Abstract: A method and an apparatus for searching a bit field whose significant bits comprise two contiguous bit fields such as the VPI/VCI bit fields of an ATM cell header. The invention uses a hash key based on CRC-n calculated on the bit field to be searched. One m bit field part of the significant bits of the bit field to be searched can be concatenated with the CRC-n to form a double hash key. It appears that, L being the total of the two contiguous bit field lengths, if L=m=n+p, p being greater or equal to 4, the scattering of data to be searched is perfect. The method comprised a first step of pointing to a first address with the hash (or double hash) key and reading a maximum of 2.sup.p addresses before reaching the addresses containing the bit field to be searched.

Abstract: A repeater device for forwarding a data packet from a first Ethernet collision domain to a second Ethernet collision domain has a plurality of ports, each port for connection to an independent Ethernet collision domain, each port has an associated receive buffer and an associated transmit buffer, and there is a means for forwarding a data packet from the receive buffer of a receiving port to the transmit buffer of a transmitting port. A data packet received at the receiving port is then first stored in that port's the receive buffer, is forwarded to the transmit buffer of the transmitting port, and is then transmitted from the transmit buffer by the transmitting port.

Abstract: A digitally recording and reproducing apparatus simultaneously records two kinds of digital signals of an identical video program, generated by high-efficiency coding, or a relatively high bit-rate signal and a relatively low bit-rate signal, onto the approximately the same positions on the tape. The apparatus is constructed so that the low bit-rate signal is commonly used for normal playback and search-playback. Further, the recording time can be lengthened by reducing the recording bit-rate.

Abstract: In order to improve a transcoder unit (TRCU) for use in a telecommunications network in such a way that digital voice signals can be transmitted at different transcoding rates, it is proposed to dispose at least two arithmetic units (FR, HR, EFR) with different transcoding rates on respective plug-in circuit boards in the transcoder unit, and to provide the transcoder unit with a subrack with backpanel wiring which receives these plug-in circuit boards. In this manner, arithmetic units each containing eight digital signal processors, for example, are provided for each of the different transcoding rates. The arithmetic unit can be optimized for each transcoding rate. Individual plug-in circuit boards can be replaced or added as supplements. The transcoder unit (TRCU) is modular in construction and can be assembled or converted very flexibly, e.g., in the manner of a backplane system. The transcoder unit is used, for example, in a wireless telecommunications network, i.e., in a mobile radio network.

Abstract: A wavelength-switching, mesh-based restoration method among a network of optical cross-connects (OXCs) is disclosed. The method is defined as "quasi-centralized" in that the network is first partitioned into a plurality of subnetworks, then a single "restoration controller" is defined for each separate subnetwork. The subnetwork partitioning is defined as being either "minimally overlapping", meaning that the OXCs are "clustered" in their network topology, with only a few links required to join the various, autonomous subnetworks, or "highly overlapping", meaning that the OXCs are defined as being included in more than one subnetwork. Each subnetwork restoration controller (SRC) includes a network graph and is therefore responsible for providing restoration around faults recognized in its own subnetwork.

Abstract: A memory device, a method of content-addressing a memory device to validate an incoming pattern and an Asynchronous Transfer Mode (ATM) communication switching system incorporating the device or the method. In one embodiment, the device includes: (1) a validation random access memory (RAM) having a plurality of addressable locations therein, the addressable locations containing validation indicators corresponding to patterns that have been programed into the validation RAM and (2) circuitry, coupled to the validation RAM, that provides an incoming pattern to the validation RAM and retrieves a corresponding validation indicator from the validation RAM, the validation indicator indicating whether the incoming pattern had been programed into the validation RAM. The memory device thereby functions as a content-addressable memory (CAM).

Abstract: A dynamic and decentralized self-adaptive method and system including allocation of all time/frequency resources available at a given moment to as many requesting mobile units as are necessary. Transmission between stations is performed by allocation of frequencies. For each frequency allocated, the transmissions are grouped in slots forming frames in a time/frequency space. Each frame includes n slots of a same duration and a same width. The method includes using the allocated transmission frequencies and the frames for each transmission from a station by occupancy of one and the same number of slots according to a modulo p operation. A search is made, during a monitoring procedure, for free slots to determine parameters of occupation of a transmission as a function of the state of occupancy of the frames of the time/frequency space existing before the transmission.

Abstract: A communications system (100) has a TDMA signal (110) accessed by one or more mobile stations (104). The TDMA signal carries both circuit switched and packet data service. A packet channel is defined within a packet data frame (208) by assigning time slots not used by other services during the packet data frame to the packet channel. A packet data seed channel (204) is used to anchor the packet channel and steer a mobile station to the packet channel. In the packet data seed channel a dynamic allocation protocol (DCAP) slot (206) appears and carries the packet channel slot assignments for the next occurring packet data frame.

Abstract: A digital signal processing system for multiplexing/demultiplexing a large number of closely spaced FDM channels in which sub-band definition filtering divides the FDM spectral band comprised of "N" channels into "K" sub-bands in order to reduce the dimension of the polyphase filter fast Fourier transform structure required to complete the multiplexing/demultiplexing. This reduces the order of the required prototype filter by a factor proportional to K. The number of sub-bands K is chosen so that it is large enough to ensure the polyphase filter, fast Fourier transform structure for each sub-band is realizable within a finite word length, fixed point arithmetic implementation compatible with a low power consumption. To facilitate efficient sub-band definition filtering, the real basebanded composite signal is inputted at a spectral offset from DC equal to one quarter the FDM channel bandwidth for the N channels and the signal is sampled at a frequency 50% greater than the applicable Nyquist rate.

Abstract: The present invention allows telephone subscriber loops carrying data traffic between computer systems to be switched to an alternative connection through a data network, thereby unloading data traffic from the telephone network. The invention operates by means of a break switch, which selectively switches a plurality of subscriber loops between a central office switching system and a data network. The break switch is coupled to a concentrator which takes a plurality of inputs from the break switch and connects them to a smaller number of modems in a modem pool. The concentrator allows a subscriber line to connect to different types of modems within the modem pool, depending upon requirements of a particular subscriber line user. The modem pool connects through a network interface to a packet-switched network, such as the Internet. A number of different methods can be used to transmit a command to switch a subscriber loop from the central office switching system to the packet-switched network.

Abstract: In a radio packet communication system between a master station and a plurality of slave stations, a contention mode is switched to a polling mode or vice versa in accordance with the amount of transmission data reserved by the slave stations to the master station.

Abstract: Arrangements for controlling a data switching network fabric and for synchronizing duplicate modules of such a fabric. A control complex, for determining new virtual connections to be established, and for disconnecting existing virtual connections, is connected through data links to the network fabric of a data switch. The network fabric has internal control processors. The control complex communicates with these processors by sending control packets over a dedicated internal ATM link and virtual connections to these internal processors to control their establishment and disconnection of user virtual connections. Duplicate modules of the data switching fabric receive identical packets and, when synchronized, transmit identical packets at the same time. The synchronization process is implemented by data links between the control processors of the duplicate fabrics to report progress on the step by step synchronization of internal queues.

Abstract: Arrangements for controlling a data switching network fabric and for synchronizing duplicate modules of such a fabric. A control complex, for determining new virtual connections to be established, and for disconnecting existing virtual connections, is connected through data links to the network fabric of a data switch. The network fabric has internal control processors. The control complex communicates with these processors by sending control packets over a dedicated internal ATM link and virtual connections to these internal processors to control their establishment and disconnection of user virtual connections. Duplicate modules of the data switching fabric receive identical packets and, when synchronized, transmit identical packets at the same time. The synchronization process is implemented by data links between the control processors of the duplicate fabrics to report progress on the step by step synchronization of internal queues.

Abstract: A cell bus, which reduces the number of conductors required to transfer data in a telecommunications switching fabric, contains a plurality of conductors, Data[X:0], for transmitting information. A cell bus interface generates a cell bus frame that includes a plurality of words, "X" bits in length, of both data and control information that includes, in part, routing information for the data. As a result of encapsulating data and control information into and cell bus frame for transmission on the Data[X:0] conductors, the number of conductors required to transmit data is reduced. An asynchronous transfer mode (ATM) switching fabric, which includes a plurality of cell buses configured in a point to point fashion between a cell routing unit (CRU)/ATM fiber bank interface unit (AFIU) and a plurality of optical line units (OLUs), is also disclosed.

Abstract: An ATM-switch for high transmission rates is built of primary switch cores. A path for a cell through the switch is determined at the arrival of the cell at the switch and this path is coded as a control word, which is transferred through the switch in parallel to the cell itself. The control word indicates directly how the transfer through each primary element of the switch is to be made. Each primary element must only have two inputs and two outputs. The control word then consists of one bit for every stage of primary switch elements in the switch and this bit indicates directly the output from which the cell is to be forwarded from a considered switch element. The switch cores are constructed of intermediate storage memories, one for each pair of one input and one output, and these intermediate storage memories can have a rather limited capacity for storing only a few cells together with their associated control words.

Abstract: A method and system use voiceband transmission characteristics to estimate the viability of deploying broadband services over a subscriber loop in the public switched telephone network. The system gives network service providers the ability to predict the performance of broadband transmission channels, such as ADSL, on a subscriber loop from a central location and without reliance on outdated loop records maintained by a carrier. Based on this predicted performance a network service provider is able to efficiently determine the viability of deploying ADSL to a subscriber and, in turn, determine the viability of deploying ADSL in entire areas by creating an ADSL--ready consumer-lead list. The method comprises establishing an end to end voiceband modem connection from a logic device to a remote computer over a facility wherein the only analog elements reside in the subscriber loop.

Abstract: The present invention is a digital FM voice paging system which uses digital signal processing (including D/A conversion and data compression) to transmit voice pager data over existing FM broadcast subcarriers.

Abstract: In a data transmission method and circuit for communication between a programming apparatus and a user apparatus to be programmed, such as a hearing aid, data as well as clock pulses are transmitted by the programming apparatus to the user apparatus for the individual adjustment of application-specific data of the user apparatus. The data and clock pulses are transmitted in half-duplex operation using a single signal line. Differently fashioned clock pulses of an outgoing signal with digital information are supplied to the signal line, and the digital information is recovered at the user apparatus by means of clock pulse variation, and the recovered information is subsequently processed with the transmitted clock pulse.

Abstract: Each packet normally consists of a preamble, start-of-frame delimiter and data. The preamble has nibbles each having a particular format. A header substituted for preamble nibbles by an individual one of the originating devices in a plurality, and an individual one of the ports in such originating device, indicates such originating device and such port. Such port in such originating device sends such modified packet to others of the originating devices and to an observing station. The header format is such that the last nibble in the header and the remaining preamble portion will not be confused with any two (2) nibbles in the header. A particular one of the originating devices indicated in the data converts the header back to the preamble format and transmits the converted packet to a receiving station. The observing station records the individual originating device, and the individual port in such device, indicated in the header.

Abstract: A data bus system comprises a number of stations which are interconnected via a bus. The bus has a limited data transmission capacity available. From a transmitter station a resource control station reads which part of the available transmission capacity is required for the relevant transmitter. The resource control station allocates the required transmission capacity to the relevant transmitter station if adequate transmission capacity is available; it is only in that case that transmission by the relevant transmitter station is enabled.