I have an interconnected Asterisk server to another server, and the second server responsible for external calls.
It turns out that depending on the recipient, works DTMF or not commands.
Mainly for mobile phones works, but for telephones (work) not.
Insufficient information. Channel technologies? DTMF handling options. DTMF log. Channel technology debugging logs showing what DTMF options the other side offered? Codecs used if using inband DTMF?
What is different between good and bad recipients?