Abstract: A plural channel amplitude modulated station carrier telephone system having a special synchronous ring detector circuit located in a station or terminal at the subscriber's end of the transmission line for signaling an incoming call for the subscriber's telephone and a special channel loop test circuit also located in the station mentioned above and employing one of the signals used in the synchronous ring detecting operation to turn on a subscriber's transmitter circuit for effecting a channel loop test.

Abstract: A universal station identification circuit arrangement for use with central office equipment that utilizes either differential or longitudinal detection methods is adapted to be connected to the tip party's subscribers drop in a two-party line without requiring access to or rewiring of the tip party's telephone. The circuit arrangement may be fabricated in a single unit which includes a ringer isolator and ANI mark circuits. The ringer isolator and the ANI mark circuits may also be used individually.

Abstract: A circuit arrangement utilized for extending the ringing range of a single party telephone service utilized on long rural line loops where the ringer and a blocking capacitor of the subscriber's telephone instrument has been connected across the tip and ring electrical conductors of the loop includes; a pair of terminals connected to the tip and ring conductors of the subscriber's line, a zener diode connected from one of the electrical conductors with a capacitor connected in parallel therewith. A switching device is connected in series with the parallel connection of the zener diode and capacitor providing a current path to a reference ground.

Abstract: A telephone ringer isolator includes an electronic switch which enables it to operate at reduced ringer voltages. In the ringer isolator, the central office ringing signal is rectified and voltage doubled across a circuit containing two diodes and two capacitors. The second capacitor is connected across a neon tube. When the voltage across the second capacitor rises to a preselected value, the neon tube is fired to emit light onto a light sensitive resistor which feeds gate current to a Triac to turn the Triac on. The Triac, in turn, grounds the telephone ringer.

Abstract: A station identification circuit arrangement for use with central office equipment that utilizes automatic detection equipment for the detection of one of four parties on a four party-line where a call is initiated from a preselected party's telephone without requiring access to or rewiring of the party's telephone.

Abstract: A plural channel amplitude modulated station carrier telephone system and method wherein two a.c. signals are applied to modulate a called subscriber's channel carrier signal at a central office to signal an incoming call for the subscriber, wherein a phase locked loop is used at the subscriber terminal equipment to lock with one of the two a.c. signals following recovery of the two a.c. signals from the called subscriber's carrier signal, wherein the output of the phase locked loop is utilized to provide for the synchronous detection of the other of the two a.c. signals, and wherein a ring circuit responds to the synchronous detection of the other of the two a.c. signals to ring the called subscriber's telephone. Central office ringing signal frequency information is contained in the above-mentioned a.c. signal to develop a local ringing signal voltage having the same frequency as the central office ringing frequency for ringing the subscriber's telephone.

Abstract: A plural channel amplitude modulated frequency division multiplexed station carrier system wherein the receivers of the subscriber and central office channel terminal circuits are each equipped with a bandpass filter which is tuned to the carrier frequency to be received and with a circuit for synchronously detecting the carrier signal to which the bandpass filter is tuned. In the subscriber channel terminal circuits the bandpass filters are of the first order type, and in the central office channel terminal circuits the order of each bandpass filter is no greater than two.

Abstract: A unit adapted to be connected to the tip party's subscriber's drop in a two-party line without requiring access to or rewiring of the tip party's telephone and having interconnected ringer isolator and ANI mark circuits. The ringer isolator and the ANI mark circuits may also be used individually.

Abstract: A repeater bypass protection apparatus includes a means of providing a low current path between the input and output transmission lines coupled to a repeater amplifier. Under normal operating conditions the low current path presents a relatively high impedance and does not interfere with the operation of the repeater amplifier. Under high voltage transient conditions the protection apparatus is activated and effectively protects the repeater amplifier from being destroyed.

Abstract: The system disclosed transiently disconnects a subscriber's telephone equipment and network from the service provider (e.g. telephone company) network for a predetermined period of time in response to a remote switching pulse to facilitate the execution of diagnostic measurements without the necessity of visiting the subscriber's premises. The disconnect action is carried out by a two stage solid state circuit incorporating gate controlled devices such as SCRs together with RC networks whereby a capacitance is charged in response to the remotely originated switching pulse and then discharges to energize a switching relay and to maintain it energized for a predetermined period. In the energized state the switching relay isolates the subscriber network and its equipment from the telephone company network to permit the diagnostic measurements. The circuit design also provides improved noise suppression, as well as protection against spurious switching and certain overvoltage conditions.

Abstract: A multi-element gas filled surge arrester is disclosed in the form of a gas-filled generally cylindrical casing having an elongated rod-like ground electrode disposed along the casing axis with its ends terminating in casing end caps, and a linear alternating array of conductive and insulative sleeves interposed between the end caps, coaxial with the ground rod, and defining the cylinder of the casing. The assembly thus provides a stack of annular interacting ionizable gaps each of which may have its annular electrode connected to a respective terminal of repeater or other multi-terminal intermediate equipment having both input and output circuits, whereby ionization of one gap due to a surge appearing at its respective line terminals will promptly trigger ionization of the other gaps thus mitigating potentially damaging differential current flow resulting from differing strike potentials.

Abstract: The disclosed protector comprises a three electrode gas tube overvoltage protector serially connected with a heating element, the combination being connected in shunt across the load to be protected. Between that protecting shunt path and the source, a normally closed switch is provided which is responsive to the heating element and opens in the event of a sustained overvoltage condition. Accordingly, a prolonged surge which might otherwise destroy the gas tube and/or the protected load is isolated from both the shunt protection branch and from the load thus preventing damage to both.

Abstract: Disclosed herein are gas tube arrestor configurations employing multiple-function fail-safe elements which coact with the gas tube arrestor to define both a fusible path for fail-safe shorting and grounding of the arrestor in the event of certain forms of excessive overloads, as well as ionization gaps to provide backup overvoltage protection in the event of gas tube failure. In the illustrated embodiments, annular fusible rings are coaxially coupled to the gas tube housing in such a way as to provide, when fused, a short circuit connection between electrodes, the fusible rings also including pole face sections for defining an ionizable gap which functions as a backup air gap protector should the gas tube fail, e.g. because of a gas leak.Novel modular arrangements embodying the foregoing for use in central office and residential applications are also illustrated.

Abstract: An overvoltage protector circuit is disclosed for protecting multiple circuits, e.g. both the antenna and power circuits of a receiver, with a single unitary protector unit. The unit includes one three electrode gas tube connected across a power circuit which has a plug for connection to a wall outlet at one end and a receptacle for receiving the receiver plug at the other. The unit further includes another three electrode gas tube protector, the end electrodes of which are connected across an antenna circuit adapted to be connected at one end to the antenna and at the other end to the receiver antenna terminals (directly or via a splitter network). The ground or neutral system in the power circuit, or a separate auxiliary ground point, is connected to the casing of both overvoltage tubes.

Abstract: A telephone transmission system in which a telephone transmission line connects a central office d.c. power source to a battery charging control circuit to apply an input voltage to the control circuit, in which a battery charger connects a rechargeable battery to said control circuit to draw battery charging current from the transmission line under the control of the control circuit, in which the control circuit is rendered effective by a lowering of the input voltage to at least a predetermined value to effectively disconnect the battery charger and the battery from the transmission line for a period that exceeds the interval in which the input voltage is lowered.

Abstract: A relayless switching circuit which provides an effectively open circuit between a telephone and a ringing generator when the ringing generator is de-energized and which is conditioned when the ringing generator is turned on to couple pulses of ringing voltage to the telephone and to effectively open the talking circuit during the occurrences of the ringing voltage pulses.