COMM ports

[Nefarious]

I'm trying to set up a fax server (hylafax) on a server but am having some difficulty with ports. I tried using the cu command to access all the /dev/ttyS* that were in the /dev folder and S0 - S4 all reported the same error message. Permission denied - Line in use. The only thing that I know which is using one of the two COMM ports is a serial interface to a smartUPS. I tried echoing the ttyS* ports and one of them reported "warning power loss deteected from UPS" indicating that I'm at least hitting the right names.

Does anyone have any cunning way of checking whats using the ports? The only thing I can think of that might be happening is that the apcupsd software is taking control of all the serial ports and only using one of them.

Any suggestions gratefully received

Thanks