I can’t get faxing through Freepbx to work. I am specifically talking about pass thru, and not relay! (Allthough any working solution would be fine…)
I have a Ricoh MPC2800 all-in-one fax, which natively supports SIP and T38 faxing. Also, my SIP provider (voys.nl) supports the T38 protocol.
Connecting the fax machine directly to my SIP provider doesn’t work, because somehow the password handshake does not work out. The nonce of my provider is very long, and the fax doesn’t understand and does not connect.
It does connect, however, to my Freepbx machine. But whatever settings I try, i get buffer overflow errors.
If I set maxdatagram=600 I get
[2014-02-24 12:08:28] ERROR[20582][C-0000018e] udptl.c: UDPTL (SIP/200950001-00000872): Buffer overflow detected (261 + 536 > 600)
If I set maxdatagram=400 I get
[2014-02-24 12:19:35] WARNING[20686][C-00000191] udptl.c: UDPTL (SIP/200950001-00000881): UDPTL asked to send 261 bytes of IFP when far end only prepared to accept 185 bytes; data loss will occur.You may need to override the T38FaxMaxDatagram value for this endpoint in the channel driver configuration.
[2014-02-24 12:19:35] ERROR[20686][C-00000191] udptl.c: UDPTL (SIP/200950001-00000881): Buffer overflow detected (185 + 382 > 400)
If I set maxdatagram=176 I get
[2014-02-24 12:31:05] WARNING[20933][C-00000194] udptl.c: UDPTL (SIP/200950001-00000887): UDPTL asked to send 261 bytes of IFP when far end only prepared to accept 92 bytes; data loss will occur.You may need to override the T38FaxMaxDatagram value for this endpoint in the channel driver configuration.
[2014-02-24 12:31:05] ERROR[20933][C-00000194] udptl.c: UDPTL (SIP/200950001-00000887): Buffer overflow detected (92 + 118 > 204)
Any ideas about what I can change to make it work?