faxing g711 over Carrier SIP Trunk ?

[Jason Aarons]

Anyone have a customer sending/receiving multi-page faxes over Verizon Business SIP trunk/g711 ?

Verizon Business indicates they don't support it, and I have 2 recent customers that it doesn't work for, and 1 current large customer telling me he's going to make it work <grin>.

The issues is the latency/jitter on fax/g711 over Verizon Business seems to spit out only 11 pages of a 15 page fax.

Anyone having faxing over PSTN SIP over G711 that is working 100% ? Any advice?

[paolo bevilacqua]

I would start looking into e-faxing if I were you.

When not using proper fax relay, nobody can guarantee anything.

[mserwon]

Jason,

Did you get any resolution to this fax issue?

[MARTIN STREULE]

"Fax and SIP Provider" is actually a hot topic. If there is no real PSTN in between you'll face all kind of interop problems.

(do the SIP providers use G711 end-to end? G.711 -> T.38? ...)

Here are some links with more insights:

http://tools.ietf.org/html/draft-jones-sip-forum-fax-problem-statement-00

http://www.sipforum.com/ (look for "SIP Forum FoIP Task Group Publishes Official Fax-over-IP Problem Statement")

BTW: even with PSTN you have less then 100%... :-)

Cheers,

Martin