Abstract: An order wire device in a communication system having a plurality of order wire devices, signals output from each of the order wire devices being serially transmitted to remaining order wire devices, each of the order wire devices being capable of simultaneously calling remaining order wire devices in an all station calling mode.

Abstract: A metallic channel unit network for interconnecting a two-wire, bidirectional signal transmitting means and a four-wire signal transmitting means in a communication system includes a voice hybrid driver, A/D signal processing circuit, D/A signal processing circuit, tip and ring switching drivers, and tip and ring sensing amplifiers. The metallic channel unit network is suitable for use with substantially all of the different alarm-signalling techniques utilized by the various alarm companies for connecting their equipment to a channel bank multiplexer coupled to the four-wire means. The metallic channel unit network provides an apparent metallic cable pair over the digital carrier in the frequency range of DC to 3.5 KHz with an amplitude variation between +200 to -200 VDC.

Abstract: A terminal repeater placed in at least one communication line connecting an exchange and at least one terminal device, comprising a DC cut-off circuit providing continuous paths for AC signals flowing through the lines while providing discontinuous paths for DC signals flowing through the communication line, a DC power supply circuit generating a DC power used in place of a DC power supplied through communication line from the exchange, and supplying the generated DC power to terminal device, a DC loop signal detecting circuit comparing a threshold level with a level of a DC loop signal as is transmitted from the terminal device to the exchange, and generating a signal corresponding to the DC loop signal, and a pseudo-DC loop signal transmitting circuit, when the DC loop signal detecting circuit generates a signal, the pseudo-DC loop signal transmitting circuit controlling a C state of the communication line in accordance with the signal generated by the DC loop signal detecting circuit, thereby to transmit a

Abstract: In a communication system wherein repeater stations and terminal stations are connected in tandem, a supervisory system in which a logical hierarchical configuration is used for the transmission of supervisory information regarding the stations and a redundant polling is used to easily and securely collect the supervisory information from the slave or repeater stations or the like. Whereby, if faults occur in some of the stations, the collection of the information is carried out without interruption and without the need to install a special information collecting line.

Abstract: A mounting for a digital service line repeater comprises a housing having a base and a removable cover, electrical components for electrically connecting the line repeater to signal wires, and a fastening device for removably attaching the base of another mounting to the removable cover. The fastening device includes a threaded hole in the cover for receiving a fastener, and the base includes an aperture aligned with the threaded hole for receiving a fastener. The mounting can be stacked on and mounted to a second similar mounting by a fastener passing through the aperture in the base for receipt in the threaded hole in the cover of the second mounting. The cover is removably attached to the base by accessible fasteners at the side walls, and the base includes a slot for receiving the line repeater.

Abstract: Circuits embodying the invention include apparatus for sensing the amplitude and the frequency of the signals received from one section of a telephone cable and for propagating onto the succeeding section of telephone cable only those received signals having an amplitude greater than a predetermined level and whose frequency is within the predetermined range.

Abstract: In a circuit arrangement for automatic connection of a remote feed current path of a remote feed loop fed from both sides for electrical loads with direct current series feed, a parallel circuit of a first four-terminal network comprising two feed outputs and a second four-terminal network containing a connecting two-terminal network, controllable by current sensors, is provided for the acquisition of a feed output per remote feed current path, this being undertaken by way of diode current branches. The circuit arrangement can advantageously be employed for the remote feed of regenerators and communications transmission links.

Abstract: A cell enhancer for use by one cellular provider in a cellular radio-telephone system particularly in a cell including a diversity function includes a first amplifier system for amplifying both up-link and down-link signals between a first set of upstream and downstream antennas and a second amplifier system for amplifying at least the up-link signals between a second set of upstream and downstream antennas. The upstream antennas have a selected minimum correlation between them to ensure that the diversity at the cell site is maintained.

Abstract: A transformerless hybrid circuit arrangement for a subscriber line interface circuit of a telecommunications exchange is disclosed. A preferred embodiment of the hybrid arrangement comprises a first and a second operational amplifier plus a differential amplifier connected together in the following manner: The non-inverting input of the first operational amplifier is connected to a first reference voltage and the output of this amplifier is connected (1) via a first resistor to one wire of the two-wire subscriber line, and (2) via a third resistor to the inverting input of the amplifier. The non-inverting input of the second operational amplifier is connected to a second reference voltage and to the receiving branch of the four-wire line of the telecommunications exchange.

Abstract: A wide band high voltage and high power amplifier is particularly useful for telephony applications. The amplifier employs a flyback converter with the capacitor storage element coupled across the line. The subscriber line is characterized in having a definite load impedance which impedance is in parallel with the storage capacitor of the flyback converter. The subscriber lines are monitored by a differential amplifier which provides a single-ended output indicative of the levels across the lines. This output is summed with the input signal to develop an error signal. The input signal to the line circuit is the particular signal of concern such as ringing, the voice signal and so on. The error signal is supplied as one input to a comparator having another input coupled to a triangular reference waveform. The output of the comparator provides a pulse width modulated waveform where the width of the pulses are indicative of the error signal.

Abstract: The invention refers to a circuit for telephone systems for the transmission of alternating current signals such as voice signals from a subscriber telephone system to a central office, wherein a signal transformer is provided with a by-pass for the direct current running in both wires to the central office. According to the invention a current path is provided by an amplifier inserted between the two wires to the central office. The amplifier is controlled by the dc current from the central office and alternating current provided by the transformer. The resistance of the amplifier changes according to control signals in the form of current supplied. The application of an amplifier as a current path between the two wires of the central office enables maintenance of direct and alternating current in the central office and simultaneous transmission and amplification of voice signals. The transformer need only supply a small part of the analog transmission signal energy.

Abstract: A receiver circuit uses a switched capacitor circuit to couple either analog or digital signals received over a two lead communication facility to connected apparatus. During a first time interval, a capacitor is connected across a lead of a facility to sample the facility voltage. During a second time interval, this capacitor is disconnected from that lead and reconnected in series between the second facility lead and the input to a voltage regenerator circuit. An appropriate regenerator circuit is selected to reconstruct either the received analog or digital signals for output to connected apparatus.

Abstract: A telephone loop signalling circuit, which automatically replicates either a loop start or a ground start configuration under virtually all operating conditions of the telephone line including those which have heavily induced power line voltages. The circuit utilizes a bias network connected to the central office side of the line together with a plurality of detectors which coact with logic circuitry to differentiate between the two configurations under these widely varying conditions.