US1650708A - Telephone-exchange system - Google Patents

Description

Novgg, 1952-7.

J. w. GOODERHAM TELEPHONE EXCHANGE SYSTEM 3 Sheets-Sheet l Filed July 20. 1923 Nov. 29, 1927. 1,650,708 M J. W. GOODERHAM TELEPHONE EXCHANGE SYSTEM Filed July 20, 1923 5 Sh Code Nw. 29, 192%?. A 1,650,708

` J. W. GCODERHAM TELEPHONE EXCHANGE SYSTEM Patented Nov. y Z9, i927,y

Y i Y ,liid

at Ac; riff-cn.

ci rnnnenonnfnncnanen sYszrni/i.

i application sied nay zo, 1923 sensi No.' 652,678; y

This invention relatesvto telephone s-yS- tems andV more particularly to means` in such` systems for controlling indicatingdecurrent impulses of' va rious charac` and apparatusfor determining the. charac-` teristicsof such impulses.. i

This invention constitutes.animprovement i over UQ S. Patent No. 1,438,743 granted to Edgar Hl ClarlnDecember 12, 1922"Whicl1 relatestoa telephonersystemin which means are providedby which an operator may be informed visually of the number of a-Wanted subscriber.` The means for` so doing includes regsters which may be set in accordance With the called number, an impulse trans mitting switch and an organization of re-l lays and sition. Y v .y Q

Ovvingto the irregularities introduced in the commercial mamifactureand adjustment of parts which go to makeup the impulse transmitting switch, it is possibleinipractice that bri efv false `impulses lmay occur .between the pulses intended to `be sent, Whichpulses may be sufficient tolcause the incorrect operation of the indicators. These ,false impulses can, ofcourse, beeliminated by perfectly adjusting each switch, butin a telephone system employing hundredsof these switches, such a procedure wouldbe decidedly uneconomical. i l

Accordingly, a feature of the present in vention is the eliminationfof such false pulses bythe use of af novel arrangement of the impulse controlling and transmitting means.

A.-further feature ofthe present invention lies in the provision of individual circuits for the transmission of impulses of di'erent characteristics as far as the trunk circuit. lnipulses of allA characteristics are then transmitted over said trunk circuitV rlliis and other features of the invention will appear in the accompanying drawing and description together with the Yappended claims. c f

The drawings with Fig. 2 placed below F l and with llig. I placed at the :right of ll'igQ diagramniatically represent portion of n tfeiephonesystem employing the present invention. lfig.. 1 shows a calling. subscribe lindicators at the operatorspoers substation and,l line With brushes of a district vselector at an operatorspositl'oma calling plug andgack at a second operators` position and a` called subscribei"s`v substation: A

apparatus and line,` y Nithin the small' dot` ted rectangle at the-left hand.; side of: Figfl, there are shown the brushes of a cordfin'der switch Whichv operates to connect anidle" `Sending device to the cord circuit which has beenconnectedto the calling line." Within the large dottedrectangle att-he right handelde of Fig. 1, there are shown an operatorskey setand the `registers-ot the sending device' for controlling the transmission.ofimpulses to the number indicatingdevice. VVithinfthe larger dotted enclosure at the left ofFigi l, there is shown an impulse transmitting device which, under the controlof` the registers,V transmits various combinations ofimpulses to actuatethe number indicating device. i

y lnliig. there are shown the viniousre,-` lays which cont-rol the liglitingof theV proper stations lamp as WellV as the switching relays which Operate to controlthe actuation ofthe thousands, hundreds, tens andunits indicat. ing" devices in propersequence.I c y 1 F ig. 3 in its lower-right handcorner shotvs" the lamps and controlling relays for` indil' cating'thethousands digit; at the'lcyver, left hand cornert lie hundreds; at the upper left hand corner, Vthe tens; andatthe upper right hand corner, the units lamps and, the relays for controlling them.

4 In this disclosure, the showingv of the apparatus and circuits for-selecting the second or B operatonsposition.has beenabbreviated but it may be of the character of the sys-4 tem Y disclosed in patent to Lundell `No. 1,168,319, January. 1S, 19164 or it may. ibesimu ilar to the system shoWnin the patent to E; H, ClarkNo..1334,7357of Marchf23, 1920.l

The trunk selecting; switchfreferrcd to in the description may` be of; the type illus` trated in the patentI to Craft and Reynolds 1,123,696 of. January 5i 19`15,.althoughit Will be readily understood that any automatic selector switch can beemployed in'` thissyss teniv Without departing from thespirit of the invention. i

lnA the' description, reference made' .to sequence switches and registers, the structure of which may befsiinilar toithat shownintlie patent Jfri-Reynolds and Baldwin l-,lQfTOSV of February 9, 1915. It is to be noted, however, that a revolution of the impulse sequence switch is divided into twenty )osi-v ti'onsof eighteen degrees each instead o the usual arrangement of eighteen positions of twenty degrees each. This is merely a matter of convenience and introduces no change in the `operation ot the switch.

It is also to be noted that this invention ually applicable to systems such as that dise osedin U. S. Patent 1,395,977 granted to F. A. Stearn and F. J. Scudder, November .1, 1921, that is, to systems in which the registers 4take the form of step-by-step i, switches or areset under theV control of the fsubscriber without the intervention of an operator.

. lIn' general, the system of the Vpresent dis- 'closure comprises a set of operators keys which controls sequence switch registers, all.

' oflvhieh are shownin the dotted rectangles Y at the right of Fig. 1; a switching device tor sending impulses as determined by the sequencey switch registers as shown in the larger left hand dotted enclosure in Fig. l;

` andan arrangement of relays for receiving im ulses as shown in Figs. 2 and 3.

n Fig. 2, there are shown three relays in series 201, 202 and 203 which respond directly to'the transmitted impulses. These relays in turn control a combination of two pulse switch to makean additional revolution, additional registers being provided. As themeans for doing so forms no part ot' the present invention, the disclosure has beenlimited, tor simplicity, to a five digit number.

` There is provided -a set of indicating lamps for each'one of the digits of the called num- .,ber, each set of lamps being controlled by a. sety oflamp controlling relays as shown in Fig. 3. The set 321, etc., controls the thousands lamps,"the set 331 etc., controls the hundreds lamps, the set 341, etc., controls the tens lamps and the set 351, etc., controls the units lamps. As shown in Fig. 2, the set 262, ete., controls the. stations lamps.

`The impulses transmitted by the sequence. switch 114 in Fig. 1 are in the nature ot a code, which consists essentially of heavy negative im ulses between which may be interposed lig t positive impulses, the heavy negative impulses being superimposed on light negative impulses which serve as switching impulses. may be omitted.

The positive impulses are produced by The'V positive impulses current from grounded battery, tlowim.y

through resistance 143 and overa parallelk path through low resistance 1li and cams controlled by sequence switch 114 and cam' contact-s closed by the sett-ing of the registers to brush 10G. Thus in etect,lswitching cams 131 to 133 and register cams 151, 153, 156, 158 and 159 together with battery and resistance 1,42 form a generating device for positive impulses only, while switching cams 145 to 149 and register cams 150, 15T, 152, 154 and 155 together with battery and resistance 144 form a generating device for Y negative impulses only.

Attention is directed to the fact that the paths followed by the positive impulses from battery to brush ^are entirely sep'- arate from those followed by the negative impulses from battery to brush 100. In im ease, does the same cam serve for bothnega tive and positive impulses. While battery throughhigh resistance 143 is continuously connected to the side of the line leading to brush 106, it produces no effect atthe time ot sending positive pulses, being shunted out by ground on cam 140.l

In the disclosure of the above mentioned Patent No. 1,438,743 to E. H. Clark, it may be seen that only two sequence switch cams are used for transmitting all the heavy pulses for eaclrdigit, one on the register sequence switch and one on the impulse sequence switch. Therefore, if the cams on the impulse sequence switch, which feed the successive pulses that go to make up the code for a given digit, are not properly adjusted, but overlap a little, it is possible tor heavy current intended for the preceding or succeedingr impulses to find a momentary path over the line in the opposite direction. thusy causing a momentary heavy pulse whereone may not have been intended. rlhe .separation of the leads from battery, through the impulse switch and the registers to the opposite sides ot the line, in accordance with the present invention, entirely eliminates the. possibility ot the current for the negative inipulses find` ing a path over the positive cams to tlie line. Cain overlap may prolong a pulse but it cannot feed it out to the wrong side of the line. It is also to be noted that the positive cams of the impulse switch are closed from slightly before the time of the first positive pulse of a digit to slightly after the time for the second Ilm ell

positive-pulse of a digit, thus preventing any l surge oitcurrentL which may occurl due to the closureof the battery leadV from interferingwith an open or non-pulse periodi Attention is alsocalled to the fact that the circuit for the pulses are further separated.

by having'the circuitstor the iirst pulse car* ried through one cutting of theregister and: impulse switch cams and the second pulse thro-ugh a second cutting on these"` cams, thus additionally insuring the" individuality ot'- the pulses. V i

The code-ot impulsesfis showndiagrammatically inthe upper part ci? Fig. 2: Positive im mises are re resented b a )lus sign As will1 hereinafter appear, the lamp con trolling relaysr such as^321, 322, 323, and are energizedwheneveran impulse ot poen tivecurrent or an impulseot heavy negative current is transmitted and thus thehcodes diagrammatically shown give anf indication of which lamp controlling relays will beenergized, it being noted that the-flinal digit ot' the numbers applied'to the relaysin eachl set is the same as'tlie number at the'headloli 'the corresponding column in the code shown in Fig, 2. y For instance, in theinumericalfcode, the series of` impulses fortlle'digiu c`on-l sists ot'` first, al positive impulse, second', `a light negativeV impulse, third, ay blank, and :tour-th, a heavy'negativeimpulse. *Asindicated, the first and fourth relays will be energized according to this code. The stations codecorresponds to the numerical code eX- ceptthatno initial positive impulsesare sent.

The method of establishing al connection from a calling substation asshownf at' 101 to a called substationl as shown at 102 will now be described.. `When the calling sul scriber removes his receiver' `trom his switchL hook, a signal (not shown) is lighted fat an operatorls position. This operator, known as an A operator, thereupon connects the cord circuit conductors 103 and" ,106ir tothe callingy line manually or by anyother suit able means. is soon as the A; operator has connected the cord circuit tothe `calling line, a cord finder whose'ljrushes are indicatedE at llland lotoperates to connect anidlesend`- -ingA devicev withV they cordI circuit taken for use. `When theoperator connects the cord circuit to the callingdv line, she ascertains theI number ofthe wan-tedsubscriber andl proceedstoset up this nuinben on the keyboard: ot liersending device.-

`Let us assume that the-wantednumber is itdistation lV. 'IlheV operator. will1 then depress the corresponding stations, thousands, hundreds, tens' and units keys 1n response to which the associated sequence switch registers will* be movedV and the sta tions register 109 will come to rest in posi? tion 7, the thousands-register 11() will stop at position fl, the hundreds register 111 .in

position 5, the tens register 112 in position'l 6 and theunits register 113` in position It will be Vassumed.that thefautomatic trunk selecting' switch whose brushes are lindicated by the numerals 107 and.lOSfhas` been eet to: select the proper` trunk for -connetting Vthe calling subscriberV with theB oper-atene position at the ollicein.` which the wanted line terminates. 1 1t will be'assumed that the; sequence Aswitch associated with this trunk selecting switch hasbeen moved" into position 11. i

fitter the sending devicelhas been set, and when the trunk selecting switch hasgbeen operated to extend-t-hecalling `line` tfothe4 l'operators position at; the desired-chics, the sequence switch associated with the cord lindcr will bein position i Where acircuit will he established to venergize relay11f. This circuit-may be4 traced from ground, sequence switclr cam 116, winding ot" relay 117, sequence ,switch camy 118 (position 11)l brush 105, upper. contact ot sequenceV switch cam 119, brush `108, lower armatureand back.

contactotl relay 120,`lower lett hand wind- Y ing ofy repeating coill 1211, winding of relay 123"to groundedY battery. Relays 117 and 123? are operated by"currentf flowing over thiscircuit. Relay 1172by the attraction of itsfarmature closes afcircuit `from ground, armature and iront contact ot relay 117, winding ot relay 115 to grounded battery whereby reluy"1i15 is energized.` At. the front Contact andarmature ot relayy 123, a circuit is closedVt'iom ground back contact and armature of relay 125, lampi 1216, to grounded battery; loampl126, in lighting,

indicates to the manual operator that a call is awaiting attention and also indicates the trunk` over whichthe call has beenextended.

The manuall operator) thereupon 'depresses key 127 to' associate'thenumber indicating' device with the trunk'over which the call has been extended; l i Upon the depression ot key 127, av circuit `is closed from ground, winding ot relay 120,y

contact otkey127, conductor 12S, winding ot relay 20() to'groundedbattery. Relay 2.00

attractsits armatures, to apply ground' to the various controlling leads ol the number indicating device:` Art the Sametime, relay 120 attracts its armatures and at its lower armature interrupts thel energizing' circuit of relay 117. With this relay deenergizedi lil() a circuit is closed from ground, through its armature and back contact. armature and front contact of sloW-to-release relay 115, magnet of sequence switch 114 to grounded battery to move the sequence switch 114 out of position 1 whereupon it Will, under the control of its master contact 124, rotate through its various operating positions back to position '1, during which a complete set of impulses is transmitted to the relays 201, 202, and 203. Relay 203 is marginal and responds only to impulses o'l heavy current, relay 201 respondsonly to positive impulses, and relay 202y responds only to negative impulses, the 'armature of these relaysk being normally retracted.

As has been mentioned, vno positive pulses are sent out in the first period of the train for the Vstations code. Accordingly the. upper contact of cam 139is not closed during the time that the sequence switch 1147is passing through positions'l-l-l/2 and the corresponding connection to positive cani 150 of stations register 109 is omitted.

When sequence switch 114 moves into position 2, a circuit is closed from grounded battery, throughhigh resistance 143, and

in parallel through loW resistance 144 over theupper Contact of cam 145, and lower cont-act of negative cam 150 of stations register 109 to cord finder brush 106, thence by way of the upper contactof cam 135, trunk selector brush 107, upper armature and front contact of relayr120, conductor 204, Winding of-marginal relay 203, Winding Yof negatively polarized relay 202, Winding of positively polarized relay 201, conductor 134,'lower armature and front contact of relay 120, trunk selector brush 108, upper contact ofV cam 119, cord finder brush 105, upper contact of cam 140 to, ground. Since the impulse circuit extends through low resistance 144, marginal relay 203 'is energized and since this impulse is negative, relay 202 attracts its armature and closes a circuit from grounded battery, left Windying of relay 209, Winding of relay 207, lett armature and baclccontact of relay 209, armature and front contact of relay 202, conductor 208, outer armature and liront contactof relay 200 to ground. The left Winding-of relay 209 is a holding Winding and able only to hold the armatures of this relay attracted when once they have been actuated by the right or pull-up Winding of this relay. Thus, relay 209 does not attract its armatures but, relay 207 does attractv its armatures in this circuit. inner right front Contact and armature ot thisrelay, a circuit for the right Winding of relay 209 is closed, but this winding is short-circuited at this time as fully. explained later.

At the outer right front contact and armature of relay 207, anv energizing circuit for relay 206 is completed from grounded battracts its armatures and at its inner right front contact and armature closes an energizing circuit for relay 210 but this last mentioned relay is short-circuitcd at this time and does not' attract its armatures. Due to the energization ofanarginal relay 203 together with the cncrgization of relay 202, a circuit is closed for stations relay 262 extending from grounded battery, left winding of relay 262, inner right armature and back contact of relay 210, outer right armature and backy contact of relay 209, armature and front contact of relay 203, armature and front contact of relay 202 to grounded conductor 208. Relay 262 encrgizcs and locks through both. windings and its right armature to grounded conductor 208.

lVhen sequence switch 114 `moves out of position 21/2, relay 202 deenergizes and retracts its armature removing the short eircuit rabout the right hand winding of relay 209. Relay 209 operates in a circuit from grounded battery, through the left winding of relay 209, winding of relay 207, right Winding of relay 209, inner right front contact and armature of relay 207 to groimd over conductor 208.

In positions 4l41/ of sequence switch 114, a heavy negative impulse is transmitted from grounded battery, low resistance 144, lower contact of cam 145, upper contact of negative cam 150 of stations register 109` in parallel With resistance 143, brush 106 and over the circuit previously described through relays 201, 202, and 203, back to brush 105 and to ground over the upper contact of cam 140. In response to this heavy negative impulse, relays 202 and 203 again attract their armatures. `With both of these relays energized, stations relay 264 is actuated over arircuit from grounded battery, left winding of relay 264, outer right hand armature and back contact of relay 210, outer right armature and front contact of relay 209, armature and front contact of relay 203, armature andv front contact ofA relay 202, to grounded conductor 208. Relay 264 is energized and at its right front contact and armature completes a, locking circuit Jfor itself from grounded battery through both its windings in series to ground over conductor 208.

Relay 202 also completes a holding circuit for relay 209 from grounded battery, left Winding of relay 209, left hand armature and front contact of relay 209, armature and front contact of relay 202, to grounded conductor 208. Relay 207 is short-circuited and retracts its armatures.l Theshort circuit about relay 210 is maintained at this time hy way of the inner right armature and iront contact of relay 209 -to grounded conductor 203. Eis soon as sequence switch 114 leaves position 4%, relay 202 becomes ideenergized and the holding circuit for relay 209 is opened. The release rof relay `209 removes the shunt around relay 210 and this relay attracts its arniatiires and locks in series lpositions Gabel/gy, no path is closed through low resistance 144 to brush 103 andA alight negative Vpulse is sent from grounded battery through high resistance 143 overthe above traced circuit and hach to ground at the upper contact ot cani 140. Relay 202enei` and energisee relay 207. ',Relay 207 attracts its armature to prepare at its in- .ner right trout Contact and armature an ein.

ergizing circuit for relay 209, and at its outer front contact and armature vcompletes an energizing circuit for relay 211 from grounded hatteryyinding ofthis relay, in ner lett armature and back contact of relay 213, inner left armature and liront Contact of relay 210, outer right ,armature and lront contact of relay 207 to groundoveij conclue-` tor 203. lWhen sequence switch 114 moves out oi' position 61/2, relay/202 deenergizes und removes the shunt from the right winding ot' relay 209. This relay energizes over its two windings and the winding of relay 207 in series. n

lWith sequence switch 114 in positions Tril/fg, a positive impulse is transmitted troni grounded battery, resistance 142, lower Contact of cam 132, upper contact ofpositive cam 151 ot' thousands register 110 lower, contact of cam 139, over the previously described circuit and back to ground at the` lower Contact ot' cam 140, Relay 201 at# tracts its armature and closes a circuit ntroni grounded battery, lei't winding of thousands lamp relay 323, conductor 302outer right armature and backv contact of relay 214, outer right armatures and front contacts of relays 211 and 206, left armature and front contact of relay 207 `armature and lront contact of relay 201 to grounded conductor 20S. Relay 323 attracts its armatures and completes a locking-circuit for itself from grounded battery, through both windings in series, its `iight front Contact and y armature, conductoiw301, inner leftyfront contact and armatureot` relay `200 to ground;

`ter 1-10., ln response jto this weak impulse,

When sequence switch 114 passes through positions 8+81, a light negative impulse 1s transmitted from grounded battery, through resistance 143,-since the contacts of negative cam 157 -are not closed in "position 4 oi regisi'ela'y 202 is enerjigized "closing the holding circuit for relay 209 and -shunting :relay 207. Relay A`207 rretracts its armatures but the shunt around relay 213 is inai-ntainedjatthe inner frighthand, armature of relay 209,` as in the `oaseot relay :210. When-sequence switch 114 leaves position S1/2, r elay 202 is deenergized, permitting relay 209 -to retract its armatures and `rela-y 213 to lock infseries with relay 211 and thelront contact otrelay 211. to grounded conductor .208, lThis completes `the selec-tion of the thousands lamp controlling relays, relay323 yalone 'hays` ingv been actuated'.` 1

.Since thehundreds register -is setlinvv positionf, no positive pulse will be 'set in position 9|91/2 of sequence switch 114. f y

in position inici, i iight negarse pulse is sent in response to which relay `202 is energized. Relay 207 is again energized through the lefthand winding of relay 209 and closes a circuit 'for relay2'14 extending from grounded battery, winding of relayv 214, inner left armature and bac-k` contact of relay 2115, inner' left varmatures and-front contacts ot relays 2131and 210, outer right armature and front contactof relay 207 to grounded conductor 208. Relay 214 at'- tracts its armatures and at its .innermost right hand armature and front contact closes an energizing circuit for Arelay 215.

ith sequence switch 114 in positions 'i 11.4-111/2, no positive Vpulse will be sent out but when sequence switch 114 leaves ,posif tion 101/2, relay 202 releases and relay 209 operates in series with relay 207.

In positions 12{121/` of sequence switch 114, a heavy negative impulse is, sent out over a circuit extending from grounded hattery, low resistance, 144 lower contact of cani 147, upper Contact of negative cani 152 of hundreds register 111 Vto brush 106 and thence over the impulse circuit to ground at the upper contact of cam 140. In response to this impulse, relays 202 and 203 are en-Y ergized and coni lete a circuit trom grounded battery, left and winding of relay 334, conductor 300, outer right armature and back contact of relay 215, outer left armatures and front contacts of relays 213 and 210, outer right armature and front contact of relay 209, armatureand front Contact of relay 203, armature and front contact of relayw202, to ygrounded conductor 208. Relay 334 attracts its armatures and completes a locking circuit Jfor itself over conductor, 301 to round.` y elay 202 also completes the holding cir' cuit for relay 209 and shunts `relay'207 'which relay"retracts its armatures. 'As soon as Asequence switch 114 moves out of position 1211/2, relay 202 retracts its armatures and relay 209 releases, removing the shunt closed atits inner right `hand armature and front contact around relay 215, and permitting relay 215 to operate in seriesl with relay 214 through the innermost armature and front contact of relay 214 to groundedr conductor 208. This completes the selection of the hundredsA lamp controlling relays, relay 334 alone having been actuated.

It Will now be noted that'the tens register 112 is set in position 6. With sequence switch 114 in position 13+131/, a positive impulse is transmittedfrom grounded battery, through resistance 142, lower contact ofcam 133, lower contact of posit-ive cam 153 of tens register 112, upper contact of cam 139, over the circuit previously described to ground through the lower Contact of cam 140. Relay 201 is actuated and completes an energizing circuit for the tens lamp controllmg relay 341 extending from grounded battery, left winding of relay 341, conductor 304, middle 'right armature and back contact of relay 217, middle armature and 'l'ront contact of relay 214, left armatures and front contacts of relays 211 and 206, leit armature and back contact of relay 207, armature and front contact of relay 201 to grounded couductor 208. 'Relay 341 attracts its armature and locks to grounded conductor 301.

With sequence switch 114 in positions 14l141/2, a light negative impulse is transmitted from grounded battery, resistance 143, over the previously described circuit to ground through the upper Contact of cani 140. -In response to this impulse, relay 202 attracts its armature. Relay 207 is energized in the manner previously described and attracts its armatures to complete a circuit for relay 217 from grounded battery, winding of this relay, inner left armature and back contact of relay 218, inner left armatures and front contacts of relays 215, 213 and 210, outer right armature and l'ront contact of relay 207 to grounded conductor 208.

With sequence switch 114 in position 154-151/2, no positive impulse is sent out but relay 202 is permitted to retract its arma ture resulting as before in the actuation of relay 209.

In position 164-161/2 of sequence switch 114, a heavy negative impulse istransmitted from grounded battery, resistancev 144, lower contact of cam k148, upper contact of negative cam 154 of tens register 112 over the circuit previously traced and back to ground through the upper contact of cam 140. Relays 202 and 203 are energized. In the manner previously described, relay 207 becomes short-,circuited and retracts its armatures. Relay 344 is also energized over a circuit including grounded battery, left hand Winding of relay 344, conductor 306, the outer right armature and back contact of relay 218, the outer left armatures and front contacts of relays 215, 213 and 210, outer right armature and front contact of relay 209, ar matures and front contacts ot' relays 203 and 202 to groundover conductor 208. Relay 344 attracts its armatures and completes a locking circuit for itseltI over conductor 301 to ground.

As soon as sequence switch 114 leaves position 161/2, relay 202 releases, permitting relay 209 to retract its armatures and relay 218 to lock in series with relay 217 to grounded conductor 208 through the inner most right armature and front contact of relay 217. This completes the selection of the tens lamp controlling relays, relays 341 and 344 having been actuated.

It will vnow be noted that the units sequence switch register 113 has been set in position 8. `Wl1en sequence switch 114 is rotated through positions 174-171/2, a positive pulse is sent out over a path from grounded battery, resistance 142, upper contact of cani 133, lower contact of positive cam 150 of units register 113, upper contact of cam 130 and over the impulse circuit to ground at the lower contact of cam 140. Relay 201 operates in response to this impulse and closes a circuit ior units lamp controlling relay 351 which may be traced from grounded battery, left Winding of relay 351, conductor 309, middle right armatures and front coutacts oi relays 217 and 214, left armatures and front contacts ot' relays 211 and 206, left armature and back contact of relay 207, armature and front contact of relay 201 to ground over conductor 208. Relay 351 operates in this circuit and locks to conductor 301 through both windings in series and its innermost armature and Afront contact.

In position 18-l181/2, a heavy negative impulse is transmitted from grounded battery, low resistance 144, upper contact of cam 149, lower contact of negative cam 155 of units register 113 over the circuit previously described to ground through the upper contact of cam 140. y In response to this impulse, relays 202 and 203 attract their armatures. Through the front contact of relay 202, the circuit is closed for relay 207. Upon the actuation of relay 207, a circuit is closed for relay 219, from grounded battery, winding of this relay, inner left armature and back contact ot relay 221, the inner left armatures and front contacts oi relays 218, 215, 213 and 210, the outer right armature and front contact of relay 207 to ground over conductor 208.

In response to this impulse, relay 352 is also operated over a circuit traceable from grounded battery, lett winding of this relay'7 conductor 308, inner right armatures and front contacts ot rela'ysa21j8, 215, 213 and 210, outer right armature and back contact of relay` 209, armatures and liront contacts ot relays 202 and 203 rto 'ground over con-` ductor 208, Whereuponfrelay 352 locks to grounded conductor 301?. i

l/Vhile sequence switch 11e: is rotated through positions 19.41191/1 no positive pulse is sent out but relay 202 is permitted to deenergize again energizing. relay 209 in theseries circuit `With relay 207 as previ-` ously described. y Y y ln positions 20+201/2,y ot sequenceswitch 114i, a heavy negative impulse is transmitted from grounded.` battery, lower Contact of cam 149, upper contact o'tnegative cam 155 or units register 113 over theimpulse circuit to ground at the upper contact ot cam 1410. Relays 202 and 203 yattract their armatures in response to this impulse and relay 202 completesV a: circuit'itlirough the, right, wind ing of relay 209 andshortcircuits relay 207..

In responsetothis impulse, relay 354 is also operated over a circuit traceable from grounded battery, left Winding .et relay 354-, conductor 311,fouter left 'armatures and front contacts 0f'relay218, 215, 218 and 210, outer right armature and front Contact ot relay 209, armatures `and iront `contacts ot relays 203 `and 202,"to ground over conductor 208 Whereupon'relay 354 locks to ground over conductor `301. l l

As soon as sequence switch 11e leaves position 20% relay 202 becomes deenergized. lnlresponse' to the retraction or" the armature of relay 202, relay 209 becomes' deenergized and at its inner right armature andy iront contact opens the shortcircuit about relay 221 which thereupon becomes energized in series with relay1219 through the inner `right armature and front contact thereof.

When relay 217 operated; it closed a cir.- cuit from ground through its left armature and fronti Contact, conductor 222, Windingoi relay 310 -to `,efrrnmded battery. This last mentioned relay `attracts its armatures to supply battery'for lighting the thousands and hundreds digit lamps. l/Vhen relay 221 attracted its armatures, at its outer lett armature and front contact, it connected ground to conductor 223 over lWhich the circuits ot certain of the stations lamps may be completed. At the outer right armature and front contact oi relay 221, a circuit is closed for lighting the selected units indicating lamps; at the outermost right armature and front Contact of relay 219, a circuit is closed tor lighting the tens indicating lamps and at the outer lett armature and front Contact of relay 219, a circuit is closed tor lighting. the selected stations indicating lamps.

lt will be remembered that the thousands digit is 4 and that. relay 323 has been actuated and locked. When relay 310 attracts inner left: armature and front contact ot relay 323, throughlamp outer lei'tarmature and "trent contact ot' relay. 323, inner right armature and` frontcontact of relay 810,` to

groundl over conductor 208. The circuits 'l for lighting the hundreds, Vtens and units digits lamps may be 'similarly traced. y

The stations lamp WV vvill be illuminated over a circuit extended from grounded battery, outer lettl armature and front contact of relay 219, conductor 224, through lamp WV, outer left armature and front contact of relay 262, right armature and front contact of relay 264, to ground` over conductor 208-.

It Willbe understood that as soon asA the impulse 'transmitting device 114 has complet'- ed its operation, it Will come to rest andi the cord lin-der rfzoae brushes are designatedby the characters 105 and 106 vas Well as the associated sequencesvvitch `are restored to normal. at" the same time, a sequence switch, only certain ofthe contacts of which are shown, associated with the trunk selecting switch ismoved rout ot position 11 to open the upper contacts of camsl and1119 and to close the lower contactsolt theseA cams. The B loperator Vupon noting` the number of the Wanted line inserts the plug l161 into the jack 162 of this line and depresses the proper ringing key 163 for applying suitable current to the called'lineto ring the station W which apps-arson this line. The B operator` releases key 127 and effects the deenergiza.- tion of relays 120 and 200. When relay 200 controlling the number indicating device appearing in Figs.' 2 and 3 are deenergizcd, due to the removal of ground from vconduc` tors 208 and 301 and the number indicating device is placed in condition to indicate a second Wanted line. y The further Operation off thefsystem in the completion of the call and the restoration ot' the apparatus on the termination of the call is as described in theabove mentioned Patent No. 1,438,743 to E. H. Clark.

The foregoing description clearly illustrates the application and utility of the present invention in a system of the character disclosed and emphasizes the i'act that. separate generating devices are employed for the positive and negative impulses Vthat is claimed is: 1. In a code impulse transmitting system, a line circuit, means to transmit a recurring` series olE impulses of. the same character thereover, and means to modify said series ico 105 retractsy its armatures, the operatedV relays y s witching device and a register individual to eachsuch generating device.

. 3. In a code impulse transmitting system, a. line circuit, means to transmit a recurring series of impulses of the same character thereover, and means to modify said series of pulses by additional pulses of opposite polarity or increased potential, there being a separate generating device for each said character of modifying impulse, each device comprising a switching device and a register individual to each such generating device.

4. In a code impulse transmitting system, a line circuit, means for transmitting impulses of various characteristics over said line circuit; comprising a plurality of registers, a sourcey of current and a switching device, there being a separate section of each register and of said switching device for associating said source with said line circuit for each character of code impulse to be transmitted.

: 5. In a code impulse transmitting system, a line circuit, means for transmitting impulses of various.characteristics over said line circuit comprising a source of current, a plurality of sequencel switch registers and a switching device, there being separate cams on each register and on said switching device for kassociating said source with said line circuit for each character of code impulse to be transmitted.

6. In a code impulse transmitting system, a source of current, a line circuit, means to transmit a recurring seriesof impulses thereover from said current source and means to modify said series of impulses by additional impulses from. said source of various characteristics comprising a switching device and a plurality of registers, each character of modifying impulse being generated by the connection of said source through an individu al section of said switching device and of each of said registers.

7 In a code impulse transmitting system, a source of current, a line circuit, means to transmit a recurring series of impulses thereover `trom said current source and means to modify said series of impulses by additional impulses from said source of various characteristics comprising a sequence switch type switching device and a plurality of sequence switch registers, each character of modifying impulse being generated by the connection of said source through individual cams on said switching device and on each of said registers. f

8. In a code impulse transmitting system, a current source, a line circuit, means to transmit a recurring series of impulses thereover from said current source and means to modify said series of impulses by additional impulses from said source of opposite polarity or increased potential comprising a switching device and a plurality of registers, each character of modifying impulse being generated by the connectionof said source through individual sections of said switching device und of eachof said registers.

9. In a code impulse transmitting system, a source of current, a line circuit, means to transmit a recurring series of impulses thereover from said current source and means to modify said series of impulses by additional impulses from said source of opposite polarity or increased potential comprising a sequence switch type switching device and a plurality of sequencev switch re isters, each character of modifying impulse ing generated by. the connection. of said source through individual cams on said switching device and on each of said registers.

In witness whereof, I hereunto subscribe my name this 16th day of July A. D., 1923.

JOHN W. GooDERHAM.

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