Remote actuated switch

A remotely actuable switch for use in a remote telephone tip and ring circuit, said switch being actuated by predetermined combinations of circuit currents and voltages, said switch being normally transparent to and conductive for both alternating and direct circuit currents normally encountered in said telephone circuit at said remote location, said switch comprising:

• at least one solid state bilateral switch having a first and a second terminal connected in series with said remote telephone circuit, said bilateral switch having a gate responsive to a gate trigger current level to initiate conduction, and responsive to a switch hold current level to sustain conduction;
• a solid state avalanche device for each bilateral switch connected between the gate and the second terminal of the bilateral switch to render the bilateral switch voltage sensitive, said avalanche device being responsive to a predetermined threshold voltage level to render said bilateral switch conductive when said circuit current level exceeds said gate trigger current level;
• said bilateral switch being rendered non-conductive by dropping said circuit current level below said switch hold current level, and rendered conductive only by the application of a voltage above the predetermined threshold voltage level;
• whereby the switch at the remote location may be rendered nonconductive to selectivity test the circuit to the remote location with voltages below said threshold voltage.

A remotely actuable switch for use in a telephone tip and ring circuit, said remote switch providing a remote subscriber switching means responsive to a control signal from a telephone central office, said switch comprising:

• at least one field effect transistor in said subscriber tip and ring circuit, said FET being in series with its respective switched circuit,
• a resistance-capacitance, time-constant circuit for normally energizing said FET and rendering said switch conductive,
• a circuit means for discharging said resistance-capacitance circuit in response to a control signal from the central telephone office,
• whereby said FET(s) may be rendered nonconductive by the discharge of said capacitor in said resistance-capacitance circuit in response to a remote control signal from the telephone central office.

A remotely actuable switch for use in a telephone tip and ring circuit, said remote switch providing a remote disconnect means for a telephone subscriber in response to a control signal or to line conditions from the telephone central office, said switch comprising:

• at least one field effect transistor in each tip and ring circuit, the source and drain terminals of each of said FETs being connected in series with the respective tip and ring circuit, and the gates of each FET being connected together;
• an avalanche device for each FET connected across the source and drain terminals of the respective FET, each of said avalanche devices being poled to normally conduct from the central office to the subscriber;
• a resistance-capacitance, time constant circuit for normally energizing said FETs and rendering said FETs conductive in response to a voltage across the tip and ring circuit;
• a diode bridge circuit connected across the tip and ring circuit for providing the proper polarity for energizing said FETs regardless of the polarity of the voltage across the tip and ring circuit;
• and
• an avalanche device connected across the capacitor in said resistance-capacitance circuit for limiting the voltage supplied to said FETs;
• whereby said FETs are rendered nonconductive by the discharge of said capacitor in said resistance-capacitance circuit, and said FETs being sustained nonconductive for the time period equal to the time constant of said resistance-capacitance circuit.

A polarity sensitive switch for connection within a telephone tip and ring circuit, said switch responsive to line conditions from a central office, said switch comprising:

• a switching circuit in at least one of the tip and ring circuits, each of said switching circuits including a field effect transistor in its respective tip and ring circuit;
• at least one resistance-capacitance, time-constant circuit within a bridge circuit for normally energizing said FET and rendering it conductive;
• a voltage and polarity detector means connected across said tip and ring circuits, said voltage and polarity detector means generating an output in response to line conditions originating from said central office;
• and
• at least one circuit means for discharging said capacitor in the resistance-capacitance circuit in response to an output signal from said voltage and polarity detector means;
• whereby said FETs are rendered nonconductive by the discharge of said capacitor in said resistance-capacitance circuit.

A tone activated remote disconnect device for connection within the tip and ring lines connecting a central office to a subscriber of a telephone system, said disconnect device comprising:

• a first switching device having at least one remotely actuable solid state switch device connected in series with said tip and ring lines;
• a first tone detector connected across said tip and ring lines, said tone detector being responsive to a first tone signal originating from said central office;
• and
• a timing means responsive to said tone detector to open said solid state switches for a predetermined time period and thereafter returning said switches to the normally closed position after said predetermined time period.

An automatic permanent release device for use in a telephone tip and ring circuit, said device being activated in response to a control signal from a telephone central office, said device comprising:

• a switching device having a first normally closed remotely actuated solid state switch connected in series with said tip line and a second normally closed remotely actuated solid state switch connected in series with said ring line;
• a tone detector connected across said tip and ring lines being responsive to a tone signal from said central office;
• a latching means connected to said switching device and responsive to said tone detector for opening said solid state switches in response to an output from said tone detector thereby setting said latching means;
• a time delay means connected between said tone detector and said latching means for delaying the setting for said latching means;
• and
• an on-hook detector means connected across said tip and ring lines and to said latching means for releasing said latching means in response to the telephone being restored on-hook, thereby closing said normally closed switch.

A DC remote disconnect device for connection within a telephone tip and ring circuit said device providing a remote disconnect means for a telephone subscriber in response to a control signal from a central telephone office, said device comprising:

• at least one field effect transistor in each tip and ring circuit, each of said FETs being in series with its respective circuit,
• a first resistance-capacitance, time-constant circuit for normally energizing said FETs and rendering said FETs conductive,
• a unilateral switch connected across said resistance-capacitance circuit for discharging said RC circuit when said unilateral switch is conducting,
• second and third resistance-capacitors circuits being connected between the respective tip and ring circuit and ground, each of said RC circuits being connected to an avalanche device for rendering said unilateral switch conductive in response to a DC control signal from the central office above a predetermined threshold voltage of said avalanche device.