Abstract: Disclosed is a digital communication control system having a serial bus buffer that includes a primary interface adapted to support serial communication over a primary bus, a buffered interface adapted to support serial communication over a buffered bus, and a controller coupled between the primary bus and the buffered bus. The primary bus is coupled to a first device and at least one second device and the buffered bus is coupled to at least one third device. The controller is adapted to receive a first data signal and a clock signal at the primary interface and replicate the first data signal and the clock signal at the buffered interface.

Abstract: A wireless network allocates uplink resources to wireless communication devices (WCDs) based on power headroom reports, with more resources being allocated to WCDs reporting greater power headrooms. Each WCD may determine a respective power headroom as a difference between its maximum transmit power and a transmit power requirement for its current uplink resource allocation. However, a WCD may report an adjusted power headroom that is obtained, for example, by decreasing its respective power headroom by an adjustment value. The WCD may then receive an uplink resource allocation that is based on the adjusted power headroom that it reported. The adjustment value could be based on a priority level of the WCD, a priority level of data to be transmitted by the WCD, and/or an instruction from the wireless network. In one example, basic-priority WCDs report adjusted power headrooms so that more uplink resources are available for high-priority WCDs.

Abstract: A method and apparatus for automatically establishing a wired protected setup between an enrollee requesting registration and a registrar granting registration are provided. The method includes: determining whether a power line communication (PLC) between the enrollee and the registrar is possible; and if it is determined that the PLC with the registrar is possible, receiving a personal identification number (PIN) from the registrar through the power line and transmitting an acknowledgement (ACK) message to the registrar through the power line as a response to the received PIN.

Abstract: Systems and methodologies are described that facilitate mitigation of interference through uplink scheduling in a wireless communication environment. Access points can assign multiple terminals to a single tile or segment of shared resource (e.g., a time frequency region) to maximize the number of terminals supported. However, combinations of certain types of terminals can cause a significant increase in interference. In particular, allocating multiple terminals having a relatively high velocity (e.g., terminals located in moving vehicles) to a single tile can cause an unacceptable increase in interference. To mitigate interference, high velocity terminals can be identified. Once identified, terminals can be allocated to the available tiles based at least in part upon avoiding combinations that result in a significant increase in interference.

Abstract: Distortions of both amplitude and phase along a transmission line are compensated for by a trace canceller inserted between a transmitter and a receiver. The trace canceller has an equalizer that compensates for a trace length between the transmitter and the trace canceller. A variable gain amplifier between the equalizer and an output buffer has its gain controlled by an automatic gain control circuit that compares low-frequency swings of the input and output of the trace canceller. The gain of the variable gain amplifier is reduced to prevent the output buffer from saturating and clipping peak voltages on its output. Thus both the variable gain amplifier and the output buffer remain in the linear region. Training pulses from the transmitter are passed through the trace canceller without clipping of peak voltages, allowing the transmitter and receiver to adjust transmission parameters to best match the transmission line.

Abstract: A base station repeater station pair, comprising: a base station (1) having an input for a broadcast signal (s(t)) and being arranged to transmit, in use, a transfer signal over a link (3) using electromagnetic (EM) radiation; and a repeater station (2) arranged to receive, in use and through EM radiation, the transfer signal from the base station (1) and from the transfer signal broadcast the broadcast signal using EM radiation, in which the link (3) between the base station (1) and the repeater station (2) over which the transfer signal is passed in use comprises a dual polarized link, whereby the base station (1) is arranged to transmit the transfer signal over the link (3) with two different polarizations, and the repeater station (2) is arranged to receive the transfer signal from the link as two differently polarized versions. Also disclosed area base station and a method of using the above.

Abstract: A relay apparatus, comprises a reception section that receives real-time data, a monitoring section that periodically detects quality of a transmission path to be used for transmitting the real-time data toward a destination thereof, a determination section that determines a length of an interleaving cycle according to the quality of the transmission path, an interleaving section that interleaves the real-time data in the interleaving cycle having the determined length, and a transmission section that transmits the interleaved real-time data to the transmission path.

Abstract: A telephone relay apparatus 200 receives a connection request from a first telephone terminal 100 to a second telephone terminal 300. The connection request includes phone numbers of the first telephone terminal 100 and the second telephone terminal 300. The telephone relay apparatus 200 stores phone numbers of a plurality of telephone terminals and codec information that indicates types of audio codecs of the telephone terminals so that the phone numbers and the code: information correspond to each other. When connecting to the first telephone terminal 100, the telephone relay apparatus 200 reads out codec information that corresponds to the phone number of the second telephone terminal, and then transmits the read-out codec information to the first telephone terminal 100. The first telephone terminal 100 performs a call process using an audio codec that corresponds to the codec information transmitted from the telephone relay apparatus 200.

Abstract: A mobile terminal and method for transferring call charges between mobile terminals are disclosed. To transfer call-related charges between mobile terminals, the mobile terminal and call charge transfer method place a call by a calling mobile terminal to a called mobile terminal to establish a call connection for conversation, transmit a call transfer request by the calling mobile terminal to impose call-related charges on the called mobile terminal, and perform, if the called mobile terminal accepts the call transfer request, a call transfer operation to impose the call-related charges on the called mobile terminal, and maintain, if the called mobile terminal rejects the call transfer request, the call to impose the call-related charges on the calling mobile terminal. As a result, during a call between mobile terminals, the called user can accept a call transfer request of the calling user to transfer call-related charges to the called party, thereby enabling flexible and efficient billing.

Abstract: A communication system includes a first communication module, and a second communication module. The first communication module may receive a first type of communication signal (e.g. a mobile telephone signal) and convert it into a second-type of communication signal (e.g., a millimeter wave radio signal). The first type of communication signal may be a mobile telephone signal from a first fire fighter's mobile telephone who is located outside of the building. The first communication module may transmit the second-type of communication signal to the second communication module.

Abstract: A home gateway includes a WAN interface portion, a LAN interface portion and an analog interface portion, and a LAN controller, an analog controller and a central controller. The WAN interface portion communicates with an external telephone set. The LAN interface portion communicates with a plurality of telephone sets configuring an IP telephone system. The LAN controller and the analog controller control the LAN interface portion and the analog interface portion such that type information is transmitted to a destination telephone set. The central controller generates the type information in accordance with a type of information to be communicated to the external telephone set, based on the information received by the WAN interface portion. Thus, a user can readily determine which telephone set is to be used to receive a call when a plurality of telephone sets can receive a call from a calling party.

Abstract: The present invention is to provide a mobile phone comprising a body and a housing. A hollow is formed within the housing and the body is slidably disposed in the hollow. The hollow has an opening in an end of the housing and the other end terminated at a closed end of the housing distal the opening. A display (e.g., LCD (liquid crystal display)) is disposed on a front surface of the housing. The body comprises a circuit board and an input device. The circuit board is installed within the body and comprises electronic circuits and devices for controlling the components of the mobile phone. The input device (e.g., alphanumeric keypad) is disposed on a front surface of the body for operating the mobile phone. The body is capable of being engaged with the housing and being slid towards outside of the hollow through the opening to expose the input device for a user to make a phone call.

Abstract: A method and apparatus for bus repeater tapering. The sizing of repeaters on a portion of one transmission line is chosen to propagate a signal transition at a particular rate. The sizing of repeaters on a substantially parallel portion of another transmission line, is chosen to propagate a second signal transition at a different rate. Thus, the worst-case capacitance coupling factor between the two transmission lines may be reduced.

Abstract: When a telephone call line from an outgoing telephone terminal to the specific telephone terminal of a specific terminal user is not opened, the telephone relay apparatus acquires periphery requirement data from user scheduled data about the specific terminal user having a scheduled date matching the present date, and selects a peripheral telephone terminal. Opening of a telephone call line from the outgoing telephone terminal to the selected peripheral telephone terminal is tried, and the outgoing telephone terminal not connected to the specific telephone terminal is connected to the peripheral telephone terminal. Thus, it is possible to increase the possibility that the telephone outgoing user and the specific terminal user can talk to each other between the peripheral telephone terminal and the outgoing telephone terminal.

Abstract: A system for reducing noise in a signal line, through which upward signals and downward signals are transmitted between a center and terminals, includes a noise-reduction device provided between the center and the terminals. The noise-reduction device attenuates the upward signals by an increased amount when a noise increase regarding the upward signals is detected on the signal line. The system further includes a noise-control device, provided at terminals, which boosts a transmission level of the upward signals by an amount compensating for the attenuation of the upward signals by the noise-reduction device.

Abstract: A radio relay apparatus including an outdoor relay unit formed of first and second receiving parts equipped out of doors and an indoor relay unit formed of third and fourth receiving parts, and a digital transmission line connecting the outdoor and indoor relay units enables radio communication even in a blind area such as an underground area and tunnel. In the first receiving part of the outdoor relay unit, a receiving antenna for receiving a high-frequency signal is integrally incorporated so as eliminate the transmission loss. The high-frequency analog signal is converted to its corresponding digital signal of a desired frequency band by a digital signal processor in the outdoor relay unit, and then, the digital signal thus obtained is transmitted to the indoor relay unit through the digital transmission line, so that high-quality radio communication can be accomplished.

Abstract: When a mobile station communicates with a base station by way of one or a plurality of other mobile stations, the mobile station acting as a relay station determines whether the data demodulated after being received is reception data for the mobile station or transfer data to be transmitted to the other mobile station or the base station, decides a modulation mode suitable for transmitting sum data of the transfer data and transmission data if the transmission data is generated in the mobile station, and transmits the sum data while modulating the sum data according to the modulation mode decided. The base station demodulates a reception signal relayed by the mobile stations according to the modulation mode of the mobile station having directly communicated with the base station, and identifies each user data multiplexed.

Abstract: An interactive remote auction bidding system for conducting an auction utilizes a data input device for communication over a network to the auction site. The system includes a data processor located at the auction site for generating bid information for communication over the network to the remote locations. A processor located at the auction side monitors the participants' data input devices for sensing participant bids generated by the participants' data input devices. The system further displays visual bid information at the auction site for transmission over the network to the participants and generates audible bid information in support of that visual bid information.

Abstract: An interactive remote auction bidding system for conducting an auction utilizes a data input device for communication over a network to the auction site. The system includes a data processor located at the auction site for generating bid information for communication over the network to the remote locations. A processor located at the auction side monitors the participants' data input devices for sensing participant bids generated by the participants' data input devices. The system further displays visual bid information at the auction site for transmission over the network to the participants and generates audible bid information in support of that visual bid information.

Abstract: A communication system that permits the coexistence of a plurality of ultrawide band (UWB) radio communication networks that use different signal systems is achieved by using the same beacon signal and specifying the format of part of the control command among a plurality of UWB radio communication networks that use different signal systems, as defined, for example, by impulse period, impulse width, spreading ratio, and spreading code. When one UWB network receives a beacon signal from another UWB network, judging from the received beacon signal it grasps the transmission parameter that is used by another party and performs time-division on the transmission frame period for its own system.

Abstract: A wireless network includes transmission power and data rate adaptation based upon signal quality experienced by the user.

Abstract: A relay station is composed of a main reception antenna 1 for receiving both a radio wave of a parent station and a go-around radio wave of a relay station, a subsidiary reception antenna 2 for receiving the go-around radio wave of the relay station, a changeable attenuator 3 and a phase shifting unit 4 for changing an amplitude and phase of a signal received in the subsidiary reception antenna 2, a composite signal producing unit 5 for producing a composite signal from a signal received in the main reception antenna 1 and the signal sent from the phase shifting unit 4, an electric power detecting unit 9 for obtaining a composite electric power from a composite voltage extracted in a directivity coupling unit 8, and a microcomputer 10 for controlling a change of amplitude in the changeable attenuator 3 and a change of phase in the phase shifting unit 4 so as to minimize an average value of the composite electric power obtained in the electric power detecting unit 9.

Abstract: Systems and methods are described for fault detection for subscriber loop repeaters. A method includes monitoring an upstream signal on a digital subscriber loop for a fault detection signal that is added to said upstream signal at a repeater; and determining if a fault has occurred. An apparatus includes a digital subscriber loop fault detection system including: a receiver circuit that monitors an upstream signal on said digital subscriber loop for a fault detection signal that is added to said upstream signal at a repeater; and a logic circuit that determines whether a fault has occurred.

Abstract: A design for passively cooled telecommunication repeater housings for use in wire transmission in the local loop outside plant provides mounting slots for repeaters and voltage protector assemblies disposed and arranged such that a repeater and its voltage protector assembly can be removed independently of each other by pulling either one in the same direction.

Abstract: When receiving a request from a telecommunications switch (106) for a telephone call to a party, a loop carrier (108) checks for errors and availability in the distribution resources that couple the called party to the digital loop carrier (108). For a distribution resource error or unavailability, the digital loop carrier (108) generates a distribution resource error message that is transmitted to the telecommunication switch (106). The telecommunication switch (106) applies terminating call features for the called party, such as voice mail or call forwarding, in response to the distribution resource error message.

Abstract: An improved thermal design for passively cooled telecommunication repeater housings for use with wire transmission in the local loop outside plant is achieved by replacing the known convection based heat transfer designs with a design based on solid thermal conduction. A thermal chassis includes thermal collection, transfer and distribution members that collect the repeater modules' waste heat through respective thermal interfaces, transfer the waste heat along respective thermal conduction paths to the environmental enclosure, and then distribute the waste heat over a substantial portion of the enclosure's available surface area to form an enlarged thermal interface for convectively transferring the waste heat to the ambient air. Heat transfer is further improved by expanding the enclosure's external surface area and fabricating the distribution members so that they are in permanent and intimate thermal contact with the enclosure's expanded surface area.

Abstract: A diversity receiving apparatus for use in an OFDM transmission radio communication/broadcasting system where OFDM signals are received by a plurality of antennas and input into a plurality of receivers. The OFDM received signals are further transformed into frequency spectra. Channel frequency responses are calculated by using OFDM received signal frequency spectra and a reference frequency spectrum generated in a reference spectrum generator. OFDM received signal frequency spectra distortions are compensated by using corresponding channel frequency responses. The transformed OFDM received signal frequency spectra are input into a selector unit as first input signals, while the distortion-compensated OFDM received signal frequency spectra are input into the selector unit as second input signals. The selector unit then selects a second input signal corresponding to a first input signal having maximum amplitude or maximum power.

Abstract: An improved thermal design for passively cooled telecommunication repeater housings for use with wire transmission in the local loop outside plant is achieved by replacing the known convection based heat transfer designs with a design based on solid thermal conduction. A thermal chassis includes thermal collection, transfer and distribution members that collect the repeater modules' waste heat through respective thermal interfaces, transfer the waste heat along respective thermal conduction paths to the environmental enclosure, and then distribute the waste heat over a substantial portion of the enclosure's available surface area to form an enlarged thermal interface for convectively transferring the waste heat to the ambient air. Heat transfer is further improved by expanding the enclosure's external surface area and fabricating the distribution members so that they are in permanent and intimate thermal contact with the enclosure's expanded surface area.

Abstract: An improved thermal design for passively cooled telecommunication repeater housings for use with wire transmission in the local loop outside plant is achieved by replacing the known convection based heat transfer designs with a design based on solid thermal conduction. A thermal chassis includes thermal collection, transfer and distribution members that collect the repeater modules' waste heat through respective thermal interfaces, transfer the waste heat along respective thermal conduction paths to the environmental enclosure, and then distribute the waste heat over a substantial portion of the enclosure's available surface area to form an enlarged thermal interface for convectively transferring the waste heat to the ambient air. Heat transfer is further improved by expanding the enclosure's external surface area and fabricating the distribution members so that they are in permanent and intimate thermal contact with the enclosure's expanded surface area.

Abstract: A control system and method suppress noise in a power-line-based system which has a device repeater connected to an electrical device, and which may be capable of remote control by signals transmitted through the power-line-based system. The control system includes a control device and a communications bus. The communications bus connects the control device to the device repeater. The control device, using a control repeater, controls a phase signal of the device repeater to suppress noise during operation of the electrical device associated with the device repeater.

Abstract: An improved thermal design for passively cooled telecommunication repeater housings for use with wire transmission in the local loop outside plant is achieved by replacing the known convection based heat transfer designs with a design based on solid thermal conduction. A thermal chassis for a thermally enhanced center housing of an 818/819 style repeater housing includes thermal collection, transfer and distribution members that collect the repeater modules' waste heat through respective thermal interfaces, transfer the waste heat along respective thermal conduction paths to the environmental enclosure, and then distribute the waste heat over a substantial portion of the enclosure's available surface area to form an enlarged thermal interface for convectively transferring the waste heat to the ambient air. The thermal collection, transfer and distribution members can be integrated into a thermal chassis.

Abstract: An improved service access and heat transfer design for passively cooled telecommunication repeater housings for use with wire transmission in the local loop outside plant is achieved by a cover, sealable to the housing's sidewall, removable to provide field replaceable, plug-in access to the repeater modules and voltage protector assemblies wherein the voltage protector assemblies can be installed and removed without first removing the repeater modules protected by those voltage protector assemblies and by replacing the known convection based heat transfer designs with a design based on solid thermal conduction. Thermal sleeves, which mount the repeater modules, collect the repeater modules' waste heat through thermal interfaces, transfer the waste heat along thermal conduction paths to the housing's sidewalls, and then distribute the waste heat over a substantial portion of the housing's sidewalls.

Abstract: Aincludes a connection terminal unit capable of connecting a telephone, a handset and a headset, a connection path selection switch capable of selecting a connection path depending upon the kinds of the telephone and the handset, and an audible signal generator which gives required information when a wiring is established by the connection terminal unit adapted to the telephone and to the handset by the connection path selection switch. Further, the connections of insulated conductors between the telephone and the handset are successively cut to search a state of connection where no voice is heard from the telephone.

Abstract: An interactive remote auction bidding system for conducting an auction among participants located at remote locations from the auction site utilizes a data input device for communication over a network to the auction site. The system includes a data processor located at the auction site for generating bid information for communication over the network to the remote locations. A processor located at the auction side monitors the participants' data input devices for sensing participant bids generated by the participants' data input devices. The system further displays visual bid information at the auction site for transmission over the network to the participants and generates audible bid information in support of that visual bid information.

Abstract: An improved thermal design for passively cooled telecommunication repeater housings for use with wire transmission in the local loop outside plant is achieved by replacing the known convection based heat transfer designs with a design based on solid thermal conduction. A thermal chassis includes thermal collection, transfer and distribution members that collect the repeater modules' waste heat through respective thermal interfaces, transfer the waste heat along respective thermal conduction paths to the environmental enclosure, and then distribute the waste heat over a substantial portion of the enclosure's available surface area to form an enlarged thermal interface for convectively transferring the waste heat to the ambient air. Heat transfer is further improved by expanding the enclosure's external surface area and fabricating the distribution members so that they are in permanent and intimate thermal contact with the enclosure's expanded surface area.

Abstract: A method and device for providing telephone subscribers serviced from digital loop carrier (“DLC”) systems access to a computer network. The described device includes a redirect repeater with the capability to redirect multiplexed channels of the DLC to a computer network. The redirect repeater is interfaced to the DLC and redirects channels of the multiplexed DLC system to the computer network in response to a redirect signal. The described method includes monitoring the DLC for a call origination message indicating a subscriber is originating a telephone call, buffering messages from the originating telephone call and recognizing a redirect signal indicating the telephone call is to be directed to the computer network. Messages indicating the telephone call is redirected to the computer network are inserted and the messages from the telephone call can then be redirect to the computer network.

Abstract: A method and system enables a fixed cellular terminal (FCT) to be automatically configured to accommodate landline phones of the country and/or landline network in which it is physically located. The FCT includes a memory and a data structure therein. The data structure includes instructions on how landline phones interface with Public Switched Telephone Networks (PSTNs). Consequently, the FCT may be connected to a landline phone in any country and/or landline network once the FCT is informed of the country and/or landline network in which it is being used. According to one embodiment, a Subscriber Identity Module (SIM), which is needed to activate cellular phones in some systems, is used to inform the FCT of the country and/or landline network.

Abstract: An improved, more intelligent network interface unit capable of processing signals received from a high speed transmission media and outputting the received signals without substantial amplification or reduction. The network interface unit comprises a regenerator circuit which detects T1 signals from said high-speed transmission media and outputs a digital stream to a serial data processor for processing via a micro-controller. A wave shaper circuit receives the output from the serial data processor and, in conjunction with the micro-controller and a level detector circuit, regenerates signals having substantially the same wave shape and amplitude as the original T1 signals received from said transmission media.

Abstract: An apparatus for improving signal quality in a communications link includes apparatus for regenerating only the speech-like characteristics of signals received over the communications link so that an estimate of the original speech signal can be retransmitted. The apparatus may include a vocal tract model coupled to a synthesizer.

Abstract: A physical layer (PHY) device which can operate as a conventional PHY or as a repeater in a communication system. The PHY repeater supports four optional modes which may be enabled by programming control register bits with a microcontroller. These optional modes are: pass all symbols, enable noise filter, pass violation symbols and pass line states. When the pass all symbols, pass violation symbols and pass line states modes are enabled, the PHY device operates as a "transparent" repeater. The repeater allows errors in a data stream to be encoded and repeated without filtering to a downstream station. The repeater also allows line states to be repeated without station management software. A single repeater may be used to couple two stations or multiple repeaters may be connected to form multi-port repeater boxes which can be connected to facilitate more reliable connections between stations.

Abstract: A disk array memory system includes a disk subsystem, a disk director module and a cable connected between the disk subsystem and the disk director module. The disk subsystem includes a disk drive backplane having disk drive connectors interconnected by a first data bus section and disk drives mounted in the disk drive connectors and coupled to the first data bus section. The cable constitutes a second data bus section. The system further includes a bus repeater located in the disk subsystem and including a first port electrically connected to the first data bus section and a second port electrically connected to the cable. The bus repeater logically interconnects the first and second data bus sections and regenerates signals transmitted in either direction between the disk director module and the disk drives.

Abstract: In a communications system containing signal enhancement circuitry capable of selectively enhancing portions of a plurality of signals carried on a corresponding plurality of channels through the signal enhancement circuitry, a system and method for controlling enhancement on a per call basis. The system includes: (1) command generation circuitry for generating an enhancement command for transmission to the signal enhancement circuitry and (2) command reception circuitry, associated with the signal enhancement circuitry, for receiving the enhancement command from the command generation circuitry and selectively enhancing the portion of the signals on the per call basis according to the enhancement command.

Abstract: To provide an electronic equipment mounting device having flexibility in the mounting direction, the device is provided with a mounting jig on which a plurality of tongues are formed and a housing whose flat faces having different areas have slits in them, the tongues being inserted into the slits in a detachable manner. The mounting jig is mounted on, for example, the surface of a wall, and then the housing is coupled to the mounting jig by selectively using one of its side faces.

Abstract: In an order wire as an auxiliary line for use in the installation and maintenance of communication equipment, a method of producing a ring-back tone includes of transmitting a DTMF signal on the side of the calling station, causing a call-in tone to be produced, on the side of the called station, when a specific condition is satisfied, transmitting a ring-back tone signal, on the side of the called station, containing data related to the station number of the calling station, and causing a ring-back tone to be produced, on the side of the calling station, when a specific condition is satisfied. By using the method, the ring-back tone is produced only in the calling station without the need for an exchange apparatus.

Abstract: A microwave digital communication system PSK-modulates a microwave carrier by using a main signal and, further, frequency-modulates it by using a service channel (SC) signal for monitoring and controlling the system. An intermediate relay station employing a space diversity reception system converts a received microwave into an intermediate frequency (IF) to extract the SC signal, and converts the IF signal into a microwave to transmit, thus performing heterodyne relay. The intermediate relay station generates a phase error signal corresponding to the frequency deviation of the IF received signal, by using the IF received signal and an IF reference signal having a fixed frequency equal to the carrier frequency of the IF received signal, and extracts the phase error signal as an SC signal. The SC signal is inputted as a control signal to a VCO for generating a receiving-side local oscillation signal so that the frequency of that follows the variation of the frequency deviation of the received microwave.

Abstract: A telephone line repeater (28) includes a pattern decoder/recognizer (100) which recognizes, inter alia, an input interrogating signal transmitted on a telephone network (20). The interrogating signal includes an address field (302) having at least one subfield (304) therein. The pattern decoder (100) determines that its repeater (28) is to be tested, if a predetermined subfield (304) of the interrogating signal is configured according to a predetermined select convention. When the repeater (28) recognizes that it is being addressed, a controller (110) causes the addressed repeater to "loop back", returning, in alternating sequence, test-indicative no-operation signals and diagnostic information ("DSM") signals generated by the repeater. Methods for testing a repeater and methods for testing telephone networks are also disclosed.

Abstract: A system of impedance matching is provided to match the total impedance of the cable system to the total impedance of the powered elements such as the repeaters. The source impedance of the power supplies may be considered as part of the cable impedance. By matching impedances, the source voltage for driving the electronics is advantageously minimized.

Abstract: A transmission input/output device for signal transmission through a telephone line, with reduced power consumption, size, and cost. The device includes: a resistor, connected to the telephone line, for setting a signal input and output impedance; and a transmission control circuit for amplifying the transmission signals to be outputted to the telephone line, including: a variable resistor, connected in series with the resistor, for supplying voltages corresponding to the transmission signals to be outputted to the telephone line into the resistor according to changes of an impedance of the variable resistor; and an operational amplifier for controlling the changes of the impedance of the variable resistor by supplying an output according to the transmission signals to be outputted to the variable resistor.

Abstract: A multiport repeater for a local area network installation has (in addition to its conventional functions) means for storing access rules for the items of equipment connected to it. It reads a portion of each frame, which may be all or part of the destination address segment and/or of the source address segment and/or of the control segment of each incoming data frame, or it could be a frame or protocol identifier incorporated in opening bytes of the data segment. It compares the data that it reads with the stored access rules to determine whether the frame is permitted or not. If not, the repeater modifies the frame which it is in the course of re-transmitting, for example by overwriting it with meaningless digits or by encrypting it. It may also report the source address, destination address and reason for deciding to modify the frame to the network controller.

Abstract: A distributed switching network (switch) routes audio and control signals throughout the switch from various audio sources to one or more audio destinations. Audio sources such as mobile/portable radio units (via RF repeater transmitters), dispatch consoles, and landline telephone subscribers (via the central telephone switching network) are preassigned and routed onto an audio channel (i.e. a time slot) on a time division multiplexed (TDM) audio bus through a corresponding interface module. These interface modules broadcast digitized audio and data signals to all other interface modules over their preassigned TDM bus slot. Audio routing is performed to the audio destinations through corresponding interface modules that selectively "listen" to active TDM network channels. A digital voice interface module is provided in the switch to permit audio sources/destinations otherwise lacking certain digital processing capabilities (e.g. encryption/decryption) to participate in such digitally based calls.