[asterisk-users] Fax Throughput

[Lee Howard]

Don Kelly wrote:

>I've tried timing faxes two ways:
>
>>From a fax machine on a station port of an AltiGen PC/PBX served by an MCI
>PRI calling back into the same PRI and reaching a RightFax server on a
>station port behind the AltiGen.
>
>>From the same fax machine on the same station port of the AltiGen PC/PBX
>served by the same MCI PRI calling a number on an XO PRI connected to an
>Asterisk system (Digium TE410P), dialing out on another channel on the same
>PRI back into the MCI PRI and reaching the RightFax server on the station
>port behind the AltiGen.
>
>extensions.conf includes:
>exten => 6122353002,1,dial(zap/g1/6122590773)
>
>Sending a one-page fax with moderate density (no graphics) takes almost five
>minutes longer going through the Asterisk server.
>

The longer transmit time is probably a result either (or both)...

1) retransmissions due to the audio being consistently corrupted, and 
ECM retransmissions to correct the corruption

2) training failure (probably due to corrupt audio) resulting in a 
slower transmission rate (e.g. 9600 bps vs 14400 bps)

As to how to fix it... it's almost certainly audio degredation occurring 
in your Asterisk configuration or linkage... so debug your Asterisk setup.

Lee.