[Asterisk-Users] Echo Cancellation Feature

[Rich Adamson]

> At 02:30 PM 4/22/2004, you wrote:
> >I would also offer feedback that we too have random calls with echo on our 
> >end, that can't be traced to a reproducible event. It's very odd and can 
> >be frustrating, as it's a big distraction for those that don't know 
> >better. Like a bad cell phone connection when you hear yourself talk. For 
> >us, this happens in a pure SIP environment on a network switch dedicated 
> >to Asterisk, a T1 PRI and 18 SIP handsets.
> >
> >HTH,
> >Ryan
> 
> We have three Cisco 7940 SIP phones and 1 POTS phone connected to our * 
> server with  TDM10B fxs card.  Our * server is connected to the pstn with 3 
> X100P cards.  We have similar echo problems but only on our SIP phones.  We 
> do not have any echo problems with the POTS phone.
> 
> We just purchased a Polycom IP 500 SIP phone to test but I expect similar 
> echo problems.
> 
> The recent thread which addressed milliwatt generators and gain adjustments 
> helped to reduce our echo but the thread was never completed.  We are not 
> sure how to test the TX gain adjustment and where on the graph to set the 
> RX gain when using a milliwatt generator tone.

The thread truly has not been completed and will likely take a few more
weeks to do it. I do believe we'll get to the bottom of it though, just
hand tight.

Rich