Reply to post: There's an old hack.

There's an old hack.

Don't know if it's work on something from the mainframe days, but the old Centronics parallel ports could be tricked by poking a wire in the right holes so that the source's 'ready' is fed straight back into 'acknowledge.' The source sees a printer attached, and keeps on sending. The data is lost, of course, but it's handy if you just want to test some program that produces printer output without wasting paper.