Abstract: A digital switching network is disclosed in which paths can be preset from any inlet to any outlet either for circuit-switched connections or for packet-switched messages (packets), as required. At any point in time, the paths preset for the packet-switched messages form a network whose nodes lie in the switching facilities of the switching network. The switching facilities contain the functional units required to switch each data packet on the path preset for it. This makes it possible to dynamically divide a single switching network into a circuit-switching network and a packet-switching network as required.

Abstract: The communications system of the present invention defines a complete feedback path consisting of first and second transceivers and an appropriate signal path. Each transceiver comprises a detector and a signal source capable of generating a signal at one of two frequencies. The detector in each of the transceivers is a two state device tuned to respond only to a predetermined desired difference frequency. If the desired difference frequency signal is present, the detector provides and output signal in a first state; if the desired difference signal is not present, the detector provides an output signal which is in a second state. The signal source can be a voltage controlled oscillator, a pair of single frequency oscillators, a synthesizer, or any signal source capable of being electrically switched between two frequencies. Data can be exchanged between the transceiver pair only when the desired difference frequency is present.

Abstract: A power line communication system which includes an electrical power line having one or more loads which feed objectionable electrical noise back into the power line. The electrical noise is attenuated across a broad frequency range to enable effective communication over the power line by a directional common mode trap located between the point where the communication signals are applied to the power line and the source of the electrical noise. The trap requires only a capacitor for each electrical phase and a 1:1 transformer having a magnetic core and single turn, straight through windings. The trap is connected to provide a low impedance path to ground for the electrical noise, while providing a high impedance to ground for the communication signals.

Abstract: In a mobile communication system having two operating systems co-existing in one area, a mobile station having a transmitting and receiving circuit and a control unit for subscribing to one of the two mobile communication systems by selecting a control channel thereof is provided. Accordingly, a normal scan of the control channel of the subscribed-to system is activated, and then an extra scan of the control channel is activated when the control channel is not available during the normal scan. The possibility of an involuntary connection to a non-subscribed-to system is thereby reduced when the mobile station is temporarily in a blind section of the subscribed-to system.

Abstract: A packet communications network and apparatus for communicating information in voice and data packets transmits and receives voice and data in accordance with standardized frames of a standardized communications format such as a standard DS-1 type trunk. An apparatus is coupled to multiplex standardized channels into a single channel wherein voice or data signals are packetized into independently addressable packets synchronized on, for example, the DS-1 frame. The network includes voice and packet data concentration apparatus operable in a multiple node trunk environment to concentrate signals into independently addressable synchronously switchable packets, thereby to provide an efficient (high density capacity) interface between trunk terminations. Up to four times as much information can be transferred between nodes with the ability to switch between nodes as compared to conventional TDM and PCM communication without compression without the ability to switch between nodes.

Abstract: A channel management apparatus provided for a plurality of master radio communication units which perform communication by selecting as desired one or more of a plurality of channels that are respectively assigned to a plurality of slave radio communication units. This apparatus is provided with a shared storage device which is capable of being set on each master unit and which contains items of data on registered channels which correspond to all of channels used by the master units, and a plurality of groups of devices incorporated in the master units.

Abstract: A two-way cable distribution system for offices and office/apartment complexes wherein a single cable is used to interconnect tenants or owners with video/audio, facsimile, security and data services; with each user being allocated dual TV channels for the simultaneous transmission and reception of programs--all with complete privacy. User's multi-channel remote switching and processing converters (RSPC) are mounted in the switching control center where they also double as precision frequency controlled channel processors and eliminate problems of switching video crosstalk that occurs with IF or baseband switching. Spectrum capacity on each riser exceeds 800 MHz and enables more than 60 users per riser, each to be assigned 12 MHz bandwidth, without the need for line extenders amplifiers. Trunking of signals between buildings within a complex is not required because of riser transmissions that assign user drops in descending frequency along the length of the cable.

Abstract: An apparatus for interconnecting a plurality of switch modules is disclosed. The interconnecting apparatus comprises a planar array of switches. Each of the switches has four switching leads, two lying in the plane of the array and one extending perpendicular to the plane on either side thereof. A programmable control enables the establishment of a switched connection between any two of the four leads comprising a particular switch. Switch modules lying on either side of the plane array may be interconnected in this manner.

Abstract: A time slot interchange matrix is comprised of a plurality of matrix modules (50-56) each for receiving data on a plurality of channels and transmitting data on the same number of channels. Each of the modules consists of separate banks of random access memory that are interfaced with an intramatrix bus (70) for receiving data from each of the matrix modules in the system for storage therein during a collection frame. During a transmission frame, this information is randomly accessed in accordance with an interconnect pattern stored in a control RAM (122) for output from the digital matrix module. Each digital matrix module stores all of the information in the system such that the system is non-blocking for any given channel stored such that information is not impeded by the interconnect pattern of another digital matrix module. A digital bridge (80) is provided for collecting the information during a collection frame and then accumulating the information in a bridge IC circuit (137) as a conference.

Abstract: N framing units block N-channel input digital signals, respectively, to provide blocked signals. The framing units respond to a common block synchronization signal from a multiplexing unit to provide the blocked signals in a time relation suitable for multiplexing. The multiplexing unit multiplexes the blocked signals from the framing units to provide a multiplexed signal (higher-order group signal).

Abstract: A multiplexer for trunking, over at least one high-speed trunk line on a multiplex basis under statistical time-division multiplexing control, transmission data on low-speed lines connected to a plurality of data terminal units, operates normally to transmit multiplexed data over leased high-speed trunk lines and, when a data buffer which temporarily stores data on the low-speed lines has its contents in excess of a certain level, operates by adding a public line as a high-speed trunking line to the leased high-speed trunk line for implementing the multiplexed data trunking.

Abstract: A bit oriented communications network includes a plurality of nodes interconnected by a broadcast communications medium. Each node samples inputs connected to it and broadcasts the values of those inputs. All of the nodes then monitor the broadcasts and map selected bits to outputs connected locally through an output mapping process. Connections are established between inputs and outputs by the output mapping process, and such connections may be changed simply by changing the output mapping selections. Both the input and output bits may be either physical devices or, as described in a second embodiment, may be exchanged with an external system through a shared memory. A Dynamic Time Division Multiple Access (DTDMA) time slot allocation scheme is used to synchronize transmissions from each node in a round robin fashion. Each node is allocated one time slot for transmission and maintains a current time slot value in a gap timer.

Abstract: A high capacity metropolitan area network (MAN) is described. Data traffic from users is connected to data concentrators at the edge of the network, and is transmitted over fiber optic data links to a hub where the data is switched. The hub includes a plurality of data switching modules, each having a control means, and each connected to a distributed control space division switch. Advantageously, the data switching modules, whose inputs are connected to the concentrators, perform all checking and routing functions, while the 1024.times.1024 maximum size space division switch, whose outputs are connected to the concentrators, provides a large fan-out distribution network for reaching many concentrators from each data switching module.

Abstract: Apparatus and method are disclosed for determining the location of a network component coupled to a local area network segment. A remote segment monitor unit is coupled to either end of a cable segment of a local area network system. The remote segment monitor unit, for each transaction on the cable segment, determines a value related to the transaction signal strength and determines the identity of the network node from which the transaction originated. By providing a record of the transaction signal strength associated with each network node (component) in both remote segment monitors, the location of network nodes can be ascertained.

Abstract: In the frequency-division multiplex broadband multimedia network of this invention, a plurality of transmission paths are laid out in a matrix, with transmission path switches being arranged at respective lattice points. Each transmission path switch monitors a transmission path current. When a transmission path switch detects that a current has been cut off, a portion where a communication trouble is caused is disconnected from the network, and the switch connects a portion at the downstream side of this tansmission path switch to another adjacent transmission path.

Abstract: A high capacity metropolitan area network (MAN) is described. Data traffic from users is connected to data concentrators at the edge of the network, and is transmitted over fiber optic data links to a hub where the data is switched. The hub includes a plurality of data switching modules, each having a control means, and each connected to a distributed control space division switch. Advantageously, the data switching modules, whose inputs are connected to the concentrators, perform all checking and routing functions, while the 1024.times.1024 maximum size space division switch, whose outputs are connected to the concentrators, provides a large fan-out distribution network for reaching many concentrators from each data switching module.

Abstract: A method and apparatus for decreasing delay and use of data processing resources in the reliable transmission of data frames in a packet network. In transmitting data from a source to a destination over a plurality of intermediate data switching points, the data processing required for each frame is selectively varied at each data switching point, according to the requirements for transmission of data frames of a message and of the succeeding link used for that message. A virtual link address is transmitted with each data frame which is translated into the mode of processing the frame at the data switching point, and into the virtual and real address of the next data link. Advantageously, such an arrangement allows for minimizing the data processing load and delay at each protocol handler of the data path through the packet network.

Abstract: A method of parallel computation capable of processing information with an improved processing efficiency is disclosed. The method utilizes the message transfer in terms of message packets in abbreviated format and the recording of the route of the message transfer. An apparatus for performing the method is also disclosed.

Abstract: A time division multiplexer is operable to sample data on parallel input channels at a sampling rate at least twice the data rate, to serially transmit the data for each channel in a respective time division, and to recover the data at a receive end. The multiplexer is provided with a bit storage register for successive samples on at least one input channel to be used as a marker channel. Gating connected to the bit storage register forces a detectable unnatural data pattern on the transmitted data for that channel whenever a predetermined bit pattern is stored for that channel. According to one embodiment, when a plurality of unchanged levels (e.g., binary one) appear in the bit storage register, a central bit is inverted to thereby mark that channel. The inverted marker bit is detected and cancelled at the receive end and/or is used to reset the channel counter if detected on a channel other than the marker channel.

Abstract: A matter sensing apparatus includes a piezoelectric transducer, having a face susceptible to matter accretions at a surface for which matter accretion detection is desired. The electrical circuit of the transducer is coupled in the feedback path of an amplifier to establish an oscillator that oscillates at frequencies determined by the resonant frequency of the transducer and the loading on its face. The oscillator signals are converted to binary signals and utilized with binary signals, provided by a thermostat, that a representative of temperatures above or below a selected temperature to provide signals indicative of whether ice or other matter has accredited on the surface.