Abstract: In a method of detecting signal degradation conditions in synchronous digital signals, the error monitors first detect the presence and/or absence of a particular bit error ratio by integrating received parity errors over time. Subsequently a monitor client reacts to notifications from bit error rate monitors that the state of the presence/absence of specific bit error ratios has changed to generate an alarm condition when appropriate.

Abstract: A latching device is provided for a circuit pack having a cable retainer carried upon the front of the operating lever of the device. The cable retainer is oriented for positional and directional control of cable by directing cable longitudinally of the faceplate of the circuit pack and away from the fronts of other circuit packs within a shelf. Also provided is a combination of a latching device and two groups of covers. The combination enables a single latching device to be used upon circuit packs requiring security and non security conditions within a shelf. It also enables removal of a faceplate held to a faceplate mounting with the circuit pack in the shelf. An orifice in an operating lever of the device is accessible with a cover of the first group mounted upon the operating lever, as orifices in these covers align themselves with the orifice in the operating lever.

Abstract: The method of potentially recovering from a short term signalling failure in a switched connection data transmission network comprises the steps of: (a) establishing a unique, network-wide, identifier for each call; (b) incorporating the unique identifier in a call setup message transmitted to each network element in the path of the call; (c) linking the unique call identifier with each bearer channel cross-connect associated with the call; and (d) upon detection of a failure in a signalling network which affects the call, (i) actuating a timed release of the cross-connects, (ii) re-transmitting the call setup message, including the unique call identifier, to each network element involved in placing the call, (iii) re-linking the unique call identifier with the surviving cross-connects thereby reclaiming the cross-connects, and (iv) aborting the release of the cross-connects provided they have all been timely reclaimed.

Abstract: A rail tracking system and method for providing precise tracking of voltage levels to a dual supply voltage Integrated Circuit. A switch mode DC-DC voltage regulator is used to derive the lower of the two voltage levels from the higher level. The switch mode regulator employs a pulse width modulator (PWM) to derive the lower voltage level. A separate supply source is utilized to power the PWM and the timing of the supply voltage is such that the PWM has reached steady state before the higher voltage level is provided to the regulator.

Abstract: A method and apparatus for packetizing data include processing that begins by determining the bit time occurrence for retrieval of at least one bit of a portion of a data word, which is stored in local memory. Next, the processing determines the status of the data word based on the bit time occurrence for retrieval of the bit. Next, the bit is retrieved from local memory based on the status of the data word. Having retrieved the bit, the status of the data word is updated based on the bit time occurrence of the at least one bit and the data word. Next, the processing applies a data packetizing protocol to the at least one retrieved bit based on the status of the data word to construct a data packet corresponding to the data word.

Abstract: A method of generating a clock from a signed correction value derived from cells carrying timing information in an asynchronous network involves deriving a decrement/increment indicator from the sign of the received correction value. A local clock is incremented and decremented in a predetermined period accordance with said decrement/increment indicator and the true magnitude of the received correction value.

Abstract: A system and method for calculating a quotient based algorithm without using a division operation. The quotient based algorithm is used to provide explicit rate values to ABR cell traffic in an ATM network. A look up table is used to obtain reciprocal values required to process the algorithm.

Abstract: A system and method for controlling queue size in a multiprocessor environment wherein items taken from queues associated with a first processor continue to use system resources in a second processor. A three pointer system is used to distinguish between an enqueue location, a dequeue location and a virtual dequeue location. The virtual dequeue pointer is indexed only after items taken from the queues have completely cleared the system. An application of the three pointer system in a Carrier Scale Internetworking (CSI) architecture is also discussed.

Abstract: A calendar based ATM cell scheduling device is used to maintain accurate shaping of cell streams in order to satisfy traffic management guarantees. In certain applications cell insertion may occur downstream of the scheduling device, potentially violating traffic descriptors. The correction means provided by the present invention allows for such downstream cell insertion without violating guarantees by generating a calendar slip in the scheduling device.

Abstract: A method of determining whether a requested parameter reconfiguration of a connected call in a switched digital communication network complies with system constraints is described. Bandwidth related parameters, in particular, are subject to reconfiguration after a call is provisioned in order to optimize utilization of network resources. The implementation of a bandwidth reconfiguration involves an assessment of bandwidth utilization by the logical or physical links routing the connected call so that the reconfigured bandwidth does not negatively impact on the connected call. Once the reconfigured parameter is determined to be acceptable the reconfiguration data is propagated to the relevant network elements.

Abstract: A system and method for increasing the use of frequency licenses in a cellular, multipoint wireless access system with non-mobile customer sites. The cell coverage of a base station is divided into sectors, for example 4, and orthogonal polarization between adjacent sectors is employed. For bi-directional communication uplink and downlink signals within each sector also employs orthogonal polarization.

Abstract: A train car with mirror image electrical couplings having mirror image halves at each end for connecting train lines in each car to corresponding train lines in adjacent cars, regardless of the end-to-end orientation of the car, has selected pairs of train lines connected to corresponding pairs of switches for each end of the car for switching the halves of each selected pair of train lines between one or the other halves of the mirror image electrical couplings, depending on the orientation of the car.

Abstract: An in-circuit contact monitor for providing reliable and safe detection of the position of fail safe, or vital, circuit contacts in railroad signaling and inter-locking control circuits comprises an impedance network arranged in a bridge configuration, a low-power, high-frequency signal source, an isolation transformer, and a pair of DC blocking capacitors. The low-power, high-frequency AC source provides energy for an isolated circuit which is used in detecting the toggling of an individual circuit contact. The circuit is configured such that the vital circuitry, which is connected to the circuit contact, is completely isolated from the DC components generated by the low-power, high-voltage AC source. The isolation transformer acts to isolate the monitor system from the in-circuit contact monitor circuitry and thus the vital circuitry.