US1326546A - Telephone-exchange system. - Google Patents

Description

D. M. TAGGAR.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED SEPT.25. 1911.

Patented Dec. 80,1919..

I II.

UEETED STATES PATENT GEFIE.

:DAWSON M. TGGART, 0F EAST ORANGE, NEW JERSEY, ASSIGNOR T0 WESTERN ELECTRIC COMPANY, INCORPORATED, 0F NEW YORK, N. Y., A CORPORATION OE NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

assente.,

Specification cf Letters Patent.

Patented Dec. 30, 1919.

To all 'whom it may concern:

Be it known that l, DAWSON M. TAGGART, a citizen of the United States, residing at East Grange, in the county of Essex and State of N ew 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 eX- change systems, and more particularly to such systems which employ automatic ringing for signaling purposes and which are provided with trunk lines extending to chief operators desks, private branch exchanges, information desks and like positions.

rThe object of this invention is to provide a system of this character in which the source of ringing current is automatically disconnected from a line before an answering operators telephone set is connected therewith, thereby to eliminate the disagreeable clicks which are usually present when an operator answers a call over a line to which is connected a trunk or cord circuit equipped for automatic ringing.

Another object of this invention is to automatically disconnect the source of ringing current from an outgoing line immediately upon connection therewith, to actuate simultaneously a signaling device at the distant end of the outgoing line, and to connect a source of tone signaling current to an incoming line which is connected with the outgoing line, thereby indicating` that the signaling device at the distant end of the outgoing line has been actuated.

ln accordance with this invention there is provided an outgoing line, such as a trunk circuit extending to an information desk, with which connection may be made by an incoming line, such as a cord or trunk cir cuit equipped for automatic ringing. rlhe trunk circuit is provided with apparatus for causing the actuation of a signaling device at the information desk, for disconnecting ringing current from the trunk line, and for connecting a source of tone supply to the incoming line.

For a more complete understanding o1' this invention, reference should be had to the following description considered in connection with the accompanying drawing, wherein Figure 1 shows a system containing one embodiment of this invention, and Fig. 2 shows a modied form thereof.

Referring to Fig. 1 there is shown a cord circuit A. located at one section C of a switchboard, and a trunk circuit B extending from this section C to section D, at which there is a signaling device, a listening key and an operators telephone set. The cord circuit A is connected with a telephone line E and serves to extend this line for connection with the trunk circuit B. It is believed this invention will be fully underA stood from a description of the operation of the system shown in the drawing.

he operator at section C, upon receiving a request from connected calling station E for connection with the information operator located at section l), inserts plug 5 of cord circuit A into j ack 6 of the trunk circuit B, whereupon lamp 7 is lighted and relay 8 operated over a circuit from battery through the lamp 7 winding of relay 8, sleeve contacts of the plug 5 and jack 6, contact of relay 16, lower normal contact of relay 17 to ground. rlhe operation of relay S causes the actuation of a ringing relay 9 over a circuit from battery through resistance 10, winding of relay 9, normal contact of relay 11, contact of tripping relay 12 and the closed contact of relay 8 to ground. rlhe operation of ringing relay 9 connects a source of ringing current 15 to the trunk circuit B, causing the operation of relay 16 over a circuit from the source of ringing current 15 through the winding of tripping relay 12, the lower alternate contact of ringing relay 9, ring contacts of the plug 5 and jack 6, upper normal contact of relay 17, winding of relay 16, tip contacts of the jack G and plug 5, and the upper alternate contactof ringing relay 9 to ground. The winding of relay 16 is of low resistance so that as soon as the circuit through this relay is completed tripping relay 12 is operated. The tripping relay, in operating, opens its contact, removing the short circuit from and permitting the operation of relay 11. Relay 11 is thereupon locked up over a circuit from battery through resistance 10, alternate con-l tact and winding of relay 11, and the contact of relay 8 to ground. The operation of relay 11 also establishes a short circuit for ringing relay 9, which thereupon releases, removing ringing current from the trunk circuit.

Upon the establishment of the above mentioned circuit through relay 16, this relay operates, opening its normal contact, thereby removing the short circuit from relay 1 7, which :immediately operates. Relay 17, in operating, removes the bridged relay 16 from across the trunk circuit B and closes a Contact in the ring strand of the trunk circuit B. Relay 17, in operating, also opens a contact in the short circuit path about itself, and in closing its lower alternate contact causes the energization and operation of the relay 18 over a circuit from battery through the winding 'of relay 18, normal contact of relay 19, and the lower alternate contact of relay 17 to ground. Relay 18, in operating, causes the lighting` of lamp 2O which serves as a line signal to the desk operator. Relay 18, in operating, also opens a Contact in the ring strand of the trunk circuit B and connects a source of tone supply 21 through resistance 22 andcondenserf23 with the incoming line, which thereby serves as a signal to the calling subscriber E that the signaling device at the information desk has been actuated. The circuit including the source of tone also includes winding 25 of repeating coil 26 which is in inductive relation with winding 27 thereof, so that current from source 21 is induced into the circuit of the calling subscribers receiver, which includes the winding 27 of the repeating coil. In this manner the source lof tone supply is connected with the calling subscriber. The subscribers line E may be considered asl being connected with the trunk circuit B, for the cord circuit A to which the calling subscribers line is connected, merely serves as an extension of the lino E.

The desk operator, upon observing the lighted condition of lamp 20, actuates listening key 30 to connect the telephone set to the trunk circuit, and causes the operation of relay 19 over a circuit from battery through the lower contact of listening key 30 and the lower winding of relay 19 to ground. Relay 19, in operating, opens the circuit of relay 18 which thereupon releases, extinguishing the lamp 20 and disconnecting the source of tone supply 21 from the circuit. Relay 19 in operating also established a locking circuit for itself, which may be traced from battery through the upper winding of relay 19 and alternate contact thereof, and the lower alternate contact of relay 17 to ground. Relay 19 is now under control of the plug 5 and remains operated until the plug 5 is withdrawn from the jack 6, thereby to prevent the relighting. of lamp 20 upon the restoration of listening key 30 to normal position. Supervisory relay 46 in the cord circuit A is operated as soon as relay 18 releases to connect a shunt including resistance 10 about the lamp 7 to extinguish this lamp. At the conclusion of the conversation, the restoration of listening key 30 to normal position releases supervisory relay 16 causing the supervisory lamp 7 to relight to furnish a disconnect signal tothe operator. The operator now removes the plug 5 from the jack 6, whereupon all apparatus is restored to normal condition.

1f the trunk circuit and apparatus of Fig. 2 be substituted for the trunk circuit and apparatus of Fig. 1, and if the plug 5 of cord circuit A is inserted into jack 36, lamp 7 is lighted and relay 8 operated as before, and the ringing relay 9 is energized to connect the source of ringing current 15 to the trunk circuit. Upon the operation of ringing relay 9, a circuit is established from the source of ringing current 15 through the winding of tripping relay 12, lower alternate contact of ringing relay 9, ring contacts of plug 5 and jack 36, winding of relay 37, condenser 38, tip contacts of the jack 36 and plug 5, and the upper alternate contact of ringing relay 9 to grounc. Relay 37 is thereupon operated, closing both of its contacts. The closure of its left contact connects a non-inductive resistance 39 in parallel with the relay 37 and condenser 38, and thereby establishes a low resistance tripping circuit for the ringing current whereby relay 12 is operated. Relay 11 is then actuated and ringing relay 9 releases in the manner hereinbefore described to disconnect the ringing' current from the trunk circuit. The closure of the righthand contact of relay 37 causes the operation of the dierential relay l0 over a circuit from battery through the right-hand contact of relay 37 and the left-hand winding of differential relay l() to ground. Relay 40 in operating establishes a locking circuit for itself from battery through the left-hand contact and left-hand winding thereof to ground. The operation of relay 37 also causes lamp 4&1 to be lighted, which is then maintained lighted upon the establishnient of the locking circuit for the differential relay 10, it being understood that relay 37 is released immediately upon the release of ringing relay 9. The operation of dierential relay ll0 also connects a source of tone supply 42 through resistance V43 and condenser la to the cord circuit A, and thence to the calling subscriber E through the inductive action of the repeating coil windings.

The operator upon observing the lighted condition of lamp 41 `actuates listening key l5 to connect the operators telephone set to the trunk circuit. The actuation of this listening key closes a circuit through the righthand winding of differential relay 40, whereby this relay releases its armatures, eX- tinguishing lamp 41 and disconnecting the source of tone supply l2 from the .calling subscribers lineV The actuation of listening key 45 also causes the operation of supervisory relay 46 in the cord circuit, which in attracting its armature, establishes a shunt circuit including resistance 10 about the lamp 7, thereby extinguishing the lamp. The extinguishment of this lamp serves as a signal to the operator at switchboard section C that the desk operator has answered the call. vWhen the desk operator restores listening key l5 to normal position, supervisory relay 46 is released, whereupon lamp 7 is lighted to serve as a disconnect signal for the switchboard operator who may then withdraw the plug 5 from the jack 3G, whereupon the apparatus is restored to normal position.

What is claimed is:

1. In a telephone exchange system, in combination, an incoming and an outgoing line. means for establishing a connection between said lines, av signaling circuit closed upon the establishment of said connection, a relay in the outgoing line actuated upon the closure of said circuit, means simultaneously operative to render said circuit ineifective, a signaling device, a source of tone supply, and a second relay energized upon the actuation of the iirst relay to operate the signaling device and to connect the source of tone supply with the incoming line.

2. In a telephone exchange system, in combination, an incoming and yan outgoing line, means for establishing a connection between said lines, a signaling circuit closed upon the establishment of said connection, a relay bridged across the outgoing line actuated upon the closure of said circuit, a second relay responsive to the actuation of said bridged relay to disconnect the bridged relay rom the outgoing line, a signaling device, a source of tone supply, and a third relay actuated upon the response of the second .relay to Operate the signaling device and to connect the source of tone supply with the incoming line.

3. In a telephone exchange system, in combination, an incoming and an outgoing line, means for establishing a connection between said lines, a signaling circuit closed upon the establishment of said connection, a relay in the outgoing line actuated upon the closure of said circuit, means simultaneously operative to render said circuit ineffective, a signaling device, a source of tone supply, a second relay responsive to the actuation of the first mentioned relay to cause the operation of the signaling device and to connect the source of tone supply with the incoming line, an operators telephone set, a switching device for connecting the operators telephone set with the outgoing line, and means operative on the actuation of the switching device to cause the disconnection of the source or' tone supply from the incoming line.

4. In a telephone exchange system, in combination, an incoming and an outgoing line, means for establishing a connection between said lines, a signaling circuit closed upon the establishment of said connection, a relay 'bridged `across the outgoing line and actuated upon the closure of said circuit, means simultaneously operative to render said circuit inoperative, a signaling device, a source of tone supply, a second relay energized upon the actuation of the bridged relay to cause the oper-ation of the signaling device and to connect the source of tone supply with the incoming line, an operators telephone set, a listening switch for connecting the operators telephone set with the outgoing line, and a relay operative upon the actuation of the listening switch to cause the denergization of the second mentioned relay.

5. In a telephone exchange system, in combination, lan incoming and an outgoing line, means for establishing a connection between said lines, a signaling circuit closed upon the establishment of said connection, a relay bridged across the outgoing line and actuated upon the closure of said circuit, a second relay responsive to the actuation of the bridged relay to disconnect the bridged relay from the outgoing line, a signaling device, a source of tone supply, a third relay energized upon the response of the second relay to Icause the operation of the signaling device and to connect the source of tone supply with the incoming line, an operators telephone set, `a listening switch for connecting the telephone set with the outgoing line, a fourth relay energized upon the actuation of the listening switch to cause the deenergization of the third relay, and a locking circuit for the fourth relay established upon the energization thereof.

In witness whereof, I hereunto subscribe my 7name this 19th day of September, A. D., 191

DAWSON M. TAGGART.

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