[asterisk-dev] [Code Review] Fax Gateway Implementation T30<->T38

[Pavel Selivanov]

05.04.2011 23:33, Klaus Darilion wrote:
>> disable echo cancellation. Echo cancellers that are G.168 compliant
>> detect CED tones generated by *called* FAX terminals and take action
>> themselves to reconfigure properly so as to not interfere with a FAX
>> transaction.
> One more note: the faxdetect code (triggered by CNG) does *NOT*
> What about the software echo cancellers in DAHDI, are they G.168 compliant?
dahdi (dahdi-base.c) is searching for CNG tone, unless you disable it 
(in dahdi_config.h).
Once CNG is detected - dahdi will switch echo canceller of.

There are a number of echocancellers.
None of the free echo cancellers g.168 compliant (can not pass all of 
the g.168 tests).
The best of the free echo cancellers (my opinion), is OSLEC.
It will not pass all g.168 tests, but it works very well (converge 
speed, attenuation, DTD).
http://www.rowetel.com/blog/oslec.html
Try it, I think it will fit your needs.