Configuring your RealPort printers with CUPS in Red Hat. Here are the steps taken for configuring a printer:
Point the web browser to http://localhost:631
Select [Add Printer]
Fill in the name, location and description.
Select the "Serial Port #1" device.
Fill in the appropriate settings for baud rate parity, etc..
Select the correct printer make.
Select the correct printer model, click [Add Printer]
Since the Digi serial port does not display in the CUPS device list, this will need to be changed to the correct tty device:
Edit the /etc/cups/printers.conf file and change ttyS0 to the appropriate tty device.
Restart the cups daemon:
Jun 23, 2019