[Asterisk-Users] TDM400P static on call

[news.asterisk.users]

Derek Lee-Wo wrote:
> I just got a TDM400P with 2 FXO cards.  I got it all configured and I
> can place and receive calls.
>
> I seem to be getting static on the call, mainly when I speak.  E.g, if
> I call someone, I can hear them just fine, but they would hear static.
> Not a lot...more like a constant background "hissing" noise.
>
> What can I look at to try and troubleshoot what is going on, or is 
> this normal?
>
> I played with the rx and tx values, but it didn't seem to make much 
> difference.

I've had the same problem plus low volume audio when the two lines are 
bridged..
Adjusting rxgain/txgain does make it louder but also increases the noise.

In your case make sure you're not sharing irq's.  cat /proc/interrupts
Also turn off printer/usb/serial (if you're not using them) in the bios.

JD