Did you know there was a contender for computer peripheral interconnectivity before USB but not Firewire, Apple Desktop Bus or others?

It’s ACCESS.bus, which effectively expanded the I²C protocol.

ACCESS.bus provides a simple, uniform way to link a desktop computer to a number of low-speed I/O devices such as a keyboard, a mouse, a tablet, or a three-dimensional (3-D) tracker. Designed from the beginning as an open desktop bus, ACCESS.bus facilitates cooperative solutions using equipment from different vendors.

The theoretical number of devices that you could daisy-chain off a single ACCESS.bus port was 125, which is all the more impressive because the communication is happening off of a single port.

It’s relatively easy to see why ACCESS.bus didn’t take off with the benefit of retrospect. It was fast enough for input devices, but kind of slow for anything else, because I²C was built for small data transfers, not big ones.

Has ACCESS.bus disappeared off the face of the planet? Technically, yes: USB and FireWire each upstaged the standard. But the Video Electronics Standards Association (VESA) co-opted the work for ACCESS.bus into the Display Data Channel (DDC). That standard allows monitors to talk back to the PC and the computer to directly communicate with the display.

See this vintage video from the Computer Chronicles and more in the Tedium article here by Ernie Smith.