Genesys Cloud CX

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  • 1.  Faxing with an Audiocodes FXS gateway

    GCAP Member
    Posted 07-12-2021 11:26

    Hi Everyone, I have a question about setting up a fax machine with an Audiocodes FXS gateway (MP-118).

    In the past couple of months we have moved from PureConnect to Genesys Cloud.  On PureConnect, I had some MP118s set up to handle our stand-alone fax machines (Ricoh MFPs) and it worked fine using T.38 for faxing.  According to this article Add an analog fax machine to the Genesys Cloud telephony system - Genesys Cloud Resource Center the BYOC Edge does not support T.38, so I have changed the configuration on the MP118 to use G711 passthrough.  For some reason, faxes when going through the FXS gateway are failing. (the call is successful and I am getting two way audio, its just that the devices don't appear to be communicating once they are connected)

    If I try to send/receive a fax by using the e-fax functionality in the interface, the majority of the time the fax is successful, so I'm starting to doubt the configuration of the MP118.

    Would anyone happen to have any suggestions or possibly a working MP1xx configuration that you might be able to share with me so I can compare and see what setting I'm missing?



    Craig Gillett
    Ingram Micro

  • 2.  RE: Faxing with an Audiocodes FXS gateway

    Posted 07-12-2021 15:02
    With the lack of support for t.38 and other factors, I shy away from fax machines and modems on Genesys Cloud.  I prefer to suggest to customers to use analog lines or get a wireless analog solution like that does t.38/t.30 from the Unit to the fax machine, transfers via https to the cloud and then sends out over PSTN.  This allows for longer faxes than traditional t.30 or t.38 directly.

    Robert Wakefield-Carl
    Avtex Solutions, LLC
    Contact Center Innovation Architect

  • 3.  RE: Faxing with an Audiocodes FXS gateway

    GCAP Member
    Posted 08-30-2021 16:52
    Hi, so I just wanted to post a follow-up on this.  I believe that we have faxing working now.  Here are the settings that we did (the parameter on the EdgeGroup was the piece I was missing):


    1.) Open 'SIP General Parameters' (Configuration|Protocol Configuration|Protocol Definition|SIP General Parameters)
         a. Fax Signaling Method = G.711 Transport

         b. Detect Fax on Answer Tone = Initiate T.38 on Preamble

    2.) Open 'Fax/Modem/CID Settings' (Configuration|Media Settings|Fax/Modem/CID Settings).

         a. Fax Transport Mode = RelayEnable

         b. V.21 Modem Transport Type = Disable

         c. V.22 Modem Transport Type = Disable

         d. V.23 Modem Transport Type = Disable

         e. V.32 Modem Transport Type = Disable

         f. V.34 Modem Transport Type = Disable

         g. Fax Relay Enhanced Redundancy Depth = 2

         h. Fax Relay ECM Mode = Disable

         i. Fax CNG Mode = Disable

         j. CNG Detector Mode = Disable


    On the Edge Group in GenesysCloud:

    Changed the interedge codec to be G.711 instead of the default Opus. This would prevent the fax call from being transcoded and introducing additional loss that could impact the signaling. This can be done by adding this custom parameter

    Property Name: trunk_media_codec
    Data Type: List
    Value: "audio/pcmu"

    Craig Gillett
    Ingram Micro

  • 4.  RE: Faxing with an Audiocodes FXS gateway

    Posted 10-13-2021 21:23
    What is Genesys Cloud end point (IP address or URL) to configure FXS to send calls to?
    Thank you!

    Mark Volodarskiy
    Electroline Data Communications Inc