More telephone stuff

We have an inexpensive Chinese PBX.

I can get voice mail and call accounting packages for it, but I would 
prefer something running under linux.  Particularly the call accounting.

I have looked for packages, but nothing seems really suitable (or current).

I also have to admit that how the pbx communicates with the PC is a 
technical mystery to me, although our telephone supplier indicates that it 
a cord connection.  I presume serial port.

Any thoughts, guidance etc would be appreciated.



Regards,

Graham Brown