[SIPForum-discussion] FAX Issue in VoIP

[Kevin P. Fleming]

On 09/13/2010 09:42 AM, Broussard, Dan wrote:
> I have found that G.711 does a better job than T.38
> 
>  
> 
> FAX devices that use V.34 to achieve 28800 bps and 36600 bps
> transmission rates are often referred to as Super Group 3 devices. 
> Customers serviced usually can achieve 28800 bps and 36600 bps
> transmission rates using G.711.  They cannot achieve these transmission
> rates using T.38.

That's because there are very few T.38 gateways deployed in carrier
networks that support V.34 FAX. Until recently, the procedures for
properly handling T.38 call setup when both V.34 and non-V.34 endpoints
are involved weren't even fully specified... but the
soon-to-be-published T.38 2010 recommendation addresses this issue
(among many others) and we hope to see deployment of V.34-capable
gateways increase in the near future.

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
skype: kpfleming | jabber: kfleming at digium.com
Check us out at www.digium.com & www.asterisk.org