Printer Interface Graffiti

I would like to inform the readers about a peculiarity within the Cardco Card/? G+ printer interface. I was playing around with my printer when it printed the following:

(c) Copyright 1983 CARDCO INC.

Jackie, This one's for you!

-Breck

Could you please tell me what this means and how I can get this to happen again?

Eric Milota

Most likely, you accidentally triggered the interface into a reset or self-test mode. It's somehow reassuring to discover affectionate graffiti hidden within the high-tech metal heart of a printer interface.