Abstract: A local alarm circuit and a remote alarm circuit carry out a plurality of failure monitoring and alarming functions for each of a plurality of digital groups (digroups), of time division multiplexed channels that are time multiplexed together on to a common bus. The local and remote alarm circuits utilize common control techniques and are of a similar circuit configuration. Each alarm circuit comprises an alarm timing store having a shared recirculating memory, and an alarm status store with a shared recirculating memory. The timing store serves to integrate and time failure indications for each of the digroups, and the status store maintains a continuing real time record of the alarm status for each digroup. When the timing store counts out a predetermined failure duration for a given digroup, the alarm status record for the digroup is changed and an alarm signal is generated.

Abstract: A multiple channel decommutator accumulator for decommutating a multiplexed ncoded signal forming a train of serial pulses on a single input line to form a series of parallel channels wherein the pulses are accumulated. A display device is provided for addressing any one of the series of channels for continuously displaying the signal accumulated by the channel.

Abstract: A station direct station selection system is provided with a time division multiplex signalling line which carries all the signals that are required to establish and to terminate connections. The control means for establishing and terminating connections are decentralized and arranged mainly at the locations of the subscriber stations and at the locations of the line transmissions.

Abstract: Disclosed is a digital multiplexer which combines N parallel bit-synchronized digital signals, each of bit rate f.sub.1, into a single composite line signal of bit rate f.sub.2, where f.sub.2 > Nf.sub.1. Before the individual bits are interleaved, each digital signal is converted to a submultiple of the line frequency, f.sub.2. By inserting gaps having a predetermined duration and occurring at a fixed rate into each of the N digital signals, the bit rate f.sub.1 of each bit stream is increased to f.sub.2 /N. This is done without sampling any bit more than once. A multiplexer sequentially interleaves each bit from the N converted bit streams along with the gaps in each bit stream, forming the composite signal of bit rate f.sub.2. The interleaved gaps form empty time slots in the composite signal into which one or more signaling bits are added. Some of the added signaling bits carry framing information to lock the transmitter and receiver together.

Abstract: A time-division multiplexing system wherein N parallel digital signals having an average bit rate of f.sub.1 are interleaved by a multiplexer to form a single composite line signal of bit rate f.sub.2, where f.sub.2 > NF.sub.1. Prior to multiplexing, signal gaps having a predetermined duration and having a fixed repetition rate are inserted into each of the N parallel signals. Adding gaps to each digital signal permits the bit rate between gaps to be increased to f.sub.2 /N, a submultiple of the composite line signal bit rate. The gap duration and their occurrence is such so as to maintain the average bit rate of each digital signal at f.sub.1. Each digital signal with the added gaps is then interleaved to form the composite line signal having the desired bit rate of f.sub.2. The interleaved gaps form empty time slots in the composite signal into which one or more signaling bits are added.

Abstract: In a carrier frequency multiplex system for single sideband transmission of telephone channels which have been converted through the transmission position of the transmission band of the system through the utilization of carriers which are whole number multiples of 4 kHz, the transmission of videophone channels which have been converted from the video position to the transmission position with carriers that are chosen such that those video carriers corresponding to the frequency zero in the video position are multiples of 4 kHz in the transmission position.

Abstract: Protection for service lines linking offices in a communications system is realized by linking the offices in a sequence with a serial connection of protection lines. Protection for service lines which bypass one or more of the offices in the serial sequence is achieved by automatically controllably cascading appropriate ones of the protection lines. The cascading of protection lines is realized on a nonhierarchical basis by assigning each service line in the system a unique address and by supplying a protection switch request message including the address of the requesting service line sequentially to each office in the serial sequence until the transmit-end of the requesting line is located. A switch is automatically effected by equipment located at the offices only if all the protection lines to be cascaded are available.

Abstract: A line concentrator for a time division data switching exchange. Asynchronous and synchronous data signals generated at asynchronous and synchronous data terminals are subjected to known multi-point and synchronous sampling to become a train of bit-multiplexed first asynchronous and synchronous data channel signals. Responsive to a train of bit-interleaved read-in pulse groups timed relative to the respective synchronous data signals, an arithmetic unit stores the data channel signals in an octet memory according to the asynchronous and synchronous data terminals. Responsive to a train of read-out pulses appearing for the respective data terminals, the arithmetic unit reproduces groups of uninterleaved data channel signals for each data terminal and composes the reproduced data channel signals into a train of second asynchronous and synchronous data channel signals given by a common and uninterleaved bit format.

Abstract: An alarm system for automatically sending a telephone message or other remote signal in case help is needed for a person residing alone. In one version, a timer cyclically activates a magnetic tape player which begins slowly to dial the number of the station at which help is available, and then transmit a prerecorded message. The timer simultaneously activates an audible warning signal so that the resident can abort sending of the message if no help is needed. The timer is automatically reset each time the resident lifts the handset in normal telephone usage so that it is unnecessary under ordinary circumstances for him to worry about resetting the timer each day. Should the audible signal be activated but there is no need for help, the signal may be shut off, the message sending aborted and the timer reset merely by lifting the handset. A manual emergency bypass switch is provided.

Abstract: Bit rate compression in a digital communications system is provided by transmitting voice information from n telephone circuits over the capacity conventionally allocated for transmission of voice information from n/2 circuits without appreciable degradation in quality. Alternatively, a doubling of the number of voice circuits may be provided with transmission at the same bit rate required for conventional digital transmission of voice information. Each frame period, at the transmitter, all n circuits are serviced and, utilizing a predictive encoding scheme, only unpredictable samples in the given frame are transmitted over the available channel capacity. A sample assignment word (SAW), which identifies the circuits corresponding to the unpredictable samples, is transmitted therewith.

Abstract: A time division digital switching network comprises first multiplexing means in which first-order digital data channels transmitting words which have a format selected amongst two formats and a first rate selected amongst a plurality of rates different from, but multiple of, one another undergo a first multiplexing converting them into a second-order digital data channel having a second predetermined rate. Each given second-order channel may comprise either a plurality of first order channels of one and the same rate or a combination of first-order channels having different rates. Thereafter there are provided second multiplexing means in which the second-order digital channels undergo a second multiplexing converting them into a third-order digital data channel having a third predetermined rate.

Abstract: A time division digital transmission system in which data are transmitted in the form of pulses grouped in multiplex words in time slots forming a recurrent frame. The invention relates more particularly to facilities in transmission line station for sampling from or introducing into the frame data words occupying certain time intervals in the frame. Each station comprises at least a multiplexer, a demultiplexer and a reception time base for restoring from the incoming frames and their framing words the time intervals and addresses of the said incoming frames, so that the component channels can be multiplexed and demultiplexed. Each station further comprises a local time base capable of producing local frames having framing words and the rhythm of which is controlled by the incoming signals, but which is able to oscillate freely in the absence of such signals.

Abstract: A time division digital switching network comprises first multiplexing means in which first-order digital data channels transmitting words consisting of a given number of bits and having first rates which are different from, but multiple of, one another undergo a first multiplexing converting them into a second-order digital data channel having a second predetermined rate. Each given second-order channel comprises a combination of first-order channels having different rates r.sub.1. In each combination, there are x.sub.i words at the rate x.sub.i and the quantity .SIGMA.r.sub.i x.sub.i defines a multiframe. Thereafter there are provided second multiplexing means in which the second-order digital channels undergo a second multiplexing converting them into a third-order digital data channel having a third predetermined rate.

Abstract: A system for addressed time multiplexed telecommunication comprising subscribers apparatus whose address selector supplies voltage levels which in a central exchange are converted to binary form and stored in address shift registers. Taken out of the registers the addresser's and addressee's addresses are converted to analogue form and compared with a step voltage from a step voltage generator, and the result of the comparison controls analogue switches which make the connection between the addresser and the addressee and break the connection when addresser or addressee presses an off-button.

Abstract: This invention is drawn to a system which simulates a communications system among a plurality of independent vehicles. The simulated system utilizes pulse width modulation to reduce noise and eliminate cross-talk. In addition, the simulated communications system includes a network having computer-controlled switches which automatically determine which simulated vehicles are sufficiently close to be in communication range with each other and which are not. Thus, this disclosure describes a system which is maintained under digital control and which utilizes pulse modulation to carry the actual transmission of intelligence.

Abstract: Digital signal generator for producing digital signalling codes employed in a digital telephone communication system including several tone generators for providing presynthesized digital tone signals which are convertible to audible tones. Permutable digital codewords are produced by a codeword generator. Some of the tone signals and codewords are combined by FSK and switching circuitry. Tone signals, codeword signals, and combination signals are stored in storage registers and read out by a multiplexer to provide a continuous TDM bit stream of 60 channels of digital signalling codes.

Abstract: In order to detect the presence of voice frequencies on a telephone line which is periodically sampled for monitoring its activity, with conversion of resulting analog samples into binary words each including a polarity bit, the polarity bits of successive samples of a given line are fed to a zero-crossing detector emitting a pulse on every polarity reversal. The pulses pass through a shift register, which is stepped at the sampling rate, into a counter whose count is periodically read to determine whether a line-signal frequency, as represented by the number of zero crossings per test interval, or the rate of change of that frequency exceeds a certain threshold to indicate a fricative or sibilant sound introducing a spoken syllable.

Abstract: A device for ensuring in an intermediate station the transfer and the branch connection of at least one channel of plesiochronous numerical data multiplexed in accordance with a specific field of the transmission system, the intermediate station comprising a general emitting element provided with a clock and a general receiving element provided with a clock, said device comprising means for synchronizing in frequency and phase the clock of the general emitting element with the clock of the general receiving element, and an emitting path card which comprises a mixer whose first input terminal is fed by the signal of the information and justification bits and whose second input terminal is fed by the justification indication signal and whose output terminal, which is the output terminal of the path card, delivers a signal in which the first half of each bit is characteristic of the information and justification signal and the second half of the same bits is characteristic of the justification indication signal.

Abstract: A circuit arrangement for facilitating the transmission of asynchronously occurring binary data values is described. Each binary value change is assigned a multi-bit pulse group in the frame of a coarse scanning pulse train. A pulse discriminator, upon the occurrence of a binary value change and upon the arrival of a scanning signal, emits a write-in command which causes the pulse group to be placed in a register. A counter is provided for counting the number of coarse scanning pulses occurring from the time of occurrence of the write-in command. Prior to reaching a predetermined count, the counter blocks further write-in commands, and after reaching the predetermined count, the write-in commands are released. Thus, a correctly formed pulse group is emitted even though the received binary values might be distorted.

Abstract: A digital telephone system is disclosed in which local groups of telephone lines are connected to respective concentrators which are themselves connected to switching centers by pulse code modulation highways. Data is transmitted on the highways as a succession of superframes where one superframe equals four multiframes, one multiframe equals 16 frames, one frame equals 30 channels and one channel equals eight digits. Channels 0 and 16 are used for signalling within the system and the remaining channels are used for data transmission between the telephone lines. The interpretation of channels 0 and 16 is determined by the particular frame and multiframe in which they occur. Each telephone line is identified by a combination of three channels representing a particular section of a concentrator, a particular block in the section, and a particular address in the block. Each concentrator has four sections and four highways. On each highway, the sections are scanned in turn, each for a period of one superframe.