[asterisk-users] Help! Echo problem even at T1 PRI?

[Vincent Tam]

Hello,

We have an asterisk setup at our client's site using a TE205P. The line to
telco is a 23 channels T1 PRI, however the line has random echo problems
(about 5-10% of the calls)!
Can anybody tell me if echo cancellation is really needed even at a T1 PRI
to the telco? Because people keep saying when they deploy voip solution in
Hong Kong using T1 PRI, there is no need of echo cancellation. (even the
local Digium distributor)

Asterisk is 1.2.13, zaptel is 1.2.10. I choosed the MARK2 canceller in the
zaptel.

The setting in zaptel is default:
echocancel=yes
echocancelwhenbridged=yes
echotraining=yes
rxgain=0
txgain=0

When I tried to adjust the echocancel value to a higher taps (e.g. 256) or
adjust the rxgain/txgain value, I can even hear echo much easier.

Anyone can confirm with me we should rather turn echocancelwhenbridged=no,
or even echocancel=no when we only use a T1 PRI at the zaptel? Or can have
other suggestions to try solving this problem? Because of some people's
information that T1 PRI does not need any echo cancellation, add a hardware
echo cancellation module is not an option here.

I think I need some sort of information from another 3rd party before my
boss will even agree to just try something out.


Really thank you!!
Vincent
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.digium.com/pipermail/asterisk-users/attachments/20070315/cddaeb34/attachment.htm