VoIP Mailing List Archives

[jkillen at allamerican...]

Turns out I had my timing sources setup incorrectly, so the te820 wasn’t synchronizing with the Telco. Turns out the spandsp FAQs are pretty good for diagnosing: http://www.soft-switch.org/spandsp_faq/ar01s08.html

-Justin



From: asterisk-users-bounces@lists.digium.com [mailto:asterisk-users-bounces@lists.digium.com] On Behalf Of Justin Killen
Sent: Thursday, November 14, 2013 3:28 PM
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: [asterisk-users] recieve fax from PRI using spandsp 65% failure rate


Hi,

On one of our servers, we’re having problems with incoming faxes. The connections come in through a PRI into a Digium TE820 card. ‘fax show stats’ yields the following:

FAX Statistics:
---------------

Current Sessions : 0
Reserved Sessions : 0
Transmit Attempts : 0
Receive Attempts : 740
Completed FAXes : 740
Failed FAXes : 486

Spandsp G.711
Success : 254
Switched to T.38 : 0
Call Dropped : 46
No FAX : 0
Negotiation Failed : 0
Train Failure : 4
Retries Exceeded : 20
Protocol Error : 219
TX Protocol Error : 44
RX Protocol Error : 153
File Error : 0
Memory Error : 0
Unknown Error : 0



I’ve read that doing rx/tx tuning on the PRI is supposed to help, but nothing there seems to make a difference (I tuned RX down to -6.5 per the article here: http://www.voip-info.org/wiki/view/Asterisk+zapata+gain+adjustment so that the RX is at around 50%. I haven’t found a good way to do TX tuning, as setting it via ‘dahdi set swgain tx’ doesn’t seem to have any effect on the dahdi_monitor output). I’ve enabled fax debugging (fax set debug on), but that doesn’t seem to do anything either (perhaps I need to raise asterisk’s debug level as well?).

What steps should I try next?


Thanks in advance,
-Justin