Asterisk won't detect DTMF

When I call or when asterisk calls me. I input my pin code on my cell phone and sometimes asterisk detects it, and sometimes it doesn’t. When it does detect, it detects through out the whole session.

I dunno why it does this. Its the same code and sometimes it works and sometimes it doesn’t. I’m using over IAX (PTSN)

Could have many reasons:

Quality of cellphone in general
DTMF signalling method by the cell provider
length of tones when bad line

Generally, asterisk is RFC2833 compliant.

I just started occasional on-call teching for a company -

They were thinking of replacing some Sangoma cards for Digium,
because of DTMF first digit failures during voice prompts
(mostly from cordless phones).

Just a Theory - Has anyone tried to filtering DTMF out (notch)
of the Voice Prompts for improved detection ?

And if there is any significant voice quality impact, maybe try to
spill any notched energy into the sidebands…

we’ve had good luck with both Digium and Sangoma cards when it comes to DTMF detection, but echo cancellers seem to cause issues regardless of the card.

you might ask exgn if they have relaxdtmf set to yes, as that has helped alleviate some of our issues…