Abstract: A telecommunication exchange system has a plurality of switch facilities over which signals are emitted on an average only during a part of their respective occupation. A signal current source for emission of the signals is provided having a call-handling capability limited by signal current load. A signalling system is provided for serving a distribution of the load and provides pulse sequences having respectively identical pulse spacings. Pulses of different pulse sequences simultaneously transmitted over different switch facilities have chronologically different phase relations and a chronological offset from switch facility to switch facility. The offset is such that the pulses of the different pulse sequences connect chronologically to one another with respect to pulse termination and pulse beginning. The switch facilities are allocated for receiving the pulse sequences from the signalling system to a respective one of the pulse sequences of a specific phase relation.

Abstract: A telephone, for use in a key telephone system, has built-in test capability for verifying the operation of components in the telephone. The test capability is such that a relatively unsophisticated user can step through and conduct each of a plurality of separate tests. Interface to the tests is provided through the same switches and indicators on the telephone used for normal telephone operation. Status of certain test routines and components being tested is indicated, during the test mode of operation, on the telephone's regular indicator lamps.

Abstract: A subscriber network interface device for multiple subscriber pairs at a common location housed internally in a compact connector block easily mounted upon a wall by screws or a known mounting bracket to eliminate the need for installation of separate one or two line network interface devices. Incoming line connection is made using quick clip elements. Outgoing line connection is made via a female connector which is used to communicate with other quick clips. The circuits are latched in actuated state by the application of a 130 volt direct current applied to the tip or ring side of the line.

Abstract: The system comprises a plurality of modules (1) fitted with wire guides (21, 22) and directly mounted on a free-standing rail (2) which is advantageously in the form of an extruded bar having fixing slots. The bar can be held in place simply by a pair of brackets, one near each of its ends. Conventional frame members can be omitted. The modules can be stacked in any desired configuration at any height up the bar. Naturally a particular installation may make use of a plurality of vertical, module-carrying bars.

Abstract: An interface circuit for providing power and signal voltages to a telephone line under the control of a microcomputer within the telephone exchange comprises four charge pumps, each comprising a pair of driver/amplifiers which charge a pair of capacitors through a first diode with two further diodes discharging the capacitors to charge a capacitor connected across the telephone line. The four charge pumps are arranged symmetrically to provide positive or negative potential at the TIP terminal and positive or negative potential at the RING terminal. Modulation of the voltages to transmit a desired signal is obtained by modulating the power voltage supplied to the amplifier/drivers. The current drawn by the telephone line is measured by sensing the current drawn from the voltage source by the amplifier/drivers and this is used to extract the received signal from a telephone line and also to extract a measurement of peak current drawn from the TIP and RING leads separately.

Abstract: A system for providing remote program selection by a held caller in a telephone hold program system wherein a caller's line is connected to a holding circuit and a program is transmitted to the held caller. When a line is being held by the holding circuit, a hold detector causes an announcement to be coupled to the held line for instructing the held caller for remotely selecting one of a plurality of programs. The held caller sends select signals, in the form of voice or tone data, which are decoded and used to select the desired program source to be coupled to the held line. The system includes a remote volume control wherein a command signal sent by the held caller controls the volume level of the program supplied.

Abstract: A system for automatically storing one or more pauses in a device for memorizing a dialing sequence such as a telephone number includes a device for instantaneously detecting the appearance, persistence and interruption of a substantially continuous signal on a line such as a telephone line in a time period shorter than a human listener requires to perceive this signal and dial one number of the sequence; a device for detecting engagement of a key for generating, on the telephone line, a signal representing at least one member of the dialing sequence; a device for delaying generation of the signal associated with the engaged key to test for persistence or interruption of the substantially continuous signal on the telephone line in a time period substantially imperceptible to the human listener; and a device for memorizing each member of the dialing sequence at its correct position in the sequence with a pause automatically stored before any member if the substantially continuous signal persisted on the teleph

Abstract: The present invention relates to a line circuit for network line junctor and more particularly to a dialling device. The dialling device according to the invention presents a high impedance for the direct current, the direct current being regulated about a predetermined threshold by means of an electronic choke, the regulation being controlled by a control circuit formed by an RC circuit with large time constant, by a diode and a capacitor. The invention is more particularly applicable to private switching equipment or to subscribers' terminals.

Abstract: A microcomputer controlled coin telephone set prevents coin call fraud and also checks the operational readiness of the telephone set to prevent the acceptance of coins into a hopper for later collection by a coin box unless or until the set is fully functional. Capable of being interrogated remotely, a local memory is used for storing coin deposit information and generating coin deposit signals in order of deposit to a central office. In those instances where the line power drops below that necessary for full operation as a coin telephone, low power sensing circuits convert the telephone to the POTS mode which allows speech and dialing capabilities. Similarly, any type of chute failure, or a full hopper causes the telephone to revert to the POTS mode. While in the POTS mode, any coins deposited in the telephone are returned to the customer.

Abstract: A pulse data signal and a DC power signal are transmitted over a pair of transmission lines interconnecting a main operating unit and telephone sets in a key telephone system. The main operating unit and each telephone set includes a pulse transmitting and receiving circuit and a transformer having a core and first and second pairs of opposed windings. The individual windings in the first winding pair are connected to input and output terminals, respectively, of the pulse transmitting and receiving circuit. One terminal of each individual winding in the second winding pair is connected to a transmission line. A DC power source is connected across the other winding terminals in the second winding pair in the main operating unit. In the telephone set, the other winding terminals in the second winding pair are connected with a power supply circuit which provides power to various component circuits in the telephone set.

Abstract: An attendant console for use with an electronic private automatic branch exchange (EPABX) includes a jack for removably connecting an attendant headset or handset to the console. A switch array in the console provides indications of attendant control action and logic circuitry connected to the switch array registers the indications. Gates are connected in series with the switch array for preventing registration of the indications in response to the attendant set being disconnected, such that control actions as may be indicated at the switch array while the attendant is away from the console are of no consequence.

Abstract: A subscriber connection circuit comprises heat resistors which can be bridged in a low-ohmic manner and an indication circuit which effects different indication functions. Four different operating states are possible, characterized by the nature of the feed, the switching threshold for the indication circuit, and the actuation of a filter element for the indication circuit, two of which operating modes represent the ringing phase and the ringing interval. During the ringing interval, the nature of the feed and the threshold voltage are identical to those in the conversation operating state, but in contrast thereto the filter element is actuated.

Abstract: A method of setting operating data is provided wherein a display, at a predetermined key telephone set, indicates the capabilities of all sets of the system to perform the various functions of which the system's key telephones are capable. The display indicates three conditions: whether all telephones are capable of performing the indicated function, whether no telephones are capable of performing the function, or whether at least one but not all telephones are so capable. The setting of operating data is facilitated by this display. Changes made in operating data are not permanent until a setting key is depressed. Before that, the original operating data may be recovered.

Abstract: A protective circuit consisting of two diodes which functions along with other external circuit elements to provide protection against transients for an integrated circuit utilized to generate dial pulses in an electronic telephone circuit. By means of included diodes, excessive transients are prevented from entering the integrated circuit internal circuitry and disturbing the memory included therein or other operational characteristics.

Abstract: An indicator for use with a multiline telephone, which displays the status of both a local and called telephone set. The status indicator is comprised of a first indicator enclosed within a second for displaying by a shade or color the status of a called line, and a second indicator at least partly surrounding the first for partly displaying the first for displaying by shade or color with the second indicator the status of the calling line, whereby a party observing the indicator obtains simultaneous indication of the status of the calling and the called lines. Preferably the first indicator is a circle, enclosed within the second indicator which is a square, both being elements of a liquid crystal display. Each square indicator can be located next to a line access pushbutton with which it is associated.

Abstract: The apparatus comprises a zero pass detector (2) for detecting zero passes in a voltage signal proportional to the line current to generate a pulse signal constituted by positive and negative rectangular pulses of equal amplitude and of width dependant on the duty ratio of the line signal, a pulse signal processor constituted by a saturable integrator circuit (4) connected to integrate the pulse signal and to deliver a triangular signal having a positive peak value which increases after ringing has been answered, a comparator (6) connected to compare the triangular signal with a positive reference voltage (+Vr) and to deliver a loop detected signal when the peak value reaches the reference value, the loop detected signal being applied to a bistable logic device (8) which serves to store the loop detected signal and to deliver an output signal from the apparatus based on the stored signal.

Abstract: An electronic subscriber junctor for connecting a subscriber line to a telephone exchange, comprising an output amplifier circuit connected to the line, first means for generating a compensation voltage proportional to a common mode voltage occurring on the line and for providing a direct current proportional to a DC component of the line current, second means for obtaining a constant current, for algebraically summing said constant current and said direct current, and for supplying to the output amplifier circuit a first control current equal to said algebraic sum of the constant current and the direct current, third means for providing from said compensation voltage, via two connecting wires and on each wire, a second control current to the output amplifier circuit so as to compensate for longitudinal currents on the line, each connecting wire carrying the first control current and the output amplifier circuit delivering on each line wire a current proportional to the algebraic sum, on each connecting wire,

Abstract: A transformerless, fully balanced, telephone line circuit is provided. Two differential amplifiers are employed, one for incoming signals and the other for outgoing signals. The latter drives the line with two out-of-phase, equal amplitude signals. A comparator detects grounding of either TIP or RING at the telephone to accommodate international applications.

Abstract: A supervision filtering function is included in a line circuit wherein tip and ring voltage amplifiers supply energizing current to a two wire communication line via tip and ring primary windings of a transformer and tip and ring feed resistors. The tip and ring amplifiers operate in response to a control circuit which is differentially responsive to resistively coupled voltage signals corresponding to current flows in the tip and ring feed resistors, and which is also differentially responsive to a.c. signals from a secondary winding of the transformer being coupled via a resistive capacitive network to an amplifier in the control circuit. An output of the amplifier provides a supervisory signal. A feed switch is operable by a ring signal to conduct ringing currents to the communication line via the tip and ring feed resistors to the exclusion of the tip and ring primary windings.

Abstract: Normal operating range of an active impedance line feed circuit is extended to at least that of a prior art passive resistance line feed circuit. The active impedance line feed circuit includes tip and ring feed resistors in series with outputs of tip and ring amplifiers for coupling a.c. signals to a two wire communication line with an effective source impedance as defined by an a.c. feedback network in response to differential currents in the communication line. Effective output direct current incremental resistances of the tip and ring amplifiers are controlled by a d.c. control circuit connected across the tip amplifier. In an instant of an OFF HOOK communication line of less than a certain resistance a predetermined constant direct current is supplied by controlling the output direct current incremental resistances to be high.