Linksys SPA3000/Cordless Phone/Severe Echo

[wifinetguy]

I've got an analog cordless phone attached to a Linksys SPA3000 that is attached to my PIAF. When using the cordless phone, local calls go via PSTN, LD goes via VoicePulse. On LD calls, everything sounds great. On all local calls, the echo is severe. I have no idea what I can adjust to help with echo suppression. Any help is appreciated. Thanks in advance.

 

[jroper]

Hi

The chances are that the carrier is using echo suppression on the long distance and not on local.

Echo is probaby present with a normal analogue handset, but there is no delay. Echo with delay is the problem. The VoIP element adds the delay.

It is therefore up to you to do echo cancellation at your end. How you do this depends on what hardware you use to connect to the PSTN.

Assuming something like a TDM400, The first thing to do is run fxotune to give the existing echo canceler a fighting chance, then set the EC parameters in zapata.conf.

If this is not successful, then install HPEC from Digium, this should be free with a TDM400 purchased in the last 12 months or so, upgrade to a TDM410P which has an EC module on it, or some other hardware with EC, e.g. Rhino, or install OSLEC.



Joe

 

[dobbs]

Have you configured the SPA3000 to pass through local calls, or is the call going through your Asterisk server first?

I've got a similar setup and tried using the SPA to handle a line-in (FXO) and FXS for the cordlsess but had the same echo issues you describe. I punted and got a card with echo cancellation and just use the SPA3000 for FXS now.

 

[wifinetguy]

Dobbs,

Thanks for the reply. I'll probably end up "punting" too. When you say you're using the SPA3000 for FXS now, can you explain? I get the FXO/FXS things confused. I'm assuming you mean coming out of the PBX into the "Line" port and having your cordless base plugged into the other port, right?

 

[Alex728]

FXS= an internal extension. you plug a telephone set into this socket


FXO = a trunk port. You connect this to your buildings phone line

I found the same echo problem with the SPA3102 adapters, at the moment I use an Atcom card (AX400P) which is equivalent to the Digium TDM400 card (but slightly cheaper), with OSLEC as echo cancellation software.