Abstract: A method for effecting full duplex communications through a plurality of ports of a processing apparatus having one timer. Each output and input signal is expressed as a plurality of bit time intervals.

Abstract: A keyboard having a plurality of selectively operable matrix element key switches, each having an actuated and an unactuated state. The state of each switch is sequentially determined by applying one of two input signals to the input of each switch. The output of the switch is integrated and compared to a predetermined value to determine whether the switch is to be recognized as actuated or not actuated. If during a particular sequence the integrated output exceeds the predetermined value (so that the switch is recognized as actuated), the second input signal is applied to the switch during the next sequence. Because the second input signal has different parameters from the first input signal, whether by a greater number of pulses or greater amplitude pulses, then if the key switch is still depressed, the integrated signal produced by the second input signal exceeds the predetermined value by a greater amount than during the prior sequence.

Abstract: An electrical apparatus configured for predetermined encoding. The apparatus is comprised of a substrate, a plurality of pairs of electrical terminals affixed to the substrate, a plurality of conductive circuit traces connecting respective pairs of terminals, and a like plurality of removable plugs in the substrate intermediate respective pairs of terminals. The conductive circuit traces respectively traverse respective plugs intermediate respective pairs of terminals so that removal of a plug interrupts the electrical continuity of the conductive circuit trace traversing that plug, thereby creating an electrical open circuit between the respective terminal pair. In such manner, logical "zeroes" (opens) can be created in the respective terminal pairs or, by electing not to remove a given plug a logical "one" (closed electrical circuit) can be programmed between a given electrical terminal pair.

Abstract: An over-center actuator switch assembly includes a U-shaped bracket having a plurality of similar switches mounted in side-by-side relation between the flanges of the bracket. Each actuator has a depressible operator extending into the bracket. An operating lever is pivoted between the bracket flanges and contacts all of the switch operators. A control lever is also pivoted between the side flanges of the bracket, and one or more compression springs is biased between the levers. Pivotal movement of the control lever moves the levers and springs through an over-center condition to effect snap action pivoting of the switch operating lever and reversal of the condition of depression of the operating members.