large background noise

Science you could not issue modprobe command, could you run dmesg and see what happened while load device driver?

Thanks all, I will try later. BTW, I have some questions about the mentioned problem.

1) How is the effect of the between setting of zone, country and the background noise and volume of conversion?

2) Where can I can the most updated opvxa1200.c for asterisk 1.4.x/zaptel 1.4.x?

ango

hi:
1) you have to set it based on which country are you from, the asterisk will adjust the tel standard for your country. it (impedance） will affect the call quality.
2) you can download the latest version of a1200p/a800p driver from our website.
regards!
James.zhu

hi,
Finally, I can the opermode. Just want to clarify the setting should be: modprobe opvxa1200 opermode=UK.

I have make some tests after setting the opermode. Below is the result.

A - IP phone connected to asterisk
B - PSTN

case 1: A1 calls A2 (normal)
case 2: A calls B (A hears B is ok but many background noise/echo from his/her area when A say nothing. Sound Volume of A is very low when B hears A. )
case 3: B calls A (same result as case 2)

Please advise anything I can do to immunize the noise hear from A and tune the volume of A when B hears A. I have adjust both rxgain & txgain but the result is the same.

How about compose a script that when somebody call into your system , you play voice file to him, not connect to SIP phone?