You can tell CUPS to print (nearly) any file “raw”. “Raw” means it will not be filtered. CUPS will send the file to the printer “as is” without bothering if the printer is able to digest it. Users need to take care themselves that they send sensible data formats only. Raw printing can happen on any queue if the “ -o raw ” option is specified on the command line. You can also set up raw-only queues by simply not associating any PPD with it. This command:

$ 

lpadmin -P rawprinter -v socket://11.12.13.14:9100 -E

sets up a queue named “rawprinter”, connected via the “socket” protocol (a.k.a. “HP JetDirect”) to the device at IP address 11.12.1.3.14, using port 9100. (If you had added a PPD with -P /path/to/PPD to this command line, you would have installed a “normal” print queue.)

CUPS will automatically treat each job sent to a queue as a “raw” one if it can't find a PPD associated with the queue. However, CUPS will only send known MIME types (as defined in its own mime.types file) and refuse others.