Abstract: Interface apparatus which facilitates asynchronous parallel transfer of data at a speed of up to at least 1.6 megabits per second between a minicomputer and a microcomputer. The apparatus includes a plurality of bidirectional data circuits parallel coupled between the minicomputer and the microcomputer for carrying data between the minicomputer and the microcomputer when either computer wants to send data to the other computer.

Abstract: The digital bus is an asynchronous, linear, open-ended digital bus which is coupled to two or more computer/controllers. The bus includes address control circuit lines comprising a bus busy line used by a controller to assert a bus busy signal thereon to gain control of the bus, and to determine if another computer/controller is using the bus, a receiver computer/controller request line used by a controller for requesting permission to send data to another controller, and a receiver computer/controller ready line used by a controller for indicating that that controller is ready to receive data. Data control circuit lines are also provided comprising a data ready line used by a controller for placing a ready-to-send-data signal thereon and a data accept line used by a controller for placing a ready-to-accept-data signal thereon. Also, address bus circuit lines are provided comprising five binary address lines used by a controller for placing an address thereon, which address can have up to five bits.