Having had a quick look on Google I have found quite a few links about the MD910 printer. It has an RS232 serial interface. Is this what you are using to generate output? If so, then sending normal ASCII text to it will produce output. One thing to remember which is forgotten these days is you must send it a carriage return and a linefeed otherwise you'll print on the same line and/or only the page will move down, and the head will not return.

Chris.