Abstract: An apparatus comprising a first line driver, a second line driver, a charge pump, and a control logic circuit coupled to the first line driver and the second line driver and configured to disable the charge pump when both a first control signal associated with the first line driver and a second control signal associated with the second line driver indicate a charge pump disable state. A network component comprising at least one processor configured to implement a method comprising receiving a first control signal and a second control signal, disabling a charge pump when both the first control signal and the second control signal indicate a charge pump disable state, and operating the charge pump to boost a voltage when the first control signal, the second control signal, or both indicate a charge pump active state.

Abstract: An apparatus comprising a first line driver, a second line driver, a charge pump, and a control logic circuit coupled to the first line driver and the second line driver and configured to disable the charge pump when both a first control signal associated with the first line driver and a second control signal associated with the second line driver indicate a charge pump disable state. A network component comprising at least one processor configured to implement a method comprising receiving a first control signal and a second control signal, disabling a charge pump when both the first control signal and the second control signal indicate a charge pump disable state, and operating the charge pump to boost a voltage when the first control signal, the second control signal, or both indicate a charge pump active state.

Abstract: In order to provide unbalanced ringing when an exchange line card provides a balanced ringing output the interface provides a ringing detector in circuit with a customer pair. On detecting balanced ringing signals from the line card, the interface takes over the customer line pair and provides unbalanced ringing signals to the customer and monitors for customer answer. By inserting the interface in circuit at the main distribution frame of an exchange, legacy customer premises equipment which is unable to respond to balanced signalling can be provided with an appropriate ringing signal without the necessity to provide differing line cards at the exchange.

Abstract: A voltage generators is provided including a boosting circuit and a boosting control circuit. The boosting circuit is configured to boost a power voltage to generate first through fourth voltages. The boosting control circuit is configured to control the boosting circuit to enable the first through fourth voltages to be generated in sequence, such that when a current voltage of the first through fourth voltages is boosted to a predetermined level, a voltage next to the current voltage is generated. Related liquid crystal displays and methods are also provided.

Abstract: The disclosed embodiments include a method of initiating a call. The method includes receiving, at a network device over a first network, an identifier associated with a called party. The method determines a first security level associated with the first network and identifies a plurality of networks associated with the called party using the identifier. The method queries a database to determine a second security level for each network in the plurality of networks and automatically selects an identified network from the plurality of networks associated with the called party having the second security level at least equal to the first security level. The method completes a call to the called party using the identified network.

Abstract: A communication apparatus including: a semiconductor DAA which performs line closing and opening processings; and a controller including; an adjustment controlling section which controls the semiconductor DAA such that a line voltage and a line current upon closing a line fall within a predetermined range; an adjustment-control starting section which starts the control; an adjustment-control stopping section which stops the control; and a change detecting section which detects a change of conditions of supply of the line voltage, wherein the adjustment-control starting section starts the control where the line closing processing has been performed and where the change has been detected, and wherein the adjustment-control stopping section stops the control when a predetermined length of time has passed, in at least one of where the line closing processing has been performed and the control is being performed, and where the change has been detected and the control is being performed.

Abstract: A XDSL line card including an allocator for allocating power to the multi-tone modulated communications on each of the subscriber lines, and for selecting control parameters sufficient to effect communications on each of the subscriber lines at a power level proximate to an allocated power level therefore. The line card also includes configurable components coupled to one another to form a transmit path and a receive path to couple to the digital subscriber lines. The configurable components are responsive to the control parameters selected by the allocator to initialize multi-tone communications over each of the plurality of subscriber lines at a power level proximate the allocated power level.

Abstract: A telephone line monitoring device is connected to a telephone line and adjacent to a telephone device using the telephone line. The telephone line monitoring device includes a rectifying circuit for generating a corresponding direct current voltage according to an effective voltage of the telephone line; a first controller for generating a first control signal when the direct current voltage is lower than a predetermined voltage; a second controller for detecting an operating state of the telephone device and generating a second control signal when the telephone device is operated; a load booster for pulling down the effective voltage of the telephone line when enabled; and a first switch circuit for disabling the load booster whenever receiving the second control signal, and enabling the load booster when receiving the first control signal while not receiving the second control signal. A monitoring method and a telephone device are also provided.

Abstract: A method and apparatus for auto-configuring layer 3 intermediate devices in computer networks by extending the Dynamic Host Configuration Protocol (DHCP). The devices generate, transmit and receive DHCP messages having novel options embedded therein. The options permit a layer 3 device to request and receive from a DHCP server a unique, overall IP address that may be assigned to the device. The device may also request and receive one or more IP subnets and corresponding IP addresses for each of its interfaces. The device may further receive the routing protocols to be used on the various subnets. The layer 3 device can thus be auto-configured with IP configuration parameters, including IP subnets, IP addresses and routing protocols without the time-consuming, manual involvement of a network administrator.

Abstract: A telephone line monitoring device is connected to a telephone line and adjacent to a telephone device using the telephone line. The telephone line monitoring device includes a rectifying circuit for generating a corresponding direct current voltage according to an effective voltage of the telephone line; a first controller for generating a first control signal when the direct current voltage is lower than a predetermined voltage; a second controller for detecting an operating state of the telephone device and generating a second control signal when the telephone device is operated; a load booster for pulling down the effective voltage of the telephone line when enabled; and a first switch circuit for disabling the load booster whenever receiving the second control signal, and enabling the load booster when receiving the first control signal while not receiving the second control signal. A monitoring method and a telephone device are also provided.

Abstract: The present invention relates to a transceiver for bidirectional frequency division multiplexed transmission, a communication system including one or more transceivers. Optionally, the communication system is a communication system for a digital subscriber line. The transceiver comprises transmission means with a voltage source output or a current source output for transmitting data in a transmission frequency range, receiving means for receiving data in a receiving frequency range, and a coupling impedance for connecting the transmission means and the receiving means to a transmission medium. The magnitude of the coupling impedance in the transmission frequency range is smaller than the magnitude of the coupling impedance in the receiving frequency range if the transmission means has a voltage source output and is higher than the magnitude of the coupling impedance in the receiving frequency range if the transmission means has a current source output.

Abstract: An extender circuit for handling a communication signal transmitted over a transmission line includes a voltage clamp and a current booster circuit. The voltage clamp is connected to a receive end of the transmission line and is operable to clamp a reflection signal caused by the communication signal received at the receive end of the transmission line. The current booster circuit is connected to the receive end of the transmission line and is operable to provide a boost current at the receive end of the transmission line during a positive transition of the communication signal.

Abstract: The invention relates to the representation, independent of access type, of ISDN accesses (PRA, BRA) in the central core (cVst) of a packet-oriented exchange (P-Vst). By adapting the signaling information transmitted by ISDN accesses in a peripheral unit (PE) it is possible to handle different ISDN access types as a uniform access type in the central core (cVst) of the packet-oriented exchange (P-Vst). The adaptation can be performed for example with the aid of a conversion table for the user data references and call references contained in signaling messages. The invention has the advantage of providing a simple, low-cost, low-overhead representation of ISDN data in the central core of the packet-oriented exchange (P-Vst). Changes such as e.g. a concentration of the user data channels can be carried out easily and flexibly by the network management (NetMg).

Abstract: A linear amplifier architecture includes first, second, and third stages. The first stage is a transconductance stage. The third stage is a current amplification stage. The second stage is an interfacing stage between the first and third stages. The interfacing stage provides a voltage bias and a current to the third stage. The linear amplifier is a class AB amplifier. Quiescent currents for the output devices of the third stage are controlled by the second stage. The stages may be fabricated on the same semiconductor substrate. In one embodiment, the amplifier is fabricated as a complementary metal oxide semiconductor (CMOS) integrated circuit using metal oxide semiconductor field effect transistors (MOSFET). In one application, the amplifier serves as a component of a driver circuit for a subscriber line. Electrostatic discharge (ESD) protection circuitry provided for the amplifier may also be suitable for other applications.

Abstract: A power offload network has a first node for receiving a first supply V1 and a second node for receiving a second supply V2. The power offload network includes a plurality of switches and a power offload element providing a supply drop of VR. The switches are configurable for selecting a linefeed supply level from the set including {V1, V2, V1?VR, V2?VR}. A subscriber line interface circuit receives the selected linefeed supply level for driving a subscriber line.

Abstract: A monolithic transceiver integrated circuit that includes a substrate, a transmitter subsystem of one or more subcircuits on the substrate, and a receiver subsystem of one or more subcircuits on the substrate. Also included is a bias current supply coupled to the receiver and transmitter subsystems to provide bias current. The bias current supply includes a first bias circuit on the substrate coupled to, and to supply bias current to, a first subcircuit of the transmitter subsystem. The first bias circuit includes a first current modulator having a first switch input to indicate that the bias current is to start or stop being supplied to the first subcircuit. The first current modulator is to control the rate of change of supplied bias current in response to the first switch input. The first subcircuit may be a power amplifier. The control of the rate of change reduces oscillator pull in at least one oscillator included in the integrated circuit.

Abstract: A ring boost circuit has a first switching device coupled to a ring node. The first switching device is responsive to a ring operation. A charge pump is connected to the ring node, and the charge pump provides a voltage offset to enhance a differential voltage between the ring node and a tip node when the first switching device is activated during the ring operation.

Abstract: Disclosed is a method and apparatus which facilitates the use of existing power that is ordinarily unused or discarded to provide power to a telephone interface circuit when the circuit is in the on-hook state, thereby alleviating the need to use loop current to power the interface during the on-hook state. Existing clock signals are used to charge capacitors that are normally used for capacitive coupling of digital data across the high voltage isolation barrier. Although only small-value capacitors are needed for transmitting data across the capacitive interface, larger-value capacitors are used and are configured to form a charge pump to generate power to the interface at all times. Thus the interface always has a steady source of power available for use, including during the on-hook state for powering circuitry that can detect, modulate, and transmit on-hook signals across the capacitive interface.

Abstract: An apparatus and method for enabling Cisco legacy power to support IEEE 802.3 AF standard power. A network power system capable of delivering data terminal equipment power via a media dependent interface includes power source equipment according to Cisco legacy power and at least one powered device according to IEEE standard power. A power compatibility module is inserted between the power source equipment and the powered device to enable the power source equipment to appear according to IEEE standard power and the powered device to appear according to Cisco legacy power. The module includes switches, a DC/DC converter, an IEEE power source equipment circuit, and an isolator. The module optionally includes a user signaling device for communicating operating conditions of the module to a user. The module may be connected to two ports of the power source equipment to supply adequate power levels to the powered device.

Abstract: A subscriber's telephone system is presented that includes at least one driver circuit connected to Tip and Ring terminals. An additional network is connected between an output of the driver circuit and the Ring terminal. This additional network includes a suitably dimensioned capacitor and a diode limiter connected in parallel with each other to minimize the overall voltage while maintaining a desired battery mean value.

Abstract: A digital direct access arrangement (DAA) circuitry may be used to terminate the telephone connections at the user's end to provide a communication path for signals to and from the phone lines. Briefly described, a means for providing a proper hookswitch transition for a variety of international phone standards is provided. The invention may also be utilized with means for transmitting and receiving a signal across a capacitive isolation barrier. More particularly, a DAA circuitry may be utilized which satisfies many or all hookswitch transition standards without the use of additional discrete devices. The hookswitch transition standards may be satisfied by ramping down the current flowing through the hookswitch prior to transitioning the hookswitch state. In this manner the hookswitch current change as a function of time (di/dt) may be decreased. Thus, the current through the hookswitch may be actively controlled prior to switching the hookswitch from an off-hook condition to an on-hook condition.

Abstract: A subscriber line driver (SLD) is provided for the continuous and automatic transformation of the characteristics of a communication system signal so that the signal conforms to a power spectral distribution (PSD) standard. The signal is transformed by the SLD which may increase (amplify) portions of the signal to a predefined specification, decrease (attenuate) portions of the signal to a predefined specification, and/or frequency modulate or filter the transmit signal frequencies to fit within the communication channel frequency bandwidth as defined by a predefined frequency band. After modification by the SLD, the transformed communication signal is injected (transmitted) into a communication transmission line. An SLD device can be employed in a variety of communication systems such as a public telephony system, a private branch exchange (PBX), a coaxial cable system, a fiber optic system, a microwave system, a radio communication system or the like.

Abstract: According to one embodiment, a network is disclosed. The network includes a first Voice Over Internet Protocol (VOIP) station a first communication medium coupled to the VOIP station a router, coupled to the first communication, that includes a network address translation (NAT) firewall, a second communication medium coupled to the router and a public proxy/gatekeeper (PPG) coupled to the second communication. The PPG masquerades un-translated NAT IP addresses received from the first VOIP station.

Abstract: A monolithic transceiver integrated circuit that includes a substrate, a transmitter subsystem of one or more subcircuits on the substrate, and a receiver subsystem of one or more, subcircuits on the substrate. Also included is a bias current supply coupled to the receiver and transmitter subsystems to provide bias current. The bias current supply includes a first bias circuit on the substrate coupled to, and to supply bias current to, a first subcircuit of the transmitter subsystem. The first bias circuit includes a first current modulator having a first switch input to indicate that the bias current is to start or stop being supplied to the first subcircuit. The first current modulator is to control the rate of change of supplied bias current in response to the first switch input. The first subcircuit may be a power amplifier. The control of the rate of change reduces oscillator pull in at least one oscillator included in the integrated circuit.

Abstract: A line terminal circuit comprises a buffer section (A, D) for connection to a transmission line (TL) and for performing at least one of the functions receiving signals from said transmission line and transmitting signals via said transmission line; a controllable current source section (S1, S2) connected to inject or withdraw a current (Iu, Id) into or from a node (ND1, ND2) between said buffer section and said transmission line in accordance with a current control signal (CS); and a common mode voltage control section (CT) for detecting a common mode voltage component on the transmission line (TL) connected to the buffer section (A, D) and for generating said current control signal (CS) in response to said detected common mode voltage component and outputting said current control signal to said current source section (S1, S2); said common mode voltage control section (CT) being adapted to output said current control signal (CS) such that said common mode voltage component is within the limits of a predetermi

Abstract: An efficient method and circuitry for transferring various levels of power across a high voltage isolation barrier. In one embodiment of the invention, a data access arrangement (DAA) is provided with system side circuitry that provides power to line side circuitry via the high voltage isolation barrier. The line side circuitry includes voltage measurement circuitry, such as an analog-to-digital converter, that periodically measures the line side supply voltage. The resultant information is transmitted across the high voltage isolation barrier to the system side circuitry, where control circuitry or a software process compares the digital representation of the measured voltage level to a predetermined value. Based on the results of this comparison, the control circuitry may alter the amount of power transferred across the high voltage isolation barrier to the line side circuitry in order to optimize power transfer efficiency.

Abstract: The present invention relates to a method and system of relaying calls with a tone provision function in the next generation mobile communication network. The call relaying procedures and functions support a Voice over Internet Protocol (VoIP) function between an originating gateway controller and a terminating gateway controller, by modifying the Bearer Independent Call Control (BICC) protocol, while receiving the tone from an external tone generating device using the BICC protocol, Media Gateway Control Protocol (MGCP), and 3rd Generation-Inter-Operability Service (3G-IOS) protocol in the next generation mobile communication network based on an Internet Protocol (IP). The BICC, MGCP and 3G-IOS protocols improve the IP-based network by supporting the VoIP function between the originating gateway controller and the terminating gateway controller, while receiving the tone from an external tone generating device.

Abstract: The asymmetric digital subscriber line receive channel includes: first and second external resistors 20 and 22 coupled to a telephone line 24 and 26; a coarse programmable gain amplifier CPGA formed in a low voltage process having inputs coupled to the first and second external resistors 20 and 22; and a fine programmable gain amplifier PGA1 coupled to an output of the coarse programmable gain amplifier CPGA, and having a very fine gain trim adjustment to compensate for a mismatch between the external resistors 20 and 22 and the coarse programmable gain amplifier CPGA.

Abstract: Disclosed is a method for providing a high-speed data service and a voice service in a transmission system employing two binary, one quarternary (2B1Q) modulation/demodulation, the transmission system including a remote terminal providing a high-speed data service, a plurality of user terminals including data service terminals and voice service terminals, and a multi-rate digital subscriber line (MDSL) terminal connected to the remote terminal through a twisted pair line, the multi-rate digital subscriber line terminal being also connected to the user terminals. During a downstream voice service, the remote terminal assembles an high bit rate digital subscriber line (HDSL) frame by including signaling signals for the voice service and signal processing mode information in a user-defined interval of the high bit rate digital subscriber line frame, and transmits the assembled high bit rate digital subscriber line frame to the multi-rate digital subscriber line terminal through the twisted pair line.

Abstract: A communication system, a mobile services switching center and a method is described, for allowing a multi-dialogue communication to take place between a first subscriber station (MS1, MS2, . . . MSn) and a second subscriber station (ISDN ST1) through a mobile services switching center (MSC/VLR) of a public land mobile network (PLMN). A mapping device (MP) of the mobile services switching center (MSC) maps several communication channels between the first subscriber station (MS1, MS2, . . . MSn) and the mobile services switching center (MSC/VLR) onto at least one second communication channel (CC2) between the PLMN and a fixed network (FN).

Abstract: A power converter forming part of a telephone subscriber line interface circuit selectively generates a ringing signal waveform, for supply to the line, or a supply voltage for a driver circuit for providing loop current on the line. First and second fixed frequency PWM signals are used to control the power converter, and hence the voltage which it generates, for the ringing signal waveform and the supply voltage respectively. The first PWM signal enables the power converter to provide a high power level needed for ringing signals. The second PWM signal has a lower frequency, and hence results in lower switching losses and power dissipation, and a lower duty cycle, suitable for the lower power level needed for the supply voltage, and is conveniently produced by masking pulses of the first PWM signal. The frequency of the second PWM signal is greater than 270 kHz, to avoid transmitting spectral energy to the line below this frequency.

Abstract: An apparatus compensates for an attenuation of a signal on a telephone line in a communication system connected to the telephone line via a transformer. A photo coupler detects a loop current at a primary winding of the transformer. A controller generates switching control signals corresponding to an output of the photo coupler based on a predetermined switching table, and controls an overall operation of the communication system by receiving coding data. A level amplifier having different gains amplifies a signal at a secondary winding of the transformer by the gain corresponding to the switching control signal. A coder codes an output from the level amplifier to generate the coding data.

Abstract: A circuit arrangement for generating charge pulses during digital telecommunications is indicated, whereby subscribers (Tln) of a telephone network are connected by cables with an exchange. The subscriber telephones are connected by electric service lines to an interface unit that is connected to the exchange. The interface unit has a digital interface on the exchange side and at least one analog interface on the subscriber side. A generating circuit (3) is located in the interface unit and produces charge pulses as a function of signals transmitted by the exchange, the charge pulses being transmitted to the respective subscriber (Tln). When loop current flows through the electric circuit of each subscriber (Tln) telephone, the interface unit measures an input voltage that is proportional to the length of the service line. The thus gained voltage value is used to adjust the voltage level of the charge pulses produced by the generating circuit (3).

Abstract: To generate a ringing signal by means of a subscriber line interface circuit having two final stages, each for supplying an individual subscriber line wire, one of the subscriber line wires is connected to one of the input terminals of an operational amplifier, the other input terminal of which being connected to the interconnecting point between two series connected resistors having the same resistance. The output terminal of the operational amplifier is connected, via a first resistor, to a current input terminal of the subscriber line interface circuit for generating a first current. A signal generator, via a second resistor, is also connected to said current input terminal for generating a second current. The final stages of the subscriber line interface circuit are supplied with current from current input terminal to drive the final stages to generate the ringing signal.

Abstract: Disclosed is a circuit for providing an appropriate amount of on-hook loss in a digital loop carder transmission system serving telephone customers. The resistance of the customer loop is measured while the customer is off-hook and an amount of loss is added based on that resistance during the off-hook interval. A predetermined constant loss is then added to the appropriate off-hook loss when the equipment returns to on-hook status.

Abstract: A supply circuit for a two-wire telecommunication line includes a voltage adjusting circuit section coupled between one of the wires and a first reference potential point and further includes a current source coupled between the second wire and a second reference potential point. A transistor in the voltage adjusting circuit section has a first main electrode coupled to the first wire, a second main electrode coupled to the first reference potential point, and a control electrode which is coupled to the first wire by way of a capacitor. In order for the supply circuit to meet strict requirements as to symmetry and demodulation, the control electrode is also coupled to the first reference potential point by way of a threshold voltage diode, which may be a zener diode. A voltage control circuit coupled to the threshold voltage diode forms a feedback loop for maintaining the line voltage at a selected value despite the presence of disturbing signals on the line.

Abstract: A method and apparatus for connecting a programmable computing device to a digital telephone via an adapter. The digital telephone includes an option bay connection, having a hierarchical control protocol. The option bay connection makes available several types of information including local analog audio, and analog voice, digital voice, digital data and telephone control streams. The adapter passes the telephony control data to and from a programmable computing device such as a personal computer, enabling an application operating on the computing device to control or monitor the operation of the telephone. The adapter includes a microcontroller and an interface for a serial port and can thus be connected to the serial port of the programmable computing device.

Abstract: An electronic interface circuit between a telephone subscriber line and a telephone main exchange is disclosed which forms, with the main exchange battery, a supply bridge for the telephone line, with limitation of the line current to a predetermined threshold value. The voltage/current characteristic of the supply bridge is balanced for lower values of the line current than the threshold current and is unbalanced whenever the line current attains said threshold current.

Abstract: The quality of speech being transmitted in a telecommunication channel is enhanced by adaptively compensating for frequency dependent attenuation in the telecommunication channel. The frequency dependent attenuation in the telecommunication channel is dynamically determined and, then, compensated for by adaptively selecting and inserting an appropriate frequency dependent gain function in the telecommunication channel.

Abstract: An active impedance line interface circuit for connection to a two-wire telephone line comprises tip and ring unity gain d.c. amplifiers having outputs d.c. coupled via feed resistors to tip and ring wires respectively. Loop current and common mode current conducted via the feed resistors are monitored individually and converted to digital signals supplied to a digital control circuit, which can be programmed to provide desired operating conditions. Digital control signals produced by the control circuit are converted into analog signals and used to control currents passed by current sources through resistors at inputs of the d.c. amplifiers, thereby determining voltages at the d.c. amplifier inputs and hence on the tip and ring wires. These d.c. voltages are smoothed by capacitors used for coupling an a.c. signal to the d.c. amplifiers.

Abstract: A circuit is proposed for adjusting the loss provided to loops in digital loop carrier transmission systems. A constant current is supplied to the loop and the resulting voltage is measured to determine the resistance of the loop. This value is fed to a microprocessor with a look-up table which controls a programmable analog/digital converter. The loss at the output of the converter is a stepwise function based on the resistance of the customer loop.

Abstract: A Data Communication Device permits extended range RS-232 communications between two devices by utilizing a current loop between the remote device and the Data Communication Device. The Data Communication Device may be used for any mix of signal or control lines specified for RS-232 and will support multiple remote devices in a broadcast mode or half duplex polled mode. Only a single Data Communication Device per remote communications circuit is required.