[asterisk-users] Still on spandsp/app_fax and T.38

[Steve Underwood]

On 02/05/2010 07:40 PM, Vinícius Fontes wrote:
> This message is pointed directly to Steve Underwood. I tought it would not be nice to directly email him with a question that interests a good part of the Asterisk community, so here it is. :)
>
> Steve, remember a few days ago when we discussed about issues on Asterisk 1.6.1.13 and T.38 fax reception? Well I opened an issue on Mantis (https://issues.asterisk.org/view.php?id=16756) and turns out it might be spandsp-related.
>
> What happens is, when I use app_fax to receive a fax using T.38, I get very low transmission rates, and about 30% of the faxes are just not transmitted at all. 2400bps is not uncommon. If instead of T.38 I use an analog landline connected to that very same Asterisk box, app_fax works wonderfully well transmitting at full 9600bps. Just to rule out Asterisk's T.38 handling, I noticed that Fax For Asterisk works perfectly with T.38, also on that same box.
>    
Is the FAX machine you are using only capable of 9600bps, because full 
speed should be 14400bps?

Can you get a packet trace of a problem call, using wireshark, and mail 
it to me?
> I'll be happy to provide you any info that could help solve this issue.
>
>    
Steve