Description:

This module provides an object-based user interface essentially identical
to the one provided by the Win32::SerialPort module.

Initialization
The primary constructor is *new* with either a _PortName_, or a
_Configuretion File_ specified. With a _PortName_, this will open the
port and create the object. The port is not yet ready for read/write
access. First, the desired _parameter settings_ must be established.
Since these are tuning constants for an underlying hardware driver in
the Operating System, they are all checked for validity by the methods
that set them. The *write_settings* method updates the port (and will
return True under POSIX). Ports are opened for binary transfers. A
separate 'binmode' is not needed.

$PortObj = new Device::SerialPort ($PortName, $quiet, $lockfile)
|| die "Can't open $PortName: $!\n";