Start minicom on your linuxbox. You can type minicom com2, when you create the following minicom configuration file:
# file: /etc/minicrc.com2
#
# this minicom configuration file is used to make
# a connection to a RAD-PAD via ttyS1 (COM2)
#
# Machine-generated file - use "minicom -s" to change parameters.
#
pr port /dev/ttyS1
pu baudrate 9600
pu rtscts No