[Asterisk-Users] TDM2400P with echo canceller not working

[James Andrewartha]

Hi,

In my case the echo canceller works, but sometimes too effectively - it cuts
out the remote party sometimes. I've been playing with the gains, but if my
txgain is less than 3 or so, the remote party reports us as being very soft,
or can't hear us at all.

Giorgio Incantalupo wrote:
> I haven't seen any led on my echo cancellation module...sorry!

My leds are being lit up in order, it's a nice fade effect.

> Messages from /var/log/messages:
> May 29 09:41:38 pbxtest kernel: VPM: Chip 0: ver 33
> May 29 09:41:38 pbxtest kernel: VPM: U-law mode
> May 29 09:41:38 pbxtest kernel: VPM: Chip 1: ver 33
> May 29 09:41:38 pbxtest kernel: VPM: Chip 2: ver 33
> May 29 09:41:38 pbxtest kernel: VPM: Chip 3: ver 33
> May 29 09:41:38 pbxtest kernel: VPM: DTMF threshold set to 1250
> May 29 09:41:38 pbxtest kernel: VPM: Present and operational

[4720736.996000] Port 24: Installed -- AUTO FXO (AUSTRALIA mode)
[4720737.006000] VPM Revision: 09
[4720737.026000] VPM: U-law mode
[4720737.282000] VPM: DTMF threshold set to 1250
[4720737.282000] VPM: Present and operational (Rev A)
[4720737.282000] Found a Wildcard TDM: Wildcard TDM2400P Prototype (24 modules)
[4720779.486000] Registered tone zone 1 (Australia)

is what I get - it doesn't go through the chips individually, zaptel 1.2.4

> Another question for you:
> which kind of test or instrument do you use to analyze echo on analog
> lines? I've heard about ztmonitor but I do not know exaclty what it does
> and infos on internet are not many. Or do you use something else? If I
> hade some sort of instrument for measuring echo my work on it could be
> easier instead of changing randomly rxgain, txgain and all the other
> parameters.

http://lists.digium.com/pipermail/asterisk-users/2004-November/064312.html
is what I see people recommend use, but finding a milliwatt line in Italy
might be a problem.


-- 
James Andrewartha
Systems Administrator
Data Analysis Australia Pty Ltd