Local ringing and ring-trip relay for carrier terminal

Claim 2

A telephone customer''s terminal comprising: a signaling line for transmitting incoming ringing voltage, telephone apparatus having a high impedance onhook state and a low impedance offhook state, said apparatus including tip and ring terminals, a ringer connected across said tip and ring terminals, and a low impedance talking circuit, said talking circuit being connected iN shunt with said ringer when said apparatus is in said offhook state to provide, in parallel with said ringer, the low impedance of said offhook state, said talking circuit being disconnected from its shunt relation with said ringer when said apparatus is in said onhook state, whereby said ringer provides the high impedance of said onhook state, a carrier terminal unit for terminating said line with tip, ring and ground terminals whereby incoming ringing voltage on said line is applied to said last-mentioned ring and ground terminals, and control means for controlling the application of a local ringing voltage to said apparatus tip and ring terminals to activate said ringer in correspondence with said incoming ringing voltage at said carrier terminal unit ring and ground terminals, said control means comprising a first electromagnetic relay having an operating winding and two transfer contacts, each movable between a first pair of fixed contacts, with a first fixed contact of a first pair of fixed contacts being connected to said carrier terminal tip terminal and said transfer contact associated with said lastmentioned first contact pair being connected to said apparatus tip terminal, and further with a first fixed contact of a second pair of said fixed contacts being connected to said carrier terminal ring terminal and said transfer contact associated with said last-mentioned second contact pair being connected to said apparatus ring terminal, a first unidirectional device, a second electromagnetic relay having an operating winding and a fifth fixed contact and a movable contact, circuit means connecting said first relay winding, said first device and said last-mentioned fifth fixed contact and movable contact in a series circuit with said carrier terminal ring and ground terminals, a local generator for supplying said local ringing voltage and having one terminal connected to said second contact of said first contact pair, a rectifier bridge connecting said second relay operating winding between a second contact of said second pair of contacts and a second terminal of said generator, said bridge having two terminals of which a first is connected to said last-mentioned second contact and of which a second is connected to said generator terminal, and a plurality of parallel branches connected between said bridge first and second terminals, a first of said branches including second and third unidirectional devices connected in series between said first and second bridge terminals and poled toward each other, a second of said branches including fourth and fifth unidirectional devices connected in series between said first and second bridge terminals and poled away from each other, said second relay operating winding having one end connected to a point common to said second and third devices and an opposite end connected to a point common to said fourth and fifth devices, said control means maintaining said first relay operating winding in said circuit means operatively connected with said carrier terminal ring and ground terminals when said apparatus is in said onhook state, and said first relay operating winding being deenergized in absence of said incoming voltage at said carrier terminal unit ring and ground terminals to engage said two transfer contacts with said first contacts of said first and second contact pairs to establish a direct current circuit between said carrier terminal unit and said apparatus tip and ring terminals, said control means further maintaining said second relay winding deenergized for causing said second relay to engage said movable contact with said fifth fixed contact to close said circuit means series circuit while said apparatus is in said onhook state, said incoming ringing voltage, when applied to said carrier terminal unit ring and ground terminals, being effective to energize said first relay operating winding to operate said first relay to actuate said two transfer contacts to engage said second contActs of said first and second contact pairs to apply ringing voltage from said generator through said bridge to said apparatus tip and ring terminals for activating said ringer while said apparatus is in said onhook state, said bridge rectifying said local ringing voltage to energize said second relay operating winding for operating said second relay to disengage said movable contact from said fifth fixed contact for opening said circuit means series circuit to operatively disconnect said first relay operating winding in said circuit means from said last-mentioned terminals and at the same time to disconnect said generator from said apparatus tip and ring terminals for deactivating said ringer when said apparatus is transferred to said offhook state.

Claim 3

A telephone subscribers terminal comprising a telephone apparatus having a high impedance onhook state and a relatively low impedance offhook state, a signal receiver and transmitter carrier terminal unit adapted to be connected to a central office by a signal transmission line, said carrier terminal unit and said apparatus being respectively provided with a first pair of tip and ring talking circuit terminals and a second pair of tip and ring talking circuit terminals, a ringing circuit forming a part of said apparatus and being connected across the terminals of said second pair in both of said onhook and offhook states of said apparatus, said carrier unit terminating said transmission line at said first pair of terminals and a further terminal to provide for the application of a central office-produced ringing voltage across said further terminal and one predetermined terminal of said first pair, ringing generator means providing a source of local ringing voltage, transfer means providing a signal transmitting talking circuit between said first and second pairs of terminals in absence of said central office-produced ringing voltage, said transfer means being responsive to the application of said central office-produced ringing signal voltage across said further terminal and said predetermined terminal of said carrier unit for interrupting said circuit connection between said first and second pairs of terminals and for connecting said ringing generator means to the terminals of said second pair to impress said local ringing voltage upon said ringing circuit and thereby signal an incoming call when said apparatus is in said onhook state, said apparatus providing a low impedance current path when transferred to said offhook state to increase the current drawn from said generator means, means including a device responsive to said increase in current that is drawn from said generator means when said apparatus is transferred to said offhook state to condition said transfer means for reestablishing said circuit connection between said first and second pairs of terminals and for disconnecting said generator means from the terminals of said second pair, first relay means forming a part of said transfer means and having an operating winding, switching means connecting said operating winding across said one predetermined carrier unit terminal and said further terminal to provide for the energization of said operating winding by said central office-produced ringing voltage, transfer contact means forming a part of said first relay means and being under the control of said operating winding to provide a signal-transmitting current path between said first and second pairs of terminals in absence of said central office-produced ringing voltage, said generator means having a pair of output terminals, one of which is directly connected to said transfer contact means, said means including said device further comprising bridge rectifier means having a pair of input terminals and a pair of output terminals, said device comprising second relay means having an operating winding bridging the output terminals of said bridge rectified means, one of the input terminals of said rectifier means being connected to the other of the output terminals of Said generator means, and the other of the input terminals of said rectifier means being connected to said transfer contact means, said transfer contact means being actuated by energization of said operating winding of said first relay means to disconnect said first pair of terminals from said second pair of terminals and to connect said other of said input terminals of said rectifier means and said one of said output terminals of said generator means to said second pair of terminals, the operating winding of said second relay means being energized by the increased current drawn from said generator means when said apparatus is transferred to said offhook state, and said switching means being actuated by energization of the operating winding of said second relay means to interrupt the energizing connection of the winding of said first relay means to said further terminal and said predetermined one of said carrier unit terminals, and resistor means bridging the input terminals of said rectifier means, said resistor means having a predetermined resistance value which is less than that of said ringing circuit to provide a voltage drop across the output terminals of said rectifier means which is insufficient to energize the winding of said second relay means when said apparatus is in said onhook state.

Claim 4

A telephone subscribers terminal comprising a telephone apparatus having a high impedance onhook state and a relatively low impedance offhook state, a signal receiver and transmitter carrier terminal unit adapted to be connected to a central office by a signal transmission line, said carrier terminal unit and said apparatus being respectively provided with a first pair of tip and ring talking circuit terminals and a second pair of tip and ring talking circuit terminals, a ringing circuit forming a part of said apparatus and being connected across the terminals of said second pair in both of said onhook and offhook states of said apparatus, said carrier unit terminating said transmission line at said first pair of terminals and a further terminal to provide for the application of a central office-produced ringing voltage across said further terminal and one predetermined terminal of said first pair, ringing generator means providing a source of local ringing voltage, transfer means providing a signal transmitting talking circuit between said first and second pairs of terminals in absence of said central office-produced ringing voltage, said transfer means being responsive to the application of said central office-produced ringing signal voltage across said further terminal and said predetermined terminal of said carrier unit for interrupting said circuit connection between said first and second pairs of terminals and for connecting said ringing generator means to the terminals of said second pair to impress said local ringing voltage upon said ringing circuit and thereby signal an incoming call when said apparatus is in said onhook state, said apparatus providing a low impedance current path when transferred to said offhook state to increase the current drawn from said generator means, means including a device responsive to said increase in current that is drawn from said generator means when said apparatus is transferred to said offhook state to condition said transfer means for reestablishing said circuit connection between said first and second pairs of terminals and for disconnecting said generator means from the terminals of said second pair, first relay means forming a part of said transfer means and having an operating winding, switching means connecting said operating winding across said one predetermined carrier unit terminal and said further terminal to provide for the energization of said operating winding by said central office-produced ringing voltage, transfer contact means forming a part of said first relay means and being under the control of said operating winding to provide a signal-transmitting current path between said first and second pairs of terminals in absence of said central office-produced ringing voltage, said generator means having a pair of output terminals, one of which is directly connected to said transfer contact means, said means including said device further comprising bridge rectifier means having a pair of input terminals and a pair of output terminals, said device comprising second relay means having an operating winding bridging the output terminals of said bridge rectified means, one of the input terminals of said rectifier means being connected to the other of the output terminals of Said generator means, and the other of the input terminals of said rectifier means being connected to said transfer contact means, said transfer contact means being actuated by energization of said operating winding of said first relay means to disconnect said first pair of terminals from said second pair of terminals and to connect said other of said input terminals of said rectifier means and said one of said output terminals of said generator means to said second pair of terminals, the operating winding of said second relay means being energized by the increased current drawn from said generator means when said apparatus is transferred to said offhook state, and said switching means being actuated by energization of the operating winding of said second relay means to interrupt the energizing connection of the winding of said first relay means to said further terminal and said predetermined one of said carrier unit terminals, and resistor means bridging the input terminals of said rectifier means, said resistor means having a predetermined resistance value which is less than that of said ringing circuit to provide a voltage drop across the output terminals of said rectifier means which is insufficient to energize the winding of said second relay means when said apparatus is in said onhook state.

Claim 5

A telephone customer''s terminal comprising: a signalling transmission line, telephone apparatus having a high impedance onhook state and a low impedance offhook state, said apparatus including tip and ring terminals and a high impedance ringer connected across said tip and ring terminals, a carrier terminal unit connected to said line and having tip, ring and ground terminals with talking voltages being applied at said last-mentioned tip and ring terminals and incoming ring voltage being applied at said last-mentioned ring and ground terminals, control means for applying a local ringing voltage to said apparatus tip and ring terminals in response to the application of said incoming ringing voltage to said carrier terminal unit ring and ground terminals, comprising; a first electromagnetic relay having an operating winding effectively connectable to and disconnectable from said carrier terminal ring and ground terminals and having a plurality of transfer contacts movable between a plurality of pairs of fixed contacts, with one fixed contact of a first pair of said fixed contacts being connected to said carrier terminal tip terminal and said transfer contact associated with said last-mentioned first contact pair being connected to said apparatus tip terminal, and further with one fixed contact of a second pair of said fixed contacts being connected to said carrier terminal ring terminal and said transfer contact associated with said last-mentioned contact pair being connected to said apparatus ring terminal, and a local generator providing a source of ringing voltage and being connected to second contacts of said first and second contact pairs, said control means being operative to complete a circuit connecting said operating winding to said carrier terminal ring and ground terminals in a normally deenergized state to engage said transfer contacts with said one contact of said first and second contact pairs for establishing a direct current circuit between said carrier terminal unit and apparatus tip and ring terminals for said talking voltages when said apparatus is in said onhook state, said operating winding being energized by the application of said incoming ringing voltage at said carrier terminal ring and ground terminals for operating said transfer contacts to engage said second contacts of said first and second contact pairs thereby applying ringing voltage from said generator across said apparatus tip and ring terminals for activating said ringer while said apparatus is in said onhook state, said control means being responsive to the transfer of said apparatus from said onhook state to said offhook state to disconneCt said operating winding from said carrier terminal ring and ground terminals to deenergize said last-mentioned operating winding for causing said relay to return to the unoperated condition to actuate said transfer contacts to reengage said one contact of said first and second contact pairs thereby reestablishing said direct current circuit for said talking voltages and at the same time interrupting the application of said local ringing voltage at said apparatus tip and ring terminals to deactivate said ringer, said control means further comprising a rectifying circuit including said relay operating winding and being responsive to said incoming ringing voltage at said carrier terminal ring and ground terminals for providing sufficient rectified voltage to energize said relay operating winding, said rectifying circuit having rectifying means serially connected with said relay operating winding, said rectifying circuit further including contact means serially connected with said operating winding and rectifying means, said contact means of said rectifying circuit being normally closed to complete a current path in said rectifying circuit, said contact means being actuated by said control means to open said rectifying circuit when said apparatus is transferred to said offhook state, said control means further comprising a second electromagnetic relay having a fifth fixed contact and a movable contact constituting said contact means in said rectifying circuit, said second relay also having an operating winding connected between said generator and said second contact of said second contact pair, said second relay operating winding, when deenergized, holding said second relay unoperated to engage said last-mentioned movable contact to disengage said last-mentioned fifth fixed contact thereby opening said rectifying circuit, said control means further comprising a rectifier bridge connecting said second relay operating winding between said generator and said second contact of said second contact pair, said bridge comprising a pair of terminals of which a first is connected to said generator and of which a second is connected to said second contact of said second contact pair, and a plurality of branches connected in parallel between said first and second bridge terminals and having a first branch including first and second unidirectional devices connected in series and poled in directions toward each other and a second branch including third and fourth unidirectional devices connected in series and poled in directions away from each other, said second relay operating winding having one end connected to a point common to said first and second devices and an opposite end to a point common to said third and fourth devices, and said rectifier bridge also including a resistor constituting a third branch and connected in parallel with said first and second branches between said rectifier bridge first and second terminals.

Claim 6

A telephone customer''s terminal comprising: a signalling transmission line, telephone apparatus having a high impedance onhook state and a low impedance offhook state, said apparatus including tip and ring terminals and a high impedance ringer connected across said tip and ring terminals, a carrier terminal unit connected to said line and having tip, ring and ground terminals with talking voltages being applied at said last-mentioned tip and ring terminals and incoming ring voltage being applied at said last-mentioned ring and ground terminals, control means for applying a local ringing voltage to said apparatus tip and ring terminals in response to the application of said incoming ringing voltage to said carrier terminal unit ring and ground terminals, comprising; a first electromagnetic relay having an operating winding effectively connectable to and disconnectable from said carrier terminal ring and ground terminals and having a plurality of transfer contacts movable between a plurality of pairs of fixed contacts, with one fixed contact of a first pair of said fixed contacts being connected to said carrier terminal tip terminal and said transfer contact associated with said last-mentioned first contact pair being connected to said apparatus tip terminal, and further with one fixed contact of a second pair of said fixed contacts being connected to said carrier terminal ring terminal and said transfer contact associated with said last-mentioned contact pair being connected to said apparatus ring terminal, and a local generator providing a source of ringing voltage and being connected to second contacts of said first and second contact pairs, said control means being operative to complete a circuit connecting said operating winding to said carrier terminal ring and ground terminals in a normally deenergized state to engage said transfer contacts with said one contact of said first and second contact pairs for establishing a direct current circuit between said carrier terminal unit and apparatus tip and ring terminals for said talking voltages when said apparatus is in said onhook state, said operating winding being energized by the application of said incoming ringing voltage at said carrier terminal ring and ground terminals for operating said transfer contacts to engage said second contacts of said first and second contact pairs thereby applying ringing voltage from said generator across said apparatus tip and ring terminals for activating said ringer while said apparatus is in said onhook state, said control means being responsive to the transfer of said apparatus from said onhook state to said offhook state to disconneCt said operating winding from said carrier terminal ring and ground terminals to deenergize said last-mentioned operating winding for causing said relay to return to the unoperated condition to actuate said transfer contacts to reengage said one contact of said first and second contact pairs thereby reestablishing said direct current circuit for said talking voltages and at the same time interrupting the application of said local ringing voltage at said apparatus tip and ring terminals to deactivate said ringer, said control means further comprising a rectifying circuit including said relay operating winding and being responsive to said incoming ringing voltage at said carrier terminal ring and ground terminals for providing sufficient rectified voltage to energize said relay operating winding, said rectifying circuit having rectifying means serially connected with said relay operating winding, said rectifying circuit further including contact means serially connected with said operating winding and rectifying means, said contact means of said rectifying circuit being normally closed to complete a current path in said rectifying circuit, said contact means being actuated by said control means to open said rectifying circuit when said apparatus is transferred to said offhook state, said control means further comprising a second electromagnetic relay having a fifth fixed contact and a movable contact constituting said contact means in said rectifying circuit, said second relay also having an operating winding connected between said generator and said second contact of said second contact pair, said second relay operating winding, when deenergized, holding said second relay unoperated to engage said last-mentioned movable contact to disengage said last-mentioned fifth fixed contact thereby opening said rectifying circuit, said control means further comprising a rectifier bridge connecting said second relay operating winding between said generator and said second contact of said second contact pair, said bridge comprising a pair of terminals of which a first is connected to said generator and of which a second is connected to said second contact of said second contact pair, and a plurality of branches connected in parallel between said first and second bridge terminals and having a first branch including first and second unidirectional devices connected in series and poled in directions toward each other and a second branch including third and fourth unidirectional devices connected in series and poled in directions away from each other, said second relay operating winding having one end connected to a point common to said first and second devices and an opposite end to a point common to said third and fourth devices, and said rectifier bridge also including a resistor constituting a third branch and connected in parallel with said first and second branches between said rectifier bridge first and second terminals.