Ztdummy appears to not be working

RedHat ES 3
Kernel 2.4.21-37.ELsmp

Zaptel 1.2.5

There is no zap related hardware in this server so I loaded the ztdummy module. An lsmod shows the module loaded but says (unused) beside it. Shouldn’t that show that it is in use?

The symptoms are that music on hold during a park goes very loud and distorted after 3 or 4 seconds. And, it only happens with in incoming call from the sip provider. Calling from phone to phone and parking works fine. I changed the moh to use the internal music and this is when this happens. Switching back to using madplay for moh works just fine.