We've typically have needed plugins to get barcodes to print well on label printers. On the old Eltron as well as newer Zebra printers we've variously we've used barcode fonts, barcode image generation plugins, and print driver plugins.
Using that route, it's pretty easy to set up the layouts and get print working... but it's then either expensive for plugin server licensing or a hassle to have one-off setups with plugins on individual workstations.
After wondering if printing directly to an EPL(2) printer is hard, finally gave it a try... In limited testing, it's not hard, and can be done without plugins. Tested with Eltron 2844 CTP and Zebra ZTC GX420d on recent desktop OSX.
Attached is an example. Script is unusual in that it stores print commands/data in a hidden file in home directory. You could probably store the commands in a variable or field if you got line endings figured out, then just pipe that data in to the print command. In this example, the EPL2 commands are built up in the file, all with "perform applescript" issued shell script commands.
Anyway, figured I'd post in case any one else looks up how to get started with a similar effort... Or perhaps to hear from others who have a better way :-)