We don’t know why it’s there, we don’t know what it’s doing – all we know is the button makes everything OK again • The registry

On guard An on-call reminder this week that everyone must adore the mysterious beige box with the single doom LED eye, no matter what you think it’s used for.

Our story comes from a regomised reader like “Mike”, an engineer on site. Mike spent the end of the 20th century on the road, rescuing customers in Britain.

Its story takes place in the 1980s, a decade that began with the beginnings of the Rubik’s Cube and ended with the arrival of the World Wide Web.

Users had not yet learned the pleasures of seeking solutions to their problems through a myriad of search engine advertising. Instead, Mike was called in to deal with their complaints.

“I worked for a company providing CAD systems,” he told us. “These systems usually had some sort of 2D plotter for the output, usually pen-based, but sometimes early inkjet technology or even some kind of wet electrostatic system.”

“Which still gives me nightmares,” he added.

The issue in question was with a powerful A1 pen tracer manufactured by Calcomp. Calcomp, for the uninitiated, was all about the plotter (besides other peripherals) and dominated the market in the latter part of the 20th century. It remained a thing until the late 1990s before it went out of business, although the name lives on.

The tracker in question was behaving badly: “Sometimes he refused to work when there were conspiracies in the queue,” Mike said. “I took a look, tested it and found no problems initially.”

It was connected via a serial port. Sometimes a reset of the plotter or the computer was necessary (“a good old DEC VAX 11/750”) to bring the device back to life.

Or sometimes a button flick on the trainer under the floor.

The what?

Mike had never heard of such a device, but the design team insisted it was there. A floor tile was lifted and, of course, nestled among the cables was a beige box with a Calcomp logo, a red LED, and a single “Reset” button. Pressing the button caused the LED to blink and then stabilized.

Mike searched around the rat’s nest, but found nothing abnormal. Instead, he decided to check for faulty cables.

“I traced the serial port cable on the VAX, through a patch panel, under the floor, and down to the plotter, completely avoiding the magic beige box.”

The suddenly redundant trainer simply glared at him, his only red LED glowing in challenge.

“I had and still have no idea what this box did,” he admitted, “other than giving a feeling of satisfaction and a strong placebo effect.”

Our money is on a piece of kit that we no longer need that an engineer couldn’t bother to take out. Or maybe, just maybe, a box to delay the inevitable legend just long enough for the change to change.

What do you think? Let us know in the comments below and share your own experience with mysterious devices that are both critical and completely unnecessary with an email to On Call. ®