VAXBI bus

The VAXBI is a multiplexed bus with fully distributed arbitration and geographic addressing.

All of the logic required to implement a VAXBI interface is contained within a single custom integrated circuit (the "BIIC") and the physical layout and printed wiring board layout for compliant cards is tightly specified, right down to the location of the dual amber status LEDs that are required.

The portion of the card that is reserved for the bus interface is referred to as "the VAXBI corner".

[2] VAXBI licensees were given the appropriate engineering drawings to allow them to exactly replicate a compliant card.

Originally conceived by its engineers to be an open bus, it was forced to be a tightly licensed bus by Digital's marketing and management, and was not nearly as successful as had originally been hoped-for.