[asterisk-users] Asterisk T38 and Dialogic DMG 2000
Hi All, I have Asterisk 1.4.21.1 and Dialogic DMG 2000 firmware 6.0.103. Trying to pass t38 fax calls setup like this: fax machine>From the fax outbound through the PRI works great, seems to be reliable, 40+ faxes with 5 different fax machines tested, plus an efax service. The problem is the other way, PRI inbound to fax, the call doesn't setup between the GW and Asterisk. I have the issued narrowed down to the SIP messaging between the DMG and Asterisk. The DMG invite sends to asterisk: m=audio 49016 RTP/AVP 0 101 [notice the m=audio] a=rtpmap:0 PCMU/8000/1 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-15 m=image 0 udptl t38 a=T38FaxRateManagement:transferredTCF a=T38FaxUdpEC:t38UDPRedundancy And Asterisk responds with the 200 OK: m=image 29475 udptl t38 [notice the m=image] a=T38FaxVersion:0 a=T38FaxFillBitRemoval:0 a=T38FaxTranscodingMMR:0 a=T38FaxTranscodingJBIG:0 a=T38FaxRateManagement:transferredTCF a=T38FaxMaxBuffer:400 a=T38FaxMaxDatagram:400 a=T38FaxUdpEC:t38UDPRedundancy I've been corresponding with Dialogic engineering on the messaging and they report that the gateway receiving m=image is not compatible or is telling the gw to immediately setup the call at T38 with is not compatible. The gateway wants to setup the call as audio first, hear the CNG tones and then re-invite to t38. So my question: Is there a way for configuring Asterisk to respond with m=audio instead of m=image? If I disable udptl in Asterisk, call setup fine with audio. Thanks. JR -- - JR Richardson Engineering for the Masses ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- AstriCon 2008 - September 22 - 25 Phoenix, Arizona Register Now: http://www.astricon.net asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Asterisk T38 and Dialogic DMG 2000
JR, On Mon, Sep 8, 2008 at 3:08 PM, JR Richardson <[EMAIL PROTECTED]> wrote: > The DMG invite sends to asterisk: > m=audio 49016 RTP/AVP 0 101 [notice the m=audio] > a=rtpmap:0 PCMU/8000/1 > a=rtpmap:101 telephone-event/8000 > a=fmtp:101 0-15 > m=image 0 udptl t38 > a=T38FaxRateManagement:transferredTCF > a=T38FaxUdpEC:t38UDPRedundancy > > And Asterisk responds with the 200 OK: > m=image 29475 udptl t38 [notice the m=image] > a=T38FaxVersion:0 > a=T38FaxFillBitRemoval:0 > a=T38FaxTranscodingMMR:0 > a=T38FaxTranscodingJBIG:0 > a=T38FaxRateManagement:transferredTCF > a=T38FaxMaxBuffer:400 > a=T38FaxMaxDatagram:400 > a=T38FaxUdpEC:t38UDPRedundancy > > I've been corresponding with Dialogic engineering on the messaging and > they report that the gateway receiving m=image is not compatible or is > telling the gw to immediately setup the call at T38 with is not > compatible. The gateway wants to setup the call as audio first, hear > the CNG tones and then re-invite to t38. That's how T.38 gateways typically work. This particular gateway seems to have some advanced knowledge that the call may be converted into T.38 later. They are offering m=image with port number set to 0 in the INVITE. By doing this, they seem to be offering a sort "heads up" that the call may be converted to T.38 later but no T.38 now because the port number is zero. This hint is of no use to Asterisk. If you can get the gateway to not send the m=image line in the first INVITE, they you may be in luck. > So my question: Is there a way for configuring Asterisk to respond > with m=audio instead of m=image? If I disable udptl in Asterisk, call > setup fine with audio. This seems like a bug in Asterisk. Asterisk is encoding the SDP in 200 OK incorrectly on two fronts. It's dropping the m=audio line completely and it's activating T.38 stream when the remote end hasn't asked it to do so. -- Raj Jain ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- AstriCon 2008 - September 22 - 25 Phoenix, Arizona Register Now: http://www.astricon.net asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
