Abstract: A control system for a solid state crossbar switch (10) which allows a plurality of switch control and interrogation functions to be implemented by time sharing related circuitry. The crossbar switch (10) includes a plurality of X ports (X.sub.1 -X.sub.N) and Y ports (Y.sub.1 -Y.sub.M), each X-Y port intersection designating a specific X-Y intersection latch which controls a plurality of associated switches for interconnecting one set of data lines associated with the X port to another set of data lines associated with the Y port. The control system disclosed continuously and sequentially addresses each of the X-Y intersection latches at a 10 megahertz rate.

Abstract: A high-speed multiplexing system of keyboard data inputs in which keyboard entered data is sequentially and automatically sampled by the multiplexing system for input to a computer. More specifically, a system is disclosed whereby a plurality of data inputs from a plurality of keyboards are applied to a multiplexer having a single output connected to a computer. A sequencer is provided which sequentially and automatically controls the multiplexer to sample each keyboard input in accordance with a predetermined sampling sequence. Whenever keyboard entered data appears on input lines to the multiplexer, the system inputs the keyboard data to the computer during a brief time interval in which the multiplexer remains at the particular keyboard address or port. Thus, a high-speed sampling circuit is provided whereby the only operator action required is data entry through a keyboard.

Abstract: An interface logic circuit permitting the transfer of information between two computers having asynchronous clocks is disclosed. The information transfer involves utilization of control signals (including request, return-response, ready) to generate properly timed data strobe signals. Noise problems are avoided because each control signal, upon receipt, is verified by at least two clock pulses at the receiving computer. If control signals are verified, a data strobe pulse is generated to accomplish a data transfer. Once initiated the data strobe signal is properly completed independently of signal disturbances in the control signal initiating the data strobe signal. Completion of the data strobe signal is announced by automatic turn-off of a return-response control signal.