Abstract: A leg assembly for a keyboard is described in which the leg operates, without the use of an actuating mechanism or direct hand intervention, to be movable between two stable positions; the first being a retracted position, the second being a deployed position. The leg assembly is of simple construction, comprised of a leg pivotally mounted to a keyboard or the like by means of a pin. Simplicity of use is inherent in the design.

Abstract: A mounting bracket for test probes for use in testing electronic circuitry. By placing a printed circuit board (PCB) from a shelf of interconnected PCBs in an extender card connected to the shelf, a mounting bracket may be attached to the extender card. The mounting bracket allows test probe assemblies to be placed anywhere over the PCB being tested. A system is thereby created wherein any point to be tested on the PCB may be readily accessed. The system may be used to test PCBs employing flat-pack, dual in-line, or surface mount integrated circuit (IC) technology. The mounting bracket is useful for testing PCBs in situations where the PCB must be operating as part of a larger, combined circuitry such as used in the telecommunications industry.

Abstract: An adjustable quick-mount test probe assembly for use in circuit testing. The test probe assembly provides a convenient means for testing printed circuit boards containing Very Large Scale Integrated (VLSI) components and high density interconnect substrates. This is due to its versatility in terms of positioning and its use of replaceable, "off-the-shelf" test probe tips. The test probe assembly provides a means of quickly connecting test clips from a test equipment unit to a circuit board, as well as providing a means of neatly arranging test leads to avoid the possibility of entanglement and reducing strain on the test probe. Test set-up time is greatly reduced, and confidence of test set-up integrity is increased.

Abstract: A bus system for exchanging information between a plurality of circuits connected to the system. The bus system includes a polling bus, a message bus, and a bus controller. The bus controller polls each circuit to see if the circuits require access to the message bus. Information between the circuits is conveyed by first transmitting the information to the bus controller where it is temporarily stored. That information is then sent to the destination circuit by the bus controller. Information is thus conveyed over the message bus twice for every exchange of informaton between two circuits.

Abstract: A wireless telephony system comprising a base station and at least one portable device. The base station employs a ratio frequency (RF) receiver and an optical transmitter. The portable device employs an optical receiver and an RF transmitter.

Abstract: A cellular mobile radio communication (e.g. telephone) system (hereinafter referred to as a private cellular system, PCS) that does not have the constraint of being a well defined, pre-planned system. The present invention differs from previous systems largely by the fact that it does not have to be well planned in advance. A user can simply install a base station virtually wherever he desires. Each base station is "intelligent" and produces a dynamic allocation. This of course means that if one were to install such a system, for example in an office building, no studies would be required. One would simply install a series of base stations.

Abstract: A novel method and apparatus for quickly allocating channels on a TDM (time division multiplex) bus to devices requesting access to those channels. In one embodiment, each channel of the TDM bus consists of nine bits and each device has a unique eight bit identification code plus one status bit (referred to collectively as a unique nine bit device code). If a channel is not occupied, each device wishing to gain access to the channel applies its own unique nine bit device code to the bus in the channel time period, sequentially, in order to significance. While doing this, each device monitors the bus to determine what code signal is on it; as soon as it detects a code bit differing from its own, it declares a conflict and stops sending its code, only to wait for the occurrence of the next channel when it retries. The device that is successful in applying all the bits of its code to the bus without conflict declares itself to be the winner, and on the next appearance of that channel (i.e.

Abstract: A path oriented routing system and method for packet switching networks with end-to-end internal protocols. It allows switch pairs to communicate over multiple paths without packet disordering. A distributed loop-free shortest path algorithm assigns a number to a path at the time it is created and this number remains valid through path changes. Consequently, existing traffic can be maintained on existing paths, while new traffic is assigned to the current (i.e. new) shortest paths.

Abstract: A solder resist paste having the feature that it is relatively easily removed is disclosed. The paste is comprised of a liquid polyglycol (e.g. Pluronic 25R2 by BASF) and either Kaoline or talc powder. In operation, the paste is selectively applied to holes in the PCB which it is desired to keep open during a soldering process. The paste is then washed out of the holes, additional components mounted via those holes, and soldered into place.

Abstract: An interface scheme is described which allows relatively convenient interconnection of, and re-configuration of, circuits for performing operations to digital signals from a bus. In one exemplary embodiment, a parallel bus, eight bits wide, having 320 channels per frame is provided. For each circuit to be connected to the parallel bus a connection memory and an input/output buffer is provided to control the accessing of the parallel bus by each circuit.

Abstract: A fuse is disclosed for protecting thick film devices. The fuse comprises two blocks of material mounted to the substrate that carries the thick film device. The blocks are mounted in close proximity to one another, in axial alignment, but in a spaced apart relationship. An electrically conductive fusible link (e.g. solder) straddles the two blocks so as to complete an electric circuit.

Abstract: A novel construction for a thick film resistor is disclosed. A substrate has a first face deposited with a layer of resistive material. Between the substrate and this first layer is located a strip of conductive material. The strip of material is oriented at approximately right angles to the current path through the first layer, midway along the current path. A second layer of resistive material is located on a second face, parallel to the first face, and the first and second layers are connected electrically in series such that the current path through the second layer is orthogonal to the current path through the first layer.