Calling party control circuit

Claim 2

A circuit for seizing a telephone line, having a plurality of line conductors, in response to the receipt of incoming ringing signals, said circuit comprising: a bidirectional switch having first, second and third terminals; means for connecting said first and second terminals of said switch across said telephone line; a first relay for connecting said third terminal of said switch to one of the line conductors; and means responsive to the receipt of incoming ringing signals for supplying an operating potential to said first relay whereupon said first relay is operated, and said third terminal is connected to one of the line conductors whereby current is allowed to flow through said bidirectional switch to seize said line and cause the cessation of the transmission of ringing signals to said line.

Claim 3

The circuit as claimed in claim 1 wherein said means responsive to the receipt of incoming ringing signals for supplying an operating potential to said first relay includes circuit means for limiting the application of said operating potential to said first relay to a time slightly beyond the ringing interval.

Claim 4

The circuit as claimed in claim 1 wherein said means responsive to the receipt of incoming ringing signals for supplying an operating potential to said first relay includes a second relay which is operated in response to the receipt of ringing signals to connect said operating potential to said first relay.

Claim 5

The circuit as claimed in claim 3 wherein said means for connecting said first and second terminals of said switch across said telephone line includes a third relay.

Claim 6

The circuit as claimed in claim 1 wherein said bidirectional switch is a triode-thyristor.

Claim 7

The circuit as claimed in claim 3 including capacitor means for storing an electrical charge and means, including said second relay, for connecting said capacitor means to said first relay upon the receipt of ringing signals whereby said capacitor means discharges through and operates said first relay.

Claim 8

A circuit for seizing a telephone line, having a plurality of line conductors, in response to the receipt of incoming ringing signals and releasing said line either in response to the calling party going on-hook or after said line has been seized for a predetermined period of time, said circuit comprising: hold means, including a bidirectional switch and a holding relay connected in series, connectible across said telephone line for seizing and holding said line, said bidirectional switch including a control electrode; enabling means connectible to said telephone line, said enabling means including a ring relay operable in response to the receipt of ringing signals; triggering means, responsive to the operation of said ring relay, for connecting said control electrode to one of the telephone line conductors whereby said bidirectional switch is allowed to conduct and seize said telephone line; and timing means, connectible to said ring relay in response to the operation of said holding relay, for sustaining operation of said ring relay and said hold means for a predetermined period of time after seizure of said line, said bidirectional switch being responsive to the current therethrough dropping to some predetermined value Whereby said switch ceases to conduct and the hole relay is released, thereby disabling said timing means and releasing said line.

Claim 9

A circuit for seizing a telephone line, having a plurality of line conductors, in response to the receipt of incoming ringing signals and releasing said line either in response to the calling party going on-hook or after said line has been seized for a predetermined period of time, said circuit comprising: hold means, including a bidirectional switch and a holding relay connected in series, connectible across said telephone line for seizing and holding said line, said bidirectional switch including a control electrode; enabling means connectible to said telephone line, said enabling means including a ring relay operable in response to the receipt of ringing signals; triggering means, responsive to the operation of said ring relay, for connecting said control electrode to one of the telephone line conductors whereby said bidirectional switch is allowed to conduct and seize said telephone line; and timing means, connectible to said ring relay in response to the operation of said holding relay, for sustaining operation of said ring relay and said hold means for a predetermined period of time after seizure of said line, said bidirectional switch being responsive to the current therethrough dropping to some predetermined value Whereby said switch ceases to conduct and the hole relay is released, thereby disabling said timing means and releasing said line.

Claim 10

The circuit as claimed in claim 7 wherein, said triggering means includes capacitor means for storing a charge and a trigger relay connected thereto, whereby upon operation of said ring relay said capacitor discharge through and operates said trigger relay, thereby connecting said control electrode to one of said line conductors.