Abstract: After the claims, please insert the following Abstract:—The invention provides a broadband mass communications network system and method comprising a plurality of patches (10), each patch including a plurality of subscribers, and each subscriber having a respective subscriber unit (12) for transmitting signals to and receiving signals from other subscribers. Each subscriber unit comprises an indoor interface unit (20) for user access to the system and an outdoor mounted communication unit (18) for the transmission and reception of signals. The signals are impressed on a carrier signal operating at frequencies in the range from infra-red to ultra-violet, the subscriber units of a respective patch being arranged to transmit the carrier signals substantially omni-directionally and to communicate by way of direct line of sight connections within the patch.

Abstract: High-speed data transfer rates are provided between a central office and customer premise equipment with a multiplexer that is interposed between the central office and the customer premise equipment, and that functions as a remote access node. The multiplexer communicates at high data rates via downstream data links such as twisted-pair conductors between the multiplexer and the customer premise equipment. By positioning the multiplexer physically close to the customer premise equipment, DSL data rates can be achieved. In one application, the multiplexer assigns a variable number of the upstream data links between the central office and the multiplexer on a dynamic, adaptive, and automatic basis to individual ones of the downstream data links. In this way, unused data link capacity of the upstream data links is used to provide high data transmission rates when required between the multiplexer and the central office.

Abstract: A bidirectional telephone communication system for supporting a multiplicity of subscriber lines between a downstream distribution terminal using only two of a multiplicity of pre-existing transmission line pairs connected between an upstream distribution terminal and a downstream distribution terminal. Said system including automatic initializing and monitoring circuitry for powering up a communication link and reestablishing the link if lost.

Abstract: This invention provides a simplified communication system that transmits voice and SDSL signals between customer premise equipment (“CPE”) on a single twisted-pair line. The system preferably includes at least one combiner for combining voice and SDSL signals into a combined voice/SDSL signal that can be transmitted to the CPE on a single twisted pair of wires, preferably a pair of wires currently being used to transmit the voice signal to the CPE. One combiner is ideally located at a common wiring closet of the building where the CPE is located. The combiner is ideally coupled to the existing pair of wires for the voice signal. This eliminates the need to add another set of wires between the common wiring closet and the CPE for the SDSL signal. A second combiner, normally located at or near the CPE separates the combined voice/SDSL signal into the separate voice and SDSL signals for processing by the CPE.

Abstract: A method and system for network address maintenance in a data-over-cable system. The method includes determining whether a network device, such as a cable modem, responds to a request in a timely manner. When updating network address tables, such as Address Resolution Protocol tables, an Internet Control Message Protocol (“ICMP”) echo message is generated and sent to the Internet Protocol (“IP”) address of a network device. If an ICMP echo reply message is not detected within a pre-determined time, the network address is deleted from the network address table. The deletion of the network address ensures that the device is isolated from the network. The method and system provide for the rapid removal of stale network addresses, freeing valuable memory space, and increasing security in a data-over-cable system.

Abstract: A method implemented by a subscriber unit for suppressing selective communications during communication rate modification, wherein the subscriber unit is coupled between first and the second communicating nodes, includes establishing a communication channel between the first and the second nodes at a first data rate; detecting a transmission from the first node on the channel; determining whether the transmission requires a change in data rates to a second data rate; switching the communication channel to the second data rate; and blocking transmissions from the second node until the second communication rate has been established.

Abstract: A multiple access communications network system in which a head-end controller (HC) broadcasts data and medium-access control (MAC) information over a set of downstream channels to several stations, and these stations send information to the HC over a shared upstream channel.

Abstract: An upstream channel change for a cable modem in a data-over-cable system is achieved via an upstream bandwith allocation map message sent from a cable modem termination system to cable modems, instead of requiring an exchange of upstream channel change request and reply messages. The result is that the upstream channel change can be made essentially immediately, in a deterministic fashion. As such, the upstream channel change method is particularly useful for time-sensitive applications, such as Internet telephony, VoIP, and Internet video on demand services. Load balancing can also be achieved more efficiently.

Abstract: A digital communications network system for multiple access has a head-end node and at least one station node at at least one other end node; the system comprises a head-end controller (3) capable of transmitting data and medium-access control information to at least one station (6), preferably a plurality of station means, over a set of downstream channels within a first frequency range, and receiving information from the station or stations over an upstream channel within a second frequency range; the upstream channel comprises at least one upstream subchannel, preferably a plurality of upstream subchannels; the system further comprises at least one connection, preferably a plurality of connections, for connecting the head-end controller with the station or stations; each station includes means for receiving data and medium-access control information from the head-end controller; further means are provided for sending a data stream at a first signal level over at least one upstream subchannel, preferably a

Abstract: Disclosed is an architecture and method for high speed transmission over a four-wire subscriber line. Each modem in the present invention includes a V.90 transmit section and a V.90 receive section. The V.90 transmit section is dedicated to transmitting data over one pair of a four-wire subscriber line, while the V.90 receive section is dedicated to receiving data over the other pair of the four-wire subscriber line. The present invention permits full-duplex transmission at 56 Kbps over a four-wire subscriber line.

Abstract: A signal demultiplexer includes serially-connected 2-demultiplexing filter banks, including band-stop filters and down-samplers for culling sampling frequencies of output signals from filters to 1/2. When the 2-demultiplexing filter bank operates on four types of filters, first to fourth filters in an ascending order of frequencies, 2-demultiplexing filter bank is arranged in one of two configurations so that a first filter bank contains at least the first filter or the second filter, or a second filter bank contains at least the third filter or the fourth filter. The filter banks are connected in such a way that signals processed through the first filter are processed by the first 2-demultiplexing filter bank in a next-stage; signals processed through the second filter are processed by the second 2-demultiplexing filter bank in a next-stage.

Abstract: A system and method of creating subscriber services in an Internet Protocol (IP)-based telecommunications network. A service creation architecture includes a Service Component Creator (SCC) that creates service proxy objects, and posts them on a Lookup Service (LUS). The LUS is accessible through the Internet by Enterprise Service Creators (ESCs). The ESCs download the posted service proxy objects from the LUS, and customize the downloaded objects to create customized services for enterprise users. The ESCs upload the customized service proxy objects to an Enterprise LUS, and the, Enterprise LUS downloads the customized service proxy objects to a Service Management Unit (SMU) serving the end user. A gatekeeper serving the end users utilizes the service proxy code downloaded to the SMU to determine the location of a Service Implementation Repository (SIR) that stores actual service code for implementing the customized service.

Abstract: This invention provides a simplified communication system that transmits voice and SDSL signals between customer premise equipment (“CPE”) on a single twisted-pair line. The system preferably includes at least one combiner for combining voice and SDSL signals into a combined voice/SDSL signal that can be transmitted to the CPE on a single twisted pair of wires, preferably a pair of wires currently being used to transmit the voice signal to the CPE. One combiner is ideally located at a common wiring closet of the building where the CPE is located. The combiner is ideally coupled to the existing pair of wires for the voice signal. This eliminates the need to add another set of wires between the common wiring closet and the CPE for the SDSL signal. A second combiner, normally located at or near the CPE, separates the combined voice/SDSL signal into the separate voice and SDSL signals for processing by the CPE.

Abstract: An asymmetric digital subscriber line transceiver unit-card (ATU-C) and a method of controlling the same. The ATU-C includes: a power supply unit; a plurality of modems to be connected to a plurality of asymmetric digital subscriber line transceiver unit-remote (ATU-R) for subscribers; a plurality of power switches for selectively supplying power generated by the power supply unit to the modems; and a microprocessor for controlling the operation of the power switches depending on the connection status between the subscribers and the modems.

Abstract: A method and system for network address maintenance in a data-over-cable system. The method includes determining whether a network device, such as a cable modem, registers in a timely manner. When updating network address tables, such as Address Resolution Protocol tables, a time value is associated with an address, such as an Internet Protocol (“IP”) address, of a network device. If a time between two registration events exceeds this time value, the network address is deleted from the network address table. The deletion of the network address ensures that the device is isolated from the network. The method and system provide for the rapid removal of stale network addresses, freeing valuable memory space, and increasing security in a data-over-cable system.

Abstract: A method, and a radio transmitter using the method, is disclosed for scheduling air interface capacity between user services in a radio system. The method includes defining a nominal service bit rate, a nominal capacity of the service, and an effective coding rate of the service, and scheduling air interface frame capacity between at least two different services. The scheduling includes computing the bit rate of a first service by multiplying the nominal capacity of the first service by the effective coding rate of the first service, and adding to this normal bit rate of the first service borrowed extra capacity of at least one other service, the bit rate obtained from the extra capacity computed by multiplying a predetermined amount of the nominal capacity of the other service by the effective coding rate of the first service.

Abstract: A method and apparatus for providing connection admission control (CAC) on a cable data system helps provide viable quality of service (QoS) capability on a cable data system. Cable data service is granted or denied to cable data service to said requesting subscriber based in part upon the determination of whether the available bandwidth is greater than, less than or equal to the bandwidth to be allocated to the requesting subscriber.

Abstract: A system for bidirectional communication of digital data between a central unit and a remote unit wherein the need for tracking loops in the central unit has been eliminated. The central unit transmitter generates a master carrier and a master clock signal which are used to transmit downstream data to the remote units. The remote units recover the master carrier and master clock and synchronize local oscillators in each remote unit to these master carrier and master clock signals to generate reference carrier and clock signals for use by the remote unit receiver. These reference carrier and clock signals are also used by the remote unit transmitters to transmit upstream data to the central unit. The central unit receiver detects the phase difference between the reference carrier and clock signals from the remote units periodically and adjusts the phase of the master carrier and master clock signals for use by the central unit receiver to receive the upstream data.

Abstract: A multicarrier transmitting modem is described. The modem includes means for receiving strings of digital data each having one of a set of different possible values, means for mapping the strings into symbols each having the same fixed amount of phase of predetermined different waveforms corresponding to the different possible values in the set, means for modulating the fixed amount of phase plus an excess amount of phase of the predetermine waveforms onto multiple orthogonal carriers in response to the symbols, and means for transmitting the modulated carriers to a distribution network.

Abstract: A method for transmitting and receiving leased line data, an apparatus for transmitting leased line data, and an apparatus for receiving leased line data are provided. The method includes storing received leased line data in a FIFO; packing the leased line date stored in the FIFO into the payload of a DSL frame; and transmitting the packed DSL frame. According to the method, leased line data can be transparently transmitted by adding minimum function blocks to the DSL modem, and with the simple circuit structure, the blocks can be integrated into one chip such that no additional external circuits are needed and a low-priced DSL modem chip that can transmit leased line data can be implemented.

Abstract: Method and apparatus for sending and displaying short messages from data network users which are linked to a telephonic network. The telephonic network comprises telephones, each with a display for visually displaying short messages to subscribers of the telephonic network. The apparatus holds a dialogue between the data network users and a software agent embedded in the telephonic network. The dialogue provides the telephonic network the content, the sender ID and the address information of each short message, stores the content and address information in a database, and displays the content of the messages on the telephone display of each destined subscriber.

Abstract: A system and method is provided for integrating the functionality of an interface to a power management driver for a communications system and the communications protocol which negotiates power management transitions. Initially, a driver power management request is received at the UPI component. In response, the UPI component, determines whether a port is open on which to send the state transition request. If it is determined that a port is open, it is next determined whether a suitable power management protocol is available. If it is determined that a port is open and the power management protocol is available, the UPI sends a power management state transition request through the EOC to the remote modem. Next, it is determined whether the remote modem has responded.

Abstract: Techniques that allow SHDSL-based systems to share the same transmission line with low frequency voice services such as POTS are disclosed.

Abstract: Systems and methods for increasing data capacity in communication systems is presented. In one embodiment, line characteristics are determined, and a downstream bandwidth is adaptively allocated in response to the determined line characteristics. In this regard, the upstream and downstream bandwidths may be seen as adaptively changing as a function of line characteristics.

Abstract: A Modular Residential Multi-Media Distribution System provides a single centralized interface for all external Wide Area Networks (WANs) which are received into the home/office environment. The MRMDS allows extensive modular flexibility in re-provisioning new services via changing or adding removable interfaces. Each WAN is individually connected to a distributor in the MRMDS. The MRMDS distributor interfaces the external WANs to a multiple of home/office Home Network Interfaces for distribution to a multiple of communication devices.

Abstract: A modem for use in Digital Subscriber Line communications transmits and receives data over the local subscriber loop in common with voice information over the loop, while avoiding the need for voice/data splitters. The modem responds to disruptions associated with “disturbance events” such as on-hook to off-hook transitions and the like by rapidly switching between pre-stored channel parameter control sets defining communications over the loop under varying conditions. In addition to changing parameter control sets responsive to a disturbance event, the modem may also change transmission power levels and other system parameters such as frequency domain equalizer characteristics. Further, provisions are made for reduced bandwidth communications under selected conditions.

Abstract: A method for flow control in asymmetric digital subscriber line (“ADSL”) devices. The method includes flow control that adapts to changes in line conditions such as noise signals, onhook/offhook signals, etc. that may result in degradations in the quality-of-service in an ADSL system. The flow control includes buffering outbound data and ceasing transmission of data at an original transmission rate on an ADSL device that is used on a customer site. An original data transmission rate is adjusted based on changes in line conditions. One more or data transmission characteristics may be adjusted before sending any data at a new data transmission rate. For example, Asynchronous Transport Mode (“ATM”) often uses ADSL devices as a physical layer to transmit data. ATM available bit-rate, constant bit-rate, variable bit-rate or unspecified bit-rate transmission characteristics or ATM quality-of -service characteristics may be adjusted before sending any data at a new data transmission rate.

Abstract: An Asymmetric Digital Subscriber Loop (ADSL) Discrete Multi-Tone system has disjoint and adjacent upstream and downstream channels. During the training phase of an ADSL connection, an ADSL DMT transmitter first determines a round trip propagation delay by transmitting a ranging signal to a far-end ADSL endpoint. During the subsequent communications phase, the ADSL transmitter synchronizes transmission of DMT symbols to a reference clock. In addition, the cyclic extensions of each DMT symbol are increased as a function of the propagation delay.

Abstract: The present invention includes a subscriber-switching device and method in a system of asymmetrical digital subscriber lines ADSL. The subscriber-switching device includes multiple subscriber units including multiple subscriber ports, respectively; a redundancy subscriber unit including multiple subscriber ports, a network unit for transmitting data inputted from the multiple subscriber units to networks, a rear unit on a back plane of a shelf for transmitting data inputted from at least more than one of the subscriber lines to the subscriber unit, a common line board for connecting the subscriber lines of the rear unit to the redundancy subscriber unit through the common line, a switching means for switching among the subscriber port of the subscriber unit, the redundancy subscriber unit, and the common line board, and a controller for controlling mutual operation flows among the above units and means.

Abstract: A method for evaluating capacity utilization of a terminus in a communication system where the terminus has a maximum capacity and accommodates a plurality of communication lines in coupled relationship with the terminus, includes the steps of: (a) identifying the plurality of communication lines; each respective line has a respective line speed and a respective character-type that is one character-type of a plurality of character-types extant in the communication system; (b) identifying the respective line speed and the respective character-type for each respective line; (c) determining type line speed contribution by respective lines having a particular the respective character-type; (d) summing the type line speed contribution by all the respective character-types to determine a total line speed contribution for all of the plurality of lines; and (e) comparing the total line speed contribution with the maximum capacity to effect the evaluating.

Abstract: Communications system and communication method which control group communication processes in a more efficient and flexible way. A downstream frame generation means produces a downstream frame for group communication, providing group communication time slots therein. An office-side group communication control means controls communications processes by sending the downstream frame and receiving an upstream frame. An upstream frame generation means produces an upstream frame. A subscriber-side group communication control means controls the group communication processes by sending the upstream frame and receiving the downstream frame.

Abstract: A communications system includes a first and second modem coupled together via a communications link. The first modem has at least two user devices coupled thereto, and modulates data generated by the user devices on a plurality of tone carriers for transmission to the second modem. The first modem determines the number of user devices coupled to it. Based upon the number of user devices determined, the first modem divides the plurality of tone carriers into a number of subsets corresponding to the number of user devices based upon a predetermined criterion. The first modem then allocates a subset of tone carriers to a respective user device. In one embodiment, the usage rate of each user device is determined, and the tone carriers are reallocated to different subsets as a function of the usage rate of each respective user device.

Abstract: A data communication apparatus includes a communication section that performs pre-communication protocol to exchange a communication function with a communication destination terminal, and transmits data to the communication destination terminal after the pre-communication protocol. A detector detects whether or not the communication destination terminal can perform a short protocol in which at least a communication protocol for line probing is omitted. When the detector detects that the communication destination terminal can perform the short protocol, a controller obtains communication parameters from the communication destination terminal, stores the obtained communication parameters in a memory in association with the communication destination terminal. The stored communication parameters are utilized to perform the short protocol.

Abstract: A communication network uses intermediate nodes to resolve local traffic contention. Intermediate nodes receive upstream signals from end users, derive traffic information signals from the upstream signals, and transmit the traffic information signals to end users. By listening to the traffic information signals from the intermediate node, the end users know whether the upstream transmission channels are idle or busy, or whether a collision has occurred. The intermediate nodes derive and transmit the traffic information signals with or without the assistance of the central office or head end.

Abstract: A variety of bi-directional data transmission systems that facilitate communications between a plurality of remote units (15) and a central unit (10) using a frame based discrete multi-carrier transmission scheme are disclosed. In each of the systems, frames transmitted from the plurality of remote units (15) are synchronized at the central unit (10). A variety of novel modem arrangements and methods for coordinating communications between a plurality of remote units (15) and a central unit (10) to facilitate multi-point-to-point transmission are disclosed. The invention has application in a wide variety of data transmission schemes including Asymmetric Digital Subscriber Line systems that includes the transmission of signals over twisted pair, fiber and/or hybrid telephone lines, cable systems that includes the transmission of signals over a coaxial cable, and digital cellular television systems that include the transmission of radio signals.

Abstract: A data communication apparatus includes a communication section that performs a pre-communication protocol and transmits data to a destination terminal. A memory stores data and communication parameters corresponding to each destination terminal, the communication parameters being utilized to perform communication with the destination terminal. When data corresponding to a destination terminal data is stored in the memory, a controller performs the pre-communication protocol with the destination terminal, using the stored communication parameters corresponding to the destination terminal. When a communication error occurs in a communication with a particular destination terminal having data stored in the memory, a memory controller deletes communication parameters corresponding to the particular destination terminal from the memory.

Abstract: The present invention provides methods and apparatus for creating a Program Association Table (PAT) for a reduced portion of a multiplexed data stream, when the multiplexed data stream has been reduced, for example, to carry fewer services over a cable television plant. More particularly, the present invention provides methods and apparatus for creating a PAT for a desired combination of multiplexed data stream subgroups contained within an incoming data stream, when the incoming multiplexed data stream is reduced. The invention enables a new PAT to be output which correctly corresponds to the services in a reduced data stream (e.g., for cable-side transmissions). The present invention is particularly useful when reducing high data rate satellite television data streams for cable-side transmission.

Abstract: Transport stream multiplexers detect the transmission rates of audio and video information of each of a plurality of programs multiplexed and transmitted. If a situation arises in which the total value of the transmission rates exceeds the maximum transmission rate allowed for the transmission path, the mulitplexer transmits (branches) partial service information to a subscriber device via a digital set-top box (DSTB) control unit by using a different high-frequency signal. As a result, the total value of the transmission rates of the multiplexed information is reduced by an amount equivalent to the service information that was branched, whereby the total value falls below the maximum transmission rate allowed for the transmission path. This makes it possible to reproduce normal audio and video at the subscriber device.

Abstract: A method and apparatus are provided for managing bandwidth operative in a digital loop carrier system. The system includes service cards connectable to at least one transport card having a given bandwidth capacity. Each of the service cards supports multiple subscriber channels. Upon initiation of a first call, the system allocates the call to a given time slot of the transport card. The given time slot is assigned a given default bandwidth, e.g., 64 kbps. While the first call is in progress, the system determines whether the call is voice or data. If the first call is voice, the system may selectively reduce the given default bandwidth allocated to the first call if necessary to ensure that a second call, if initiated while the first call remains in progress, can be assigned the given default bandwidth.

Abstract: A wireless communication system combines time and space diversity to reduce fading and simplify receiver design. In particular, a data packet which carries digital telephone traffic, is transmitted at three different times from three different antennas. The mobile subscriber receiver thus receives the same data packet at three different times from three different antennas, and uses the best data packet or combination of the data packets to reduce the effects of fading. A transfer station receives a time division multiplex multiple access (TDMA) signal from a base station carrying telephone data packet traffic to form three data packet repeats at spatially diverse antennas locations. The transfer station further modulates a code division multiple access (CDMA) system using a TDMA signal which links the mobile subscriber receiver to the transfer station. Each data packet received at the transfer station is thus retransmitted at three different times to the mobile subscriber station on a CDMA link.

Abstract: A method for use by a terminal (or a set of terminals all communicating via for example time division multiple access) of a communication access network seeking to communicate with the head end of the network, the head end for communicating with many terminals in a signal comprising many different frequencies, one frequency for each of many corresponding transceivers of the network, where the communication between the terminal and the head end is via communication between the terminal and a particular transceiver, and the method is used to establish a correspondence between the terminal and the particular transceiver. The method involves exchanging initialization packets between the head end and the terminal seeking to communicate with the head end, initialization packets that convey to the terminal the frequency to use to communicate with the particular transceiver, and that communicate to the particular transceiver the identity of the terminal.

Abstract: A splitterless digital subscriber line modem adapted to be coupled to a subscriber line including a sending end and a receiving end, the modem being capable of simultaneous access to the subscriber line with other telephone equipment operating in a frequency band below four kilohertz is disclosed herein. The modem includes a data terminal and a control circuit. The data terminal couples the modem to the subscriber line. The control circuit is coupled to the data terminal and receives and transmits signals to and from the data terminal. The control circuit utilizes line coding techniques to measure signal and noise at the receiving end and adjusts amplitude of the signal in response to the signal and the noise whereby power of the signal is optimized.

Abstract: A system for use with a subscriber line carrier such as a SLC-5 or other SLC type system. In accordance with a specific embodiment, the system provides a multiplex channel unit 25 that inputs T1 line signals, and outputs multiple telephone line signals in a format such as 2B1Q or 4B3T over a twisted pair 13 to an RT 35. The RT 35 converts the full duplex multiplexed signals to analog service for a subscriber 12.

Abstract: A system for bidirectional communication of digital data between a central unit and a remote unit wherein the need for tracking loops in the central unit has been eliminated. The central unit transmitter generates a master carrier and a master clock signal which are used to transmit downstream data to the remote units. The remote units recover the master carrier and master clock and synchronize local oscillators in each remote unit to these master carrier and master clock signals to generate reference carrier and clock signals for use by the remote unit receiver. These reference carrier and clock signals are also used by the remote unit transmitters to transmit upstream data to the central unit. The central unit receiver detects the phase difference between the reference carrier and clock signals from the remote units periodically and adjusts the phase of the master carrier and master clock signals for use by the central unit receiver to receive the upstream data.

Abstract: An ADSL termination unit, which at the transmission end includes a descrambler and a compressor between its scrambler and interleaver. The present invention provides for the use of compression on the data in a channel to remove some of the inherent redundancy, in order to yield much better throughput, particularly in conjunction with certain powerful FEC schemes. In this manner the compression may be performed on unscrambled data that has a higher redundancy than scrambled data, thereby improving compression. At the reception end, the ADSL termination unit includes a decompressor and a scrambler between its deinterleaver and descrambler.

Abstract: A wide area communications network (500) includes a first digital subscriber line (502). A first network interface device (504) connects to the digital subscriber line (502). The first network interface device (504) separates an ISDN channel (508) from a digital subscriber channel (510). An ISDN telephone (508) is connected to the network interface device (504). A protocol translator (512) is connected to the network interface device (504) by the digital subscriber channel (510). A hub (514) is connected to the protocol translator (512). A plurality of devices (516, 518) is connected to the hub (514). A digital subscriber line access multiplexer (506) is connected to the first digital subscriber line (502). The digital subscriber line access multiplexer (506) separates the digital subscriber channel from the ISDN channel (522). A public switched telephone network (523) is connected to the ISDN channel (522).

Abstract: A system for implementing multiple communication channels on a single twisted pair transmission line is disclosed. The system derives additional communication channels by way of a separate transceiver unit for each derived line. Each transceiver unit communicates in a separate predetermined frequency band. Each transceiver unit, upon connection to the transmission line, automatically utilizes the lowest unoccupied frequency band by monitoring each frequency band for the presence of signal power. Thus, as many derived lines as will be supported by the customer transmission loop can be readily added.

Abstract: An architecture, as well as various components, of an asynchronous transfer mode (ATM) subscriber access multiplexer (ASAM) system can be implemented using an XDSL (x-Digital Subscriber Line) using DMT (Discrete Multitone) or CAP (Carrierless Amplitude Phase Modulation) between a plurality of subscribers and a corresponding plurality of line termination equipment in a shelf that also includes network termination equipment for connection to an ATM network. The line termination and network termination equipment are interconnected by a bus internal to the shelf for providing subscriber access. Separate lowpass filters are provided at each end of a twisted wire pair between the shelf and each subscriber equipment. A shelf can be used as a hub for connecting to a remote shelf that includes the line termination equipment for connection to subscribers.

Abstract: A system for bidirectional communication of digital data between a central unit and a remote unit wherein the need for tracking loops in the central unit has been eliminated. The central unit transmitter generates a master carrier and a master clock signal which are used to transmit downstream data to the remote units. The remote units recover the master carrier and master clock and synchronize local oscillators in each remote unit to these master carrier and master clock signals to generate reference carrier and clock signals for use by the remote unit receiver. These reference carrier and clock signals are also used by the remote unit transmitters to transmit upstream data to the central unit. The central unit receiver detects the phase difference between the reference carrier and clock signals from the remote units periodically and adjusts the phase of the master carrier and master clock signals for use by the central unit receiver to receive the upstream data.

Abstract: A LAN constituted over a pair of buildings, located a distance from each other, comprises hubs, a server and personal computers. In the LAN, a wired LAN including a wireless transmission section between the pair of buildings, and a wireless LAN including wireless access sections between an access point and wireless terminals are connected to each other. A transmission frequency band (5 GHz) used in the wireless transmission section and a transmission frequency band (2.4 GHz) used in the wireless access sections are set to be distinct from each other so that the deterioration of transmission quality by interference of electric waves used in both of the wireless sections can be securely prevented.