Ring trip circuit

Claim 2

In a ringing circuit for a two-wire communication switching system including a ring trip relay, said ringing circuit traversed primarily during ringing intervals by alternating current and traversed when the ringing is answered by direct current as well, a ring trip arrangement comprising first circuit means for conducting alternating current and electrical transient currents and including first resistor means connected in a selected one of said two wires and capacitor means connected in shunt across said first resistor means, at least one optical coupler means having a light emitting diode and a light coupled transistor, said light coupled transistor being operated by said diode upon electrical conduction thereof, second circuit means for conducting direct current and including second resistor means and said light emitting diode connected in electrical series with each other and connected in shunt across said capacitor means, said light emitting diode being poled to conduct said direct current, and driver circuit means having the input thereof supplied by said operated light coupled transistor and having the output thereof connected to the winding of said ring trip relay for energizing said winding when said light coupled transistor is operated thereby to trip the ring.

Claim 3

A ring trip arrangement as claimed in claim 1 wherein said capacitor means comprises a pair of capacitors connected in electrical series, a pair of rectifying means are connected in electrical sEries with each other and in shunt with said capacitors, respectively, to form two shunt circuit combinations connected in series, and said rectifying means are oppositely poled with respect to each other for conducting unidirectional currents therethrough during opposite half cycles of said alternating current for alternately providing a series circuit path for said alternating current extending through the capacitor of one shunt circuit combination and the rectifying means of the other shunt circuit combination.

Claim 4

A ring trip arrangement as claimed in claim 2 wherein said first circuit means includes a plurality of voltage variable resistor devices connected in series with each other and collectively connected in shunt across said pair of capacitors and across said first resistor means for limiting the voltage potential to be applied across said pair of capacitors and across said resistor means.

Claim 5

A ring trip arrangement as claimed in claim 3 wherein said first resistor means comprises a variable resistor means for adjusting the voltage drop across said first circuit means.

Claim 6

A ring trip arrangement as claimed in claim 1 wherein said light emitting diode has rectifying means connected in shunt therewith and oppositely poled with respect thereto for providing protection against reverse voltage potentials, and temperature variable resistor means connected in shunt across said light emitting diode for providing temperature compensation for the operation of said light emitting diode.

Claim 7

A ring trip arrangement as claimed in claim 1 wherein said second resistor means of said second circuit means and said capacitor means of said first circuit means present a preselected time constant for providing a predeterminable time delay between direct current flow in said ringing circuit and the conduction of said direct current by said light emitting diode and thus the operation of said ring trip relay.

Claim 8

A ring trip arrangement as claimed in claim 1 wherein said ring trip relay includes at least one normally open contact set connected in series with the winding of said ring trip relay for providing a direct circuit connection to said ground potential when said ring trip relay is operated, whereby said ring trip relay is locked in the operated state.

Claim 9

A ring trip arrangement of a ringing circuit traversed by both alternating and direct current and including a ring trip relay, said ring trip arrangement comprising first resistor means connected in the called party loop circuit, an a.c. and noise immunity circuit including a pair of capacitors connected in series with each other and in parallel with said first resistor means, a pair of oppositely poled diode rectifiers connected in series with each other and in parallel with said pair of capacitors, respectively, for providing two series shunt circuit combinations, the capacitor of one of these shunt circuits and the diode rectifier of the other of the shunt circuits comprising alternate current paths during opposite polarity half cycles of said alternating current, optical coupler means having a light emitting diode and a light coupled transistor, said light coupled transistor being operated by said diode upon electrical conduction thereof, direct current conducting circuit means including second resistor means and said light emitting diode connected in electrical series with each other and connected in shunt across said capacitor means, and said diode being poled to conduct said direct current, driver circuit means having the input thereof supplied by said operated light coupled transistor and having the output thereof connected to the winding of said ring trip relay for energizing said winding when said light coupled transistor is operated thereby to trip the ring.

Claim 10

A ring trip arrangement of a ringing circuit traversed by both alternating and direct current and including a ring trip relay, said ring trip arrangement comprising first resistor means connected in the called party loop circuit, an a.c. and noise immunity circuit including a pair of capacitors connected in series with each other and in parallel with said first resistor means, a pair of oppositely poled diode rectifiers connected in series with each other and in parallel with said pair of capacitors, respectively, for providing two series shunt circuit combinations, the capacitor of one of these shunt circuits and the diode rectifier of the other of the shunt circuits comprising alternate current paths during opposite polarity half cycles of said alternating current, optical coupler means having a light emitting diode and a light coupled transistor, said light coupled transistor being operated by said diode upon electrical conduction thereof, direct current conducting circuit means including second resistor means and said light emitting diode connected in electrical series with each other and connected in shunt across said capacitor means, and said diode being poled to conduct said direct current, driver circuit means having the input thereof supplied by said operated light coupled transistor and having the output thereof connected to the winding of said ring trip relay for energizing said winding when said light coupled transistor is operated thereby to trip the ring.