Saw this on the Technical Specification page:
IBM® 224 character set, code page 437 (default) Individual country character sets by software selection
I would think you'd have to mimic that for the printer to see your data as a valid message coming in.
I was looking for some hint of a Windows/MAC driver, nothing jumps out at me on that page.
If there was, you could monitor that as you send some test messages and see what actually goes across.
This might be helpful: