US1312768A

US1312768A - Telephone-exchange system

Info

Publication number: US1312768A
Authority: US
Publication date: 1919-08-12
Anticipated expiration: 1936-08-12

Description

D. M. TAGGART.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED NOV- n, 1911.

1 12,768. Patented Aug. 12,1919.

7 To all whom it may concern:

UNITED STATES PATENT OFFICE. V

DAWSON M. Tacoma, or EAST canton, NnW Ens Y, nssreivoa T0 ELECTRIC COMPANY, INCORPORATED, or NEW YORK, 11:, A CORPORATION on EW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed November 1 7, 1917. Serial No; 202,515.

Be it known that I, DAWSON M. TAGGART, a citizen of the United States, residing at East Orange, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Telephone- Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems,- and more particularly to such systems as the central energy type.

Theobject of the invention is to provide 7 improved signalin means for such systems.

In accordance w1th the feature of this invention, apparatus associated with a link circuit connected with a telephone line functions upon the opening and subsequent closure of the tele hone line to cause the intermittent operation of a signalin device which is common to a plurality of link circuits, thereby to furnish a recall signal to a this invention, reference should-be had to the following description considered in connection with the accompanying drawing illustrating one embodiment of this invention, and wherein there are shown two tele phone lines A and B which maybe connected through a link circuit C.. It is to be understood that many lines similar to A a and B may terminate at the same central oflice and that a plurality of link circuits similar to C may be employed for interconnecting such lines. The apparatus shown within the dotted rectangle 5 is common to a plurality of. link, circuits. It-is thought .that the nature of this invention is such that a complete understanding thereof may.

be had from a description of the operation of the system disclosed in the drawing, and

it will be so described. I

Subscriber A, in initiating a call, removes the receiver from. the switchhook, thereby causing the lighting of line'lamp 6 in the 'usual manner. The'operator, upon observing the lighted condition of the line lamp 6,

inserts answering plug 7 of cord circuit G into line jack 8, whereupon cutoff relay 9 and supervisory relay 10 operate, Answerright-hand normal contact '0 tact thereof, contact of supervisory relay .10, left-hand alternate contact of relay 15, resistance coil 16, sleeve contacts of the ing of cutoff relay 9' to ing supervisory 'lamp 11 is not lighted at thls tune for the reason that a low resistance shunt, lncluding a resistance coil 12 and the left-hand winding ofrelay 13-isestablished therefor by the operation of the superyisory relay 10. p The left-hand windmg of relay 13 is of low resistance, while its right-hand winding is of high resistance, the urpose of which will more fully hereinafter appear. The establishment of this shuntcircuit about the lamp 11 causes the operation of the relay 13 over a circuit from battery through the contact of switch 14, left-hand 'windin of relay 13,

f relay 15, contact of supervisory relay 10, left-hand normal contact of relay 15, resistance coils 12' and 16, sleeve contacts of the answering plug 7 andjack 8, and the winding of the cutoff relay 9 to ground. The operation of relay 13 connects an interrupter 17 in circuit with a pilot lamp 18, thereby causing the intermittent operation thereof. This pilot lamp 18 is common to a plurality of link circuits. The intermittent operation of this pilot lamp is an indication to the operator that some action upon her part is-required in establishing a connection.

The operator thereupon actuates listening key 20, causing the operation of relay 15, over 7 a circuit from battery-through the right-hand winding thereof and the contact of listening establishes a locking circuitfor itself from battery through the right-hand alternate conanswering plug 7 and jack 8, and the windmind. The opera tion of relay 15 opens the hereinbefore-men- I tioned shunt circuit, which includes the low resistance'winding of relay 13, and substitutestherefor another shunt circuit includingfthe left-hand windlngof the relay 15,. 100

which is in the locking circuit of relay 15.

The left-hand winding of relay 15'is of low resistance to prevent the lighting of the answering supervisory lamp 11. The opening 7 of the first-mentioned shunt circuit releases 105 the common relay 13, whereupon the pilot lamp 18 is extinguished. V

The operator, upon'bemg advised that the connection is desired with the line of subscriber B,restores the listening key '26 to, 110

PatentedAug. 12,1919. 7

normal position and inserts calling plug 21 in line jack 22, whereupon calling supervisory lamp 23 is lighted and cutoff relay 2% operated. Subscriber B may be signaled by the operation of the usual ringing key 25 and, upon responding to the operation of the call bell, the removal of the receiver from the 'switchhook causes the operation of calling supervisory relay 30. Upon the operation of this supervisory relay 30, a shunt circuit, including resistance coil 31, is established for and extinguishes the lamp 23.

Upon the conclusion of the conversation, the subscribers restore the receivers to the switchhooks, whereupon the answering and calling supervisory relays 10 and '30 are deenergized to open the shunt circuits about the answering and callinglamps 11 and 23, whereupon these lamps are lighted to furnish disconnect signals.- The deenergization of the answering supervisory relay 10 also opens the locking circuit for the relay 15, which thereupon releases its armatures. If, before the plugs are withdrawn from the jacks, the calling subscriber A desires to initiate another call, the mere removal of the receiver from the switchhook causes the intermittent operation of the pilot lamp 18, due to the operation of the common relay 13 upon the energization of the answering supervisory relay 10. The operation of the supervisory relay 10, in closing the energizing circuit through the left-hand low resistance windingof the common relay 18, also thereby establishes the low resistance shunt circuit including the resistance-12, whereupon the answering supervisory lamp 11 is extinguished. The operator, then, upon observing the flashing of the pilot lamp 18, may actuate the common switch 14, thereby opening the contact thereof and removing a short circuit of the high resistance righthand winding of relay 13. This high resistance winding is then included in the shunt circuitrabout the lamp 11, thereby making this shunt circuit of such high resistance that the lamp 11 will be lighted. In this manner, the operator may definitely determine which of several engaged cord circuits is connected with the line which has initiated a recall. The key 1 1 may now be restored to normal position, and the listening key 20 actuated to connect the operator with the line upon which the recall has been made. If another connection is desired, this may be completed in the usual manner.

When both supervisory lamps are lighted a disconnect signal is furnished the operator, who may thereupon withdraw the plug from the jacks and restore all apparatus to normal condition. 7

What is claimed is:

1. A telephone exchange system comprising telephone lines, a plurality of link circuits for interconnecting the lines, one of which is connected with one of the lines, a

supervisory relay and a signaling device in the engaged link circuit, a signal device common to the link circuits, means controlled by the supervisory relay and rendered effective upon the opening and subsequent closure of the engaged line to cause the operation of the common signaling device, a normally ineffective energizing circuit for the signaling device individual to the engaged link circuit, and a switch actuated subsequent to the operation of the common signaling device for rendering the energizing circuit effective for energizing the individual signaling device.

2. A telephone exchange system comprising telephone lines, a plurality of link circuits for interconnecting the lines, one of which is connected with one of the lines, a supervisory relay and a signaling device in the engaged link circuit, a signaling device common to the link circuits, a relay responsive to the opening of the telephone line, a relay responsive to the subsequent closure of the telephone line and cooperating with the second-mentioned relay to cause the intermittent operation of the signaling device when the supervisory relay is energized, a normally ineffective energizing circuit for the signaling device individual to the engaged link circuit, and a switch actuated subsequent to the operation of the common signaling device for rendering the energizing circuit eflective for energizing the individual signaling device.

3. A telephone exchange system comprising telephone lines, a plurality of link circuits for interconnecting the lines, one of which is connected with one of the lines, a supervisory relay and a signaling device in the engaged link circuit, a signaling device common to the link circuits, a relay individual to the engaged link circuit responsive to the opening of the telephone line, a relay common to a plurality of link circuits responsive to the subsequent closure of the telephone line and cooperating with the individual relay to cause the intermittent operation of the common signaling device while the supervisory relay is energized, a

normally inefiective energizing circuit for the signaling device individual to the engaged link circuit, and a switch actuated subsequentto the operation of the common signaling device for rendering the operating circuit effective for energizing the individual signaling device.

4. A telephone exchange system comprising telephone lines, a plurality of link circuits for interconnecting the lines, one of which is connected with one of the lines, a supervisory relay and a signaling device in the engaged link circuit, an operators telephone set, a listening key for connecting the operators telephone set to the engaged link circuit, a relay individual to the engaged energization of both the supervisory and individual relays followed by the energization of the supervisory relay, and interrupter mechanism brought into circuit with the common signaling device by the energization of the common relay.

5. A telephone exchange system comprising telephone lines, a plurality of link circuits for interconnecting the lines, one of which is connected with one of the lines, a supervisory relay controlled over the. engaged telephone line, a supervisory lamp in the engaged link circuit, a signaling device common to the link circuits, means con-j trolled by the supervisory relay and rendered effective upon the opening and subsequent closure of the engaged line to cause the operation of the common signaling device, and a switch subsequently actuated to cause the lighting of the supervisory lamp.

6. A telephone exchange system comprising telephone lines, a plurality of link circuits for interconnecting the lines, one of which is connected with one of the lines, a supervisory relay controlled over the engaged line, a supervisory lamp in the engaged link circuit, a lamp common to the link circuits, a relay individual to the engaged linkcircuit responsive to the deenergization of the supervisory relay when the engaged line is open, a relay common to the link c1'rcu1ts responsive to the subsequent energization of the supervisory relay upon the I closure of the engaged line and cooperating with the individual relay to cause the'light ing of the common lamp, and a switch sub sequently actuated to cause the lighting of the supervisory lamp. 7

7. A telephone exchange system comprising telephone lines, a plurality of link circuits for interconnecting the lines, one of which is connected With one of the lines, a supervisory relay and a signaling device in the engaged link'circuit, a normally inefi'ec-,

tive energizing circuit for the signaling device rendered effective by the deenergization of the supervisory relay and inefiective by the energization thereof, a signaling device common to the link circuits, a relay individual to the engaged link circuit responsive to the de'energization of the supervisory relay, a relay common to the link circuits responsive to the subsequent energization of the supervisory relay and cooperating With the individual relay to cause the operation of the common signaling device, and a switch subsequently actuated to render the energizing circuit of the individualsignaling device efiective While the supervisory relay is energized. I

In witness whereof, I hereunto subscribe my name this 14th day of November A. D.,

' DAWSON M. TAGGART.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C.