[asterisk-users] Linksys SPA9x2 echo problem

[Dubravko Caric]

Hi all,
we have
this annoying problem with Linksys SPA9x2 phones and echo cancellation. I have read
posts on other sites about this problem but they are more than one year old and
people were using older firmware. Linksys/Cisco has released 6.1.5a firmware
but we still experience the same problems. SPA phones have low sound volume of
handset microphone and people on the other side (PSTN, GSM) are complaining
that they hear us very badly. I increased Handset gain to +6 and lower Additional
handset gain to -3 to get amplification of +3 what gives higher volume on the
other side but not as much as I would like. That is one problem, the other one
is that now VoIP to VoIP calls in our company are much louder than those to
PSTN and GSM, and if we receive two calls immediately one after another there
is a big difference between PSTN and VoIP calls in the sound volume on our side
and our users are complaining. 
We are
using SIP trunk towards PSTN (so I can’t use txgain and rxgain in zapata.conf),
for GSM calls we are using PORTech SIPtoGSM GW (but I can’t increase volume on
it anymore because I am getting echo) and I can’t increase volume on Linksys
phones anymore because our internal VoIP calls would then be much too loud.
Does anyone
have same issues even with this new firmware and if so how do you handle those problems?
Any help
would be much appreciated

Best
regards 
Dubravko