMF.

OK Its a SIP Trunk with Yealink and Polycom phones on VPS hosted

I have experience with talking to people on cell getting the DTMF during call

What is “DTMF Signaling” set to on your extensions in FreePBX (extensions page)

Cellular networks transmit DTMF out of band, although I’m not sure if they support DTMF at all towards the phone. I wouldn’t expect a cellular phone to recognize DTMF coming through its microphone, but you never know.

Extension is set to RFC 2833

Any suggestions on the DTMF Signaling setting to help with this?

First find out where the problem is occurring. If outside Asterisk, no setting will help.

Typically inband all the way is the only completely safe option. This requires A-law or Mu-Law codecs. Mobile phones are never inband and never use those codecs, on the other hand, the only voice to DTMF coding that might happen for a mobile source call is in the phone itself.

inband is not normally advised with VoIP because it is particularly vulnerable to packet loss.

I have the same problem on incoming calls. I’ve installed an internal card with 4 GSM modules. I quite often get DTMF signalling on incoming calls via the GSM line and would also like an advice how to solve that problem. I use a card by Allo (