Abstract: A microcellular digital packet communication system is provided for digital communication having a plurality of repeating packet-mode fixed-site transceivers each being at a plurality of different sites and each being capable of communicating on mutually-common frequencies, including for example by means of frequency-hopping spread spectrum, wherein a terminal transceiver directly communicates substantially simultaneously with at least a few of the fixed-site transceivers on the mutually-common frequencies and distributes information packets of a single originating message among the fixed-site transceivers, the fixed-site transceivers forwarding the information packets via multiple communication links to a single destination terminal on the mutually-common frequencies at which the message is reassembled. The system enables reliable handoffs and robust connectivity by maintaining multiple simultaneous communication links between terminal transceivers and repeating transceivers.

Abstract: A multi-master serial bus system supporting, for example, up to 32 masters, and usable in applications requiring high-speed communications within a shelf. A plurality of nodes (2, 3, 4, 5) are interconnected by a highway (1) over which data is transmitted between the nodes. Each node has access control means (6) which ensures only one node accesses the highway at a time by means of an arbitration scheme. Data transmission involves an arbitration phase and a transmission phase and the highway comprises three lines, two of which are shared and perform respective functions in the arbitration and transmission phases (FIG. 1).

Abstract: A method and apparatus for routing packets through a multinode communication network includes a packet format with a sub-field in which a routing list (RL) having entry addresses and exit addresses for ports of nodes, through which the packet must be routed. Each node on receiving a packet, extracts routing information specific to the node and forwards the packet according to the extracted routing information.

Abstract: System for processing signalling relating to user equipments for the core system of a telecommunication installation constructed around circuit mode units connecting user equipments, auxiliary units and/or control or processing equipments. Each unit has means for adapting the signalling information for said user equipments, auxiliary units or control or processing equipments connected for transmission of said signalling information internally in a standardized form which can be switched by the unit and means for preprocessing signalling information to the benefit of the microprocessor, the auxiliary unit or the control or processing equipment responsible for processing it.

Abstract: A multistation communication bus system including a plurality of master stations and a slave station for transmitting information from the master stations and slave station using a frame based arbitration process. The master station which wins the arbitration transmits a framewise organized message including locking and unlocking signals for respectively, locking and unlocking an addressed slave station, thus blocking any other master station from accessing the slave station for a duration of multiple frames of the message.Any other master station, upon detecting this blocking condition, executes a first sequence of retry undertakings at a combined time length that is substantially less than a standard maximum value of the duration. A second sequence of less frequent retry undertakings at a combined time length that is more than a standard maximum value of the duration may then be attempted.

Abstract: While participating in a group call on a first wireless communication resource 114, senior members 104-107 of a communication group 108 can initiate a semi-private call. A central controller 110 allocates a second wireless communication resource 115 for the semi-private call. Furthermore, executive members 106-107 can initiate an executive call to be established on a third wireless communication resource 116. Executive members can participate in the executive call, the semi-private call, and the group call, whereas senior members can participate in the semi-private call and the group call. Junior members 101-103, normally allowed to participate only in the group call, can be selected by senior members to temporarily participate in the group call and the semi-private call.

Abstract: An exchange having a digital switching network and peripheral units connected thereto, the peripheral units serving to interface with subscribers, other exchanges, or maintenance devices or to perform other functions, and the switching network serving to establish arbitrary traffic relations between the units, particularly to establish switched connections between attached subscribers or exchanges, characterized in that at the interface to the peripheral units, the digital switching network is overdimensioned more than twofold. The switching network may advantageously be an ATM switching network, and the interface between the switching network and the peripheral units may have narrow-band and broadband inputs and outputs.

Abstract: The bandwidth of a packet data transmission node is switched asynchronously without interruption of data transmission and with a minimum of circuit complexity. In particular, a packet channel is permitted to "breathe", gaining bandwidth when additional bandwidth becomes available from other temporarily unused digital channels and losing such additional bandwidth when such unused digital channels revert to other use. To permit such uninterrupted asynchronous operation, a "pad" or "throw away" character is defined which is ignored or discarded when it is received by another packet network node. Such a "pad" or "throwaway" character is unique only in the sense that it is distinct from and may not be confused with characters or bytes which may occur in normal data transmission sequences.

Abstract: An optical fiber ring network carries data in frames of bit intervals that define a number of independent communication bands each represented by a series of spaced apart bit intervals no more than one of which falls within any given frame. The network serves a collision detection protocol by nodes that communicate with the user devices in accordance with the collision detection protocol but communicates with the ring in accordance with a non-collision type protocol. The network uses light that is amplitude modulated at more than two levels. The data frame boundaries are defined by violations of an alternate mark inversion data encoding technique. Phase synchronization of two streams of frames is accomplished by sampling frames at times governed by a selected one of two frame boundary clocks derived respectively from the two frames.

Abstract: A tributary interface, which performs interfacing between a high order transmission system and itself and includes a working tributary interface and a protection tributary interface as a pair for time slot interchanging with respect to the high order transmission system, is constructed so that the working tributary interface and the protection tributary interface can be operated independently. Thereby, in a time slot interchange unit of the SDH transmission system, the number of interfaces operable at a lower order side is temporarily increased so as to be able to cope with a request for temporarily increasing the number of interfaces from a user.

Abstract: A plurality of ATM networks may be interconnected to allow communication of voice-band signals between them by using one or more PSTNs and a novel interface that converts ATM formatted data packets to a format usable by digital multiplication equipment (DCME). Such an interface thus allows the DCME to advantageously function as a gateway between the ATM network and PSTN by providing for optimum bandwidth usage between the networks. In an illustrative example of the invention, a DCME available from AT&T as the Integrated Access and Cross Connect System ("IACS"), is provided with an ATM-to-DCME interface that converts ATM formatted packets to a regular channelized bitstream usable as an input by the IACS. The interface and the IACS are positioned on both ends of a PSTN to allow for connectivity between the PSTN and a plurality of ATM networks, as well as the required optimization of bandwidth usage.

Abstract: A method and apparatus for routing a message embodied in a signal received by an electronic messaging system includes formatting a search key using address codes parsed from a user address specified in the message, where each of the address codes corresponds to a different level of specificity for the user address. An attempt is made to retrieve a record from a database of routing information using the search key. If no record is found, the address code corresponding to the most detailed level of specificity in the user address is stripped from the search key and another attempt is made to retrieve a record. This process continues until a record is successfully retrieved from the database or a predetermined base level of specificity is reached.

Abstract: A source station writes addresses of destination stations in a data field of a frame, and sends the frame to a data transmission network by using one of those address as a destination address. A station which receives the frame, after writing information in the frame, sends the frame to another station whose address is written in the data field of the send frame and which has not received the frame. These operations are repeated until the frame is sent to all destination stations. Thus, when a frame is sent to a plurality of stations, traffic density can be reduced, and a transfer sequence can be set according to the state of the transmission network and the stations, Further, when a frame cannot be sent to any destination station, information about this failure to send is written in the frame, and the frame is sent to another station which has not received the frame.

Abstract: A terminal is disclosed for use with a system for digital conferencing over narrowband channels which allows use by multiple simultaneous speakers and which allow for interfacing between systems which operate at different bit rates. For each conferee, the terminals interconnect between an A/P converter and a modem, and contain an analyzer and a synthesizer. The analyzer receives digitized speech and encodes it at the system data rate for transmission to the bridge by the modem. The synthesizer receives encoded digital data streams and produces therefrom artificial speech at selected data rates that are inversely proportional to the number of external speakers. One technique used by the synthesizer is the use of overlap-add synthesis which allows for a particularly simple method for synthesizing multiple speakers. With the over-lap add technique a speaker's parameters, pitch voicing, and spectrum, are used to fill out an FFT buffer. The inverse transform is taken and summed in the usual overlap-add manner.

Abstract: A method of de-interleaving ISDN channels for an information signal transceived through an ISDN interface.

Abstract: A method for controlling packet communications between a source and destination causes a source to perform the steps of: transmitting a message to the destination which requests an allocation of a specified number of credits from the destination, a credit manifesting a portion of memory space in the destination that has been set aside to store a received packet; updating a stored credit value at the source upon receipt of a message from the destination which grants at least some of the requested credits; and transmitting a packet or packets from the source to the destination and decrementing the stored credit value for each transmitted packet. The source also includes means for transmitting a packet debit command which returns to the destination credits that are no longer required by the source, thus enabling the destination to reallocate the debited credits to another source which wishes to communicate.

Abstract: In a call disconnection method and a system for executing the same in an ATM (Asynchronous Transfer Mode) network, a plurality of timers are provided corresponding to each call in an exchange of an ATM network. A connected call is detected, and a data cell is not transmitted for longer than a predetermined time, by using the corresponding timer, and disconnecting the detected call from the ATM network.

Abstract: A method and apparatus for concurrent communication of analog information and digital information. In general terms, when the communication channel is viewed as a multi-dimensional space, the digital information signal is divided into symbols, and the symbols are mapped onto the signal space with a preset distance between them. The analog signal, generally limited in magnitude to less than the distance separating the symbols, is converted to component signals and added (i.e., vector addition) to the symbols. The sum signal is then transmitted to the receiver where the symbols are detected and subtracted from the received signal to yield the analog signal components. The transmitted analog signal is recreated from those components. Both half-duplex and full-duplex operation is available in accordance with the disclosure.

Abstract: An improved method for exchange of data in data processing installations, especially Controller Areas Networks (CAN), permits acknowledged and segmented transmission of data strings, of arbitrarily long length, between at least two stations in the network or other data processing installation. The method includes the transmission of the messages associated with the data by means of frames; the frames contain a header field and a data field. In the event of contention between multiple stations of the data processing installation for access to the bus connection, which frame has priority is determined by evaluating the respective header fields. In the data field of the frame, there is a control information field (58, 95) containing a message code which serves to identify the message type. The message codes distinguish among activation messages (AR, AC), data messages (DT), and acknowledgement (AK) messages. This permits transmission of data strings, of limited length, with acknowledgement.

Abstract: A communication control method for sequentially allocating transmitting rights to a plurality of nodes commonly connected to a single transmission line, wherein each of the nodes forms, when the own node has a transmitting right and when the own node has no data to be transmitted, a predetermined period of a no signal state in which any signal is not transmitted to the transmission line, whereby the circulating time of the transmitting rights from the node having the minimum node number to the node having the maximum node number can be shortened.