I guess my English is worst than I was thinking ;)
I have two Win32 machines, each with a modem.
The first one should dial the phone number of the second machine.
I know how to use the Win32::Serialport to do that, and I know how to exchange data through a normal phone when you know the protocole at server side.
I just need to know how the second machine can listen at the serial port and get the line if called.