US623437A - Telephone-switchboard circuit - Google Patents

Description

No. 623,437. Patented Apr. l8, I899.

E. H. SMYTHE. V TELEPHONE SWITCHBOABD CIRCUIT.

(Application filed Feb. 23, 1898.)

(No Model.)

41- Invento Urrr. STATES PATENT men.

EDlVIN II. SMYTHE, OF FREEPORT, ILLINOIS, ASSIGNOR TO THE AMERICAN BELL TELEPHONE COMPANY, OF BOSTON, MASSACHUSETTS.

TELEPHONE-SWITCHBOARD CIRCUIT.

SPECIFICATION forming part of Letters Patent No. 623,437, dated April 18, 1899.

Application filed February 23, 1898. Serial No. 671,360. (No model.)

T at whom it may concern: tomatic signaling-circuits having one or more Be it known that I, EDWIN H. SMYTHE,16 substations in circuit can be interconnected siding at Freeport, in the county of Stephenat the same switchboardtable and with the son and State of Illinois, have invented cersame pairs of linking or switching cords and 5 tainImprovementsinTelephone-Switchboard plugs that are used to unite substation-cir- Circuits, of which the following is a specificacuits of the same kind, so that the discontion. necting or supervisory signals are readily op- To meet the requirements of modern teleerated with every possible combination of conphone service, several difierent kinds of sysnections and without requiring switch cords IO tems of substation apparatus and circuits and plugs of diverse character.

have been devised, the members of all of By means of the invention it becomes poswhich have to be provided with means for sible to place the terminals of the automatic linking one with the other for through comcall or party-line circuits upon the same munication at the central station at which switchboard,togetherwith dissiinilarcircuits, 15 they terminate or to which they converge. instead of locating them at a special section It is well known that a substation is supof the board, and they may be connected beplied with means for calling the central ofiice tween themselves orwith lines of other classes when a connection with another substation is by the same means as is employed in the condesired and also with means for ordering a nection or interconnection of the more ordi- 7o 20 disconnection from the circuit of such other nary circuits.

substation, and the most common form and In carrying out the invention the magnetoarrangement of circuit and apparatus is that generator substation circuits are provided in whicha magneto-generator is employedin at the central station with spring-jacks or sending the call to operate an electromagswitch-sockets and annunciatorsin theusual 2 5 netic line-annunciator placed at the central manner and the test-rings of the sockets or station, the same generator being employed jacks are connected to ground. The autoto cause an electromagnetic device in the cordmatic signal substation-circuits are branched circuit to indicate the Wish for a disconnecinto their several substations and have acalltion. Among other forms of circuit, howbell and condenser in a bridge between the 3o ever, which have been devised is one in which main conductors, which are shunted by the the removal of the telephone at the substatelephones when the receiving-telephone is tion and the consequent closure or alteration off its hook, or, alternatively, the station-bells of the circuit by the automatic rising of the may be in ground branches from the two hook-switch,permittingthe circulation ot'curmain conductors, as described in the patent 35 rent from a centralized source of current of A. S. Hibbard,to which reference has been supply, causes the line-signal to indicate the made. Means are provided for momentarily call, and in like manner when the telephone grounding one side of the line direct'when is hung upon the hook-switch the centralized the telephone is removed and also when it is source of energy operates the closing-out or replaced upon the hook-switch. At the ceno 40 supervisory signal. Moreover, various artral station one conductor of the line termirangements of these types of circuithave been nates at the test-rings, while the other condevised, some having but one substation on ductorterminates at the plug-tip jack-spring, the circuit and others a plurality of substawhich rests upon a contact connected to the tions on the same circuit. When the latter line-annunciator battery and ground. Asec- 5 5 are employed, they may be fitted with select- 0nd spring in the jack adapted to register or ive signals in the manner indicated by Let'- to be brought into contact With the front ters Patent No. 555,725, granted to Angus S. sleeve-contact surface of the plug is connect- Hibbard March 3, 1896, and are then desiged to ground through a battery. nated selective-signal circuits. In providing a cord-circuit to connect the 50 The present invention provides means two types of circuits indicated it was neceswhereby magneto-generator circuits and ausary that it should be so constructed that when a disconnecting-current was sent in from a substation having a magneto-generator it should have no opportunity to pass through the connections and ring the bells of the substations on the connected party-line circuit, or for the clearing-out-battery current from an automatic signal-circuit substation to pass through them to the substation having the magnetogenerator. Hence in a board accommodating battery-call and magneto-call circuits and where the connections include these mixed circuits the cord-circuit connection is made conductively discontinuous, and this is done by the use of a condenser in each cord of the circuit or by the similarintroduction of a repeating-coil. Each plug is provided with a tip and with front and rear sleevecontact surfaces. The tip and rear sleeve contact surface of each plug are conductively connected with each other, respectively, through the magnet'coils of the clearing-out or disconnecting signal, and constitute the registering parts of the talking-circuit with the spring-jacks, and the front sleeve-contact of each plug is connected by a third strand to the middle point of the said annunciator-magnet coils. By this division of the cord-circuit when a clearing-out signal is given from a substation supplied with a magneto-generator the current passes from the generator to line and through the tip of the plug, the supervisory signal or clearing-out annunciator, the rearward sleeve-contact of the plug, and the test-ring to ground or other return-conductor, and when the clearing-out signal is given from one of the automatic signal-line substations the circuit is momentarily closed by the hook-switch at said station, over which current flows from the central battery by way of the forward sleeve-contact of the plug, one coil of the clearing-out signal, the tip-contact of the plug, and one main conductor of the circuit to ground at the substation, all of which I now proceed to describe and claim.

Of the accompanying drawings, Figure l is a diagram of two telephone-circuits, one arranged at its substation with magneto-generator call appliances and the other there provided with automatic devices for calling and clearing out, both circuits being shown as terminating at the central office 0 and associated with a cord-circuit adapted to link or switch them together. Fig. 2 is a diagram of a cordcircuit, showing a modification in arrangement.

L represents a telephone-circuit extending from a substation A to the central station 0, and 27 is its line conductor, which connects at the latter station with the line-spring 2 of the jack J, this normally resting upon contact 3, connected through the call-signal D to ground. The jackis provided with a testring 6, united by wire 5 to ground. It willbe understood that the circuitL is provided with a jack at all the switchboard-sections if a multiple switchboard be employed.

M represents the telephone apparatus at the substation, and comprises a magneto-generator and call-bell a, telephone, and a transmitter-battery.

L is a metallic substation-circuit, which, as indicated, is arranged to supply communication for a plurality of substations, each of a which is connected by branches 21 and 22 with the conductors 19 and 20, respectively. The branch 21 terminates at the hook-switch 2e, and the branch 22 includes the receivingtelephone and secondary 2' of the inductioncoil 1 and terminates at the upper limitingstop an. Thelocal circuit 19 connects with the branch 22 atthe point it and includes the primary 2' of the induction-coil, transmitter T, and battery rand terminates at the limit-stop g. A bell e and condenser h are bridged between the said branches. A projection f from the hook-switch is adapted to swing against the grounded spring 25, forming a transient earth connection for the main conductor 19 when the telephone is removed and replaced. Conductor 2O terminates at the test-ring 15 of the switch-socket J and conductor 19 connects with the contact-spring 17 of the said socket, which spring normally rests upon contact 18, giving a normal connection by wire 13, call-signal D and battery G to ground. A second contact-spring 16 of the jack J has its free end projecting forwardly to a position between the test-ring and the free end of spring 17 and at its fixed end is connected by wire 14.- with a battery H and ground.

The plugs of the cord-circuit have three contact surfaces-viz. the tips I) and the front and rear sleeves c and (Z- The cord-circuit shown in Fig. 1 is divided into conductivelyseparate but inductivelyunited terminal loop-sections by the condensers F and F placed between the tip and rear sleeve contacts of the plugs P P respectively, in the cord-strands 7 and 9, and the two loops thus formed between the tip and sleeve contacts I) and d of each plug are made to include in their circuits, by means of the wires 10 and 11, the clearing-out signals E E The conducting-strand 8 of the forward sleeve-contacts of the plugs connects in each case with its loop at a point 12 at the middle of the magnet-winding of the said clearing-out aununciator.

In the cord-circuit shown in Fig. 2 the two loops are conductively separated but inductively united by the repeating induction-coil I, whose windings t' and 2' are connected at their ends to the opposite cords 7 and 9 in each of-the said loops. In this case the loops are closed in parallel through one winding of the re pea-ting-coil and through their clearingout signals, but neither interferes with the operation of the other.

In the operation of the invention the subscriber at substation A, in makinga call, actuates the magneto-generator and causes the operation of the line-signal D in the usual IIO manner. When the plug P is inserted into the jack J, its tip l) raises the spring 2 from contact 3 and the cord strand 7 is made continuous with the conductor 27, and when the subscriber rings otf current from the generator flows by conductor 27, spring 2 of the jack, tip-contact Z) of plug, cord-strands 7 and 10, signal E, cord-strands l1 and 9, rearward sleeve-contact d, test-ring 6, and wire 5 to ground; and when a subscriber at B wishes to signal the central station he removes the telephone t from the switch 24, which rises to make contact with the limitstops 9 and m, while the part f, moving reversely, makes momentary contact with the sprin and completes a circuit by way of the ground, wire 26, spring 25, switch 24, wire 21, conductor 19, spring 17 of jack or socket-switch J cont-act 18, wire 13, line-signal D and battery G to ground, over which current flows, which causes the shutter of the signal to fall and indicate the reception of a call. When the plug P is inserted in jack J its tip-contact b registers with spring 17, the sleeve-contact c with spring 16, and the sleeve-contact cl with test ring or frame 15, and the spring 17 is thus raised from the point 18, thereby cutting off the line-signal and battery. lVhen the telephone at Bis returned to the hook-switch, its weight depresses the same and the part f rising makes transient contact with the spring 25 and closes a circuit for the current of battery H from ground by way of wire 26, spring 25, switch 24, wire 21, conductor 19, spring 17 of jack J tipcontact Z) of plug P cord-strands 7 and 10, one coil of signal E cord-strand 8, sleevecontact 0, spring 16, wire 14:, and battery H to ground, over which current flows from. the battery 11, which causes the operation of the signal E indicating to the operator that the communication is finished and that the lines may now be disconnected.

130th plugs have the same construction, and each is perfectly adapted to operate with jacks or sockets of either character shown, the only difference in the structure of the system being located in the plug-sockets and the only difference in operation consisting in the fact that when inserted in such a socket as J the tip and rear sleeve contacts of the plug only are concerned, while when placed in such a socket as J all three contacts are employed. In the former case the currents operating the disconnecting-signal pass through both coils thereof, but in the latter case through one coil only. Experience has, however, shown that under the conditions of the latter case one coil can be relied upon for the certain operation of the signal. I

The invention and its mode of operation being thus disclosed, I define it particularly in the following claims:

1. In a telephoneswitchboard apparatus, a switch-plug and cord-circuit connection comprising two terminal switch-plugs, each having two main contact-surfaces adapted to engage spring-jack contacts; two inductivelycontinuous but conductively-discontinuous main strand-conductors extending respectively between the corresponding contacts 0t the said plugs; and a disconnecting signal deconnecting-signals bridged between the said two strands, one on each side of the said condensers or induction-coils; substantially as described.

3. The combination in a telephone system, of a series of main circuits whose clearing-out current is broughtinto action by temporarily grounding the line at a substation and a second series of main circuits having a magnetogenerator at their substations, and Whose clearing-out current is developed by the operation of said generator; with a switch-cord connection having terminal plugs adapted for insertion in the switch-sockets of the said lines respectively, the said cord connection being divided by interposed induction devices one in each cord-strand,into two conductivelyseparate, but inductively united terminal loop-sections; each extending between the two main contact-surfaces of its own plug through an independent clearing-out annunciator; and means for bringing the clearingout annunciator of either terminal loop-section (when any two main circuits are united by the said switch-cord connection) into operative relation with the signal-sending appliances of the main circuit connected therewith, without regard to the series to which the said main circuit belongs; substantially as and for the purposes specified.

4C. 111 a telephone central-station apparatus, the combination of a spring-jack or switchsocket having two main switch-contacts, and an auxiliary switch-contact united to a source of current; and a plug-and-cord switch connection comprising terminal switch-plugs, each having three contact-surfaces adapted to engage the said three socket-contacts respectively, two main strands extending be tween the corresponding main contacts of the said two plugs, two inductive devices one in each stn nd, dividing the same conductively; clearing-out annunciators bridged between the strands, one on each side of the said inductive devices; and a third strand-conductor in each division of the cord connection eX- tending from the middle point of the Winding of the said annunciators respectively, to the third plug contact-surface; for the purposes specified.

5. The combination in a telephone-switch apparatus, of two independent spring-jacks or switch-sockets representing main circuits of diverse construction having their switchcontacts differently arranged, or of diverse number, but having their main circuit-contacts similarly placed; with a switch-plug having contact-surfaces similar in number and arrangement, to those of the switch=socket containing the greatest number of said contacts, and similar in arrangement to those of the remaining socket; substantially as described.

6. In a switch-plug and cord-circuit connection for a telephone-switchboard, a switchplug having three contact-surfaces, two of which connect with the terminals of a cleartwo subscribing witnesses, this 16th day of 5 February, 1898.

EDWIN H. SMYTHE.

Witnesses:

E. M. JACKSON,

L. G. RICHARDSON.

Images