Troubleshooting DeviceMaster LT: NS-Link Linux Installations

Pepperl+Fuchs Comtrol, Inc. has available lcom(1), which is a multi-port serial I/O test program. You can use lcom in test mode to send test data to any serial port.

The following examples use ports ttySI0 and ttySI1. You may need to substitute the port numbers that you will be testing.

You can also refer to the procedures below to check the ports:

You can transfer a file using the following information. The default settings are 9600, 8, n, 1, and no parity. To send a file you can redirect output to a device, where x is 0 through 7, for example:

cat /etc/inittab > /dev/ttySI0

Sends the contents of the /etc/inittab file to the ttySI0 device at 9600 baud, 8, n, 1, and no parity.

Use the following information if you need assistance changing or viewing the baud rate settings.

To change the baud rate, use the following example, which changes the baud rate to 19200, where x is 0 through 7.

stty 19200 </dev/ttySI0

To view the current serial port settings for ttySI0, enter:

stty -a </dev/ttySI0

Add the appropriate line or lines to the /etc/inittab file then restart.

Some distributions use the agetty command and other distributions use getty. Check the documentation for your Linux distribution if you are unsure.

Terminal Example:

T0:23:respawn:/sbin/agetty -L ttySI0 57600 vt100

Modem Example:

T1:23:respawn:+/sbin/mgetty -m ‘"" AT&F OK’ -D -x9 -s 115200 ttySI0

If necessary, see the manual pages for more information on mgetty.

You can also use minicom, which is shipped with most Linux operating systems, to test the serial ports. A Pepperl+Fuchs Comtrol, Inc. document is available for using minicom.