> Date: Thu, 24 Jun 2010 15:32:39 -0400 > From: Ben Winslow <[email protected]> > Subject: [asterisk-users] T.38 on a MAX/Lucent/Ascend TNT > To: [email protected] > Message-ID: <[email protected]> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Hello folks, > > I've been trying to get T.38 over SIP working with calls terminated by a > MAX/Lucent/Ascent TNT. As far as I can tell, SIP and T.38 are actually > working perfectly; however, I can't get the TNT to properly terminate a > FAX call. Does anyone have a working configuration for SIP and T.38 for > calls from a TNT or APX? > > Here's a brief description/diagram of my test setup: > > Laptop --RS232--> Modem --POTS--> Channel bank (ADIT 600) --CAS T1--> > TNT --Ethernet/SIP--> Asterisk --SIP--> t38modem. > > The TNT is running TAOS 11.0.4 with both the SIP and realtime fax > features licensed. I've tried using several modems, and with each I can > establish a data call without any problems (although at a maximum of > 31200bps/3429 baud using a 33.6 modem, for reasons I haven't dug into > yet.) Whenever I try to send a fax from the laptop, however, the call > always seems to fail in the first HDLC phase (phase B) with either a > timeout or error 23 (COMREC invalid command received.) The modem is > connected directly to the channel bank and the channel bank is connected > directly to the TNT in an attempt to reduce the number of variables. > > With my current configuration, the call to Asterisk will come up as a > voice call, then be dumped into t38modem when Asterisk receives the > 1100Hz CNG tone from the sending modem. At that point, the call is > dumped into t38modem which re-invites the TNT with the T.38 options, and > the TNT usually sends a T.38 t30-ind of 0x00 (no-signal) or 0x3a (???), > although I do occasionally see more promising messages like > v29-7200-training or t30-data/hdlc-fcs-ok. Shortly thereafter, the > dialing modem will give up and terminate the call. > > If I try dumping the same call into iaxmodem instead of t38modem, the > call actually progresses further -- the real modem receives and decodes > the HDLC CSI/DIS from iaxmodem, but the high-speed trainup always fails > for calls coming from the TNT. > > Does anyone have any advice or suggestions? Has anyone actually made > T.38 work with one of these devices running ANY TAOS version? > > Thanks, > -- > Ben Winslow <[email protected]> >
What version of Asterisk are you running? I've struggled to get this working as well but with TNT TOAS version 14 and Asterisk 6.1.x I managed to get reliable T38 faxes one-way: from fax to PSTN Fax machine><SIP T38 ATA><Asterisk><SIP T38><MAX TNT><PSTN PRI The other way does not work, the call doesn't switch to T38 and I haven't had time to investigate too deeply. Fax handling in TOAS was greatly improved in 14.0 version, I would suggest you upgrade to that if you can and start there. JR -- _____________________________________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
