This is mostly a list for my own purposes, but I got a Eltron/Zebra LP2844 to print raw files generated on my Mac to send over USB.
First, you need to find the device URI:
$ /usr/libexec/cups/backend/usb direct usb://Zebra/LP2844?serial=42J094403339 "Zebra LP2844" "Zebra LP2844" "SERN:42J094403339;MFG:Zebra ;CMD:None;MDL:LP2844 ;" ""
Add the printer to CUPS, accept, and enable it:
$ lpadmin -p zebra -v usb://Zebra/LP2844?serial=42J094403339 $ cupsaccept zebra $ cupsenable zebra
(cupsaccept is for Mac, “accept” works on all other flavors of UNIX.)
Try a test:
$ lpr -P zebra test.raw