Pbx Inband Dtmf Digit Instead Of Dialtone Breaks Outbound

[BrendanG]

I have a problem when using VG7 with our PBX (an ancient Comdial DXP). The VG is configured for 4 single line extensions off our PBX. These extensions are designated as Voicemail ports to enable the inband signaling digits which we use to determine what line a call came in on. The trouble is when we use VG to place an outbound call it fails. This seems to be because the PBX provides a DTMF digit (1) instead of dialtone for these type of voicemail extensions. I tried extending the Offhook Delay in the Config.xml file but this breaks the inbound scripts. I can get around this by adding a pause to the PhoneNumberPrefix in my XML files, but I'd rather get VG to natively recognize the 1 as a valid signal for dialtone, or at least extend a timer for the first digit dialed in an outbound call. What is the best practice in this situation?

[SupportTeam]

This seems to be because the PBX provides a DTMF digit (1) instead of dialtone for these type of voicemail extensions.

So when you'd pickup a telephone handset attached to those lines the PBX would play a DTMF 1 instead of the dial tone?

 

The solution would be to set the outbound calls to not wait for any sort of a dialing tone and just dial the number after pickup up the line. You can add delay between the time the handset is picked up and when the number is dialed by adding a comma or two at the beginning of the number.

 

I thought that by default VoiceGuide does not wait for dialtone before dialing the number, so it's puzzling as to why you are having problems.

 

Please post the vgEngine and the ktTel traces (see \log\ subdirectory) capturing system startup and the outboind call and we can then see what happened.

 

When posting traces/scripts please .ZIP them up and post them as attachments.

 

 

 

 

[BrendanG]

So when you'd pickup a telephone handset attached to those lines the PBX would play a DTMF 1 instead of the dial tone?

Yes, this is a common option with many PBX/VM integration setups.

 

The solution would be to set the outbound calls to not wait for any sort of a dialing tone and just dial the number after pickup up the line. You can add delay between the time the handset is picked up and when the number is dialed by adding a comma or two at the beginning of the number.

 

I thought that by default VoiceGuide does not wait for dialtone before dialing the number, so it's puzzling as to why you are having problems.

 

As I mentioned in my original post I can get it to work by adding the pause (comma) to front of the prefix (9) which is dialed. I was hoping there might be a more global fix, so I don't have to include this pause in all outbound dialing scripts/files. It sounds like there isn't an appropriate global timer to adjust, but I would suggest adding one in the future.

 

I thought that by default VoiceGuide does not wait for dialtone before dialing the number, so it's puzzling as to why you are having problems.

You are correct, VoiceGuide does not wait for dialtone, I believe the problem is that it start dialing too early before the PBX has dialed the 1, which causes the PBX to miss the first digit dialed. I can determine this by using a DTMF Grabber listening on the port which displays 916101240, the 9 is the prefix VoiceGuide is dialing, the first 1 is the DTMF signal the PBX is dialing.

 

Attached are the logs from a restart of the service, then an outbound call placed.

 

In summary, I can work around this, but was surprised there was no previous discussion that I could find, since in my experience many PBXs replace the standard dialtone with a DTMF digit when configured to use inband signaling. Thank you for the quick response. I will be posting a separate topic shortly as it involves a separate but similar topic (PBX DTMF disconnect detection).

Outbound_OffHook_DTMF_logs.zip

[SupportTeam]

As I mentioned in my original post I can get it to work by adding the pause (comma) to front of the prefix (9) which is dialed.

 

...

 

In summary, I can work around this, but was surprised there was no previous discussion that I could find, since in my experience many PBXs replace the standard dialtone with a DTMF digit when configured to use inband signaling.

I guess that other users that have PBX lines that play DTMF tones on outgoing calls just add a delay (using commas) when loading calls. The PhoneNumberPrefix field in the outbound calls databse is available to allow prefix addition at call load time, and in any of the VocieGudie script modules the prefix would need to be set in each module once.

 

We will add a new entry to VG.INI, [VGDialer] section that you can use to set any prefixes globally as well. Note that this will apply to all calls made on all lines in the system. The field will be called GlobalDialPrefix

 

eg. to set global prefix to ,,9, have this in VG.INI file in the [VGDialer] section:

 

GlobalDialPrefix=,,9,