Certain IVRs do not respond properly

[zingapuro]

Hi,
I've been using 3cx for about a month now and I'm very happy with all aspects of it.
Except for one intermittent issue I've noticed.

Certain automated IVR systems (e.g. Best Buy, certain govt. offices, Rogers...) don't seem to respond properly to my digits.
I'll get a standard, default recording like, "one moment please, you have entered an invalid extension" or "Thank you for calling. If you are calling from a touchtone phone, ..."
On most IVRs it works properly (as expected), and even on "problem" IVRs, every once in a while it'll work.

I'm using voip.ms service, and I also have a Sipura SPA2100, the weird thing is that it works through the Sipura - only the 3cx gives me "weird" responses. So I doubt it's voip.ms configuration issue (though I have played around with the DTMF mode).

Any ideas on what to try?
Thanks.

 

[leejor]

It might be the particular codec that is being used, G711A and G711U are best. If it is intermittent then I might also suspect either a DTMF level or duration problem.

 

[gpsjeff717]

I also had DTMF problems when I first installed the 3CXPhone many months ago.
For me, the solution was to set:
Connections --> Advanced Settings
to "Support RFC2833 DTMF" (only)

Be sure the other DTMF settings are Not Checked.

I discovered that the problem was that the 3CX Phone had multiple DTMF settings enabled at the same time (by default).
Only enable "Support RFC2833 DTMF".
This setting works with CallCentric and Voip.ms services perfectly.

While Inband DTMF support (by itself) should work with PCMU/PCMA (G.711u/G.711a), I find that the RFC2833 DTMF support setting (by itself) is the most reliable with all my SIP VoIP providers.

(I connect direct to my Voip providers with the 3CX phone softphone and not using 3CX Phone System IP-PBX system)