Problem with sound


I have a big problem, a PBX has installed FreePBX 2.2-1 over Debian Sarge, this PBX has a Digium TE12xP, the problem is that if a call arrive the operator tha has XLite installed with a SIP extension, the operator listen pretty well to the caller, but the caller listen with problems, the same problem exist from SIP to SIP, and another interesting problem is that if make a Echo Test, this didn’t work, I compile Asterisk, Zaptel, the kernel version is 2.6.8-4-686, the Digium card has a unique IRQ, the IDE Disk is using UDMA, I don’t know what is the problem, please help me.

Roly Morales