US869119A - Telephone system. - Google Patents

Description

H. G.- WEBSTER.

. TELEPHONE SYSTEM.

APPLIGATIOIf FILED 3110.13.1902.

PATENTED 001. 22, 1907. Q

. UNITED STATES PATENT ossios.

HARRY G. WEBSTER, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SWITCHBOARD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A .OORPORATIQNOF ILLINOIS.

TELEPHONE SYSTEM.

I Specification of Letters Patent.

Patented Oct. 22, 1907.

Application filed December BL 1902- Serial No. 135,028-

To all whom it may concern:

Be it known that I, HARRY G. Wnssrnn, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Telephone Systems, of which the following is a specification.

My invention relates to telephone systems wherein subscribers lines terminate at the central ollice or offices and at which provision is made for inter-connecting the various lines for conversational purposes. It has special reference to those systems employing. central sources of current supply, by reason of which the signaling to the central olfice by the subscriber is automatic, whereby current for transmission purposes is supplied from the central cities and whereby the supervisory apparatus is all actuated by current from the said central source.

This invention has for its object the simplification of the circuits, connections and. arrangements by which the above operations are accomplished, and the provision of a system that is at once rapid, positive and eflicient.

In the accompanying drawing, in which the same reference characters indicate like parts throughout, the

figure is a diagram of two subscribers lines leading to a central office and-the apparatus at the central oflice for initiating and completing connections for conversational purposes. i

In this figure L and L represent subscribers lines extending from their respective substations to the central oliice. Upon the line L a single sub-station A is located, at which is provided an ordinary signaling bell 4, and a condenser 5 preferably permanently connected between the two line conductors and a transmitter 6 together with a receiver 7, in abridge (if said line conductors, which bridge ,is normally open at the switchhook 8. This'apparatus, it will be understood, is in-.

tended merely to typify any desired common battery subscribers set.

At the central office the line is I in thc'line conductor 2 which is grounded or connected "with the common ofiice return and the other, the relay Rf, connected in the line conductor 3 which is conductively joined with the omnibus bar 9 leading from an intermediate pole of the battery B. These line relays are of high resistancerelatively, say 1000 ohms each, and control through theirnormally open contacts the local circuit of the line signal S, which is preferably in the form of a small incandescent lamp.

I have shownupon the line L, we substations C and provided with an an swering jack J, and with any number of multiple jacks, I

D, each of which is provided with a transmitter 6, a re ceiver 7 and a switch-hook 8 in the same relation as described with reference to the sub-stat'on A located on the line L. As before, these parts may-represent any typeof common battery subscribers sets. The signal ing bells at these stations, however, are not bridged across the line but are shown connected with the different line conductors and with ground. That at the station 0 is connected with the sleeve side of the line I 3, while that at station D is normally joined through the switch-hook with the tip side of the line 2. At the central-olfice a line signal S is provided; the local cir-' cult of which is controlled through the normally open contacts of the two high resistance line relays R and R located respectively in the tip and sleeve conductors of the line, the sleeve conductor of this line being I shown as united through a conductivepath over the omnibus bar 9"- with an intermediate pole of the battery B". These batteries B and B are preferably grounded at one pol and are ordinarily of the storage battery 7 5 type, having a voltage of 24 .volts, the bars 9 and 9 being joined with said batteries at a point to include about 18 volts. These proportions may be varied Without departing from the principleoi' the invention, but are such as I now prefer to employ.

The operators apparatus comprises a cord circuit, provided with an answering plug 1? and with a calling plug P, the tip andsleeve contacts of which are adapt-- ed toengage with corresponding contact surfacesin the jacks of the lines. The tip contacts of the plugs are joined together through the flexible strands t and t and the interposed condenser 13, while the sleeve contacts of said plugs are joined by the strands sand s and the interposed condenser 0 The battery 13 is bridged across the answering end oi the cord circuit .and includes upon the tip and sleeve sides thereof the supervisory relays r and 1 each preferably of about ohms resistance, and which-control the local cir- .cuit of the supervisory lamp S which is preferably energized from the same battery B and whose said 95 local circuit is normally open at the contacts of relay r and normally closed by the contacts of relay 1. The calling 'end of the cord circuit is likewiseconnected with the battery B and is provided with the supervisory relaysfr and 7*, which similarly control the 106 local circuit of the supervisory lamp 8.

The sleeve supervisory relay 2' is provided with an additionalset of contacts, the spring 10 serving in its -forward position to complete the tip strand t for.con

versational purposes, but in its normal position to connect the forward portion of said strand with conductor 11 leading to a high resistance and high impedance test relay 1, the opposite pole of which is connected I ,by conductor 12 with the junction point 13 l00ated.

upon conductor 14 which is connected with -tlie lead: I1,

9. The conductor 14 contains a retardation coil 15 vand is thence led through the operators transmitter- 16 to ground. In shunt of the transmitter 16 is connected the primary winding of the operators induction coil 17 and a condenser 0 The forward contacts of the test relay r complete a path to ground from a are adapted to be connected in a bridge of the callingend of the cord circuit by means of a pair of springs l9 of a listening key which may be any of the usual or desired types.

A ringing generator 20 having one pole grounded is arranged to deliver alternating current through suitable branches 21 and 22 containing resistance. lamps to the tip and sleeve sides respectively of the cord (ircuit. For example, pressure upon the springs 23 ot' a suitable ringing key connects the tip spring of the pair with the generator and impresses upon the tip conductor oi the telephone line a suitable ringing cur rent which is arranged to operate the subscribers bell l at the station D. At the same time the sleeve spring connects in its forward position with a conductor 24 containing a 50 ohm noninductive resistance 25, and leading to the bar 9*. The operation of the other pair of springs 26 connects on the other hand the ringing generator with the sleeve conductor of the line and thereby operates the bell located at the station C, the tip spring being simultaneously grounded. I

The operation is as follows: The subscriber A desiring a connection takes up his receiver with the result that current flows from the main portion of the battery y B serially over conductor 9, line relay R the sleeve its conductor of the telephone line, through the transmitter and receiver at the substationan'd thence back to the central oiilce over tip conductor 2, the line relay R, and through ground back to the grounded pole of the battery. The relays It and R are energized by this current and close the localcircuit of the signal lamp S which is lighted to indicate the fact of the call at the central ofiice. Upon observing the signal the operator inserts the plug P in the answering jack of the line L, thereby establishing other paths for current from the battery 13. Instead of flowing through the tip high resistance line relay R, a shunt path is now I provided for the current through the tip supervisory relay T, which is 'o'i comparatively low resistance and which is now placed under the control of the subscriber, since it is responsive to current flowing over the telephone line. Similarly, the current which before followed the path through the high resistance line relay R now finds an easier path through the sleeve supervisory relay 1' and thence over the telephone line. Either the relay R or R, or, in case ofcertain line re sistances, both, will fall back now to render the line signal inoperative. The sleeve relay 9' will therefore be operated to close the local circuit of the lamp S Owing to the fact that the subscribers receiver is off the hook, the tip relay 1" is now energized so that the lamp S remains dark even though the sleeve supervisory relay 1' be operated. The operator connects her receiver with the cord circuit to converse with the calling subscriber. Her transmitter is now charged by current'from the battery. B ,.which linds a. path .the branch containing the said supervisory relay.

4 supervisory relay is therefore operated toclose the local 'circuit ol the supervisory lamp S, which owing to the v fact that the tip-supervisory relay r is' not yet oper-- through the retardation coil 15 and through the transmitter 16 to earth. The sound waves impinging the diaphragm of the transmitter 16 set up variations in the current flow and effect the charge upon the condenser c which causes a flow of current through the primary winding of her induction coil corresponding to speech waves. Upon learning that a subscriber upon the line L is desired the operator tests the condition of the wanted line in the usual manner by touching the tip of her calling plug to the test ring of one of the multiple jacks. If the line is busy the said test rings are connected through the sleeve strand of the inserted plug with the live pole of one of the batteries B or B'-, and will be raised to a potential of about 24 volts. The tip of the testing plug, however, is only at 18 volts so that a flow of current through the said test relayresults, which relay attracts its armature and closes a path for current through the primary helix of the operators induction coil 17 This causes a click in'the operators receiver and indicates to her that the line is busy.

4 If the line is idle, the test rings are at the same potential as the tip of the plug, that is 18 volts all being connected with the intermediate poles of the batteries, and no click is received. The calling plug P is therefore inserted and the set of springs 23 or 26 operated to ring the desired subscriber. It the subscriber located at station 0 is wanted, ringing springs 26 are operated-to connect the generator 20 with the sleeve conductor. It is apparent that the ringing current has two paths, one being over the sleeve conductor to the sub-station, and the other'being back through theline relay R and the'larger portion of battery B to ground. The latter path, however, is of high resistance so that a sufiicient current will flow over the former path to opcrate the subscribers bell. The lamp S does not light during ringing, even though the ringing current might tend to operate the relay R for the reason that the cooperating relay R is shunted by the tip ringing spring 26. In case the subscriber responds during the sending of the calling current therefore, the line relay R does not respond for the reason that it is shunted by the tip spring 26.

In case the subscriber D is wanted, the springs 23 ot' the ringing key are depressed, the tip spring serving to connect the generator with the tipconductor, while the sleeve spring connects a shunt paththrough the noninductive winding 25 around the line relay R The resistance and impedance of the line relay R prevents the passage of the ringing current to such an extent as to deprive thesub-station of sufficient current to operate its bell, while the said shunt path prevents the operation of the line relay R? in case'the subscriber responds during calling. 1 g y in case of the release of the ringing key before the called subscriber s response, the supervisory relay '1 is included in a local circuit which consists of the sleeve strand s-, the sleeve conductors of thojaclcs, the portion of the sleeve conductor 3 including the-winding of the line relay R the omnihusbar 9 and the smaller portion of the battery B included between the said bar 9* and This ated, is lighted and indicates to the operatotth'at the tit) called subscriber has not yet responded. At the satire time the spring 10 of the relay 1" closes its forward contacts thus completing the tip strand L of the trunk circuit l' r conversational purposes. Upon the rosptmso ot' the called subscriber, the tip supervisory relay r is operated by current from the battery it [lowing o\'oi the line circuit and thuscxtinguishos the supervisory lamp H The subscribers are now in communication and the battery B is furnishing current. over the line L for transmission purposes and for the operation of supervisory relays r and r The battery B is simultaneously providing the subscriber upon lino [F with current lot transmission and for the operation of relays r and 'r.

At the termination of the conversation the subscriber's return their receivers to the hooks with the result that,

the line circuits are opened-and the tip supwrvisory relays are deprived of operating current, thereby closing the circuits of the supervisory lamps S autLS which are lighted to indicate the. fact. ol' the cud'of the conversation to the operator. The sleeve supervisory relays are not doenergizod at this time owing to their incitision in the local circuits with the smaller portions of the batteries li and B Even though the relays R which are also included in those local circuits he now energized, the line signals S do not operate owing to the fact that. the relays it remain donorgized. Upon ohsorving the supervisory signals the operator takes down the connection and restores all parts to normal condition.

it will he understood that the several grounds men iionedmay he the common otlice ground or the common oflice return and that the proportions of the relays and other parts mentioned herein are not intended to be arbitrary and may be varied according to tho con .litions of pra tice.

Inst ad of thespecial party lino shown and described,

' other types of line may ho employed and additional parties may he placed thereon. The generator may be arranged to deliver pulsating current of different.charat'lcr to tho line, or it. may send current of different frequent-ir s thorooverand the substations may be suitably arranucd to r p nd to such currents of different. charactors it will he noted that whenever ihoriuging gem orator is conn cted with one side ol tho lino a shunt is suitably arranged around the lino relay associated Willi tho opposite side oi tho lino. employed lor metallic ringing tho return path t'orcurront would be provided through the said shunt paths.

1 claim:

1. in a telephone system, the combination with a telephone lino, of two line oloct'ro ninguels therefor, one in series with oach limb of llti line, a line signal controlled by said electionia:xnots. n stun-co of current. associated with tho line. means at tho subscriber's station for causing current from said source to traverse said electro-niagnots to actuate said signal. and means for shuntin; one of said mag-nets to retire said si znal or prevent Its opo' ion when a connection is established with the title, substantially as described.

2. in a telephone s stem. the combination with a telo' phone line, two high resistance ole ll'U-lllHLt'lllLS oins rially connected in each limb of the line at the central otlit'o, a

in case tho generator is lino signal controlled by said magnets, tuoans controlled established with the line for convei described.

ation, substantially as phone line, or two line (Electra-magnets therot'or, one connected in each line conductor at the central oilice, a line signal controlled by said etectro-magncts, a source of current associated with the line, means at the subscriber's station for causing current. from id source. to operate said electro-ma suets to operate the .ignal, means for rendering one of said eloctro magnets inoperative when a connection is established with the line for conversation to thereby render the line signal inoperative, and means for sending current over one of said electroman'nets whereby said signal is not operated substantially as described.

t. in a telephone system, the combination with a lPll. phone line, of two high resistance rel ys therefor at. the central otiico, one connected with or lino conductor, a. line signal having, its circuitv closed through normally open contacts of both said relays, a source of current; associated with the line at the central otiice, means at the substation for closing the circuit. or said source over the metallic line to energize said relays and thereby to operate said signal, and means to deprive one of said relays ot' operating cur rent when a connection is established with the line for convex atiou to thereby render the line signal inoperative while sending-current over the other of said relays, substantially as described.

5. in a telephone system, the combination with a tele phone line, of two line relays therefor at the central.

' pair of supervisory relays a. soclated therewith, and means for contracting said relays in shunt of said line relays when a connection is established with the line, substantially as described.

Ti in a telephone system, the combination with a telephone line, of two line rel: 5 associated therewith, a cord circuit. a pair 01' supervisory relays associated with said cord circuit, and means for including one of said super visor-y relays in parallel with one of said line relays when connection is established with the line by said cord rcuii. the other supervisory relay being arranged to be actuated by current flowing over tire line circuit, substantially as described 8. In a telephone system, the combination with a tele' phone line, of a separate electro-magnet associated with each line conductor, a line signal controlled by said electro magnets. and means for sending ringing current orer the path of one at said in: "nets without actuating said signal. substantially as described. I

.l. in a telephone system, the combination with a telephono line, or an electro-iuagnet associated with each line conductor, a signal for the line operated whenever both of said electroniagnets are energized, and means for sending ringing; current out over the path of either of said magnets without operating said signal, substantially as described to. In a telephone system, the combination with a tele phone line, of an (l0l'llU-ll\:l;:ll(.i; assuciatcd with each line conductor, a line signal controlled by both said electronntunots, the calling generator. and means for connecting; said generator with one litre conductor and sending ringing current through one of said magnets and at Lln same time rendorii said olecirtstuagnct in the other line conductor inopcr. ivo, whereby the said line signal, is not actuated. substantially as described.

ii. in a tclophoi-ie sy tom, the combination with a micphone line. ot an olectro-maunct associated with each line t'uiltillclut, a line si, all controlled by said electromagnets. a callii: gonorator. lll s for connecting said generator with the line to call a wanted subscriber, and at the same time shuntin: ono of said eloctro-ntagnets to prevent the operation ot said signal, substantially as dosoril-t'tl.

IL, in a telephone system, the rinbinatiou with a tote phone line, of a line relay assu ited with each line coil Cit -w.ith the other side of the line,

vented from operation during ringing, substantially as described.

13. in a telephone system, the combination with a tele phone line. of a line relay associated with each line conduetor, a line signal having its circuit controlled through contacts 01' both said relays, a ringing generator-means fut-connecting said generator with either side of and at the same time rendering the line relay connected with the other side of the line inoperative, whereby id signal is prevented from operation during ringing si'ibfzi'n tialiy as described.

' 14. in a. telephone system, the com hi'nition with a telephone iinzfot a pair of relays, one in series with each limb the line r of said line, a central source of current permanently com i nected to said line through the coils of said relays, 21 line I signal controlled by said relays; a cord circuit zitlapted to be conneL-ted with,suid line for riversti a 'liji'ervisury relay iisocinted with the cord circuit. 111 for connecting said supervisory relay in series with one of said line relay and a portion oi nriid central source of current. when :1 connection in eii'tiibiished with a telephone line, and means thereaftfi'ren current flows in the telephone line, Y S'z'lid 'i'i n e relay of its :ictnntin: (-nrrrnt uitlr its ('irrnit, substantially as (inscribed. d v inc :lt (fliirngof county of (Junk, Siute 0i Ilii %Olfi. this I'M h day of December 1590;.

Witnesses In mnm Liawm A .n as,

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