Forwarding to an external call causes doubled keypress data

Discussion in '3CX Phone System - General' started by SupportRequestor, Jun 27, 2017.

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  1. SupportRequestor

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    I forwarded a number to an external phone number. The call connects and their IVR immediately prompts for an ID as expected. However, whatever key presses I input end up being doubled as I can hear their IVR repeating it back to me saying it is invalid. E.g. If I input an ID of 1234 then press # I hear it repeating back to me "11223344 is not a valid ID".

    I did confirm that calling their number direct does not result in this and I've used different devices to eliminate that as a potential source.

    Anyway to solve this? I'm still on 3CX v14.
     
  2. leejor

    leejor Well-Known Member

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    This generally caused (and may be resolved) by changing the DTMF method. You don't say what type of trunks you are using. In some cases PSTN Gateways will change SIP DTMF methods into tones AND pass DTMF audio generated by the keys on the set resulting in the two sets of tones. Make sure you record the original settings before making any changes, in the event the change causes more problems. Check, and perhaps change the DTMF method on the set to NOT send audio (only a SIP message, there are various types), and check the gateway, if involved.
     
  3. SupportRequestor

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    Thank you for the reply, I am not using PSTN. Everything goes out on the SIP trunk. Could this be an issue with the PBX delivering audio?
     
  4. leejor

    leejor Well-Known Member

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    I don't believe that is the issue. I suspect that the set(s) are sending an audio DTMF tone as well as a SIP message, that is causing another DTMF tone to be generated "down the line".
     
  5. SupportRequestor

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    Not sure how I could fix that since the call can come from any device and it currently doesn't work on any device (e.g. a cell phone, my desk phones, et cetera).
     
  6. leejor

    leejor Well-Known Member

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    Take one set and try changing the DTMF Method, then test.

    In many cases, if all else fails, changing the CODEC of the sets to a low bit rate CODEC will usually prevent DTMF audio from getting through. It's a last ditch effort.

    Have you spoken with your provider to see if they can provide any insight on exactly what is happening and if any changes can be made at their end?
     
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