Abstract: A plurality of routing modules in a switching network of a telecommunication system each includes several interfaces connected to a first channel concentrator via respective data stores receiving and temporarily memorizing incoming data words coding the voltage levels of message samples from associated peripheral units served by the respective interface. In response to commands from a control unit, included in the module, this first concentrator selectively transmits memorized data words in respective phases of a PCM frame to all the modules in the network. Outgoing data words issuing from any routing module are registered in other data stores and selectively extracted therefrom by a second channel concentrator under instructions from the control unit, the extracted data words being distributed by a channel expander commanded by the control unit to registers assigned to respective peripheral units.

Abstract: An interface interposed between a PCM data terminal and a processor comprises a bus accessor dialoguing with the processor, input and output circuitry coupled to the terminal, and intervening logic circuits and data stores designed to supply the processor in a time-division mode with preprocessed messages received or to be transmitted over a multiplicity of channels. The interface is operable according to dialogue procedures of HDLC type such as those corresponding to CCITT recommendations X25, X75 and N. 7, with switchover from one protocol to another.

Abstract: A concentrator is connected to a line test bus (BL) and a terminal test bus (BT) which are common to a plurality of concentrators. A concentrator is constituted by a plurality of terminal units (UT1 to UTm) connected to a spare bus (BS) internal to the concentrator. Each terminal unit includes a plurality of terminals (T1 to Tn) with associated terminal relays (R1 to Rn), a control logic circuit (LOG) and an isolating relay (RI) connected firstly to the spare bus, to the line test bus and to the terminal test bus, and secondly to the terminal relays by line wires (LA1, LA2) and junctor wires (LJ1, LJ2). In one of the terminal units of the concentrator, one of the terminals is a spare terminal (TS) and its associated terminal relay is a spare relay (RS) and the spare relay is directly connected to the spare bus.

Abstract: A multiplexed data communications modem providing high speed data communication via a single twisted pair of conductors having a distance up to two kilometers between a plurality of data terminals and remote communications equipment is provided. A burst mode ping-pong transmission scheme is utilized. A control portion selectively multiplexes data from each data terminal, and the variation of actual data rate of each data terminal has no effect on channel capacity of the other multiplexed data channels. A plurality of data interface circuits provides an asynchronous/synchronous interface between the multiplexed data terminals and a synchronous transceiver.

Abstract: In a packet communication system of a multiaccess type in which a single communication medium is used commonly and divided into a plurality of channels, respective users observe states of the channels and the probability of packet transmission to respective channels is controlled in accordance with observed information, respective users are assigned parameters corresponding to respective channels and the probability of packet transmission onto the channels is controlled according to the parameters, a dummy packet is continuously transmitted for a predetermined time at in channels having low utilization factors, for data requiring immediate transmission. In a modification, a setup packet is sent for data requiring immediate transmission. All the users determine whether the received packet is the setup packet and the set the stored parameters.

Abstract: The invention relates to a multiplexer, a demultiplexer and to multiplexing-demultiplexing equipment with configurable frames.The reconfigurable frame multiplexer comprises a synchronous multiplexer, means for inserting a frame locking word, transmission management means, monitoring means and a microprocessor for controlling or communicating with the aforementioned means. A time base emits timing and synchronization signal for emitting a frame. This time base comprises a memory containing data, which codes the present frame configuration. During the reading of this memory by a fast time base, another memory is filled by the microprocessor in order to code a new frame configuration.

Abstract: The method of growth of the digital switchblock is for use in telecommunications. The switchblock comprises a plurality of superplanes each including a plurality of central digital switching modules interconnected to a plurality of demultiplexer-mixer-remultiplexer stages; and, a plurality of outer digital switching modules connected to the demultiplexer-mixer-remultiplexer stages on each side of the superplanes. The outer digital switching modules are increased linearly as the number of telecommunication lines is increased from a first order of telecommunication lines. The number of superplanes is increased linearly as the number of telecommunication lines increase from the first order of telecommunication lines to a second order of telecommunication lines and thereafter remain constant as the number of lines increase.

Abstract: In a telephone system, particularly a mobile radio-telephone system, incorporating statistical multiplexers and control concentrators for the arranging and formatting of digitized data, the data is formatted with operational codes designating specific meaning and any one of a plurality of levels of protection to be offered data transmitted via the telephone system. A back-up memory is connected to the statistical multiplexer to enable a retransmission of a batch of data in the event that the batch had been received with error. Full duplex communication is provided. A circular sequence number interleaved among batches of the data is utilized by an error detector at a receiving site to determine the presence of all portions of a batch of data. Transmission of specified operational codes and additional data as required in the reverse direction commands a retransmission and also provides for acknowledgement of receipt of a data batch with and without error.

Abstract: A method of simultaneously transmitting both isochronous and nonisochronous data on a local area network includes the steps of: circulating around the network, a first unique signal pattern and at least one occurrence of a second unique signal pattern with a constant time interval between each unique signal pattern and the next one; writing nonisochronous data onto the network from any station and subsequently removing the same in response to a counter that is synchronized to the first unique signal pattern; and simultaneously, writing isochronous data onto the network from any station in response to a counter that is synchronized to each occurrence of the first and second signal patterns.

Abstract: Time Division Multiple Access (TDMA) is being utilized widely in domestic and international communication networks. The types of TDMA networks in operation fall into two categories: Wideband and Narrowband. In the past few years, a number of Wideband and Narrowband TDMA networks have gone into operation. However, these networks have typically operated as independent nets. As the existing Wideband TDMA networks expand into cities with a smaller amount of originating traffic, a major economic problem occurs. It becomes difficult to justify the cost of a Wideband TDMA station for the smaller amount of traffic.This invention presents an approach that solves the above problem by providing an integrated network with Wideband TDMA for the large cities and Narrowband TDMA for the smaller cities.

Abstract: A data transmitting-receiving system including both a transmitter part and a receiver part. The transmitter part transmits a modulation signal on one of the vertically and horizontally polarized waves and, at the same time, transmits a carrier on the other of the waves. The modulation signal on one of the waves is received and demodulated by the receiver part with the carrier on the other of the waves also received by the receiver part.

Abstract: Fair and fast service to a plurality of channels served by packet switches at nodes interconnected through a common carrier facility is achieved by controlling the quantity of data sent from any one channel to another. When data arrives at a node from a channel, the channel address is entered in line in the first of two channel address queues and the data is entered in a separate data queue. Each channel address is read from the first queue, a predetermined number of data bytes is read from the corresponding data queue and sent in a frame to a distant node. Thereafter, the channel address is entered at the end of the second, lower priority queue. The frame may have data bytes from other first queue channels but the frame length is limited either by a predetermined number of bytes or when no more channel addresses remain in the first queue. When no channel addresses remain in the first queue, a new frame is started by reading a channel address from the lower priority second queue.

Abstract: A data communication system allocates use of a common data communication medium shared by a plurality of stations. During each transmission cycle, the communication medium carries data packets of varying priority which each station receives. The stations are allocated use of the communication medium during one or more priority intervals as a function of the priority of the packet which the station is ready to transmit. Each station is synchronized to a transmission cycle period which is divided into subperiods. Certain types of packets are relegated to transmission and reception within predetermined subperiods.

Abstract: A method and apparatus for protecting the integrity of data in a multi-loop communication network is disclosed. A source station generates and forwards a frame with a unique format and a frame check sequence (FCS). At each bridge, an algorithm is provided to process the frame. If the frame is at a source bridge and not discarded, the FCS is preserved by encapsulating it in the Information field. The source bridge generates a new FCS, appends it to the frame and forwards the frame. Thereafter, each intermediate bridge generates its own FCS, appends it to the frame and forwards the frame. At the target bridge, no FCS is generated. The preserved FCS is forwarded as the FCS of the frame.

Abstract: Multiservice packet telecommunication network in which each packet has inserted in an address field thereof a sequence of addresses respectively assigned to the successive switching network included in a route from a packet sender station to a packet receiver station and defining in these networks groups or bundles of outgoing channels. In each bundle the seizure of an outgoing channel is made by scanning and searching a free channel in the bundle.

Abstract: A station interface for a digital electronic telephone switching system is disclosed. The station interface couples a plurality of digital telephone instruments to a digital data bus having PCM encoded signals representative of analog voice signals time-division multiplexed thereon. The station interface enables two way communication between the telephone instruments and the digital data bus and includes a frame store memory for temporarily storing digital data on the data bus and assigning the digital data to system time slots. The output of the frame store memory is selectively supplied under microprocessor control to a digital audio processor which processes the PCM encoded voice signals from the telephone stations and supplies these signals to the audio processor. The audio processor digitally processes both the selected data from the frame store memory and the data from the telephone stations forwarded by a multiplexer, in respective system time slots, under microprocessor control.

Abstract: A satellite communications system has a number of earth stations sharing an uplink carrier in a time division multiple access mode. One of the earth stations is designated as the master station for the carrier. The uplink transmissions from each station are synchronized by computing the time interval between the arrival at the satellite of the signal from the master station and the signal arrival from each of the other stations. The actual time intervals are compared to the optimum intervals for a properly synchronized transmission from each station. If the comparison indicates that a given earth station is not properly synchronized, that station's time of transmission is adjusted until the actual interval substantially matches the optimum interval.

Abstract: A time division multiplex conferencer for continuously summing and outputting digital message samples received from n subscribers in n respective time slots. Message samples collected from each subscriber of a conference connection are summed during a first time frame and outputted during a second time frame. The conferencing is carried out in real time under common control to provide one or more conference-type connections between two or more subscribers. The conferencer also has the ability to establish transmit-only or receive-only connections for one or more subscribers. The conferencing is conducted in a manner that is completely independent of time slot assignments within a frame.

Abstract: In a multiple access system for performing packet communication involving sharing of a single communication medium by a plurality of users, the single communication medium is divided into a plurality of channels. Each user monitors the condition of each channel, and probability of packet transmission to each channel is controlled in accordance with a monitored result.

Abstract: Speech bit rate reduction by robbing, e.g. periodically not transmitting, a percentage of speech data samples in a communication system employing differential pulse code modulation (DPCM) or adaptive differential pulse code modulation (ADPCM). To overcome feedback interference introduced in the code by sample robbing, a robbed sample is replaced by its estimate so that the coding process continues in a normal manner. The estimate is established on the basis of autocorrelation statistics of the speech data samples. At the receiving end of the communication system, the robbed sample is estimated by the same process and re-estimated again using delayed interpolation after one period of delay. The technique is particularly useful where graceful degradation is desired under heavy traffic loading on the data channel, and is found most beneficial when the bit rate is about 24kb/s or lower where a relatively larger quantizing noise masks the interpolation noise introduced by sample robbing.