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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Hi;<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Faxback Support - SUP-00019595<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I am attempting to get T38 Fax working between two FS/FusionPBX installations using </span><span style='color:#1F497D'>faxback VOIP plugin extensions</span><span style='color:#1F497D'>. </span><span style='color:#1F497D'>The fax TX (FS#1) endpoint drops the call due to “Ack Timeout” after two pages.</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Faxback VoIP client plugin:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><a href="http://www.faxback.com/Products/FreeMSFaxDownload.aspx">http://www.faxback.com/Products/FreeMSFaxDownload.aspx</a><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I am able to successfully receive a fax using this faxback endpoint if transmitted by FS/spandsp.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Note that zrtp is disabled for fax calls, due to T38 udpl (not rtp media) incompatibility<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Thanks Brian West!: “T.38 Fax takes place over UDPTL, There for it can NOT be encrypted as there was never really a standard for doing so.”<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Details (both FS’s):<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>SIP Provider: freephoneline.ca (claims T38 capable)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>freeswitch - 1.4.18<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>x86_64<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Topology:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>FS#1: rossco.org, using </span><span style='color:#1F497D'>faxback plugin (x1019) </span><span style='color:#1F497D'> to send fax<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>FS#2:rossco.duckdns.org, using </span><span style='color:#1F497D'>faxback plugin (x1019)</span><span style='color:#1F497D'> to receive fax<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>(</span><span style='color:#1F497D'>faxback</span><span style='color:#1F497D'> x10</span><span style='color:#1F497D'>19</span><span style='color:#1F497D'>)FS#1 -> cloud -> FS#2(</span><span style='color:#1F497D'>faxback</span><span style='color:#1F497D'> x</span><span style='color:#1F497D'>1019</span><span style='color:#1F497D'>)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Key variables for fax sender (FS#1), during call:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>$domain= rossco.org<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Faxback</span><span style='color:#1F497D'> Fax extension: 10</span><span style='color:#1F497D'>19</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>t38_passthru = </span><span style='color:#1F497D'>true</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>zrtp_secure_media = false<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>fax_enable_t38 = </span><span style='color:#1F497D'>false (not set)</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>fax_enable_t38_request = </span><span style='color:#1F497D'>false (not set)</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>fax_use_ecm = off</span><span style='color:#1F497D'> (not set)</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>inbound-late-negotiation = true<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>ignore_early_media = </span><span style='color:#1F497D'>true</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Key variables for fax receiver (FS#2), during call:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>$domain= rossco.duckdns.org<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Faxback</span><span style='color:#1F497D'> Fax extension: </span><span style='color:#1F497D'>1019</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>t38_passthru = </span><span style='color:#1F497D'>true</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>zrtp_secure_media = false<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>fax_enable_t38 = </span><span style='color:#1F497D'>false (not set)</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>fax_enable_t38_request = </span><span style='color:#1F497D'>false (not set)</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>fax_use_ecm = </span><span style='color:#1F497D'>false (not set)</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>inbound-late-negotiation = true<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>ignore_early_media = false<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Full Logs w/siptrace:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Sender(rossco.org): <a href="https://pastebin.freeswitch.org/24117">https://pastebin.freeswitch.org/24117</a><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Receiver(rossco.duckdns.org): <a href="https://pastebin.freeswitch.org/24118">https://pastebin.freeswitch.org/24118</a><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Note that the SDP’s are correct for T38:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'> v=0<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'> o=Sippy 177245968 2 IN IP4 208.65.240.165<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'> s=FreeSWITCH<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'> t=0 0<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'> m=image 49714 udptl t38<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'> c=IN IP4 208.65.240.165<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'> a=T38FaxVersion:0<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'> a=T38MaxBitRate:14400<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'> a=T38FaxRateManagement:transferredTCF<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'> a=T38FaxMaxBuffer:200<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'> a=T38FaxMaxDatagram:72<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'> a=T38FaxUdpEC:t38UDPRedundancy</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Questions:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>1 - According to my interpretation of logs, T38 </span><span style='color:#1F497D'>and t38_passthru </span><span style='color:#1F497D'>is negotiated<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>2 – I do not have the expertise (yet) to determine the reason for “Ack Timeout”<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>2 - What am I missing?<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Thanks;<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Bill Ross<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D;mso-fareast-language:EN-CA'><o:p> </o:p></span></b></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p></div></body></html>