Abstract: A Power Line Communication (PLC) device that is resilient to cross-band interference. The PLC device is configured to communicate on AC power wiring in the frequency range of 9 kilohertz to 500 kilohertz and does not use automatic gain control prior to analog-to-digital conversion. The PLC device includes an over-sampled analog-to-digital converter with a sample clock of at least 10 megahertz and includes a loop filter that maintains a noise power spectral density that does not exceed three decibels above a minimum noise floor, of the noise power spectral density, at 80 kilohertz or above, and a digital filter and decimator configured to remove quantization noise, where a decimation factor of the decimator is such that it provides an output decimation rate between 350 kilohertz and 1.6 megahertz.

Abstract: The invention relates to a method for transmitting sensor signals, comprising the following steps: a first sensor (4), in particular a rotational speed sensor, supplies an alternating signal, which is present in the form of a sequence of sensor pulses (50) and pulse pauses (52) of predetermined duration, wherein in the pulse pauses (52) additional data (54) is transmitted as a bit sequence and wherein the bit sequence contains at least one free bit (56); a binary information sequence (60) comprising data from at least one further sensor (12, 14, 22, 30, 38a, 38b, 38c) is generated, which has a transmission length of a plurality of bits; and the data of the first sensor (4) and of the at least one further sensor (12, 14, 22, 30, 38a, 38b, 38c) is transmitted through a common data line (18) in that a processing unit (20) distributes the information sequence (60) to a plurality of chronologically sequential bit sequences and the at least one free bit (56) of the additional data (54) is assigned at least one bit

Abstract: The present invention relates to a low-power and high-speed transmission and reception apparatus which reduces consumption power of a sending-end circuit by increasing a value of a termination resistor included in a sending-end circuit and a receiving-end circuit so that the value is greater than a characteristic impedance value of a transmission line.

Abstract: A computer system includes a processor, and the processor includes at least one interface for communicating with an electronic component. Each of the at least one interface has a set of interface settings. The computer system further includes a memory containing machine executable instructions. Execution of the instructions causes the processor to: monitor communications traffic on the at least one interface; store, eye distribution data acquired during the monitoring of the communications traffic in a database; compare the eye distribution data to a set of predetermined criteria; and generate a set of updated interface settings if the eye distribution does not satisfy the set of predetermined criteria.

Abstract: A method of equalizing signals from a plurality of balanced transmission line cables having different lengths includes providing a first cable having a first length and a second cable having a second length, the first cable coupled to a variable resistor. A first signal is transmitted along the first cable to the variable resistor such that the first signal is attenuated to assume a first frequency domain characteristic. A second signal is transmitted along the second cable such that the second signal is attenuated to assume a second frequency domain characteristic. A voltage of the first signal is divided in the variable resistor such that the first signal assumes substantially the second frequency domain characteristic. The first signal having the second frequency domain characteristic is outputted.

Abstract: A system includes an analog front end (AFE) unit to be coupled to a power line network, and a controller coupled to the AFE unit. More specifically, the AFE unit is to receive a packet signal from the power line network wherein, based on a first gain parameter, the AFE unit is to amplify the received packet signal. The controller is configured to calculate a root-mean-square (RMS) power of the amplified packet signal. Further, the AFE unit is to calculate a second gain parameter based on the calculated RMS power of the amplified packet signal and the first gain parameter, wherein the second gain parameter is to be used to amplify the received packet signal instead of the first gain parameter.

Abstract: A technique for generating a bit log-likelihood ratio (LLR) in a communication system includes generating a demodulated signal based on a received symbol and a reference symbol. An input for a bit LLR generator is generated based on the demodulated signal and a normalization value that is based on the received symbol or the reference symbol. A bit LLR is generated for the received symbol, using the bit LLR generator, based on the input.

Abstract: A weighting filter is provided for use in a device for transmitting and/or receiving an analog signal. The device is capable of transmitting and/or receiving the analog signal in a predetermined frequency band consisting of two adjacent sub-bands, referred to as first and second sub-bands. The weighting filter includes: a first branch, which attenuates the analog signal; a second branch that filters the analog signal and has a bandwidth corresponding to the first sub-band or to the second sub-band; and a module that combines signals from the first and second branches.

Abstract: A reception circuit that receives data in serial communications through a plurality of lanes includes a plurality of buffers provided for each of the plurality of lanes that each stores data received through corresponding lane, a multilane control circuit that detects the skew between the lanes, and outputs an adjustment instruction for adjusting a read address of a buffer and a deskew information indicating that a skew adjustment between which buffer the lanes is to be performed based on the detected skew, and a plurality of address control circuits provided for each of the plurality of lanes that each transmits the adjustment instruction to a corresponding buffer when receiving the deskew information, wherein the buffer that has received the adjustment instruction adjusting its read address.

Abstract: An active common mode current limiting mechanism limits common mode currents in a powerline communication device. A powerline coupler determines a common mode signal component of an output signal of the powerline communication device. The powerline coupler provides voltage estimates of the common mode signal component to a signal processing unit. The signal processing unit generates samples of the voltage estimates of the common mode signal component. The signal processing unit adjusts transmit voltage levels of the powerline communication device based on the samples of the voltage estimates of the common mode signal component to limit the common mode signal component of the output signal.

Abstract: As disclosed, a two-way automatic communications system (TWACS) and method are used by an electrical utility in which outbound messages are sent from the utility to a consumer and inbound messages are sent from the consumer to the utility. The respective outbound and inbound messages are sent and received over the utility's power distribution system. A receiver including an analog filter component, an A/D converter and a digital processor detects the outbound messages. A substation transceiver is configured for sending analog outbound messages from the utility to a consumer. A transponder is configured for sending inbound messages to the transceiver from the consumer to the utility, the respective outbound and inbound messages being modulated on a mains signal of the utility's power distribution system. The receiver in another form includes an analog filter component, a detecting circuit and a demodulator.

Abstract: A device includes a transmitter coupled to a node, where the node is to couple to a wired link. The transmitter has a plurality of modes of operation including a calibration mode in which a range of communication data rates over the wired link is determined in accordance with a voltage margin corresponding to the wired link at a predetermined error rate. The range of communication data rates includes a maximum data rate, which can be a non-integer multiple of an initial data rate.

Abstract: In a MIMO communications system a communication device receives one or more receive signals on at least one receiver port. A receiver unit recovers, from the at least one receive signal, at least a first transmit signal transmitted to the receiving communication device via a transmission channel. A multi-link decoder unit decodes the receive signals using a multi-link decoder algorithm with parameters derived from a first channel state information describing the transmission channel and second channel state information describing at least one interference channel via which one or more second transmit signals arrive at the communication device.

Abstract: A first network device detects at least a first orthogonal code included in a preamble of a network packet received at the first network device from a second network device in an orthogonal frequency division multiplexing (OFDM) communication network. The first network device determines whether the first orthogonal code included in the preamble is associated with an assigned orthogonal code for the first network device. The assigned orthogonal code for the first network device is orthogonal to other assigned orthogonal codes for other network devices in the OFDM communication network. An operational mode of the first network device is changed from a sleep mode to an awake mode in response to determining the first orthogonal code is associated with the assigned orthogonal code for the first network device.

Abstract: Transceiver self-diagnostics for electromagnetic interference (EMI) degradation in balanced channels. Selective operation of transmitting a common mode signal from a communication link implemented for supporting differential signaling, and appropriate processing of any detected signal energy, such as that corresponding to differential signal energy, provides a measure of electromagnetic compatibility (EMC) corresponding to the communication link. Comparison of detected differential signal energy to one or more thresholds may provide indication of whether or not the communication link is balanced or unbalanced, a degree or margin with which the communication link is compliant in accordance with EMC in accordance with one or more protocols, standards, or recommended practices. Multiple successive measurements of detected differential signal energy may be used to determine a trend of performance, such as whether or not the communication link is trending toward imbalance, failure, or noncompliance.

Abstract: Transmitting and receiving arrangements and methods in a Digital Subscriber Line (DSL) system having a plurality of modems and vectored transmission capability. A first part of an available frequency band is reserved exclusively for vectored DSL transmission and reception using modems operating in the first part of the frequency band. The remaining, second, part of the available frequency band is reserved for both vectored and non-vectored transmission using modems operating in the second part of the frequency band.

Abstract: An outdoor radio communication system comprises a first radio unit, a second radio unit, and a single cable coupling the first radio unit to the second radio unit. Each radio unit includes a downconverter, a radio processor that is communicatively coupled to the downconverter, and a XPIC module. The cable further includes a first twisted-pair of wires for communicatively coupling the first downconverter to the second XPIC module and a second twisted-pair of wires for communicatively coupling the second downconverter to the first XPIC module. The first XPIC module generates a first reference signal using a signal from the second downconverter to cancel cross-polarization interference in an output signal of the first radio processor. Similarly, the second XPIC module generates a second reference signal using a signal from the first downconverter to cancel cross-polarization interference in an output signal of the second radio processor.

Abstract: A transceiver architecture can contain an encoder and a decoder for communicating high speed transmissions. The encoder can modulate signal data for being mapped in a constellation that is generated based on concatenations of a leech lattice having binary and non-binary codes. The data can be transmitted at a high speed according to the constellation with an embedded leech lattice configuration in order to generate a coding gain. A decoder operates to decode the received input signal data with a decreased latency or a minimal latency with a high spectral efficiency.

Abstract: A detecting circuit includes: a first offset generating circuit, arranged to apply a first offset to an input signal pair and accordingly generate a first output signal pair; and a first sampling circuit, coupled to the first offset generating circuit, the first sampling circuit arranged to sample the first output signal pair to generate a first sampling signal, wherein the first sampling signal is utilized to identify a data signal on the input signal pair, and the first sampling circuit is controlled by a first signal that is irrelevant to the input signal pair.

Abstract: A method and system for connecting to line protection relays and providing a communications channel between a first end and a second end of high voltage transmission lines for digital Line Current Differential Protection are disclosed. At each of the first end and the second end of the high voltage transmission lines, a Broadband Power Line Carrier (BPLC) gateway device is connected to the line protection relay. The BPLC gateway has a coupling device to physically attach to the line and is configured to transmit and receive data communications over the high voltage transmission lines so as to allow the protection relays to communicate with each other via the existing high voltage transmission lines.

Abstract: Disclosed is a method and apparatus for reducing outbound interference in a broadband powerline communication system. Data is modulated on first and second carrier frequencies and is transmitted via respective first and second lines of the powerline system. A characteristic of at least one of the carrier signals (e.g., phase or amplitude) is adjusted in order to improve the electrical balance of the lines of the transmission system. This improvement in electrical balance reduces the radiated interference of the powerline system. Also disclosed is the use of a line balancing element on or more lines of the powerline system for altering the characteristics of at least one of the power lines in order to compensate for a known imbalance of the transmission system.

Abstract: A method and apparatus for harmonic distortion compensation in power line communications. In one embodiment, the method comprises analyzing a waveform generated by a transmitter of a power line communications transceiver (PLCT), wherein the waveform is analyzed to determine harmonic information for one or more harmonics of a carrier waveform of the PLCT; computing, based on the harmonic information, one or more harmonic compensation coefficients; and pre-distorting, based on the one or more harmonic compensation coefficients, the carrier waveform such that the one or more harmonics are reduced below a threshold.

Abstract: Embodiments provide methods, devices, circuitry and systems for supporting or implementing functionality to provide a filtering circuit, and for providing a transmitter, receiver or transceiver system incorporating the same. One embodiment provides a circuit for filtering signals. The circuit comprises a first connection configured to be connected to a signal line carrying varying signal voltage and a second connection. The circuit also comprises a first circuit portion comprising a parallel resonant circuit having a variable capacitance connected in parallel with a first inductor; and a second circuit portion comprising a second inductor. The first circuit portion and the second circuit portion are connected in series between the first connection and the second connection.

Abstract: An apparatus for converting terminal polarity for RS communication includes a comparator configured to discriminate polarities of a first signal line and a second signal line by comparing voltage levels indicated on the first and second signal lines of a cable for RS-485 communication, a switch unit configured to connect a TRXD+ terminal to the first signal line and connect a TRXD? terminal to the second signal line, or to connect a TRXD+ terminal to the second signal line or connect a TRXD? terminal to the first signal line in response to a provided switch control signal, and a switch controller configured to transmit the switch control signal to the switch unit in response to a polarity discrimination result by the comparator relative to the first signal line and the second signal line.

Abstract: The present invention concerns a method of reducing interference between a carrier current signal (SCPL) transmitted over an electrical line (Le) and a signal of the VDSL type (SVDSL) transmitted over a telephone line (Lpots) that is situated close to the electrical line (Le). Said signals (SCPL, SVDSL) routing data in the form of bits that are attributed to carrier frequencies (Fk) distributed in the same frequency band on different frequency planes, characterized in that it comprises.

Abstract: In a method for transmitting frames of data across a physical media that has a selective frequency response, a packet of data bytes is received by a media access (MAC) layer of a communication protocol from a local application for transmission to a remote receiver. The packet of data bytes is padded to from a padded packet of data bytes having a predetermined frame length, wherein the predetermined frame length is a frame length that is predetermined to provide correct transmission of a frame of data across the physical media that has a selective frequency response. The padded packet of data bytes is encoded by a physical (PHY) layer of the communication protocol to form multiple tone symbols. The multi-tone symbols are then transmitted on the physical media to the remote receiver.

Abstract: The present invention relates to a clock-embedded or source synchronous semiconductor transmitting and receiving apparatus and to a semiconductor system including same. The semiconductor apparatus according to one embodiment of the present invention includes: a data providing unit for providing differential data; a multi-phase clock generator for generating a first clock signal provided to the data providing unit, and a second clock signal having a different phase from the first clock signal; and a combining unit for receiving the differential data and the second clock signal and combining same to generate a combined signal, wherein the second clock signal is a single clock signal and has n (here, n is an integer of two or greater) times a symbol period of the differential data, the first and second clock signals have a 90 degree phase difference, and the combination signal is transmitted to the outside through differential transmission lines.

Abstract: In a modular signal mirroring system each point-to-point RF transceiver end has a controller module coupled to one or more I/O modules. The I/O modules have various input and output circuits. A signal received at the near end is reconstructed at the far end after being transmitted in an RF packet. The reconstructed signal may be the same as the input signal, inverted from the input signal or level-shifted from the input signal. It is representative of the input signal following the input signal's state after a time-quantization latency. Transmission between the two ends is via a periodic transmission controlled in a master slave protocol. If a transmission is not received in a timely manner or, in some systems, if intentional interference with transmissions is detected, the reconstructed signal is forced to a safe state determined by local switch settings. The settings include the last known good state.

Abstract: According to one embodiment, there is provided a power electronics device in which a controlling unit selects a first power electronics device and a second power electronics device from power electronics devices, based on power attribute information and communication attribute information of each power electronics device, and the first power electronics device is a master of power allocation control of electric energy that the power electronics devices connected to one power line of power lines perform input and output on the one power line, and the second power electronics device is a master of output power phase synchronization control of power which the power electronics devices connected to the one power line outputs to the one power line.

Abstract: A master device and slave devices are connected with each other through an SDA and an SCL, and at least one of a serial communication data signal communicated through the SDA and a serial communication clock signal communicated through the SCL is latched with use of a noise removal clock signal whose frequency is higher than that of the serial communication clock signal, and is taken in.

Abstract: In communication method for communicating via a transmission channel to which first communication apparatuses communicating based on a first communication system, second communication apparatuses communicating based on a second communication system, and third communication apparatuses communicating based on a third communication system are connected, a data transmission domain and a notification domain for notifying a data transmission within the data transmission domain are allocated to the first communication apparatuses, the second communication apparatuses, and the third communication apparatuses, respectively. In the communication method, notices of the data transmission for each of the first communication apparatuses, the second communication apparatuses and the third communication apparatuses are transmitted within the notification domain, and the data transmission domain is reallocated in accordance with the notices transmitted from the first, second and third communication apparatuses.

Abstract: Common wave and sideband mitigation communication systems and methods are provided that can be used with both wireless and wired communication links. The systems and methods provided can enable faster data rates, greater immunity to noise, increased bandwidth/spectrum efficiency and/or other benefits. Applications include but are not limited to: cell phones, smartphones (e.g., iPhone, BlackBerry, etc.), wireless Internet, local area networks (e.g., WiFi type applications), wide area networks (e.g., WiMAX type applications), personal digital assistants, computers, Internet service providers and communications satellites.

Abstract: A receive attenuation system for a trainline communication system utilizing an intra-consist electrical cable has an analog front end amplifier, a trainline communication processor, an adjustable attenuator, and a gain controller. The trainline communication processor is configured to generate a receive gain control signal configured to control receive gain of the analog front end amplifier. The adjustable attenuator is capable of being coupled to the intra-consist electrical cable and configured to variably attenuate signals received from the intra-consist electrical cable before transmitting the signals to the analog front end amplifier. The gain controller is coupled to the adjustable attenuator and configured to detect the receive gain control signal generated by the trainline communication processor, determine a supplemental attenuation control value based on the detected receive gain control signal, and control the adjustable attenuator according to the supplemental attenuation control signal.

Abstract: A system for driving a first signal onto a wireline includes a driver and feedback circuitry. The driver drives a deterministic signal onto the wireline with an unknown impedance load. The feedback circuitry measures a quality of the output signal from the wireline and modifies a gain of the first signal based on the quality of the output signal. The driver then drives the first signal onto the wireline with the modified gain.

Abstract: Examples disclosed herein provide daisy chain communication system. The daisy chain communication system includes a plurality of transceivers coupled to devices which provide data signals to, and receive data signals from, their one or more coupled transceivers. The transceivers are configured to transmit and receive an amplitude modulated signal having edges corresponding to edges of a clock signal and amplitudes corresponding to a digital value of the first data signal.

Abstract: A method for optimizing the performance of an active HDMI cable. An active cable compensator is provided within the HDMI cable itself. This device applies an individually-adjusted equalizer to each of the TMDS video data lines. A non-equalizing amplifier is applied to the two TMDS clock lines. An accelerator is applied to the I2C data bus. The parameters controlling each of the active components (such as parameters setting gain and frequency distribution) within an individual HDMI cable are set through a programming process. In that process, a calibration source sends known signals through the cable to a programming unit. A programming unit analyzes the signals through the cable and sends commands to the active cable compensator in the cable. The commands adjust the parameters in order to optimize the performance of the individual cable.

Abstract: According to an example embodiment, a communications receiver may include a variable gain amplifier (VGA) configured to amplify received signals, a VGA controller configured to control the VGA, a plurality of analog to digital converter (ADC) circuits coupled to an output of the VGA, wherein the plurality of ADC circuits are operational when the communications receiver is configured to process signals of a first communications protocol, and wherein only a subset of the ADC circuits are operational when the communications receiver is configured to process signals of a second communications protocol.

Abstract: A method for transmitting digital data via a line includes the steps of providing a clock signal and of transmitting the digital data in synchrony with the clock signal, the clock signal having a frequency that is variable over time.

Abstract: A fuel dispenser has internal fuel flow piping, a flow meter located along the internal fuel flow piping, and a displacement sensor operatively connected to the flow meter to generate information representative of an amount of fuel passing through the flow meter. The fuel dispenser also has a control system comprising a memory. In embodiments, however, the control system does not comprise a real-time clock. The fuel dispenser also comprises a synchronization module in electronic communication with the control system. The synchronization module comprises at least one antenna configured to receive a carrier wave modulated with synchronization information. Methods for obtaining accurate time information at the fuel dispenser are also disclosed.

Abstract: A multi-mode I/O circuit or cell (10) is provided for transmitting and receiving data between ICs, where each IC contains at least one of the I/O circuits. Each data link includes transmitter circuitry (12) and receiver circuitry (14). The transmitter circuitry sends data to a receiver circuitry in another IC, and the receiver circuitry receives data from a transmitter circuitry in another IC. The I/O circuit is constructed with CMOS-based transistors (e.g., CMOS or BiCMOS) that are selectively interconnected together by a plurality of switches to operate as two single-ended, current or voltage mode links, or as a single differential current or voltage mode link. In the preferred embodiment the transmitter circuitry sends data to the receiver circuitry in another IC over a first pair of adjacently disposed conductors, and the receiver circuitry receives data from the transmitter circuitry in another IC over a second pair of adjacently disposed conductors.

Abstract: Methods and systems for using a signal to generate a pilot tone to modulate the bias point of an amplifier that amplifies the signal.

Abstract: Systems and methods are described for the implementation of a full band cable receiver by using a combination of tuners (e.g., ultra-low power Tuners) and Analog-to-Digital Converters (ADCs) to attain the goal of digitization with reduced power and/or cost. The full-band capture cable receiver can overcome the constraints of conventional cable receiver systems and deliver multiple channels, thereby allowing operators to provide consumers with an increased number of services.

Abstract: A method of powerline communications (PLC) includes compiling a data frame for physical layer (PHY) by a first communications device at a first communications node on a powerline of a PLC network. The data frame includes a single tone PHY header portion and a data payload portion in a set of tones including at least one tone having a frequency different from a frequency of the single tone. The PHY header portion includes tone mask identification information identifying the set of tones. The first communications device transmits the data frame over the powerline to a second communications device at a second communications node on the powerline. The second communications device receives the data frame, and decodes the data payload using the tone mask identification information in the PHY header portion.

Abstract: In one embodiment, a transmitter circuit is provided for data transmission from endpoint devices to collector devices over power distribution lines. The transmitter includes an amplifier circuit configured to receive and convert a first data signal to a pulse density modulation (PDM) encoded signal using high frequency pulses that introduce high frequency components. A low-pass filter of the transmitter is configured to filter the high frequency components of the PDM encoded signal to produce a second data signal, which is an amplification of the first data signal. A coupling circuit of the transmitter is configured to communicatively couple the second data signal from the low-pass filter to the power distribution lines. The coupling circuit filters the frequency of the AC and prevents high voltage of the power distribution lines from damaging the transmitter.

Abstract: The present invention relates to a power line communication system for a large capacity load which greatly improves the recognition ratio and accuracy of a communication signal even for a large capacity load in that it: includes a switch unit as a transmission means wherein a first switch made of semiconductor elements and a second switch made of relay elements are connected in parallel; and generates and transmits a communication signal by selectively using the switches.

Abstract: A communication apparatus repeatedly outputs a first multi-carrier signal SS during predetermined periods T1, T2, T3, . . . , and outputs a second multi-carrier signal RS whose phase vector is different from that of the first multi-carrier signal SS, at a predetermined timing based on the first multi-carrier signal SS. The communication apparatus further detects the second multi-carrier signal RS output from another communication apparatus, which uses a different communication method from the communication apparatus. Accordingly, both communication apparatuses can differentiate the first multi-carrier signal SS from the second multi-carrier signal RS without performing relatively cumbersome modulation and other processes.

Abstract: A serial communication apparatus includes a slew rate control circuit, an output circuit, a detection circuit, and a switching circuit. The slew rate control circuit has a predetermined impedance, and supplies a constant current from an output according to an input signal. In the output circuit, first capacitance is charged and discharged by the constant current from the slew rate control circuit. The output circuit outputs a digital signal from an output terminal according to a drive voltage. The noise detection circuit detects noise propagated from the output terminal, and outputs a switching signal according to a detection result. The switching circuit switches an impedance of the slew rate control circuit to a value smaller than the predetermined impedance according to the switching signal.

Abstract: In a charging communication system in which a charging control device performs communication between an electric vehicle and a charging equipment, the electric vehicle is equipped with a first communication device and a second communication device both configured to communicate with the charging equipment by using the same signal line in the charging cable; and a signal line connection device configured to switch connection/disconnection between the second communication device and the signal line. The charging control device, which controls a battery on the electric vehicle, calculates an amount of change in a signal line voltage between before and after the signal line connection device connects the second communication device to the signal line, and the charging control device causes, when the amount of change does not fall within a predetermined allowable range, the signal line connection device to disconnect the second communication device from the signal line.

Abstract: A master unit and a plurality of slave units perform a multi-hop communication. The plurality of slave units include hybrid slave units are configured to select at least one of wireless communication and power line carrier communication. One hybrid slave unit includes a function of reporting, to the other hybrid slave unit in which a hop number in the power line carrier communication between the one hybrid slave unit and the other hybrid slave unit is one, the minimum route cost when the wireless communication is used for a channel on an upper side. The one hybrid slave unit includes a function of adopting the power line carrier communication when a route cost reported by the other hybrid slave unit is smaller than the minimum route cost of the one hybrid slave unit, and otherwise adopting the wireless communication.

Abstract: A bicycle electrical system is provided with a first electric component, a second electric component, and a third electric component. The first electric component includes a first electric power line communication section. The second electric component includes a second electric power line communication section. The third electric component includes a third electric power line communication section. The first and second electric power line communication sections are connected with a first electric power line such that the first and second electric power line communication sections conduct communications via the first electric power line. The second and third electric power line communication sections are connected with a second electric power line such that the second and third electric power line communication sections conduct communications via the second electric power line.