Abstract: A system for determining the physical location of a home terminal unit senses that a cable carries a communication signal from a home terminal unit to an optical network unit. The system includes the home terminal unit, the optical network unit, and a cable that connects the home terminal unit to the optical network unit. Additionally, energy detection circuitry associates with the cable to detect the presence of a communication signal on the cable and generates a detection signal in response to detecting the energy on the cable. Status circuitry for reading the detection signal connects with the energy detection circuitry and communicates the detection signal from the energy detection circuitry to the telecommunications network.

Abstract: A VT group optical extension format (FIGS. 7 and 8) defines a transport frame for the transfer of 135 bytes, each byte comprising 8 bits, the format providing a line rate of 8.640 Mbit/S. Each frame comprises a transport overhead portion and a payload portion. The transport overhead portion is comprised of 27 bytes and defines various operations, administration and maintenance functions, whereas the payload portion is comprised of 108 bytes which directly correspond to one VT group of an STS-N frame (FIG. 1). The VT group optical extension format line rate is determined as an integer multiple (i) of an STS-N network element clock where i is 6 if N is 1 and i is 18 if N is 3.

Abstract: Constant light output is provided by a laser diode over various temperatures or operating points by adjusting the bias current in accordance with a midpoint of a detected peak and a detected valley of an output power level and adjusting the modulation current amplitude in accordance with the difference between the detected peak and the detected valley output power.

Abstract: A telecommunications system having 1:n group facility protection is disclosed. Two cross-connects are provided, each organized in a distributed fashion, and which have a group of member ports bidirectionally coupled to one another in corresponding fashion via a plurality of paths, such as of the DS-3 data frame type. Each of the cross-connects also include a bidirectional protection port, coupled to the protection port of the other cross-connect by way of a protection path, also preferably of the DS-3 type; the protection port for each cross-connect is assigned to the member port group, and is implemented to be managed by the same distributed interface processing unit as the protected member port group. The cross-connects monitor their member input ports for received facility errors, such as signal failures or excessive failure rates, and request a third-stage bridge from its mate cross-connect in the event of such error.

Abstract: During ISDN signal transmission from a network trunk line (21) to an access line (18), a word (202) provided from the network trunk line is broken into two bytes including a data byte (205) and a performance monitoring byte (206). After signal transmission through common equipment (14) and an access line shelf (10), a line card (12) verifies the composite parity of the data byte and the performance monitoring byte to determine if an ISDN signal transmission error has occurred. During ISDN signal transmission from an access line (18) to a network trunk line (21), the line card (12) forms a data byte (305) by combining pairs of data bits from the access line, and simultaneously forms a performance monitoring byte (306) by combining pairs of performance monitoring bits corresponding to the pairs of data bits.

Abstract: A method for electromagnetically shielding the end of a rigid cable (10) containing a large number of conductors to provide increased bending flexibility is disclosed along with a ground strap assembly (24). Ground strap assembly (24) is designed to shield a cable (10) that consists of a plurality of insulated conductors (18) surrounded by one or more conducting shields (14) (16) and outer insulating sheath (12). A portion of the outer insulating sheath (12) is removed to expose a protruding portion of conducting shield (14). The protruding portion of conducting shield (14) is folded back along a remaining portion of outer insulating sheath (12) thereby exposing the ends of the conductors. Ground strap assembly (24) comprises a braided conducting ground strap (26) that has a cable end portion (32) extending to a central portion (34). Central portion (34) extends to grounding portion (36).

Abstract: A bit resolution phase detector can be realized for a parallel elastic store by comparing a write bit clock and a read bit clock to determine when stuff bits are required; upon detection of phase alignment between the write and read clocks, the phase detector will output a signal which will enable the insertion of a data bit into the stuff opportunity bit and cause the write clock to lag the read clock by one bit period.

Abstract: A network element includes a plurality of routing circuits coupled by internal communication circuitry. Each routing circuit includes one or more external ports for communicating with external devices, one or more internal ports for communicating with other of the routing circuits, a database for storing address and path information received via the internal and external ports and circuitry for retransmitting address information received from an external device to other of the routing circuits.

Abstract: An automatic inventory retrieval system collects inventory and status information regarding the presence or absence of plug-in master and slave units in the slots of various shelves in a telecommunications terminal, such as a network element, by having independent masters in each shelf polling associated slaves at a relatively frequent polling rate and collecting information for storage until reception of a relatively infrequent master polling signal provided from a network control unit to all of the shelves. Communication between the control and the various shelves is provided over a balanced serial link interface comprising differential pairs, whereas communications internal to the shelves and the network control may be by means of single-ended signals. Redundancy in the network element is accommodated with a single serial link between the central control and the shelves by use of time-division multiplexing.

Abstract: An assembly transfers heat from the heat generating components of a circuit board to a surrounding housing. A removable heat transferring member is inserted into the interior of the housing. The removable heat transferring member is thermally coupled to the heat generating components, physically coupled to the circuit board, and thermally coupled to the housing. The coupling between the removable heat transferring member and the housing is such that the member, and thus the heat generating components and circuit board, can be easily removed from and reinserted into the housing. A portion of the housing is configured as a heat sink to dissipate heat.

Abstract: A method and system that provides several pre-defined user templates that may be combined in various ways to represent all known network configurations of a digital cross-connect network. The system interrogates the user concerning the network configuration. The results of the interrogations determine the type of network monitor and control system configuration templates that the user will see. The system creates a database as a result of the combination of the templates and places on line the user templates and associated software to represent of the entire digital cross-connect network. This monitoring system can be used to not only vividly display the node from which a component error comes, but can illustrate the specific sub-component that provides the error and a representation of the various error lights that appear on the sub-component.

Abstract: An ECL to CMOS signal converter circuit including built-in toggle-fault detection circuitry and method of conversion are provided in which an RF transformer is used to translate ECL level digital signals to CMOS level signals. A diode biasing circuit shifts the average DC level of the CMOS level signals in a positive direction to avoid signal undershoot. An AC peak detection circuit is connected to the inactive leg of the RF transformer to monitor toggling of the ECL level input signal lines. A DC comparator circuit compares the detected peak voltage with a predetermined threshold voltage, and generates an alarm signal representing a toggle-fault whenever the detected peak voltage is lower than the predetermined threshold.

Abstract: An assembly for routing fiber optic cables transversely across an electronics housing interior. The electronics housing interior supports circuit boards, some of which are optically coupled to the fiber optic cables requiring routing. The assembly includes a support member for coupling with the housing interior, and this support member is pivotally coupled to a fiber optic cable retaining member. The fiber optic cable retaining member routes the fiber optic cables across the housing interior, and it can be pivoted away from the electronics housing, enabling one to remove a circuit board for service, testing, or replacement without handling of or with minimal handling of individual fiber optic cables. A cover is pivotally coupled to the fiber optic cable retaining member, and it can be opened to facilitate the routing of the fiber optic cables or closed to protect the routed fiber optic cables.

Abstract: A circuit for communicating electrical signals and assembled at least in part by an automated assembly machine is disclosed. The automated assembly machine is operable to select from a plurality of components. The circuit includes a material having a first and second surface and a length. A strip conductor is positioned along the first surface of the material. A ground structure is disposed along the length of the second surface. Finally, a low impedance device selected from the plurality of components is electrically coupled to the ground structure on opposite sides of the strip conductor, wherein the coupling of the low impedance device to the ground structure forms a circumferential shield around the strip conductor. Various alternative embodiments, as well as fabrication methodology are also disclosed.

Abstract: A consistent, repeatable ground connection between a high frequency circuit board and a mating ground structure within a high frequency system is disclosed. The high frequency circuit board includes a dielectric layer located between a conductive backing and a microstrip transmission line. The conductive backing has a groove formed along one of its edges near the transmission line. An elastic, electrically conductive member is positioned within the groove so that it maintains electrical contact with the conductive backing and the mating ground structure. The invention reduces manufacturing costs by permitting less stringent manufacturing and machining tolerances, by eliminating the need for impedance matching between mating components, and by eliminating the need to utilize copper shims with adhesive backings between mating components. In addition, the invention maintains a consistent ground connection when the high frequency system is exposed to a range of operating temperatures.

Abstract: In a fiber-optic communications system, a shut-down apparatus in the event of a fiber-optic cable disruption includes a first optical fiber cable for propagating signals in a first direction and having a plurality of adjacent amplifiers disposed along the first cable. A second optical fiber cable for propagating signals in a second direction, opposite the first direction, includes a plurality of adjacent amplifiers disposed along the second cable. Each of the amplifiers in the second optical fiber cable are interconnected to one of the amplifiers of the first optical fiber cable to form a plurality of amplifier pairs. Circuitry is provided for terminating operation or reducing the output power level of an amplifier within the first or second optical fiber cables in the event of a cable disruption between adjacent amplifier pairs, such that an amplifier within an amplifier pair adjacent to the cable disruption terminates generation or reduces its power level to a safe level at its output.

Abstract: To maximize the usefulness of micro controllers, a single micro controller is programmed to selectively perform multiple functions based on code segments stored within the micro controller, so that a single programmed micro controller may be used to perform one of a number of different tasks depending upon where the micro controller is used. A pin of the micro controller is adapted to receive a logical signal to which the code responds and selects the function to be performed by the micro controller. The programming of a micro controller to perform multiple functions takes advantage of the full capacity of the micro controller and reduces the numbers of micro controllers that must be inventoried to satisfy the required functions.

Abstract: A serial rate conversion circuit converts the serial rate of a stream of signals, for example, from a SONET overhead data link (ODL) rate of 6.48 Mb/s to and from a data communications channel (DCC) rate of 4.096 Mb/s. The circuit includes a low data flow memory and address select circuit for communicating the stream of serial formatted signals at a low data flowrate and a high data flow memory and address select circuit for communicating the stream of serial formatted signals at a high data flowrate. Clock rate conversion circuitry associates between the low data flow memory and address circuit and the high data flow memory and address select circuit to convert the high data flow serial formatted signals back and forth between the low data flowrate and the high data flowrate while maintaining said stream in a serial format.

Abstract: A refresh control system and method for refreshing DRAM memory in a data processing system, such as a communications system, are disclosed. A timer increments a refresh request counter each time that a desired refresh interval elapses. The contents of the refresh request counter is compared with the contents of a burst refresh counter, and a bus request signal generated responsive to the contents differing from one another, such difference indicating that a refresh operation should be performed. The bus arbitration scheme assigns no higher priority to the refresh priority request than for other bus operations; at such time as bus access is granted to the refresh operation, burst refresh is performed until the contents of the burst refresh counter again match the refresh request counter, at which time the bus is released.

Abstract: A method and system for finding a path through a communications matrix represents the assignment of a center stage switch through an input switch to input gates by an input stage array, center stage switch connections between an input stage switch and an output stage switch by a center stage array, and output stage switch connections to output gates by an output stage array, as well as representing idle input switch links to the center stage switches by an idle input array and idle output switch links from the center stage switches by an idle output array.