Hi, The best option is to contact Broadsoft. I do not know the implementation of fax support in Broadsoft's products but typically, you start a fax call using a vo-coder (G.711 in your case) and then some implementations *may* switch to fax relay using T.38. Some implementations do not support t.38 and use G.711 pass-through mode which works fine for G3 fax in a number of deployments.
Unless the originating SIP UA is a fax-only device that is always communicating with the same server (enterprise), you cannot just offer one media description in SDP with just t.38 (this will break most fax call negotiations). The SDP negotiation framework (http://tools.ietf.org/html/draft-ietf-mmusic-sdp-capability-negotiation -09) could be a way to indicate support for alternative potential SDP configurations. But that is likely not supported yet. Jean-Francois. > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:sip- > [EMAIL PROTECTED] On Behalf Of Somesh S. > Shanbhag > Sent: Friday, September 19, 2008 3:27 AM > To: Rohit Aggarwal; Neranza Bundova; sip- > [EMAIL PROTECTED] > Subject: Re: [Sip-implementors] Broadsoft FAX problem > > Rohit, > > You may be right, may be driven by configuration or may be because > the client > didn't indicate the T38 capability its switching automatically to > G711 Mode. > > Somesh S Shanbhag > M G L Bangalore > > > > -----Original Message----- > From: Rohit Aggarwal [mailto:[EMAIL PROTECTED] > Sent: Fri 9/19/2008 2:51 PM > To: Somesh S. Shanbhag; Neranza Bundova; sip- > [EMAIL PROTECTED] > Subject: RE: Broadsoft FAX problem > > Hi > > If I understand it correctly, Somesh is suggesting addition of T38 > media stream in offer from the endpoint whereas Neranza's query is > how to make Broadsoft initiate T.38 fax instead of Pass-Through on > tone detection? I think Neranza wants that Broadsoft should add T38 > stream in the Re-INVITE, probably some server configuration?? > > Please correct me if my interpretation of the original query is > wrong. > > Regards > Rohit Aggarwal > Aricent > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:sip- > [EMAIL PROTECTED] On Behalf Of Somesh S. > Shanbhag > Sent: Friday, September 19, 2008 2:42 PM > To: Neranza Bundova; [email protected] > Subject: Re: [Sip-implementors] Broadsoft FAX problem > > I think you will have to put something like this in SDP > > m=image 10000 udptl t38 > a=T38FaxVersion:0 > a=T38MaxBitRate:14400 > a=T38FaxFillBitRemoval:0 > a=T38FaxTranscodingMMR:0 > a=T38FaxTranscodingJBIG:0 > a=T38FaxRateManagement:transferredTCF > a=T38FaxMaxBuffer:200 > a=T38FaxMaxDatagram:300 > a=T38FaxUdpEC:t38UDPRedundancy > > Somesh S Shanbhag > M G L Bangalore > > > > -----Original Message----- > From: [EMAIL PROTECTED] on behalf of > Neranza Bundova > Sent: Fri 9/19/2008 12:56 PM > To: [email protected] > Subject: [Sip-implementors] Broadsoft FAX problem > > Hello All, > > > > I have a problem with sending a T38 FAX over a Broadsoft server. > > I am sending to a PSTN FAX so the Broadsoft server is terminating > SIP > point and it should send me REINVITE for T38 but it does not. It is > just > accepting the FAX transmission over G711. > > My question is there some specific advertisement(media attribute or > media description) which I should add in my initial INVITE request > to > the Broadsoft server to make it understand that I support T38? > > I saw also something called "Broadsoft FAX Messaging" but did not > find > any description. > > > > Thanks > > > > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > > > > EMAIL DISCLAIMER : This email and any files transmitted with it are > confidential and intended solely for the use of the individual or > entity to whom they are addressed. Any unauthorised distribution or > copying is strictly prohibited. If you receive this transmission in > error, please notify the sender by reply email and then destroy the > message. 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