How do I read from and write to serial ports?

Serial ports can be opened just like files in ActivePerl.
To open COM1, just do this:

    open( PORT, "+>COM1" ) or die "Can't open COM1: $!";

You should be able to read from and write to the file handle
using the standard I/O functions (read() and print()), but not
the system functions (sysread() and syswrite()).