I installed asterisk 1.2.18 on CentOS 4.4 (Kernel 2.6).
Before doing that I compiled and installed libpri and zaptel.
All this installation was done in Microsoft VirtualPC.
Asterisk is working fine, but when I load ztdummy (modprobe ztdummy) I get choppy sound and a lot of echo.
Do you have any idea what might be happening?