Hacker News new | ask | show | jobs
by nyx_ 2225 days ago
On today's edition of "Things You Shouldn't Be Able To Do From a Browser"...

Seriously though, sending PJL commands directly to printers on port 9100 is such a neat hack. Back when I was working help desk in college, much fun was had the day I discovered you could change the "READY" string on HP printer displays to anything you wanted. "INSERT COIN", "CHECK ENGINE", etc.

1 comments

Haha that's actually how I got started with this project. We had some printers with character displays, and I was creating small C programs that opened a socket to the printer to update the display. Used it to play pranks on my sister. At some point I wondered if it was possible to do it with HTTP requests and a PJL payload in the body.