Abstract: Quiescent current control for Class AB output stages is provided that is responsive to a sum of current of the pull-up and pull-down transistors in the crossover region, and responsive to a minimum of the pull-up or pull-down transistors otherwise. Replicating transistors operate responsive to activation of the pull-up and pull-down transistors. Additional circuit elements provide a summed current output that corrects for quiescent current variation, while having good operation over PVT variations, and having minimal distortive effects. Use of scaled replicating transistors reduces the current in the quiescent current control circuit. Additionally, a current limiter or topology change may be used to reduce current spikes in replication of the output stage current. Adjustment of a reference current can also prevent turning off a non-active output element to reduce the need to stew the element back on.

Abstract: In accordance with a non-limiting example, a system and method minimizes collisions between transmitted connectivity fault management (CFM) packets. Maintenance association endpoints are formed from a plurality of network switch elements to form a maintenance association. The clocks between each network switch element within the maintenance association are synchronized. A unique transmission window is assigned to each maintenance association endpoint as part of the maintenance association. A respective CFM packet is transmitted as a continuity check message (CCM) within the unique transmission window.

Abstract: An enclosure for electronics includes a chassis and an interface connector positioned within the chassis and configured to provide power. A fan shelf module is received within the chassis and has at least one fan to provide air flow through the chassis. The fan shelf module includes a pinout connector along a horizontal or vertical line of symmetry and configured to engage the interface connector and receive power therefrom, such that the fan shelf module is selectively installed in one of two opposing directions allowing a fan air flow direction to the chassis to be selected as either pulling air or pushing air through the chassis depending on the installed direction of the fan shelf module.

Abstract: A system and method detects within an IP network an offending network device that has been adversely affecting the IP network performance. A discovery protocol frame is propagated to successive network switches and is formed as a field having a query for inquiring within each network switch to which the frame is propagated whether the network switch has a database entry regarding the MAC address and switch port for the offending network device to locate the offending network device. This discovery protocol frame includes a command for any network switch that has the offending network device connected thereto to disable the switch port to which the offending network device is connected or block all data traffic from the MAC address of the offending network device.

Abstract: Improved digital driver with transition time control of an output stage output transistor of the digital driver. A predriver circuit has a resistor that forms an RC time constant with a feedback capacitor of the output transistor. The RC time constant is adjusted to control corner resolution of the output transistor in output switching. The RC time constant can be controlled by a digitally-controlled variable capacitor. Additionally, a delay may be introduced in the turning on of the output transistor as compared with the turn off time to reduce simultaneous conduction or shoot-through current.

Abstract: The present disclosure generally pertains to systems and methods for swapping span power modules that are used for supplying power to network interface units (NIUs). A span power module in accordance with one exemplary embodiment of the present disclosure has logic capable of communicating with logic of another span power module. When one module is to be swapped for the other module, the module being swapped-in is configured to automatically disable the other module shortly after it has powered up and is supplying electrical power across a span line. The amount of time that both modules supply power to the span line is sufficiently small such that damage to electrical communication equipment receiving power from the span line is prevented.

Abstract: A communication system comprises a network server connected to a telephone at a customer premises via a subscriber line. The server is further connected to a cellular communication device through a cellular network. Upon installation of telephony equipment at the customer premises, a service technician uses a cellular communication device to communicate with the server of the network such that the server initiates a voice call to the telephone via the subscriber line. The technician then takes the telephone off hook, aligns a speaker of the cellular communication device with a microphone of the telephone, and aligns a microphone of the cellular device with a speaker of the telephone such that the telephone and the cellular device are acoustically coupled. A plurality of acoustic tones are communicated between the telephone and the cellular communication device in order to test the quality of the inbound and/or outbound connections for the telephone.

Abstract: The present disclosure generally pertains to surge protection systems that protect outside plant equipment from high-energy surges. In one exemplary embodiment, a protection system is used for protecting Ethernet equipment that is coupled to an outside Ethernet cable. The protection system provides protection and remains capable of coupling signal energy between an Ethernet cable and Ethernet equipment without significantly degrading Ethernet performance. However, the protection system, while allowing the desirable Ethernet signals to pass between the cable and the equipment, prevents the electrical voltages and currents of high-energy surges, such as surges from lightning or AC power faults, from damaging the Ethernet equipment.

Abstract: In accordance with a non-limiting example, the system and method places a call from a first call device used by a party A to a second call device such as used by a party B by routing the call from the first call device into a communications server that establishes an internet protocol (IP) call between the communications server and the second call device. A third call device such as used by a party C monitors the second call device. A first SIP invite command is sent from the third call device to the communications server as a pick-up call instruction for the call to the second call device when it has not answered the call from the first call device. A second SIP invite command is sent between the third call device and communications server and the call is transferred from the second call device to the third call device to establish a communications session between first and third call entities.

Abstract: A frequency monitoring system comprises a plurality of circuit cards. Each circuit card, such as a primary multiplexer card and a backup or redundant multiplexer card, has an oscillator that provides a reference clock signal. On each circuit card, a respective frequency compare element is configured to receive a clock signal to be measured and to provide a frequency error signal indicating a frequency error of the clock signal relative to an average frequency of a plurality of reference clock signals. Accordingly, the frequency measurements for the circuit cards are based on the same reference frequency (e.g., the average frequency of the reference clock signals from the oscillators).

Abstract: A communication system for propagating time division multiplexing (TDM) fault notifications has a first interworking function (IWF) of a packet network and a second IWF of the packet network. The second IWF detects a TDM fault of a TDM network and transmits continuity check messages (CCMs) to the first IWF. Further, the second IWF controls the CCMs in response to a detection of the TDM fault such that a TDM fault notification is propagated from the second IWF to the first IWF based on the CCMs, and the first IWF propagates the TDM fault notification to a second TDM node via a TDM signal.

Abstract: A power amplifier provides relatively stable quiescent current while maintaining relatively high signal gains and peak to quiescent current ratios. The power amplifier has an input stage and a current mirror stage and incorporates a control transistor between these stages. The control transistor transitions to the triode mode for small inputs and offset voltages thereby reducing the amplifier circuit's gain. However, the control transistor transitions from the triode region to saturation as the input signal becomes larger thereby allowing the amplifier circuit to maintain a relatively high gain for large inputs. Accordingly, better quiescent current characteristics can be obtained without significantly sacrificing performance.

Abstract: A system for monitoring batteries comprises a current control element coupled in parallel to a diode and across a battery. The current control element measures current on the cathode end of the diode. Once the voltage potential reaches a threshold, the current control element routes the current from the cathode end of the diode to the anode end of the diode thereby reducing the voltage potential across the battery terminal. Accordingly, a battery sensing element is prevented from falsely sensing a presence of an operable battery due to leakage current of the diode.

Abstract: An interworking function (IWF) at an edge of a packet network comprises a primary receiver and a backup receiver. The primary receiver receives data packets and timing information from a packet network. The primary receiver interworks data from the data packets into a data signal that is based on a local clock signal. The primary receiver uses the timing information from the packet network to adjust the frequency of the local clock signal such that it is synchronous to a network clock signal, such as a clock signal at an IWF, referred to as the “transmitting IWF,” that transmitted the data packets. In addition, the primary receiver from time-to-time provides timing information, such as a frequency control word, to the backup receiver, which uses such timing information to synchronize a clock signal of the backup receiver to the network clock signal upon an occurrence of a switchover from the primary receiver to the backup receiver.

Abstract: A method and apparatus for network access control includes an apparatus for granting a computing device access to a network, the apparatus having a plurality of substantially similar access devices, wherein each access device comprises a status-determination module to determine an access status based at least in part on whether the computing device is compliant with an access policy, an access-grant module configured for receiving an access status corresponding to the computing device from one or more of the access devices, and granting the computing device access to the network according to at least one of the access status determined by the status-determination module or the received access status.

Abstract: A system and method transmits data and receives data packets within a bonding engine. The data packets are fragmented into a plurality of packet fragments for communication across a bonded group of subscriber lines. A Frame Check Sequence (FCS) in the data packet is inverted on one direction of the bonding group to prevent any data packets from propagating towards the network during a loopback condition.

Abstract: A power supply and associated method include a power supply converter having a power output and configured to provide a supply voltage through the power output to a communications device. A simplified boost circuit is connected to the power supply converter in parallel but isolated from the power supply converter's bulk input capacitance during normal operation. The boost circuit includes at least one power storage circuit and a charging circuit connected thereto and configured to charge and maintain the power storage circuit to a predetermined voltage and switch the power storage circuit into the power supply converter during an undervoltage condition to transfer the stored power from the power storage circuit to the power supply converter and maintain the supply voltage to the communications device connected thereto for a required hold-up time.

Abstract: Signals entering outside plant (OSP) telecommunications enclosures typically do so through weather tight connectors, with one connector mounted to the enclosure and a mating connector connected to a cable bringing the signals to the OSP housing. Such connectors are expensive and require extensive effort to connect the wires of a cable bundle to the connectors. These problems are avoided by allowing cables pre-installed with a cable seal and pre-terminated to cable connectors to pass through an opening in the wall of an OSP housing and seal the cable bundle to the housing to prevent the ingress of environmental elements into the housing through the opening. This permits easier installation and retrofitting of electronic equipment contained within the housing.

Abstract: An anomaly detection system comprises an echo canceler and anomaly detection logic. The echo canceler has a plurality of taps respectively associated with a plurality of tap coefficients. The anomaly detection logic is configured to determine a difference between a new tap coefficient associated with one of the taps and a previous tap coefficient associated with the one tap. The anomaly detection logic is configured to perform a comparison between the difference and a threshold and to detect an anomaly along a telecommunication line based on the comparison.

Abstract: The present disclosure generally pertains to surge protection systems that protect outside plant equipment from high-energy surges. In one exemplary embodiment, a protection system is used for protecting Ethernet equipment that is coupled to an outside Ethernet cable. The protection system provides protection and remains capable of coupling signal energy between an Ethernet cable and Ethernet equipment without significantly degrading Ethernet performance. However, the protection system, while allowing the desirable Ethernet signals to pass between the cable and the equipment, prevents the electrical voltages and currents of high-energy surges, such as surges from lightning or AC power faults, from damaging the Ethernet equipment.