Hi,

Few months back I configured Asterisk 11.6.0 for an outbound fax using T.38
protocol as listing down the flow below;

Asterisk Fax server -> (IP) -> Cisco VGW ->(IP) -> Carrier

The issue I’m currently getting when Asterisk receives warnings as listed below, it is overloading the Cisco VGW, therefore need to restart Asterisk service or sometimes reboot VGW to clear these warnings.

[Mar 24 09:25:01] WARNING[28645][C-00000004] app_fax.c: Unable to write frame to channel; Resource temporarily unavailable
[Mar 24 09:25:01] WARNING[28613][C-00000002] app_fax.c: Unable to write frame to channel; Resource temporarily unavailable

The configuration in sip.conf for T.38 is listed below;

t38pt_udptl = yes,fec,maxdatagram@0
faxdetect = t38

Udptl.conf;

udptlstart@00
udptlendI99
udptlfecentries = 3
udptlfecspan = 3
use_even_ports = no

Please advise at earliest to overcome this issue.