faxing g711 over Carrier SIP Trunk ?

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Jul 31st, 2009
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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?

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paolo bevilacqua Fri, 07/31/2009 - 07:38
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I would start looking into e-faxing if I were you.

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

mserwon Wed, 12/09/2009 - 06:53
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Did you get any resolution to this fax issue?

MARTIN STREULE Tue, 12/29/2009 - 02:45
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"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://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%... :-)




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