Serial Modems

Is there any way I can tell if my modem is plugged into ttyS0 or ttyS1 (I have 2 at the back of my computer and I don't know which is which). I tried running a program called serial_probe (it sounded like what I wanted), however it exited after about 2 seconds giving no output.

try wvdial, it can automatically probe both serial ports, find the modem, and set it up. all you need to do is add a phone #, username, and pw. oh, and i think there are several gui frontends to it, but ive never used any of them... wvdial itself is pretty easy