Multibus I Backplanes

Multibus I cards and card cage

Multibus wire wrap cards in a Multibus I card cage. See Z8000 Static Tester, where a Z8002 communications design was wire wrapped onto a Multibus I development board. The above card cage, wire wrap boards and bus extender were manufactured by National Semiconductor.

Work done from 1983 to 1985


Multibus was known as Multibus I after Multibus II was introduced in 1987. It was developed by Intel with a robust market of over 100 vendors in 1982 according to the Wikipedia Multibus entry. We wire wrapped some Multibus boards but were too busy multi-tasking to put them into production. When we bought the Multibus card cage, extender board and wire wrap cards, they were cheap, but the commercial boards were certainly not.

The VME backplane was announced in 1981 with the initial specifications placed into the public domain. With a better edge connector and processor, our transition was away from Multibus to VME. In the early 1980s, there were a few large companies in South Africa working with Intel ICE plugged into Intel Multibus I cards, but they were not going to buy anything from us, so we did not invest any more effort. We were not going to purchase Intel emulators, and that market appeared to be meshed together behind the scenes with corporate-to-corporate deals.

It would also be risky adopting technology from a small outfit that did not have commercially available systems, which we could also appreciate.