Abstract: This invention relates to apparatus which can detect both interruptions and reductions in an alternating current input extremely quickly. This allows an orderly shut down of the equipment before the output of the equipment power supply decays. The device can be utilized in any application requiring detection of changes in an alternating current input.

Abstract: This invention is a two-dimensional pressure sensor which can be used to determine a pressure distribution across a two-dimensional object which comes in contact with the sensor. The sensor includes a light source, a matrix of light transmitting fiber endings which includes an alternate pattern of transmitting and receiving light fibers, a transmitting fiber sub-array located a distance from the matrix and composed of transmitting fibers, a receiving fiber sub-array located a distance from the matrix and composed of receiving fibers, a semi-transparent deformable medium located above the matrix, a retro-reflective material located on top of the deformable medium, a flexible membrane located adjacent said retro-reflective material and positioned to contact an object, and apparatus such as a photodetector array, for detecting light which is reflected by the retro-reflective material and transmitted to the receiving fiber sub-array.

Abstract: Apparatus is disclosed which is capable of determining the two-dimensional connectivity profile of a prescribed binary variable associated with a surface. This apparatus comprises a "connectivity-matrix" of switch cells and a two-dimensional sensory array of sensor cells. The sensor cells are responsive to the presence or absence of the binary variable and control corresponding ones of the switch cells in the connectivity matrix.

Abstract: An input/output processing module utilized for processing of signaling information and arranged in a central control unit of a local central office of a digital telecommunications system. Each central office further includes a central switching network and a plurality of trunks dedicated to common channel signaling each locally associated with a signaling link controller unit. Within the processing module, a microprocessor system is provided for initiating, starting and controlled resetting of transfers of signaling information under supervision of the central control unit. The signaling link controllers utilized for common channel signaling are residing on a separate signaling link bus. A signaling link bus control arrangement is connected to both the microprocessor system and the signaling link bus and includes programmable control means for sequentially executing transfer operations of signaling information.

Abstract: The invention relates to a circuit for switching between a ring signal and a message waiting signal in a telephone system, such as a PBX, without the occurrence of "bell tap". The instantaneous value of the ring signal is compared with a D-C value of the message waiting signal to generate a smooth transition between the ring and message waiting states of the composite RAC/MW signal. The circuit selectively suppresses the controlling edge of the ring synchronous signal whenever a particular subscriber station would be connected to the RAC/MW signal at an inappropriate time. Accordingly, the problem of "bell tap" is eliminated.

Abstract: A method is disclosed for testing a complex digital circuit that is designed as a serial access scan path. The circuit incorporates a number of flip-flops, at least some of which are selectively connectable into a scan path shift register. The circuit also has a number of primary inputs, primary outputs, a scan path input and a scan path output. In the testing method, a first digital test pattern is applied to the primary inputs and a second digital test pattern is shifted into the scan path shift register. The digits appearing at the primary outputs are repeatedly compared with those of a first digital number indicative of the proper operation of the circuit as each digit of the second digital test pattern is shifted into the scan path shift register. If the digits appearing at the primary outputs are not equal to those of the digital numbers to which they are compared, a signal indicative of faulty circuit operation is produced.

Abstract: A method and apparatus for storing, in scrambled form, information relating to the personal features of a person. This information can be stored on a portable storage medium which can be carried by the person and used to gain access to a secured area by on-site decoding and verification of the stored information.

Abstract: Apparatus for producing a time standard including a source of radiation, two fibers of different length to transmit the radiation, and means to produce a signal representative of the difference in propagation time through the fibers that is constant despite temperature changes.

Abstract: A method and apparatus for detecting and managing overloads in a telecommunications exchange having a central processor for controlling certain operations of the exchange, line/trunk groups connected to the central processor which include telecommunication trunks and/or subscriber lines, and a switching network connected to the central processor and to the line/trunk group which enables telecommunication trunks and/or subscriber lines to communicate with one another. The exchange also includes apparatus for sending a message to the central processor whenever the telecommunication trunks and/or subscriber lines are to communicate with one another, and apparatus for the central processor to receive the message and send a responsive message back to the line/trunk group.

Abstract: This invention relates to a method and apparatus for transmitting digital data between data terminals via a telecommunications exchange. Data is transmitted asynchronously between the terminals and the exchange and synchronously within the exchange. Transmitted data and internal exchange signals are differentiated even when they are identical. This is accomplished by using a data frame comprising both an information code and a control code which indicates whether the information code contains data to be transmitted. If the transmitted data is not identical to specific digital codes reserved for internal processing in the exchange, the control code is set to one state and the information code contains the data to be transmitted. If the data is identical to one of the digital codes reserved for the exchange, the control code is set to a second state and prescribed substitute digital data is inserted in the information code portion of the data frame.

Abstract: Apparatus is disclosed for detecting the position of an object within a viewing field, such as a CRT display screen. The apparatus includes point sources of radiation arranged at spaced locations around the edge of the viewing field and a retro-reflective surface disposed around the perimeter of the viewing field. The retro-reflective surface reflects radiation received from its originating source back toward this source. A radiation receiver is arranged adjacent to each source to receive the radiation reflected back from the retro-reflective surface and to determine the angular position of an object within the viewing field which interrupts the path of radiation.