Abstract: A voice bus on a computer backplane provides point-to-point connection between a plurality of slots on the backplane to a particular slot. Connection from the plurality of slots is provided by third connectors which lie between first and second connectors defining the slots. Connection to the particular slot is via its respective second connector. In particular, the computer backplane is physically and electrically compatible with the IEEE standard 1014-1987 defining the VMEbus. The presence of the third connector is compatible with the VMEbus standard both electrically and physically.

Abstract: A miniature electro-mechanical transducer uses a body of elastomeric material composed of alternate layers of flexible dielectric material and flexible conductive material. The ends of the layers form opposite surfaces. An actuating member moves against one surface and the other surface contacts two spaced electrodes. The arrangement is such that a progressively increasing number of layers of conductive material are brought into an electrically parallel circuit between the electrodes.

Abstract: A measuring rule has a coilable steel measuring blade extensible through an opening in a housing and is marked along its length with regularly spaced dark areas separated by light areas. Two pairs of light sensors are located near the rule each associated with a light emitter. Each sensor is 180.degree. out of phase with the other sensor of the pair and 90.degree. out of phase with the other two sensors. The outputs of each pair of sensors are used to produce a difference signal. The difference signals are used by a counter to measure the magnitude and direction of movement of the blade. Each sensor output signal is divided by voltage divider to give a divided signal and each sensor output signal is compared with the complementary divided signal at the instant the difference signal of the other pair of sensors changes state and a fault signal is generated if its minimum is larger than the maximum of the complementary divided signal.