In Linux the end of my print jobs are being cut-off and never print the end of the document.

This behavior is due to the spooler closing the connection prior to the port buffer draining.

The following command can be used to hold the port open so all of the data prints:

# cat < /dev/ttyx## > /dev/null &

Where ttyx## represents the actual tty id.

This command can be placed in a start-up file to run upon reboots.