Abstract: A repeater for a submarine cable installation which allows remote control of amplifier gain, equalizer losses and oscillator frequency. A control signal of selected frequency is transmitted to the repeater and converted to a d.c. control signal to adjust the selected component. The signal from the remote control may be in the form of pulses of a desired frequency or signals of longer duration.

Abstract: A telecommunications system which is capable of implementation in many configurations. The simplest and smallest configuration is that of a single processor-controlled module or unit using time division switching. Within a module, a processor and its attendant memory provide program memory and control the functioning of an automatic scanner driver, the automatic scanner driver interfacing between the processor and the system terminal circuits. In addition the automatic scanner driver has capability of storing temporary information during call processing through a time division switching network. For configuring larger systems, plural modular units are combined, the units being combined with control elements common to the system such as a control processor, including memory and a processor to module interface and module to module interface. The common elements act to control the feeding of information between modules.

Abstract: A data processing system using a central processor, in which the free time of the processor is monitored at predetermined intervals. A count is maintained as to the state of the processor at each monitoring, i.e., free or occupied. The chosen interval for monitoring is at least equal to the normal cycle time of the processor between program cycle interrupts. The amount of free time of the computer is determined by this monitoring. The work load or occupancy level of the process is regulated periodically when the free time count is found to be outside of the upper and lower limits which may be revised periodically. This regulation takes the form of limiting or increasing the work input to the system.

Abstract: A TDM communication method and system provides signaling between a digital central office and a remote line switch over a T1 line involving combined common-channel and D2 signaling with retention of twenty-four PCM communication channels. The invention also embodies novel means and techniques for out-of-frame detection and reframing.

Abstract: A toll programming system includes a plurality of processors having individual memories and sharing a common memory for controlling a toll telecommunication switching system by executing a plurality of programs divided in a first and second series. Each program of the first series is executed by one processor only (function distribution), whereas each program of the second series is executed by two or more processors (load sharing). In the latter case, conflicts are resolved by the use of treated-by-me tables. The processors employ mask words in their memories to enable them to distinguish which programs they may execute.

Abstract: A phase-locked loop which simultaneously switches both the phase of the reference signal received from the voltage-controlled oscillator of the loop and the sign of the d.c. channel gain. The switching is performed at a frequency lying between the phase of the incident wave and the loop cut-off frequency.

Abstract: A circuit for producing sinusoidal wave-forms representative of signals used in voiceband signaling for telephone dialing, frequently referred to as DTMF signaling. A sine wave is broken into a predetermined number of time increments. The amplitude changes for each increment may be indicated in the form of a binary digital word for a quadrant of the curve. The remaining quadrants will exhibit essentially the same change characteristics at like time increments with only the bit order reversed or the polarity changed thus, the basic binary word is unchanged for each quadrant. A programmable memory is set to produce the binary word at a selected clock rate. In this way, synthesis of a plurality of sine waves may be readily produced using delta modulation techniques. For all sine curves, the number of time increments remains the same, the rate of pulsing the increments is varied responsive to the keyboard signals generated. For telephone use, a high and a low signal are synthesized at essentially the same time.

Abstract: To connect one out of a plurality of peripheral units to a data bus, each unit is connected to two wires of an address matrix. When a unit wants to connect itself to the data bus, it applies a starting voltage to both wires. The central unit then searches in both matrix coordinates for the two wires of the starting-voltage-transmitting unit and connects the unit so found to the data bus by excitation via the wires.

Abstract: A repeater suitable for use in submerged signal transmission systems, the repeater having inherent protection against power surges. The repeater includes a signal path including an amplifier and a separate path for powering the amplifier. The power path includes a zener diode and gas discharge tubes. One or more tubes are connected to conduct on a power surge to reverse bias the zener diode and effectively switch the diode off to protect the circuit during the incidence of the power surge.

Abstract: A line circuit for a key telephone system using two relays, a ring delay (B) and a combined off-hook and hold relay (C), and solid state devices including a first and a second optical coupler. On a ring signal from the exchange, the first optical coupler is activated to cause the energization of the ring relay. On a station of the line going off-hook (busy), the conventional A lead ground operates the C relay and causes de-energization of the B relay. When a station of the line goes into hold, the circuit must differentiate this condition from a hang-up condition. This differentiation is performed by sensing the line voltage as low (continued loop closure at the start of hold) or high (open loop at the stations of the line). The C relay is held during this determination so that the circuit may enter the hold condition when indicated.

Abstract: A duplex transmission circuit using electronic components in place of either the multiple winding polar relays or combinations of differential amplifiers currently being used. In the circuit, algebraic additions and subtractions of voltage are performed and the results compared within an operational amplifier to produce the known outputs for E and M signaling in telecommunications systems. An additional operational amplifier is provided to produce a delayed response to signals of longer than a predetermined duration.

Abstract: A line circuit for a key telephone system using as the main operative components, two relays i.e. a ring relay and a combined off-hook and hold relay and an optical coupler and rectifier bridge combination. On a ring signal from the exchange, the optical coupler is activated to cause the energization of the ring relay. On a station of the line going off-hook, the conventional A lead ground operates the off-hook relay and causes de-energization of the ring relay. When a station of the line goes into hold, the circuit must differentiate this condition from a hang-up condition. This differentiation is performed by the coupler sensing the line voltage as low or high. The line voltage is high if the line loop is open indicating a hang-up condition. The line voltage is low if the line loop is still closed during the sensing period as a preliminary to the hold condition. The off-hook relay is held during this sensing operation so that the circuit may enter the hold condition when indicated.

Abstract: A handsfree telephone set uses a single transducer as microphone and speaker. A switching arrangement senses and compares the relative strength between received and transmit signals, and switches signal paths accordingly. By sensing the input of the receive path versus the output of the transmit path, the detectors are thus asymmetrically coupled, to provide a break-in capability from one side (the telephone central or calling party) only.

Abstract: Disclosed is apparatus for providing a completely flexible arrangement for relating key telephone lines to stations and to provide special features as desired to selected stations and lines. A patch or jack panel is provided with appearances for each station and for each line or trunk. Interconnect or cross connect cords or cables may be secured between stations and lines to provide line appearances at the respective stations for each cross-connection made. Further provisions are made for providing line to station ringing on selected lines under power failure conditions and for providing selected class of service for selected lines. Use of this apparatus allows the interconnection of lines to key appearances to be made as desired on installation of the system, on location. In addition, changes can readily be made in the interconnections whenever such changes are required.

Abstract: A synchronization circuit for a system in which digital coded data is received by an exchange from a transmitting station in time division multiplex form and is transmitted in time division multiplex form. In such a system, the incoming data is received at a clock rate dependent on the clock of the transmitting station and is stored in a memory at that rate. Read out from the memory is at the exchange rate. Since only one operation in the memory, either read or write, can occur at a time, control must be imposed to separate in time the reading and writing operations. To provide this separation, a time shift equal in duration to one time slot is introduced to delay the later-started of two operations.

Abstract: An arrangement for providing signalling to the lines of a telecommunications system employing non-metallic switching crosspoints such as a solid state switching network or time division switching network. In a system employing either type of network, line signalling such as ringing, coin control signalling, wire chief testing, and such other signals which are essentially high voltage signals cannot readily be transmitted through the switching network. The present system as disclosed provides an arrangement employing a common, multiplex highway between one or more signal sources and the line circuits. Operation of a switching element such as a relay in a line circuit selected by the common control completes a metallic path from the source bus to the selected line through closed contacts of the relay. In addition, signals of one or more different types may be multiplexed within a signal cycle to produce signals to a number of lines during the period when one line is being signalled.

Abstract: Synchronization control circuit for a time divisional data transmitting and receiving system. Data is received at an exchange at a clock rate determined by the transmitting station and is stored in memory at that rate. Read-out of data from the memory is based on the internal clock rate of the exchange. Since only one operation -- read or write -- can occur on a memory at any one time and the operations are controlled at rates which may be out of synchronism with one another, conflicts may occur. To prevent such conflicts, a time shift of predetermined duration is inserted between operations when the out-of-synchronism interval is less than a predetermined time interval.

Abstract: An arrangement for providing signalling to the lines of a telecommunications system employing non-metallic switching crosspoints such as a solid state switching network or time division switching network. In a system employing either type of network, line signalling such as ringing, coin control signalling, and such other signals which are essentially alternating current or high voltage signals cannot readily be transmitted through the switching network. To switch a source of current such as ring current on a per-line basis to the line circuits normally requires considerable expenditure in additional switching hardware networks. The present system as disclosed provides an arrangement employing a multiplex highway between one or more signal sources and the line circuits. Operation of a switching element such as a relay in a line circuit selected by the common control completes a metallic path from the source bus to the selected line through closed contacts of the relay.

Abstract: A matrix arrangement is disclosed of bistable, magnetically latched reed relays. Each matrix multiple includes a selection unit comprising a generator for transmitting successive pulses of opposite polarity which switch the relays on that multiple to a first stable condition. The relay coils are arranged so that superimposing the pulses of two multiple selector units switches the corresponding relay or relays to the second stable state.

Abstract: A control and apparatus are provided for visually displaying the identifying number of a calling line at a remote display associated with a called station of a telephone system. In processing a call to a line equipped with a calling line display, call completion is automatically delayed for a predetermined time period until the calling line is identified and stored. For a multiple line key telephone, a display may be provided for each line to which the station has access.