US1279875A - Telephone-exchange system. - Google Patents

Description

C. W. KECKLER.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED NOV. I7. 1911.

1,279,875. I PatentedSept. 24,1918.

//1 vemor: C/rq/ /es l V. ffec/r/en' Affy.

UNITED srnrns rn'rnnr onmon. f

CHARLES W. KECKLER, OF NEWARK, NEVJ JERSEY, ASSIGNOR'TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of letters Patent.

Patented Sept. 24,1918.

Application filed November 17, 1917. Serial No. 202,501. I

To all whom it may concern:

Be it known that I, CHARLES W. KEGKLER, a citizen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Telephone-EX change 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 of the central energy type employing connecting or link circuits provided with apparatus for automatically applying ringing current to the called-for line upon connection being made therewith. An object of this invention is to provide improved signaling means for such systems. Another object of this invention is to provide a system of this character in which ringing current cannot be connected with a busy telephone line.

In accordance with the various features of this invention, a connecting or link circuit is provided with relay mechanism and an interrupter which cooperate, upon connection of the link circuit with an idle telephone line, to connect the source of ringing current thereto, and which, when connection is made with a busy telephoneline, cooperate in a different manner to prevent-the connection of ringing current thereto. Upon the line becoming idle by the disconnection therefrom of the previously connected link circuit, the link circuit apparatus functions automatically to connect the source of ringingcurrent' to the line. By utilizing the present invention there is obtained a system in which a waiting connection may be established with the busy line and in which, when such line becomes idle, ringing is automatically connected thereto for causing the operation of the usual call bell associated therewith.

For a more complete understanding of this invention, reference should be had to the following description considered in connection with the accompanying drawing illustrating one embodiment thereof.

'In the drawing the apparatus shown within the dotted lines in the upper left-hand corner is located at a central oflice X, while the other apparatus shown on the drawing is located at a central oflice Y, at which terminates a telephone line B. A telephone line A, similar in all respects to B, terminates at the central office X and may be connected in any desired manner with the cord I circuit C. A trunk circuit D extending between the central ofiices X and Y may serve to connect cord circuit C with the telephone line B. The telephone lines A and B and the cord circuit C are of the usual type,-while the trunk circuit D embodies the features of this invention. It is to be understood that a plurality of line, cord and trunk circuits like those shown in the drawing may and usually are provided, but for convenience only the one cord circuit, one trunk circuit and two line circuits are illustrated. This invention can probably be best under stood from a description of the operation of the system illustrated in the drawing, and

it will be so described.

The operator at central oflice ing advised by the initiating subscriber A that connection is desired with the line of subscriber B, may communicate over an order wire circuit (not shown)to the operator at central office. Y the number of the wanted line, whereupon the operator at central officc Y assigns a trunk circuit to be usedin establishing the connection between lines A and B. Assuming that the assigned trunk circuit is trunk circuit D, the operator at central office X inserts plug 5 in jack 6 of the trunk circuit, thereby lighting calling supervisory lamp 9. Trunk relay 7 also operates X, upon be over a circuit from battery through the winding of supervisory relay 8, ring contacts of the plug 5 and thejack 6, both windings of the trunk relay 7 and tip con-' tacts of the jack 6 and the plug 5 to ground. Upon the operation of the trunk relay 7, lamp 10 is lighted over a circuit from battery through the lamp 10, contact of trunk relay 7 lower normal contact of relay 12, and resistance coil 13 to ground. The operator at central oflice Y, observing the lighted condition of the lamp 10, notes that the'origi nating operator has connected the cord circuit O to the proper trunk circuit and-may thereupon test the line B to determine the idle or busy condition thereof. Assuming this line to be idle, plug 20 of the trunk circuit D is inserted in jack 21 of the line B, whereupon the relay 12 and cutoff relay 22 are operated over a circuit from battery through lamp 10, the winding of relay 12,- sleeve contacts of the plug 20 and the jack 21, and the winding of cutoff relay 22 to ground. Relay 12, in operating, disconnects the resistance coil 13 from the circuit of the lamp 10 and causes the operation of relay 23 over a circuit from battery through the winding of relay 23, normal contact of relay 24, normal contactof tripping relay 25, lower alternate contact of relay 12, contact of trunk relay 7, the winding of relay 12, sleeve contacts of the plug 20 and the jack 21 and the winding of cutofi relay 22 to ground. The winding of relay 23 is of low resistance so that, upon being included in a shunt circuit about the lamp 10, it causes this lamp to be extinguished. Relay 23, in operating. closes a contact in the circuit including the righthand winding of relay 26, so that when the circuit is completed at interrupter 27, the relay 26 operates. The attraction of its armature upon the energization of relay 26 causes the immediate operation of relay 29 over a circuit from battery through contact 30 of relay 12, the winding of relay 29, and the alternate contact of relay 26 to ground. Relay 29, in operating, immediately locks up through its left-hand contact and prepares at its right-hand contact a circuit for relay 28 which is completed by the subsequent deenergization of relay 26. This subsequent deiinergization of relay 26 takes place when the brush of interrupter27 comes in engagement with the insulating segment thereof. The circuit through the right hand winding of relay 26 being open when the insulating segment of the interrupter 27 comes into ongagement with the brush thereof, relay 26 releases to cause the operation oi relay 28. Relay 28, in operating, connects ringing current to the called-for line B o er a circuit from a source of ringing current. through the winding 01 tripping relay 25, lower alternate contact of relay 23, lower alternate contact of relay 28, ring contacts of the plug 20 and the jack 21, call bell 36 and condenser 37 of station B, tip contacts of the jack 21 and the plug 20, middle alternate contact of relay 12, middle alternate contact of relay 23, and upper alternate contact of relay 28 to ground. Subscriber B, in responding to the operation of the call bell 36, removes the receiver from the switchhook, thereby causing the operation of the tripping relay 25. Relay 25, in operating, opens a short circuit about the winding of relay 2 1, permitting the operation thereof. Relay 24c, in operating, completes a locking circuit for itself and in so doing establishes a short circuit for the winding of relay 23, which immediately releases, disconnecting ringing current -from the called line. The winding of relay 24 which is now substituted for the winding o1 relay 23 in the shunt circuit about the lamp 10 is also of low resistance so that the lamp remains extinguished. Relay 23., in releasing completes the talking circuit,

whereupon supervisory relay 38 operates.

Supervisory relay 38, in operating, short circuits the left-hand winding of trunk relay 7, thereby reducing the resistance in circuit with the winding of the supervisory relay 8 and permitting the operation. thereof. Supervisory relay 8 in operating completes a shunt circuit, including resistance coil 39, about the calling supervisory lamp 9, which is thereby extinguished.

At the conclusion of the conversation the subscribers restore the receivers to the switchhooks. he restoration of the receiver to the switchhook at station B causes the deenergization of supervisory relay 3S, whereupon the left-hand winding of the trun; relay 7 is again included in circuit with the winding of the supervisory relay 8. Supervisory relay 8 thereupon releases, permitting calling supervisory lamp 9 to be lighted. The lighting of this calling supervisory lamp 9 and the lighting of the answering supervisory lamp (not shown) of the cord circuit C serve as disconnect signals to the operator, who may thereupon withdraw the plug 5 from the jack 6. The trunk relay 7 thereupon releases, opening the shunt circuit of the lamp 10, which lights to furnish a disconnect signal. to the operator at central oflice Y. The operator, upon observing the lighted condition of this lamp, may withdraw the plug 20 from the jack 21, whereupon all apparatus is restored to normal condition. 7

Should another trunk circuit, similar to D, or a cord circuit, similar to C, be connected with another "jack of line B at the time the plug of truck circuit D is inserted in the jack 21, relays 12, 23, 26 and 29 operate in the order hereinbefore described. The relay 26 will not. however, be deenerwhen the circuit of the right-hand winding thereof is opened at the interrupter 27, for the reason that the relay 26 remains operated due to a circuit from battery furnished through previously-connected cord or trunk circuit, ring contacts of the plug thereof and the engaged jack, ring contacts of the jack 21 and the plug 20, lower normal contact of relay 28, and the left-hand winding of relay 26 to groun Belay 26 will, therefore, remain energized as long as the other trunk or cord circuit remains connected with the line B, and ringing current cannot be connected thereto by way of the trunk circuit D so long as the other connection remains up. This circuit including the left-hand winding of the relay 26 is completed as soon as the plug 20 is fully inserted in the jack 21 so that an energizing circuit independentof the right-hand winding is established when the trunk circuit D is connected with a busy telephone line.

Then the previously-connected cord or trunk circuit is disconnected from the line B, the circuit including the left-hand winding of relay 26 is opened, and the circuit,

including the right-hand winding thereof, will be opened whenever the insulating segment of the relay 27 engages the brush thereof, so that relay 26 is then deenergized, causing the operation of relay 28, as before described, whereupon ringing current is connected with line B. Upon the response of subscriber B to the operation of the call bell, the tripping relay 25, relay 24, ringing relay 23, supervisory relays 38 and 8, function in the manner hereinbefore described.

It will be observed that ringing current cannot be connected to a line until the following cycle of operations have been performed: first, the energization of relay 26; second, the energization and locking-up of relay 29; third, the release of relay 26; and fourth. the energization of relay 28. "By providing apparatus functioning in this manner, a waiting connection may be established with a called-for line, and when the connection rendering the line busy is interrupted by the disconnection of the cord or trunk circuit from the line, ringing current is automatically projected over the called-for line by way of the trunk or link circuit forming what was the waiting connection.

What is claimed is:

1. A telephone exchange system comprising a telephone line, a link circuit for connecting therewith, a first and a second relay in the link circuit energized upon connection thereof with the telephone line, a third relay operating upon the energization of the second relay, a source of ringing current, and a fourth relay energized upon the subsequent deenergization of the second relay while the third relay is operated to connect the source of ringing current to the telephone line.

2. A telephone exchange system comprising a telephone line, a link circuit for connecting therewith, a first and a second relay in the link circuit energized upon connection thereof with the telephone line, a third relay operating upon the energization of the second relay, a source of ringing current, and a fourth relay energized upon the subsequent deenergization of the second relay while the third relay is operated to connect the source of ringing current to the telephone line through contacts of the energized first and fourth relays.

3. A telephone exchange system comprising a telephone line, a link circuit for connecting therewith, a first and a second relay energized upon connection thereof with the telephone line, a third relay operating upon the energization of the second relay, a looking circuit therefor completed upon the operation thereof for rendering this relay independent of the second relay, a fourth relay, an energizing circuit therefor completed by the subsequent denergization of the second relay and including a contact of the third 7 relay, and a source of ringing current connected with the telephone line upon the energization of the fourth relay.

4. A telephone exchange system comprising a telephone line, a link circuit for connecting therewith, a first relay energized upon connection of the link circuit with the telephone line, a second relay, a normally open energizing circuit for the second relay partially completed upon the energization of the first relay, an interrupter. for alternately closing and opening the energizing circuit of the second relay, a third relay operating upon the energization of the second relay, a source of ringing current, and a fourth relay operating upon the subsequent deenergization of the second relay while the third relay is operated to connect the source of ringing current to the telephone line.

5. A telephone exchange system comprising a telephone line, a link circuit for connecting therewith, a, first relay energized upon connection of the link circuit with the telephone line, a second relay, a normally open energizing circuit for-the second relay partially completed upon the energization of the firstrelay, an interrupter for alter-.

nately closing and opening the energizing circuit of the second relay, a third relay. operating upon the energization of the second relay, a locking circuit for the third relay established upon the operation thereof, a source of ringing current, a fourth relay when operated connecting the source of ringing current to the line, and an operating circuit for the fourth relay including contacts of the second and third relays and completed upon the subsequent deenergization of the second relay.

6. A telephone exchange system comprising a telephone line, a link circuit for connecting therewith, a first relay energized uponconnection of the link circuit with the telephone line, a second relay, a normally open energizing circuit for the second relay partially completed upon the energization of the first relay, an interrupter for alternately closingand opening the energizing circuit of the second relay, a third relay operating upon the energization of the second relay, a source of ringing current, and a fourth relay energized upon the subsequent deenergization of the second relay while the third relay is operated to connect the source of ringing current with the telephone line through normally open contacts of the first and fourth relays.

7 A telephone exchange system comprising a telephone line, a link circuit connected therewith, a second link circuit, a relay in the second link circuit energized upon connection thereof with the telephone line and over a circuit including a portion of the first link circuit, a source of ringing current, and

source of ringing current.

8. A telephone exchaiige systein'coinpris ing a telephone line, a link circuit connected therewith, a second ll llliilli'tlllt, afirstre lay in the second link cii'cuit energi'zed upon connection thereof \Ylili the telep'l'ione 'hne,

a second relay in the second link circuit energized'uponconnectionthereof with the --prising a telephone line, link circuits for telephone line and orer'a circuit including a portion or the first link circuit, a third relay operatiiig upon the energiz'ation of the second'relay; a fourth relay; an energizing circuit therefor including an engaged con-' tact of the ope 'ated th rd relay and coin pleted'uponthe'deen'ergization of the 'second relay when'the first link'circuit is disconnected "from the line,and a source of ringing current connected with the tele-' phone line through normally open contacts of the first and fourth relays upon'the energization of the fourth relay.

9. A telephone exchange-system compris ing a telephone line, a link circuit connected therewith, a secoi'i'd'link circuit, a first-relay in the second link circuit energized upon connection thereof with the telephone line and over a circuit inclu'din'ga portion of the first link'circuit, a second relay operating upon the eiiergization of the firstu'elay, 'a third relay, an energizing'circuit therefor includingun engaged contact of the operated second relay I and completed by the .deenergization of the first relay when the first link circuit is disconnected from the tele phone "linejand a source of ringii-i'g current connected with the telephone line by the energiz'ation of thethirdrelay.

10. A telephone exchange system coinprising a telephone line, link circuits for connectingtherewith, a relay in each link Dopie'a'uf thispeteiifmay'b'e'bttahid'fbnfive meteor, by addre ssiri'g the Commissioner of P atehts,

determined period if no other link circuit is connected therewith and it another link circuit is connected therewith then within the predeterminedperiod after the disconnection of the other link circuit therefrom,

'a source of ringing current, and a second relay responsive to the deenergization of the first relay to connect the source of ring ing current to the telephone line.

11. A telephone exchange system coinconnecting therewith, a relay in each link circuit energized upon connection with the telephone line and deenergized within a pre determinedperiod it no other link circuit is connected therewith and if another link circuit is connected therewith then within the predetermined period after the disconnection "of the other liiikciiciiit therefrom, and a source of ringing current connected with the telephone line upon the detinergization of therelay. I

12. A telephone exchange system comprising a'tele'phoneline', link circuits for connect- -'ing therewith, a relay in each link'circuit enei'gized upon connection with the telephone line and deenergized within. a predetermined.

period if no other link circuit is connected therewith and it another link circuit is connected therewith then within the predetermined period after the disconnection of the other link circuit therefrom, a second relay energized and locked up upon the en ei'gization or the first relay, a source of ringing current, a third relay, and an energizing circuit therefor including a contact Washington, D. C.

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