Abstract: Traffic measurements and network management controls are applied in an exchange in real-time on a per-route basis. Selection of an idle circuit between two exchanges is done by first selecting a route and path based on a route busy/idle status map, a source destination restriction map defining restriction on a route for certain sources, and a second connection map defining availability of a second link in a two link connection. A circuit group busy/idle map for a selected route is consulted to find an idle circuit group and finally, a circuit is selected from a circuit group which is known to have at least one idle circuit. Traffic measurements, including measurements of attempts, seizures and answers are recorded on a per-route basis with a specific indication as to the source of the traffic in the event of a direct route.

Abstract: Foreign exchange subscriber service is provided via a local ISDN exchange which selectively establishes switched connections between a customer's ISDN terminal and a trunk circuit dedicated to the foreign exchange line. The same ISDN subscriber line may be used for local service and foreign exchange service to several different foreign exchanges. The customer's ISDN terminal has a separate call appearance for each foreign exchange line and call appearance information is used in ISDN messages transmitted between the local exchange and the customer's terminal to uniquely identify local and foreign exchange service connections.

Abstract: A structure connecting superconductor transmission lines to integrated circuits comprises a plurality of interconnection substrates having superconducting transmission path deposited thereon in contact with metallic contact areas, and integrated circuit chip carrier substrates for mounting integrated circuits and having metallic contact areas. The substrates are mounted in a retainer structure and are separated by spacers which have apertures in registration with the contact areas. Contact devices are selectively inserted in the apertures to establish an interconnection pattern between the substrates. The retainer structure applies force to the substrates to assure physical contact between the substrates and the contact device. The structure may be assembled and disassembled for replacement of parts or reconfiguration of interconnections, without the application of heat or other processes which are incompatible with relatively brittle and heat sensitive superconducting materials.

Abstract: In a telecommunication system having a plurality of cooperating exchanges and using a separate signaling network, an existing exchange is replaced by a new exchange by a piecemeal transferring of interexchange trunks from the existing exchange to the new exchange and testing the trunks on the new exchange. All signaling messages pertaining to trunks originally resident on the existing exchange are addressed to the existing exchange, are intercepted and are selectively forwarded to the new exchange on the basis of recorded data defining trunks moved to the new exchange. One embodiment uses a point code converter connected between a signal transfer access point for the signaling network and both the old and the new exchange. The converter receives all messages addressed to the existing exchange and transfers the messages to either the old or the new exchange, depending on the present location of the trunk.

Abstract: Broadband terminals, such as video terminals and a video conferencing system, are directly connected to broadband digital access crossconnect systems and connections between the terminals are established via the crossconnects and DS1 or DS3 interconnecting links under control of telephone exchanges associated with the different crossconnects. A broadband terminal is connected to an associated exchange, as well as, a crossconnect and a connection from one terminal to another may be requested by transmitting a special code to the exchange together with a directory number assigned to the desired broadband terminal. The central office, on the basis of the directory number, area code and exchange code, selects a broadband interconnecting link from the crossconnect to which the originating terminal is connected to the crossconnect to which the terminating terminal is connected.

Abstract: An electronic system having components operating at low temperature at various locations within the system, cryogenic fluid and electrical power are distributed by means of the same conduit. In one embodiment, the conduit consists of a supply section and a return section with each section comprising a channel for conveying cryogenic fluid having superconducing walls for conveying electrical power. In another embodiment of the invention, the conduit comprises a copper rod having channels formed therein for the transport of cryogenic fluid and a channel for supporting a rod of superconducing material therein. The superconducing rod conducts electrical current to a subsystem while being cooled by cryogenic fluid in nearby channels and the cryogenic fluid is used at its destination for cooling purposes.

Abstract: In an ISDN network, terminals connected to an S-bus (4) are fed via this S-bus (4) by a d.c. supply arrangement (6, 7, 20). The d.c. supply arrangement comprises a main supply unit (7) and an emergency supply unit (6) which are coupled with opposite polarity to the S-bus (4) via a coupling circuit (20). Consequently, the emergency supply unit (6) needs to supply only those terminals which are also made suitable for voltages with opposite polarity, and which generally present only elementary telecommunications functions. An electrically arranged coupling circuit (20) includes a monitoring circuit which monitors the value of the main supply unit output voltage and inhibits the output from the main supply unit and connects the emergency supply unit when the output voltage drops below a predetermined threshold.

Abstract: Method and apparatus are disclosed for establishing a wideband communication facility from a plurality of narrow bandwidth channels through a switched communications network from a first to a second terminal in response to a call from the first terminal indicating a customer-selected bandwidth for the wideband facility. Apparatus is also disclosed for establishing a wideband communication path through an illustrative switching system interconnecting groups of narrowband time division multiplexed channels established for the wideband facility. The path has a bandwidth greater than any of the TDM channels. Additional buffer memories and memory control arrangements are added to the initial and final stages of a time-space-time switching network to prevent any of the time slot data of a given time frame from being delayed and included in another time frame.

Abstract: A cache memory system reduces cache interference during direct memory access block write operations to main memory. A control memory within cache contains in a single location validity bits for each word in a memory block. In response to the first word transferred at the beginning of a direct memory access block write operation to main memory, all validity bits for the block are reset in a single cache cycle. Cache is thereafter free to be read by the central processor during the time that the remaining words of the block are written without the need for additional cache invalidation memory cycles.

Abstract: Disclosed is a method and apparatus for avoiding accessing of defective locations in disks and other storage media. A disk file controller uses manufacturer-provided information about the location of defects to construct a sequentially ordered list of addresses of defective storage locations in the disk, and the list is stored in a table in the disk. During use of the disk, the disk file controller reads the table of defects into its memory and uses it to translate virtual addresses into real addresses. The translation process skips over real addresses of defective locations. The virtual address is translated into a real address by being incremented by the number of defects whose addresses are lower than the real address. Subsequent contiguous virtual addresses are translated into real addresses by being incremented by the number of contiguous defective locations that follow the location associated with the preceding virtual address.

Abstract: A detector circuit detects one of two impedances presented by a communication line for each one of a plurality of operative modes. The circuit comprises a network having three parallel branches. The first includes two serially connected resistors which develop a reference potential in response to current flowing in the line. The second branch includes two oppositely poled light-emitting diodes (LEDs) which form a sensor to detect current flow in the line in either direction. The third branch includes a varistor to limit the magnitude of unexpected potentials applied to the sensor. When the magnitude of the reference potential is sufficient to forward bias either LED and the magnitude of the current is greater than a predetermined level, one of the LEDs will generate an output signal representative of one impedance of the line. Otherwise, the LEDs generate a second output representative of the other impedance of the line in a particular operative mode.

Abstract: In a communication system which includes a plurality of stations interconnected for communications by a first bus, a second station includes a device, such as a processor, and a resource, such as a memory or a peripheral unit, interconnected for communication by a second bus. An interface mechanism connecting the first bus with the second bus allows the device to access the first bus over the second bus, and allows a first station to access the resource via the first and second buses. Deadlock detection circuitry detects cotemporaneous attempts by the device to access the first bus and attempts by the first station to access the resource. Deadlock resolution circuitry responds to deadlock detection by disconnecting the device from the second bus to allow the first station to access the resource, and by reconnecting the device to the second bus when the first station ceases to access the resource.

Abstract: A socket connector (10) for printed wiring boards (37) in which signal or voltage connections may be made between the connector pins (14, 15) rather than by wiring printed on the board. A typical connector (10) is formed to present two lengthwise slots (19, 20) in either side wall (21, 22) of the connector housing (11) to provide access to the connector pins (14, 15). Electrically conductive strips (23, 30, 33, 40, 43) having bifurcated tabs (26, 27, 31, 32, etc.) extending therefrom are fitted into the housing slots (19, 20), the tabs clasping the selected pins (14, 15) to make the electrical connections required. The four slots and the underside of the connector housing make possible a number of pin interconnection combinations. Surface areas of the board are thus freed for other circuit purposes.

Abstract: An arrangement for detecting defective communications circuits in a telecommunications system. Communications circuits are arranged in groups according to destination. Unacknowledged communications are counted for each group. A group whose incidence of such unacknowledged communications is especially high is likely to contain one or more defective communication circuits. More detailed measurements, including a count of attempts to use each member of such a group, are then taken to identify individual defective communication circuits. A communication circuit having an especially high count of attempts to use is likely to be defective.

Abstract: A worm (10) and worm gear (12) mechanism in which the gear (12), in addition to its gear teeth (20), also has a helical thread (22) formed thereon. The helical thread (11) of the worm (10) conventionally meshes with the gear teeth (20) of the worm gear (12), rotation of the worm (10) causing a corresponding rotation of the gear (12). The gear (12) is fitted in a threaded hole (21) so that, as it is rotated by the worm (10), it is also caused to move along its longitudinal axis within the hole (21).

Abstract: In a cellular mobile telecommunication system, a method and apparatus for controlling the process of locating a mobile unit from the cell sites. When a mobile unit goes beyond the radio range of its associated controlling cell site, that cell site sends a message to nearby cell sites to measure and report the strength of the received signal from that mobile on each of their directional antennas and to report radio channel availability. These reports are returned to the controlling cell site which compares the received signal strength mesurements against stored thresholds. The controlling cell site generates and transmits to the mobile telecommunications switching office (MTSO) a hand-off request message including a list of candidate hand-off cell sites and directional antennas. The MTSO then selects an available channel associated with one of the candidate cell sites and antennas and generates a sequence of messages to hand-off communications control from the controlling cell site to a candidate cell site.

Abstract: A multipoint access data communication system which includes a communication bus, a plurality of transceivers connected to the bus for communication, and a remote collision detector associated with each transceiver for detecting collisions between communications on the medium, has improvements which adapt the transceivers for connection to a plurality of network interface units, and local access arbitrators associated with the transceivers for preventing collisions between transmissions simultaneously attempted by two or more network interface units connected to a transceiver.

Abstract: An arrangement for indicating when different types of electrical components, such as circuit boards and the like, are concurrently joined with connector assemblies. Common to the connector assemblies is a plurality of output conductors which is connected to corresponding plurality of output terminals positioned on each of the connector assemblies, respectively. On each component is a plurality of identification conductors arranged to identify the component through the application of a distinct pattern of potentials on the output conductors when one of the components is joined with one of the connector assemblies. When different types of components are concurrently joined with associated connectors, the identification conductors interconnect all the output conductors, such that only a predetermined pattern of potentials other than the distinct patterns may be applied to the output conductors.

Abstract: An improved multipoint access data communication system with collision detection provides a duplicative communication medium, network interface units adapted for connection to transceivers on both media, transceivers adapted for connection to a plurality of network interface units, and a local collision detection circuit associated with each transceiver for detecting collisions between transmissions simultaneously attempted by two or more network interface units connected to the transceiver.

Abstract: A data processing system having a processor, main memory, and a cache memory system which implements the least recently used replacement algorithm in replacing cache memory words with main memory words. The cache memory system is comprised of a cache control circuit and a plurality of cache memories. Each cache memory stores cache memory words having a similar time usage history. The first cache memmory stores cache memory words which are more recently used than the cache memory words in the second cache memory, and the second cache memory stores cache memory words which are more recently used than the cache memory words in the third cache memory. When a main memory word must be transferred to the cache memory, the main memory word is stored in the first memory; and the first cache memory's least recently used cache memory word is stored in the second cache memory. The least recently used cache memory word from the second cache memory is stored in the third cache memory.