USRE11306E - sgribner - Google Patents

Description

2 Sheets-Sheet 1. U E. SGRIBNER.A

y MULTIPLE SWITGHBOARD SYSTEM.. No. 11,306. Reissued Feb. 7, 1893.

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MULTIPLE SWITGHBOARD SYSTEM.

Reissue-d Feb. '7, 1893.

rllllfllllll'l'llgl'l UNITED STATES PATENT OFFICE.

CHARLES E. SCRIBNER', OF CHICAGO., ILLINOIS, ASSIGNOR TO THE WESTERN v ELECTRIC COMPANY, OF SAME PLACE.

Mu LTIPLE-swlToHBoARo SYSTEM.

SPECIFICATION forming part of Reissued Letters Patent No. 11,306, dated February 7, 1893. riginal No. 442,143, dated December 9, 1890. Application for reissue tiled November 6, 1891. Serial No. 411.100.

To all whom, it may concern.:

Be it known that I, CHARLES E. SCEIBNER, 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 llultiple-Switchboard Systems, (Case No. 175,) of which the following is a full, clear, concise, and exactdescription, reference being had to the accompanyingdrawings, forming a part of this specification.

In muitiple switch board 4systems of telephone-exchange, single wire telephone-circuits and metallic telephone-circuits have been heretofore used upon the sameswitchboards and various means have been einq ployed for enabling vthe operator at one board to test any wire called for to determine whether the line is busy.

Myinvention herein relates more especially to the operator-s apparatus, and by its use the circuits are simpliiied. The metallic circuits lare balanced, so as' to avoid the effects of induced currents from other circuits. The testfor all lines, Whether metallic or grounded,is

made uniform, While the single or grounded circuit lines may be extended to form metallic circuits without disturbing theconuections upon the switch-board'with the springbranch normally extending from ground at the subscriber-s station, throughthe generator and bell to the telephone switch, and thence to the central station, where it is connected through the spring and contact of al diiferent switch on each of the switch boards and from the contact of the switch on the last .board through an individual annunciator to ground. The other branch extends` from a. contact near the telephone-switch, through the telephone at the subscribers station and thence to the ring or test-piece of the several sw'itches'through which the other branch is connected. The single or grounded telephone circuits extend each from ground at the subscrbers'station, in the usual manner, to the 55 central station through a spring and contact of a different spring-jack switch on each of the boards and from the contact of the switch on the lastboard through an annunciator to ground. The rings or test-pieces of the spring- 6o jack Aswitches are connected together by a test-Wire which is grounded through high resist-ance-say tive hundred ohms. At each switch board I provide pairs of loop-plugs, a test-plug, a telephone, and generator, in con- '65 nection with switching apparatus arranged for receiving the subscribers orders, testing-lines called for, and making the connections and 4 disconuections between the lines.` The strand of each pair of cords connecting the sleeves 7o of the plugs of the pair I connectthrough a self-induction coil of, say, six hundred ohms resistance, and Wound with, say, ten thousand convolutions of No. 32`copper wire through a., test battery, which may bea storage battery 75 of, say, ten volts to ground. rihe other strand of each pair-that is'tc say, the strand connecting 4the tips of the plugs-is connected 4through a self-induction coil of the vsame resistance and `wound in the same manner lto 8o ground. When two lines are looped together in metallic circuit, the opposite sides'of the' metallic circuit thus formed will therefore be connected to ground on one side through a self-induction coil only and on the otherside 85 through a self-induction coil and testbatter f.

In connection with each lpairpof cords I-priivv vide aswitch bymeans of which the telephone, which is included in anormally-open grouridcircuit, maybe connected by a half connection 9o witlrthe strand of the cord connecting the tips. In order that the balance of the different sides of the metallic circuits may be maintained, I provide a dummy telephone set in a normally openground-circuit so arranged thaty when 95 connection is made from the strand connecting the tips through the regular telephone set another connectionY will be .made from the strand connecting the sleeves through vthe dummy telephone set to ground. As the roo Adummy set I preferably use a regular microphon e-indnction coil anda self-induction coil having the same number of convolutions and the same amount of iron as are usd in theh telephone, in order that the dummy set may have the same self-inductive effects as the regular telephone set. The strand connecting the sleeves of each of all the pairs of cords on the different boards maybe connected with the same test-battery.

In the accompanying drawings, which are illustrative of my invention,.Figure 1 is a diagram showing three telephone-liuesl-two metall-ic and one single-connected with three switch-boards and an operators outfit at two of the boards. Fig.2 is a detailed view illustrative ot a pair ot' cords and loop-plugs and the connections with the different strands thereof to ground through the self-induction coils, together with the switch for connecting and disconnecting the telephone set and the corresponding self-induction and induction coils with the different sti-ands, the test-plug and its circuitv through one coil of an induction-coil, the other coil including the telephone,the test-battery,and a connection therefrom leading to a second pair of cords. Fig. 3 is a detailed sectional view ot' one of the loop-plugs.

Like parts are indicated by similar letters and numerals of reference throughout the different figures.

Subscribers station 1 in Fig. l is connected with the switch-boards, 1, 2, and 3 at the central oice by a metallic circuit a., consisting of two branches or limbs a a2. The normal circuit of, limb a may be traced from ground at subscribers station 1, through the generator and bell at said station to the telephoneswitch, and thence, as shown, to the central office, and thence through the spring and contact of switches b b2 b3 on the different switch-boards, and from the contact of the switch b3 on thelast board, through an individual annunciator c, and thence to ground. The circuit of the limb or branch a2 may be traced normally from a contactpoint near the telephone-switch of station 1, through the telephone at said station, and thence, as shown, to the central office to the test-pieces or insulated tubes of the series of switches b yb2 b3. The metallic circuit as thus traced is old and well known. The single or grounded telephone-line d extends in the ordinary way from subscribers station 2 to the central office, and thence through switches e', e2, and eS-one on eachl ofthe sWitch-boards-and from the switch on the last board through an individual annunciator fto ground. This grounded circuit is provided With-a test-wire g,'which connects ltogether the frames or testpieces of the switches e e2 e3, and through resistance g of, say, five hundred ohms, to

vground at theceutral station. Thus the testy wire of each single line is'provided with a connection or terminalon each o f the switches of the line, the terminals/or test-pieces heilig normally open, the test-circuit-being provided, however, with a permanent groundconnection through high resistance. The connection to ground through hi gh'resistance is a novel feature of my invention.

The metallic circuit h o'f station* 3 is connested with switches i2 i3, and through an annunciator kin the same manner heretofore described with respect to the circuit of station 1. shown au operators outt. telephone lines ad are shown looped togeth'er'. At board 3 connection has been made with switch i3 of line h, and the test-plug is shown touching the test-piece-of switch b3, as if the subscriber 3 had called for subscriber 1., and the operator, having received the call, was in the act of testing to find out whether the line of subscriber l was in use. As line aof subscriber 1 is connected with line (Z of subscriber 2 at board 1, the -operator testing at board 3, as shown, will find the busy-test indicated. l

In Fig. 2 I have shown an operators outfit in detail in the position indicated at board 3, Fig. 1.

I will describe the operators outfit shown in Fig. 2 in detail. The loop-plugs Z Z are of the form shown in Fig. 3, and are connected by a pair of flexible cords. Strand m con- At each of boards l and 3, I have At board 1 thefi neets the insulated sleeves of the two loopground. From the strand n, which connects the tips, a' branch n extends through a selfinduction c'oil n2 to ground. Thus we .have from each of the strands of 'the cords connecting loop-plugs L l,a branch connection to ground, and in each of these branches is included a self-induction coil, the branch from the strand connecting the sleeves after passing through its self-induction coil fm2 being connected through a test battery m3. These self-induction coils n2 and m2 should be of the same construction', in order that their self inductive effects will be the same. upon the differ,- ent sides ot' a metallic circuit formed when two metallic telephone-lines are looped together by means of the loop-plugs Z 1 aThe operators telephone o is connected in branch wire o with the strand n, which conneets the tips of the loop-plugs. This branch o includes spring o2, and telephone-contact o3 of a loop-switch, and after passing through the telephone set is connectedwith ground.

To balance the self-inductive effects of the telephone' set o, I provide a braiich p from the strand m, connecting the sl'eeves of the plugs, which'branch p extends through spring p' and contact ,p2 through a self-induction coil p3 and an ordinary microphone-induction coil p4 to ground. Thus whenever the telephone o is connected with the strand n, as

lOO

shown in Fig. 2, a branch p is closed to the other strand mbt the cords through apparatusrfp3 pt, having the same self-inductive capacity as the telephone set. Bridged across ferent position.

the telephone is a wire q, including av wind; ing of the converter or induction-coil q. Test plug q2 is simply an ordinary terminal which isprovided with a single connection or strand Q3, 'which includes the'otherwinding of converter q and extends to ground. i

It is evident that the presence-of a vibratory or pulsatory current upon wire g3 will be indicated to one 4listening at the telephone o.

NVire fr; connecting between self-induction coil m2 and battery m3, is simply a connection with a strand of another pairof cords. There may be, for example, twenty pairs of cords at each switch-board. I will not spe-' ciiically describe the clearing-out annunciator, the calling keys, and the generator connections, since they are old and their operation understood by those having any knowledge-of telephone-exchange apparatus.

The operators apparatus at board 3, Fig. l, is lettered to correspondwith the same apparatus in Fig. 2. The operators apparatus at board 1 of'lig. l is the same, though shown in a dif- At board 3 the telephone o is in circuit, while at board 1 the telephone circuit is open at the loop switch s, the plunger of said switch s being forced down so as to lift thesprings of said switch from their contacts. The test-plug s is resting in its socket, while the two loop-plugs .s2 ss are shown inserted in the spring jack-switc`hes e b', so as to loop the telephone lines a and d together.

When an ygtwo lines are connected together, whether metallic or single or a metallic circuit with a single circuit, as shown, the testbattery m3 will be connected to the test-pieces to all the spring-jack switches of the two connected lines. In case of metallic circuits it is essential that the connection with the testbattery be through a self-induction coil, and it is especially desirable, though, not essen tial, that the other branch or limb of the circuit be provided with a corresponding branch ground-connection. through a self-induction coil of the same character, in order that there' may be aV balance between the diiferent sides of the metallic circuitA When the' operator p pleting the connections, and disconnecting nunciator-drop, as la, falls.

the lines when the subscribers are doneltalking arebrieily as follows: The individual an- The operator at once inserts the answering loop-plug Z in the spring jack switch of the corresponding line and brings the telephone o into circuit and receives the order. Thereupon the test is made of the line called for by applying terminal q to the test-piece of the springjack switch of the line thus required. lf the line la busy, the test-piece of the spring-jack 'over his line. -ceived upon a clearing-out annunciator inswitch tested will be connected with battery and current from said battery will be sent over wireg, which will cause a sound in the' telephone o.l This will be notice to the operator that the line tested is busy and the calling subscriber will be notified to wait. If, however, there isv no sound in the telephone when the test is made, the operator will know that the line wanted is idle and will at once complete-the connection by insertin g the other plug of the pair, as Z,in the spring-jack switch of the line.A The connections will then be complete, and the called' subscriber will be notiiied by current sent `from the generator The clearing-out signal is recluded in the strand connecting the tips of the plugs. The operator, seeing the clearingout drop fall, listens to make sure that the subscribers are through and then simply pulls out the loop-plugs. f

ItV will be observed. that the balance is maintained during ih e entire time that the two lines are connected.

My invention admits of various modifications that would readily suggest themselves to those having any special knowledge of telephone-exchange apparatus, and I therefore do not limit myself to the details o f construction shown.

Having thus described my invention, I claimas new and desire to secure by Letters Patent- 1. The combination, with metallic-circuit telephone-lines looped together inv metallic circuits by a pair of loop-plugs and flexible cords, of a branch circuit to ground from the strand connecting the sleeves of the plugs, said branch including a self-induction coil and a battery, said telephone-lines being connected 'each with diierent switches on each of two or more switchboards, andthe sleeves of said plugs being connected, respectively, with the test-pieces of the switches of there spective lines, whereby the test-battery is connected to said test-pieces, while the flow of induced currents upon the metallic circuit is prevented, substantially as described.

2. The combination, with a telephone-line connected with switches distributedfon different switch-boards, of testpieces, one on each switch, the test-,pieces being permanently connected together by a wire connected through resistance, of a loop-plug inserted in one of said switches, the tip of said plug lifting the spring of the switch in which itis inserted and forming contact therewith, while the'sleeve 'of said plug is connected with the test-piece of said switch, a branch 'circuit to ground from the strand of the cord connected with the sleeve of the'plug, and a self induction coil and battery included insaid ground branch, substantially as and for the purpose specified.

3. A pair of loop-plugs and flexible cords adapted to connect two telephone-linestogather, in combination with a branch circuit IOO IIO

outiit may be connected to the differentstrands of the -cords, substantially as described.

' 5. Thecombination,with thetwostrands ot a flexible cord, each strand being provided with a permanent ground-connection ,of two branch circuits to ground connected with the diierent strands of the cord, one brauch containing a telephone and the other branch containing a corresponding self-induction coil, and aswitching device whereby the telephone and the corresponding self-induction device may be connected at the same time with the different strands, respectively, of the cord.

6. In a telephone-exchange apparatus, a

pair of cords provided with terminal loop plugs adapted to formv connections between the telephone-line terminals, of a permanent branch connection from one ot' the strands of said cords through aselt-induction coil and a battery to ground, substantially as and for the purpose specified. l

7. The combination, with a metallic circuit a, extending from a subscribers station to the central oflice and being there normally connected with several spring-jack switches b b2 b3 on different switch-boards, of a single, telephone-line circuit d, extending from its subscribers station to the central oce and being there connected with several spring-jack switches e e2 e3 on different switch-boards, the test-circuit g, connected with the insulated frames or test-pieces of said switches e', eesaid test-circuitsbeing connected through resistance g' to ground, a pair of loop-plugs 's2 553 and their cords connecting said telephonelines together upon one of the switch-boards,

a test-battery, and a self-induction coil branched to the strand of the cord connecting the sleeves of the plugs, anda currentin'A boards, the test-circuit g, connected with the insulated frames or test pieces of said switches e e2 es, said test-circuits beingy connected through resistance g to ground, apair of loopplugs s2s3and their cords connecting said telephone-lines together upon one of the switchboards, a'test-battery, and a selfinduction coil branched to the strand of the cord connecting the vsleevesof the plugs,acorrespond ing brauch to ground from the other strand of the cord, including a corresponding selfdnduction coil, and a current indicating device at another board adapted to be connected to the testring of either ot the switches of said line, whereby it may be determined whether either of said lines is in use.

9. The combination, with a metallic circuit a, extending from asubscribers station to the central oiiice and being there normally connected with several spring-jack switches h b2 h3 on diierent switch-boards, of a single telephone-line circuit d, extending. from its subscribers station to the central office and being there connected with several spring-jack switches e e? e3 on different switch-boards,

the testcircuit g, connected with the insulated frames or test-pieces of said switches e c2 e3, said test-circuit being connected through resistance g to ground, a pair. oty loop-plugs s2 sa and their cords connecting said telephone lines together upon one of the switch-boards, a test-battery, and a self-.induction coil branched to the strand of the cord connect-v ing the sleeves of the plug, and a cor-responding branch to ground from the other strand of the cord, including a corresponding self-induction coil, substantially as and for the purpose specified.

Vl0. The combination, with .two metallic telephone-line circuits looped together at one of several .multiple switch-boards with which said lines are connected, of' a branch circuit from the side of the united circuit, said lines connected with the test-pieces of the switches, said branch including a self-induction coil and battery, and a corresponding branch circuit to ground from the other side of said metallic circuit through a corresponding self-induction device, wherebythe said circuit is balanced with respect to inductive eiects, substantially as and for thepurpose specified.

' 1L The combination,withan operators telephone connected in circuit o', 'and switching apparatus, of a bridge wire q between the terminals of said telephone, said bridge-wire containing one coil of a converter; and a ground Acircuit qa, including the other c`oil of said converter, and provided with a movable terminal q2, substantially as shown and described.

l2. The combination, with the telephone connected with a strand of a flexible cord in the united circuit of two telephone-lines, of a converter with one of its coils bridging said telephone, a circuit provided with a movable terminal, including the other coil of said converter, and a test-terminal, of another telephone-line, to which Said movable-terminal is IIO ` insee 5 applied, substantially as and for thepurpose switch-boards, the test-pieces of the switches specified. of the dierent lines respectively being per- 13. The combination, with a telephone-line manently -connected together, the terminals connected with switches on different switch- 'of the diderent loop-plugs being adaptedto z 5 :.5 boards, the switches of said line being proclose the one to the line terminal or spring of vided with test-pieces permanently connected the switch in which it is inserted and the other together, of a loop-plug inserted in one of the terminal to the test-piece of the switch and a switches of said line, one point or terminalof battery branched through different self-inducsaid plug being connected with the spring or tion coils to the strand of each of the pairs of 3o lo line terminal of the switch and the other point cords, which strand connects with the termi.

or contact of said plug connected with the testnals of the plugs which close upon the testpiece of vsaid switch, the strand' of the cord pieces of the switches, Wherebya common batcounecting with the terminal of theplug which tery supplies current for many test connecis\c1osed to the test piece of the switch being tions.

. 35 15 branched through a 4self-induction coil and In witness whereof I hereunto subscribe my battery to ground, substantially as and fol-.the name. n purpose specified. f 14. The combination, with several pairs of ,CHARLES E SGRIBNER' cords and their loop-plug terminals, of tele- Witnesses: 2o phone-lines each connect-ed withy two or more ELLA EDLER,

v spring-jack switches distributed on 'diierent GEORGE L. CRAGG.

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