Abstract: In a telephone exchange system comprising a time division exchange system and space division concentrators connected to said exchange system with a PCM lines, said concentrators are controlled by said exchange system, thus those volume of hardware in the concentrators can be considerably reduced. Said concentrator comprises a space division switching network having self-latched electronic contacts, which are controlled by a periodical drive pulse from a cyclic readout type memory.

Abstract: An analog-digital code converter in a digital telephone switching system is disclosed wherein when an analog voice signal from an analog line is applied to an analog per line unit it is sampled at a high rate and a high speed sampling digital code produced by .DELTA.M-PCM modulation is converted to a low speed sampling digital code through a digital filter provided in a common unit for application to a time division digital speech path switch, and when a wide band broadcasting service signal from the same analog line is applied to the analog per line unit, a path is provided between the analog per line unit and the time division digital speech path switch which path bypasses the digital filter without allowing the conversion of the high speed sampling digital code of the analog per line unit to the low speed sampling digital code, whereby wide band communication as well as ordinary speech band communication are attained.

Abstract: A method and apparatus for distributing an accurate time reference to numus locations, such as to the nodes of a digital communications network which can also be used to synchronize the network, which method and apparatus entails the functions of measurement of the local clock's time error, assignment of weighting factors to the paths over which the time reference is distributed through the network, and correction of the time error of the local clock, wherein the first two functions are not affected by the correction of the clock error at any other mode and wherein the time reference distribution system does not contain any closed (reentrant) distribution paths.

Abstract: A communication switching system of PABX uses a number of time division multiplexed send and receive highway pairs each servicing a plurality of peripheral devices or ports providing two-way communication with the outside world by means of associated telephones, trunk line interfaces, or similar apparatus. All highway pairs are multiplexed in accordance with the same time division format and the maximum number of two-way peripheral devices serviced by each highway pair is dependent on the number of time slots of the format assigned for audio communication. Each peripheral device transmits on a given audio time slot of its send highway. Switching to establish communication paths between peripheral devices is achieved in part by receiving means in each peripheral device responsive to command signals transmitted on command time slots on the associated receive highway instructing each peripheral device on which audio time slots of its receive highway to receive.

Abstract: A multifrequency sender/receiver in a telephone system operating in time frames each including a plurality of time slots, including a sender for generating and connecting selected multifrequency tone signals in pulse code modulated format to a first group of the time slots. The receiver is responsive to the presence of a multifrequency tone in a second group of the time slots and provides a data signal representative of the tone signal present. Control means specify the selected tone signals to be sent in the first group of time slots.

Abstract: A digital time division multiplex (TDM) telecommunication network is described wherein the subscriber terminals are located on a common TDM highway and are served from a central office in accordance with the sequencing principle. The flow of information can be switched on branch routes using branching switching devices, a fixed sequence being adhered to in this case, as well.

Abstract: A data throttling arrangement is advantageously incorporated in a pulse width modulated (PWM) to pulse code modulated (PCM) signal converter for controlling the output rate of the PCM data stream. PWM data is converted to PCM data and stored in a memory. New PCM data is received and compared with the stored PCM data. The difference between the stored and the new PCM data is compared to a preselected threshold value. If the difference between the new and stored data is greater than the threshold value, the new PCM data is permitted to output; otherwise, the new data is disregarded as redundant or insignificant. Circuitry is provided to adjust the values of incoming PCM data by comparing it to predetermined zero offset values. Additional circuitry is provided to permit adjustment of the preselected threshold values in response to the rate of the PCM output data stream.

Abstract: A frame synchronizing equipment is disclosed which enables the TDMA technique to be used in a mobile communication system or a small-scale stationary communication system and requires no reference station. Plural radio channels separated from one another on a time-sharing basis are monitored upon initiation of a call by one of plural radio stations to detect the presence of a unoccupied channel. When an occupied channel followed by an unoccupied channel is detected, a pulse is extracted in a frame period synchronized with a burst signal of the occupied channel immediately preceding the unoccupied channel. A phase synchronization oscillating circuit generates a frame synchronization signal in synchronism with the extracted pulse.

Abstract: An apparatus in a digital communication system having the capability for transmitting or receiving a partial byte in the final byte position of the information field. Thus, a non-byte-oriented message may be blocked into bytes of any convenient size, and the final bits, if they do not completely fill up the final byte, can still be accommodated using the partial byte capability. The size of the final byte is indicated by adding a pointer bit to the character in memory. The partial character is right justified in its byte and a one (i.e. pointer bit) is inserted immediately to the left of the character and zeros are filled to the left to complete the byte. This byte is placed in a transmit register; a partial byte is shifted to the right until a pattern of all zeros and a one remain in the register; this pattern is recognized by the hardware and indicates that the end of the partial byte has been transmitted. For received data, the process is reversed.

Abstract: The present invention relates to telephony switching circuits which are used in electronic automatic exchanges operating on the time-division multiplex system known as PCM. According to the invention, a spatial and time switching circuit comprises a plurality of registers for memorizing the binary words of an input PCM frame, a plurality of time-slot registers for memorizing the output time-slots of the binary words, means for reading out the binary words registers when the time-slots defined by the time-slot registers occur, means for spatially switching the binary words thus readed out onto a plurality of output PCM links, and means for filling the output time-slots into the time-slot registers and selecting the output PCM links.

Abstract: An apparatus in a digital communication system having the capability for transmitting or receiving a partial byte in the final byte position of the information field. Thus, a non-byte-oriented message may be blocked into bytes of any convenient size, and the final bits, if they do not completely fill up the final byte, can still be accommodated using the partial byte capability. The size of the final byte is indicated by adding a pointer bit to the character in memory. The partial character is right justified in its byte and a one (i.e. pointer bit) is inserted immediately to the left of the character and zeros are filled to the left to complete the byte. This byte is placed in a transmit register; a partial byte is shifted to the right until a pattern of all zeros and a one remain in the register; this pattern is recognized by the hardware and indicates that the end of the partial byte has been transmitted. For received data, the process is reversed.

Abstract: A device for permanent installation in series with a time division multiplex digital data transmission line for accessing data signals carried by the line without interruption or degradation of the signals. This novel device is a regenerative line access module (RLAM) that receives incoming data signals that may be attenuated and distorted, and regenerates or reshapes the pulses thereof. The regenerated signals are passed to the output of the RLAM, amplified, and retransmitted on the transmission line, and are also used for generating a clock signal having a fundamental signal equal in frequency to the fundamental frequency of the incoming data signals but delayed slightly therefrom. When it is desired to access a selected subscriber channel, the RLAM blocks the throughput of the incoming bit stream during the period of the selected subscriber data byte. The data byte thus deleted may be dropped for local use if desired.

Abstract: An integrated fully programmable circuit is provided, with particular usefulness in the area of telemetry, for programmed commutating of multiple data inputs and signal conditioning, wherein only one amplifier path is utilized for conditioning of all channels of the commutated multiple data input signal. A programmable counter is employed to drive a gate matrix for cyclically commutating the multiple data inputs into connection with the conditioning path, the counter concurrently providing programmed inputs for switching predetermined circuit elements in the conditioning path corresponding to each parameter of each respective data input which is conditioned.

Abstract: A circuit arrangement for facilitating the transmission of asynchronously occurring binary data values is described. According to prior art systems, each binary value change is assigned a multibit pulse group by means of channel units. These channel units require considerable technical complexity if a great many data sources are present. It is the principal object of the invention to replace the channel units by a centralized device. In accordance with the teachings of the invention, there are provided at the transmit and receive ends centralized coarse and fine time slot Raster counters and bit transition discriminators which process the pulse messages of all channels.

Abstract: Time division multiplex telecommunication exchange in which each bit group received is compared, in the incoming line circuits, with the preceding bit group. When two successive bit groups are equal, the second group is not supplied to the switching device which serves for the exchange of data between the connected transmission lines. The outgoing line circuits retransmit the bit group when no new bit group is received from the switching device within a predetermined time.

Abstract: A time division multiple access (TDMA) communication system has a plurality of geographically separated stations including a first group of stations, each of which can communicate with any other station in the first group through a first transponder in a predetermined portion of a TDMA frame (intra-group traffic), and a second group of stations, each of which can communicate with any other station in the second group through a second transponder in a predetermined portion of a TDMA frame associated with the second transponder (intra-group traffic). The TDMA frames of the first and second transponders are synchronized and inter-group traffic, i.e., communications between a station in the first group and a station in the second group, takes place in another predetermined portion of each of the frames which is exclusive of the predetermined portion of both frames used for intra-group traffic.

Abstract: A service generator and method for generating a plurality of tones for use in a telephone system operating in time frames each consisting of a plurality of time slots. The service generator includes tone generators for generating each time frame pulse code modulated tone samples for a plurality of tones, a tone multiplexer for multiplexing the tone samples onto a common bus each time frame, matrix means connected to the common bus for connecting selected ones of the tone samples to selected time slots in each frame, and control means connected to control the matrix means for specifying the selected ones of the tone samples and for specifying the specified time slots.

Abstract: A modulation system for use in analog signal transmission processes input information in multiple analog communication channels, for multiplexing onto a data channel. The system includes:A delta modulator and logic circuitry connected therewith to suppress data transmission when the modulator produces alternating 1's and 0's and to signal activation of pulse transmission when a successive sequence of at least two 1's and two 0's is transmitted by the modulator.

Abstract: Method and apparatus for detecting the presence of signal components of predetermined frequency, in multifrequency PCM signal, especially in signalling tones. The incoming signal is multiplied by sine and cosine waveforms representing a particular frequency, for each of the frequencies to be detected, the two sets of multiplicands thus derived are summed. If the sum is greater than a reference value, said particular frequency is present in the incoming signal.

Abstract: PCM telephone transmission apparatus and particularly the use of several ra binary positions in a multiplex frame. These positions are used in one or several units auxiliary to the main unit which processes PCM telephone signals. The auxiliary unit(s) include(s) a signalling time base identical to the signalling time base of the main unit. The counting signals for this auxiliary time base are at a lower rate than the counting signals of the main unit, but they are applied in such a way that a part of the auxiliary time base counts at the same rate as the corresponding part of the time base in the main unit. This structure enables an evolutive use of the extra bits without modification of the main unit.