[asterisk-users] TDM2400P Voice Quality Problem

[Noah Miller]

Hi Shariq -

> I m facing problem with TDM2400P pstn card. When someone dials, the voice
> quality is crappy....Instead of hearing.
>
> Echo cancel almost works, but the callee hear what they describe as a
> 'background crackle/buzz' coming back when they talk.

Crackling noise is usually caused by an unbalanced hybrid or a shared IRQ.

Have you used the fxotune tool?  This is the first thing you should do
with any analog card.

If you still have issues after running fxotune, check to see if your
card is sharing interrupts with anything else like a network card or
disk controller. You can use "lspci -vv" or "cat /proc/interrupts" for
this.


- Noah