Solved Cannot enter pin code in voicemail or use IVR (Internal DTMF issue?)

[Brian Lowrance]

I upgraded our 3CX installation from 15.5.3849.1 (15.5 SP1) stepping through each update until reaching the latest 15.5.13103.5 (15.5 SP5). All seemed to go well.

I've since learned that we can no longer enter our pin code when calling the voicemail extension when using our voip phones. We also cannot enter options on the Digitial Receptionist (IVR) menus. We can call in using our cell phones, etc and access the voicemail extension and IVR properly but internal calls to these are not working allowing DTMF entry.

I am using a Yealink T41P phone. After discovering this issue, I upgraded the firmware on the phone to the latest that 3CX showed was applicable (36.83.0.20). I also switched my extension to use the default 3CX provided Yealink template just to be sure it wasn't a custom template issue.

 

[Brian Lowrance]

Reprovisioning via 3CX phones menu or on reboot would not resolve.
Factory reset of the phone did resolved the issue.

 

[leejor]

What DTMF Method are the phones set to use? If set to "audio", then what Codecs are used? DTMF Audio does not "play well" with lower bit-rate Codecs.

 

[Brian Lowrance]

The Yealink phone defaults to DTMF Type RFC2833 and the 3CX Yealink template uses the default as well.

#Configure the DTMF type; 0-INBAND, 1-RFC2833 (default), 2-SIP INFO, 3-AUTO+SIP INFO;
account.1.dtmf.type =

I have external services that are beyond my control and will not work with this though (phone based time clock being one of those), so I have to edit the template to change to INBAND.
I set: account.1.dtmf.type = 0

After more testing, it seems that the IVR/Voicemail menus are not responding to key presses when INBAND is used anymore.

The Codec list in order of priority is (this is default):
PCMU
PCMA
G722
G729

 

[leejor]

I will usually go with the option that has the word "auto" . I figure...let the two ends "work it out", and in the majority of cases, it seems to work.

 

[Brian Lowrance]

I've set account.1.dtmf.type = 3 which is "AUTO+SIP INFO"
and account.1.dtmf.info_type = 1 which is "DTMF-Relay"
#Configure the DTMF info type when using the SIP INFO; 0-Disabled (default), 1-DTMF-Relay, 2-DTMF, 3-Telephone-Event;

That combo seems to be working with 3CX voicemail/IVR as well as the remote time clock system I am dialing out to.

I've confirmed that 3CX Voicemail/IVR is no longer responding to INBAND DTMF though. I set the 3CX Phone client to use INBAND and 3CX voicemail/IVR doesn't respond to digit presses. It responds if RFC2833 or SIPINFO is selected.

I think I am good with the dtmf.type "AUTO+SIP INFO" along with the dtmf.info_type "DTMF-Relay" on the Yealink phones and "SIPINFO" on the 3CX phone client.

 

[leejor]

Inband may not work if the end (trunk/set), that does the initial registration negotiation, has a low bit-rate Codec at the top of the list, and, that Codec is available at the other end.

 

[Brian Lowrance]

Yes, I understand that. The call over the trunk to the remote time clock system and the internal/non-trunked call to 3CX voicemail/IVR is working using SIPINFO.
With our Yealink as well as with 3CXPhone, INBAND no longer works with 3CX voicemail/IVR. This is what used to work (15.5 SP1 and earlier) but quit working somewhere in upgrades to 15.5 SP5.

This may help visualize better:

3CXPhone/Yealink (SIPINFO) > 3CX > POTS/Trunk > Remote timeclock works
3CXPhone/Yealink (INBAND) > 3CX > POTS/Trunk > Remote timeclock works
3CXPhone/Yealink (RFC2833) > 3CX > POTS/Trunk > Remote timeclock doesn't respond

The following do not use a trunk. They are direct/internal from 3CXPhone/Yealink to the 3CX server's voicemail/IVR system:
3CXPhone/Yealink (SIPINFO) > 3CX > Voicemail/IVR works
3CXPhone/Yealink (INBAND) > 3CX > Voicemail/IVR doesn't work
3CXPhone/Yealink (RFC2833) > 3CX > Voicemail/IVR works

The only workable path then (for our system) is to use SIPINFO

 

[Brian Lowrance]

I found this setting in another thread:
MSADDRFC2833FORINBANDDTMF - Allows Media server to distribute recognized in-band DTMF as RFC2833 to other participants of the call.

I checked this parameter in our system and it's value was 0. I changed it to 1 as a test and set my phone back to INBAND and it's working with voicemail/IVR again.

Problem Solved!

 

[YiannisH_3CX]

Glad to see the issue has been resolved and thank you for updating the thread with your solution.