what's type of DTMF should I used in IP-Phone

[lotsu99]

what's type of DTMF should I used in IP-Phone ?
Inband or Outband ?? Thx

 

[William400]

Hi

It would be best to use RFC2833 for DTMF. It is the most reliable.

 

[Powermage]

The most important thing is what your voip provider support's,
the problem is that when you dont have a provider that isnt using the RFC DTMF you will have problems when 3cx is delivering audio (by default on you voip line)