US883093A - Divided-central telephone system. - Google Patents

Description

PENTEB MAR. 24, 19GBs W. WL BEAN. EVIDED GNRAL TELEHGHE SYSTEBLL -APLIUATZGN PILEO JUNE 15. 1.903.

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UNITED sTATEs PATENT oEEIcE.

WILLIAM W. DEAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SWITCRBOARD & SUPPLY COMPANX, 0F CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

DIIIDED-.CETRAL TELEPHONE SYSTEM.

No. sse-3,093.

Specification of Letters Patent.

Patented March 24, 1908.

Application led June 15, 1903. Serial N o. 161,531.

To all whom it may concern.'

Be it known that I, WILLIAM W. DEAN, a citizen of the United States of America, and resident of Chicago, county of Cook, and State of Illinois, have invented a certain new and useful Improvement in Divided-Central Telephone Systems, of which the following is a specification.

My invention relates to tele hone systems of the divided central type. n this class of systems, the lines are each provided with slgnals upon different divisions ofthe switchboard and the subscriber is furnished with means for selectivelyl operating the said signals. By y thus being able to call the different sections of the switchboard, the multiple jacks for eachfline need be placed upon `one only of said sections, whereby a' considerable reduction in the .multiple in-l stallation over that of the straight multiple board is secured.

My invention has for its objects to provide a system of this type which shall be comparatively simple and which operates wholl y current from a central oflice and in whic the call res onsive devices in the several sections of the board for each line are-oper'- ated by means of signaling currents of different strengths and. controlled front a subscribers station.

My inventionv is illustrated by the aid of the accompanying drawing in which f Figure 1 is a diagram of a telephone system embodying my improvements. Fig.. 2 shows one wayof arranging the contacts of the line relays of my-invention. 'l f L- indicates a subscribers telephone line extendin in two limbs 2and 3 from the substation tothe central oiiice. At the substation an ordinary bell 4 and a condenser 5 are included as usual in the permanent bridge ofthe line conductors while Va' transmitter 6 and receiver7 are located infav bridge of said conductors, whose normal discontinuity is maintained by the switch hook `8 ,and the receiver held thereby. This apparatus is adapted for use in connection with the common source of current located at the central oflce and typifies any desired subscribers outfit.'

At the central 'oice the line is provide upon the four divisions of the switchboar with answering jacks J, line signals S and a suitable pilot signal S2. Upon one ofthe divisions of the switchboard, division C in the case of line L shown in the drawing, multiple jacks J2 and J3, in any number, are rovided, Each line is also rovided with our line relays R, R2, R3 an R4, and a cut-off relayer1 which, when operated, serves to sever the rela s and signaling apparatus from the externalyline circuit .and to connect the spri jacks of the switchboard with said externll line circuit for conversational urposes. In the normal extension 9 of the' lline conductor 2 are located the linerelays R and R4, the form'er having an actuating winding of greater resistance than the latter, 200 and 100 ohms respectively having been found` satisfactory, said conductor being connected by conductor 10 through normal contacts of the relay R4 thence by conductor 11 throughv normal contacts of'relay R and likewise by -j oined to a wirel -1 5 including the high and low i resistance actuating windings of line relays R2 and R3 and which wire is likewise joined by conductors 10, 11, 12, 13 and 14 with said battery. The said line relays are suitably provided with locking windings to maintain the same actuated after once being energized. At the substation four keys, a, b, c,

and d are provided, the keys aand b being adapted to close the opposite line-conductors through a high resistance 16 to ground, while the keys c' and d close the said conductors through low resistance or directly to ground.

The cord circuit for establishing connections with the lines, and with which each operator at the'several sections is provided in anyn number desired, each includes an answerin plug P and a calling plug P2 having tip an sleeve contacts ada ted to register with the like contacts of t e jacks ofthe telephone lines, the tip contact-s of said,

plugs being-connected by the strands t and t2 and the interposed condenser c, while 'the sleeve contacts are similarly .connected by the strands .s and s2 and the interposed condenser c2. Across the answering end of the cord circuit supervisory relays r3 and r together with the commonbatte B are con; nected, said relays controlling t ough their 'lam ' adapted to be connected across the cord circuit by means of any suitable listening key,

while the ringing generator is ada tend to be connected with the cord circuit or ringing the wanted subscriber. I

' Assuming that the subscriber E wishes to call a subscriber whose multiple jacks are located upon the division A, he presses the key a at his station, thus completing a path for current from the battery B at the central oflice, over conductors 14, 13, 12, 11, 10, 9 and 2, and thence through the high'resistance 16 to ground. Owing to the presence of the high resistance 16 in this path, the current is sufficient to operate only the high resistance relay R, the low resistance relay R4 remaining unoperated. The operation of'rel lay B, closes a local circuit from the .battery B over conductor 14 to junction point 19,

thence over conductor 20, spring l21 and ifnormal contact of relay B4, conductor 22, spring 23 and forward contact of relay B,

' subscriber releases his push button.-

thence through the locking winding of relay B and over conductor 24 through the line lamp and the pilot relay for the operators Qposition', and thence by way of conductors 25 and 26 and through the normal contact and s ring 27 of cut-'od .relay 1" to ground. The line lamp and the pilot relay are actuated over this circuit and the line relay R is locked so that it is not denergized when Ttle local circuit at spring 23 of relay R. must obviously be completed before the circuit through the outer spring is opened, as shown in Fig. 2. Said ligure shows a forni of line relay having the superposed contacts mounted thereon, arranged so that the forward set of contacts will be made before the back set of contacts is broken. The relay coils are woundv upon the spool 50 which carries an angle armature 51 adapted to rock upon the edge of the magnetic structure as shown. When the lower projecting end of the arma ture is attracted it will be noted that the con tact s rings will be actuated by the other end o said armature' as described with reference to the line relays shown in Fig. 1. The same is true of all the other line relays. v

lf the subscriber whose multipleA jacks are located upon the B section of the switchboard is wanted, the subscriber pushes key l) with the result that line relay R2 which is of high resistance is operated in the manner just described with reference to the relay B connected with the other side of the line, the low resistance relay B3 remaining inoperative. The path for current in this instance The voperators receiver 17` @sacas is the same as that traced for the relays over the other side of the line except that it is over` the other line conductor. The actuation of this line relay closes a local circuit over the conductor 14, through spring 28 of relay R3 and its back contact, conductor 29, spring 30 vand forward contact of relay R, the locking winding of said relay, conductor 31 and thence through the line lamp S located upon the B` division of the switchboard,4

through the pilot relay, andby way of conductors 25 and 26 to ground as before. The relay Rlfis thus locked and the signal located upon the B division of the switchboard is operated. ln a similar manner the depression of key c at the substation serves to closethe line conductor 3 through a low resistance path to central with the result that both relays R2 and R3 in that line conductor are actuated, the current flowing the same as before traced except that instead of passing through the high resistance in the substation it is now directed through the low resistance path. The operation of the relay B3 closes a ocal circuit om the conductor 14 through spring 28 of said relay and its forward contact, the locking winding of the said relay, conductor 33 to the lamp S located upon the C division of the switchboard and thence by way of common conductors 25 and 26 to ground. In the same manner the operation of key d at the substation operates the low resistance vrelay R4 over the line conductor 2, the local circuit for the lamp in this instance including the conductor 20, the locking winding of said relay and conductor 34 leading to the line lamp located upon the D division of the switchboard.

Assuming that the signal upon the C division has been operated, the operator inserts the calling plug P of her cord circuit, thereby permitting current to flow from the battery B over the sleeve strand of the cord circuit and the sleeve conductors 35, 36 and 37 of the switchboard section of the line andthrough the winding of the cutoff relay r to ground. This operates the cut off relay which severs the connection with conductors 9, 10 and 15 and connects the line conductors 2 and 3 with the said switchboard' section. Likewise the-local circuits for the lamps are opened at the said cut-off relay to render them inoperative. (Dwing to the fact that the subscriber has taken up his telephone the tip relay r2 is actuated by current flowing over the metallic line so that the supervisory 1' his response the tip superviso `is idle, said ring is connected with ground through the cut-off relay, and since the tip of the said plug is likewise` grounded no iiow of current results and no click is received.

5 When the line is busy, however, said test ringsare connected with the live pole of one of the central batteries so that when the testing plug is brought into engagement therewith acurren't flows over the tip strand and a 1 0 surge of current takes place through the 'operators receiver. vAssumix'igthat the line is found idle, the plug is inserted in one of the multi le jacks of the called subscribers line and t e ringing key springs 40, 40 depressed.

y The'generator 18 sends ringing current out overfthe telephone line, the return path for which'iscompleted throughthe central bat-.

l tary -l 3`..,"the auxiliary path 41 being completed around'the supervisory relay 1*5 by the 'sleeve spring ofthe ringing key. The current from Vthe battery B serves to maintainthe cut-offv relay of the called line actuated duringrin "Y" After the subscriber has been called'but before his response, the rela 1.5 is actuated j to' close the ocnl circuit o a supervisory P'signal S, which is lighted lto indicate that the subscriber has not yet responded. Upon 3 so vactuated and serves to open sai supervisory signalcircuit whichrenders the same inert during conversation. The batteries B and B furnish current to the connected lines .for conversation, and for `the operation of the various relavs and signals associated therewith. At the termination of the conversation, the return of -thesubscribers receivers to their hooks denergizesA the tip superviso relays r and r which closes the local 40 circuits of lamps S and Ss which are lighted to indicate .to the operator that the conversation has terminated. Upon observing this the operator takes down the connections and returns all parts to normal position.

4I claim:- 1. ln a telephone system,'the combination with a telephone line having a plurality of connection terminals located u on the ditferent'divisionsof a divided centra switchboard, Vof asignal for the line upon each division of said switchboard, cord circuits at each of the divisions ofthe switchboard to establish connections with the line through the medium of said connection terminals for 56 conversational purposes, a common source of current at the central oflice adapted to be connected with the telephone line by means of said cord circuits to furnish current over the line for talking, and means cont-rolled 60 from the substation for causing currents of different strengths to flow from said source over the telephone line to selectively operate said si nals upon the various divisions of the switch oard, substantially as described.

2. In a telephone system, the combinarelay -1'4 is tion with a telephone line having a plurality `vof connection terminals located upon t-he different divisions of a divided central switchboard, of a. signal for the line upon each division of said switchboard, cord circuits ateach of the divisions of the switch-board various divisions of the switchboard, substantially as described.

3. In a four-division, divided central telephone circuit, the combination with a tele- 'phone line, having a connection terminal i upon each of the four divisions of the switchboard at the central oiiice, a signal for the line in each of said divisions of the switchboard, cord circuits at each division of the switchboard to establish connections with -the telephone line through'the mediumof said lconnection terminals for conversational purposes, a. common source of current at the central office associated with said cord circuits adapted when a connection exists at any of said divisions to furnish current over the line for talking, 4two of said signals being connected with each line conductor of the telephone line, and means at the substation to cause current of different strengths to flow from said source over eitherV of said line conductors to selectively operate the signals connected therewith, substantially as described. y

4. ln a telephone system,the combination with a telephone line terminating in connection terminals upon the various divisions of a divided central switchboard, of a plurality of signals for the line-one upon each of said divisions, a central common source of current, a resistance at .the substation of the line, and meansunder the con- 'trol of the subscriber to close circuits from said central source over the telephone line and to at will include or exclude said resistance to thereby selectively operate said signals, substantially as described.l

5. ln a telephone system, the combination with a telephone line, of a. plurality of signals therefor located upon the diiierent divisions of a divided central switchboard, a central common source of current, a relay at the central office connected with the line foreach of said signalfand serving to control the same, said relays being responsive to currents of diiierentfstrengths, and means at the substation for causing currents of different strengths toilow over the line from to establishconnections with the line through telephone -line from said common source to selectively operatevv said signals upon the said source and selectively operate said relays .means to cause said signals to selectively respond to the .currents over said different paths, substantially as described.

7. In a telephone system, the combination with a telephone line, of a plurality of signals therefor located upon the different divisions of a switchboard, a central source of current, means at the substation for closing diiierent paths Jfor current and of. diiierent resistances over the telephone line, means to cause said signals to selectively respond to such different currentsand a cut-oil' relay for the line actuated when connection is established therewith, at any of said divisions to render said signals inoperative, substantially as described 8. In a telephone system, the combination with a telephone line, of a plurality of signals therefor located upon the diierent divisions of a dividedcentral switchboard, a central common source of current, a relay at the central oflice connected with the line for each. of said signals and serving to control the same, each of said relays having two windings, one of said windings of each of. said relays being responsive to currents of diier-v ent strengths and being adapted toenergize said relays when a subscriber calls central, the other winding of each of said relays being in the circuit of the corresponding signal, and constituting a. locl'ing winding for said relays, and means at the substation for causing currents of different strengths to iiow through said'first mentioned windings from said source to selectively operate said relays, substantially as described.

9. Ina telephone system, the combination with a telephone line, of a plurality of signals therefor located upon the different divisions of a divided central switchboard, a central common source of current, a pair of relays at the central oiiice connected with each line conductor and adapted to control the circuit of said signals, the relaysassociated ith each line conduct-or being responsive to currents of dierent strengths, a resistance atL th'e substation, andineans for including or eirclh'ding said resistance from the circuit of ths/ relays associated with eitherot` said line conductors, 'whereby saidrelays are selectively energized by current from said source and the corresponding signal selectively controlled, substantially as described.

10. In al telephone system, the combination with a telephone line, of a plurality of signals therefor located upon the dierent divisions of a divided central switchboard, a central common source of current, a plurality of relays at the central office connected with the line for selectively controlling said signals, each of said -relays having two windings, one of said windings ofv` each relay being responsive to currents of different strengths, means at. the substation for sending currents of different strengths over the line to selectively energize said .windings, normally-closed contacts for lsaid lrelays in the path of current through said winding, the vvother winding of eachrelay constituting '.a locking winding therefor, nbrmally-open contacts for each relay in the path of current through said locking windings, and means for maring said last men-- tioned contacts before saidiirst mentioned. contacts arel broken, whereby said locking winding maintains said relay energized after the selective calling current is'broken and t/he corresponding signal remains exposed," substantially as described.

11.- In a telephone system, the combination with a telephone line, of a plurality of signalsltherefor located upon the different divisions of a switchboard, relays at thecentral oiiice associated with said signals, a central source of current, l,means at the subvstation of the line for closing diHerent paths of different resistances over the telephone line and through the windings of aV plurality of said relays in series from said source, and means to cause said signals to selectively respond, to the currents over said different paths, substantially1 as described.`

Signed by me at Chicago, county of Cook and State of Illinois, this 12th day of June 1903.

WILLIAM W. DEAN.

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