Well the rxgain=-3.0 has made a big difference. However I am still having trouble with echo.
the generated system.conf has:
fxoks=1
echocanceller=mg2,1
When the line echocanceller=mg2,1 is in the system.conf there is no echo from the caller on the other end when calling out on a voip trunk.
But this causes the asterisk system to not recognize touch tones after a call is placed. For example dialing *97 for the voicemail system works, but when you enter your password asterisk doesn't recognize any of the tones the asterisk log reports the password entered as an empty string ''.
commenting out the echocanceller=mg2,1 in the system.conf restart asterisk and the above voicemail scenario works.
Is there another way that I can reduce echo? Or can I turn off echo cancellation for interal routes?
Zaptel/DAHDI DTMF Detection Problems
DTMF detection problems can be caused by a number of different factors. The most common is running the X Windows System. Another cause of DTMF detection problems is the relaxdtmf option in Zapata.conf/chan_dahdi.conf. It may need to be turned on or off.
SIP DTMF Detection Problems
If you are having problems sending DTMF digits amd are using a SIP phone, make sure the dtmfmode they have set is the same on the phone and in Asterisk. Also make sure you are not sending both inband and out-of-band (rfc2833) tones.