Why is there constant static on one of my fxo modules?

anyone know why there is constant static on one of my fxo modules? its not the cabling because i pluged another working line into it and it does the samething. a workaround is to reboot, but it comes back in a day or so, but can manefest itself on another fxo module. any suggestions on how to diagnose this would be greatly appresiated!

Make sure the PC is properly grounded.

its pluged into a apc ups battery power supply. i have tried pluging it directly into the wall too, same effect…

Try to get a better Power Supply. Like the Antec or Enermax.

Switching the fxo modules.

any ideas why a reboot fixes it?

Install the latest zaptel 1.2.4

thats the version i have…