[asterisk-users] Faxing issues

[Lee Howard]

Todd S wrote:
> Our call path is  Sip trunk from MAX TNT - Asterisk - T1 - Adtran 
> endpoint converting sip trunk to copper line for house wiring.
>  
> Users at the endpoint can receive faxes without a problem.  However, 
> sending faxes are not so friendly.  1 out of 5 faxes will send 
> successfully.  The remaing 4 continually fail with the fax machines 
> reporting "Poor Line Quality".  QoS is setup on both ends and working 
> as expected across all traffic to and from both sides of the call.  
> Voice quality is good on calls from the same lines.  I've checked all 
> sides and had all vendors look at their equipment and they are all 
> pointing the finger at each other.  I've got sip traces from both ends 
> and both look good with the exception of random BYE's being sent from 
> the Adtran side of the call during random fax calls.  T.38 is enabled 
> on both ends as well. 
>  
> Anyone have any possible ideas where to look further or an idea of how 
> i could at least improve the situation?

Is T.38 actually being used?  If not, then please see:

http://hylafax.sourceforge.net/docs/fax-over-voip.pdf

If T.38 is being used then it's probably due to a T.38 bug in one or 
more of the gateways, and you'll need to work with the provider of that 
T.38 gateway for a resolution.

Thanks,

Lee.