US2383759A

US2383759A - Revertive pulse repeater

Info

Publication number: US2383759A
Application number: US565440A
Authority: US
Inventors: Avery Robert Campbell
Original assignee: American Telephone and Telegraph Co Inc
Current assignee: AT&T Corp
Priority date: 1944-11-28
Filing date: 1944-11-28
Publication date: 1945-08-28
Anticipated expiration: 1962-08-28

Description

Aug. 28, 1945. R. c. AVERY REVERTIVE'PULSE REPEATER Filed Nov. 28,V 1944 4 Sheets-Sheet 1 IN VEN TOR HAN wlo'omx fau/@afg una ATTORNEY ww am 4 Sheet-Sheet 2 SBN.

R) c; AVERY REVERTIVE PULSE REPEATER Flled Nov 28 1944 Aug. 28, 1945.

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. REVERTIVE PULSE REPEATER Aug. 28, 1945.

Filed No l 28, 1944 4 sheets-sheet "5 Till L Cygne/ry ATTORNEY Aug..2s,194;-1.v R. C. AVERY 2,333359 FUEIVIERTIV'IEEv PULSE lREEATER Filed Nov. 28, 1944 4 sheets-sheet 4 FE? me lll G IN INVENTOR (ZUery HY Muir@ M ATTORNEY Patented Aug. 28, 1945 Robert Campbell Avery,Jackson Heights, N. Y., assignor to American Telephone and'lelegrap Company, a corporation of New York Application November 28, 1544,A Serial` No. 565,440

13 claims. y(ol. 179-18) This invention relates to automatic telephone systems and, more particularly, to apparatus. in such systems for controlling the selection and operation of selectors. Still more particularly,

this invention relates to apparatus, commonly known as revertive pulsing apparatus, by `which a sender in the office vof a calling subscriber may control the movement of selectors or the setting of registers in the oilice of the called subscriber.

set into position c-ne by one under-the control ci a sender located in the originating oice. In

order to connect the calling line tc an outgoing trunk at the originating oiiice, a district selector is operated and, .in many cases,` an oice vselector is also operated. The action ofthe selectors is to seize an outgoing trunk which. is connected to the terminating cmce. At theI terminating oice an incoming selector which is associated with the particular trunk seized is then operated to pick one of a group of nal selectors having access to the called subscribers lineand the nal selector then connects ythe callingsu'bscribers line tc the called subscribers line.l

The district and office selectors above referred to are controlled vby the sender of the originate ing oflice in accordance With the ofce code registered, which may then be translated interms of outgoing trunk locations by means `of .a decoder.

The incoming and final selectors .of thel terminating ciiice are also controlled by Athesetting of the numerical registers of the sender/of the originating cnice. This invention relates primarily to revertive pulsing apparatus by which pulses produced and generated at the terminating office are transmitted vto the .sender .of n" the originating office which then controls themoven ment of the various selectors or the settingj of the various' registers in the terminating oice.

'In a called oiiice of the panel typethe physical arrangement of theY incoming and final frames and selectors is such that thethousan'ds and hundreds digits of .they called number must rbe translated into terms of lincoming'brushfs'election, incoming group selection and nal brush selection, whereas the tens and units digits of the called number may be -caused to controlthe selectors directly. Inasmuch as the average commodates five hundredlines, twenty sections i of nal frame multiple1are therefore Vprovided `in the central office` Each incoming .frame must have access to each of the twenty sections of the nal multiple. Consequently, the, incoming .multiple must be divided into twenty groups to vcorrespond lto the same number of sections of nal multiple. Each -of the incoming frames is arranged with ve banks of terminals' and each bank of the incoming frame isdivided into four groups, thus providing .access to all twenty sections of the :final multiple.` The incoming brush select-ion used corresponds 'to the incoming frame bank required,y while the incoming group selection used is subsequently` arranged to c crrespond with vthe final selector grouping required. The nal Vbrush selection used, which selects the bank in which the called number appears, is also determinedin a similar manner. Actual selection ofthe individual line desired out of the one hundred'linesl appearing in Ithe bank is made under direct control of the tens and units'digits or the called number, the one hundred lines appearing injnumerlcal order in the bank.` n.

In the c rcssbar type of system, a similar trans'- lation of the called number is performed in order that the ofces of both the panel and crossbar v.types may be properly co-ordinated with each other. In a terminating oice of the vcross- 'bar type" thecalled numberisregistered on'a 'fundamental circuit includes a line relay with battery at the terminating cnice connected to the tip conductor of the trunk extending from the originating oilice, 'the tip conductoratthe originating office being ccnnectedthrough the winding ci a stepping relay to the ring conductor of the trunk which leads back to the terminating cnice. At the terminating office, the ring conductor maybe connected tc lground,either directly as is the usual case in a panel type of'ofce,

or through the winding of another stepping relay as is the case in a crossbar cnice. The closure of the fundamental circuit at the time when a selection is to be made causes the stepping relay at the originating office and the line relay at the terminating oice to be operated in a series circuit. In a panel type of oice, the line relay operated causes a panel selector to move upward so as t generate ground pulses one by one which are to be transmitted to the tip conductor of the trunk and to the winding of the line relay. The number of pulses generated by the panel selector corresponds to the distance traveled by the selector. Similar pulses are generated and counted in a crossbar terminating office. by the action of a group of relays. In either case, these ground pulses intermittently short-circuit and release the stepping relay in the originating office, which in turn operates a series of counting relays employed for counting the number of such pulses received. from the terminating oice. When the number of pulses so recorded in the originating office-equals the number required for the selection at the terminating office as determined, for example, by the dial register of` the originating oice, a relay which ,forms part ofthe counting relayv circuitat the yoriginating oflice then opens the fundamental circuit, therebyy releasing the line relay at the terminating office at the end of the pulse transmitted. This action in turn stops the panel selector at the terminating oice at the desired point of its travel, or stops the count which controls the crossbar register of the crossbar terminating' office. This action selects the required terminal at the terminating office or causes the required count to be registered. at that oflice. Similar action will take place at intermediate trunk switching points where there may be tandem senders orV distant office selectors operating in like manner under the control of ground pulses traversing the fundamental circuit.

From the foregoing it will be evident that the ground pulses used for a particular selection are generated and transmitted from the terminating office backwardly to the originating ofce, but that the signal for stopping the generation of the ground pulses and completing the selection is transmitted forwardly. from the originating oice to thel terminatingoflice. It will also be evident that any delay in the effectiveness of the latter signal to nx the completion of the selection might cause false additional selector travel or registration, thus resulting in connecting the calling party to a wrong number. Due to the importance of this time or delay factor, it has not been practicable heretofore directly to repeat the ground pulses or the completing signal from one oice to another through an intermediate point. The distance over which these selections maybe made effectively has been circumscribed byexperience t0 be somewhere around thirty miles.4

It is an object of vthis invention to provide means for repeating ground pulses and completing signals ofthe type above referred to without introducing false operation of the selecting apparatus. It is also an object of this invention to provide for the transmission of ground pulses in one direction without unduly delaying the transmission of the completing signals in the opposite direction. The apparatus used for accomplishing these objects may be located at a trunk repeater station or in a tandemsender or in any other ,intermediate point.- If the apparatus is located i in a trunk repeater station, it will increase the range over which revertive pulses may b'e transmitted to around sixty miles by the mere addition of but one such repeater. Moreover, the range of the revertive pulsing may be increased to proportionately greater distances by the addition of two or more repeaters spaced at intervals of around thirty miles. If the revertive pulsing equipment of this inventionis incorporated at tandem senders, it will reduce the amount of equipment now required for completely registering and retransmitting the ground pulses. The repeating apparatus may be used in connection with the transmission of oice codes as Well as called numbers,the former being at present represented by revertive pulses in both crossbar tandem senders and panel distant office selectors, In fact, the invention may be used with practically any type of panel or crossbar originating and terminating equipment.

'I'his invention will bebetter understood from the more detailed description hereinafter following when read in connection with the accompanying drawings, in which Figure l illustrates circuits of a crossbar originating office; Fig. 2 shows a form of trunk circuit which may be used with the revertivepulse repeater of this invention; Fig. 3 illustrates circuits 0f a crossbar terminating cnice; Fig. 4 shows a fonm of the revertive pulse repeater according to this invention, and

Fig. 5 shows the arrangement of Figs. l to 4 as described in this specification.

It will be assumed that a calling subscriber (not shown) connected to the originating oce of Fig. 1 has dialed the office code'and numerical digits corresponding to a desired line, and that the originating oiice circuits have functioned in the usual manner to select a trunk circuit such as is shown in Fig. 2, which extends to terminating ofce of nating and terminating offices.

Fig. 3. It will be further assumed that the originating and terminating oflices of Figs. l and 3, respectively, are about sixty miles apart, and that the trunk circuit of Fig. 3, together with the associated repeater equipmentof Fig. 4, are locatedat a distance of about thirty miles from the origi- It will be noted therefore that the trunk and repeater` equipment of Figs. 2 and 4, which will hereafter loe called the repeater circuit or station, actually divides the path extending from the originating ofce to the terminating oice into two parts. One of these parts extends from the originating office to the repeater circuit and includes conductors T1, R1 vand the other part extends from the repeater circuit to the terminating office and includes the conductors T2, R2. These two parts are connected together at the repeater station so that speech may be transmitted therethrough, the coupling for this purpose including a repeat coil RC. In a similar manner it will be shown that the fundamental circuit referred to above, which normally extends from the originating ofliceto the terminating office, is also divided into two parts. More specifically, there are two separate fundamental circuits involved in this invention. The rst fundamental circuit designated FDi ,connects the originating office to the repeater station, and the second fundamental circuit designated FDz connects the repeater station to the terminating offce. The terminating cnice of Fig. 3 is,l illustrated as a crossbar subscriber oii'ce, but it will be understood that the description may be equally applicableto panel subscriber oliices, or tandem f olces, or panel distant office selectors, etc.

When the originating sender of Fig. l is ready to make an incoming brush selection, it will close .the fundamental circuit FD1. The fundamental circuit FD1 includes the conductors T1, R1 which extend through the oiiice link OL,`the districtlink DL, 111e district junctor DJ and sender link -sL to the conductors FT and FR, the Vwinding of relays vOF and STP and the armature and contact of terminating ofce and involves only one repeater station (Figs. 2 and 4). The closure of'the fundamental circuit FD1 causes the relay Au of'Fig. 2 to' be operated in a circuit which may be traced to include, not alone the fundamental circuit FD1 already described, but also a path which includes the upper'armature and back contact of relay To,

-theV upper vleft Winding of the repeat coil RC, the

left winding of relay An, battery and ground, together with another path which includes the `lower armature of relay To and its back contact, the upper outermost armature and back contact ofrelay Do and ground. The operation of relay Ao isaccompanied by the operation of relay S'I'Pu of the -fundamental circuit FD1, but relay OF which is of the Dolar typeand is also included in this circuit, does not operate at this time. 'The operation of STPu closes ground at its` contact through the sequence relays for incoming brush selection IBS1, tothe thousands vertical conductor TV1 of ythe dial register DR shown in Fig. 1, y ythis ground being then connectedthrough the l cross points4 of the dial register DR previously closed by the manipulation of the subscriber in dialing the called number, and then to the countingA relays to battery. If the called number happenendto be 6200, for example, the cross point Xs onthe register conductors TV1, TVz and TV3 and cross point XXz on the hundreds vertical conductors HV1 and HV; will have been operated. Consequently, the groundl previously traced from the contact of relays STPo will be closed through conductor TV1 and its cross point Xs, through terminal K3 and IQa to the armature and back contact of relay W3', and through the winding of relay W3 to battery vand ground. The originating sender is now ready to start brush selection. r:lhe incoming brush selection at the terminating olice of Fig. 3, after certain operations ofthe repeater station of Figs. 2 and 4 have taken place, presently will be described. The .counting relay We operates in response to the `operation of relay STPO and in turn will short-circuit the winding Vof relay-W3', the short-circuiting path including the circuit previously described from ground at the contact of STPo and conductor TV1 to the upper terminal of the winding -of relay W3', aswell as ground at the armature and make contact of relay W3 to the lower terminal of the winding of relay In response to the operation of relay Ac of Fig. 2` ground will be connected from its armature and make contact through the lower inner armature and back contact of relay Dn to the start lead ST of the crossbar link circuit CBLC. The crossbar link circuit CBLC represents a link circuit such as is commonly used in crossbar Systems. The purpose of this link circuit is to .connect any-.one of a plurality of trunk circuits, such as the one shown in` Fig. 2, to any one of a smaller number of repeaters of the type shown in` Fig. 4. This link circuit CBLC may be any type of switch mechanism as will be understood and hence has not been described in detail. The ground now applied to the start lead ST causes the link circuit CBLC to connect the trunk `circuit of Fig. 2 to an Aavailable repeater circuit such as is shown in Fig. 4. The availability of the repeater circuit -will be made apparent by the presence of battery on the lead N, -battery being .connected to the lead N through resistor R1 and the upper outermost armatures and back contacts of relays RVE and ON. The trunk circuit such as Fig. 2 makes its appearance on one of the hori- Zonta-l elements, such as HORS, of the vcrossbar link circuit CBLC` and is controlled by a select magnet SMQ, whilea repeater, such yas the one of Fig. 4, appears on a vertical element, such as VRTQ, and is controlled by va hold magnet HM. The operating circuits for the select magnet SMQ and the hold magnet HMS are lnot shown as they are of Well'known type. When these :magnets operate. contact between the horizontal element HORs and Vertical element VRTQ will be established at a corresponding cross point such as C1299. The latter cross point controls the connection of the leads FT1, FR1, CO1, D1, F'Iz and FB2, corresponding to thetrunk circuit of Fig. 2, to the leads FT11, FRn, C011, D11, FT12 vand FRiz, respectively, corresponding to the repeaterv oi Fig. 4.

The operation of the link circuit CBLC will cause relay L of Fig. 4 to operate over a circuit which includes battery and the winding of relay L, the upper armature andback contact Iof relay PR, the'make-beiore-break cont-act of relay FC, the upper inner armature and back contact of relay RVE. the upper make-beforebreak contact of relay RV, conductors FTn and F'I1, to the fundamental circuit F131, then back over con-- ductors FR1 and FRn, the lower make-beforebreak contact of relay RV, the'lower inner back contact and armature nf relay RVE, the lower outer back contact and armature of relay L1 to ground. The operation oi relay L causes relay L1 to operate over a circuit which includes battery, the winding of relay L1, the make contact and armature of relay L, the lower back contact and armature of relay RVE and ground'. "Ihe operation of relay L14 causes relay ON to operate over .a circuit which includes battery, the winding of relay ON and its make-before-break contact, the lower outer make contact and armature of relay L1 and ground. Relay ON then is locked inits operated position, the locking path including kthe lower inner make contact and armature ofrelay ON, the back contact and armature of relay TC, conductor G and the right make contact and armatureA of hold magnet. vHMH and ground. The ground which is applied to conductor G is also transferred through the lower outer .armature and make Contact of relay ON to conductor H, then through the left armature, make contact and winding of the hold magnet HMS, battery and ground, so as to loclr` the hold magnet HMQ. At the same time the operation of relay ON opens the circuit to conductor Nat the upper outer armature of relay ON, thereby removing battery from conductor N. This indicates thev unavailability of the repeater of Fig. 4 to the link circuit CBLC. Moreover, the operation of relay ON causesthe yoperation lof 'relay PLS, this circuit including battery, the winding of relay PLS, the upper intermediate back contact and armature of relay RVE, the'upperinnermake contact and armature of relay ON and ground..

Relay PLS now causes relay To *of Fig. 2 to 4operate, the operating circuit here including the upper inner armature and make contact of relay ON,the upper armature and make contact of relay PLS, conductors CO11 and CO1, the winding of relay To, battery and ground. The operation of relay To disconnects relay Ao from its operating circuit previously described and hence relay A11-releases. The release oi relay Ao now removes ground from the start lead ST, thereby making the link circuit CBLC available for connecting another trunk similar to that shown in Fig. 2, to anotherrepeater similar to that shown in Fig. 4; However, the cross point CPss of the link circuit CBLC will remain closed under the control of the hold magnet HMS.

One terminal of the winding of relay STP1 of 'Figj/l is permanently grounded while its other terminal is normally connected to ground at the lower outer armature and back contact of relay L1. Moreover, the latter terminal of the relay winding is also normally connected to ground through the lower inner armature and back contact of relay RVE, the lower make-before-break contact of relay RV, conductors FRn and FR1, the lower armature and back contact of relay To, and the upper outermost armature and back contact of relay Do. The operation of relay L1, as already noted, however, will remove the' former of these normal grounds from the winding of relay STP1. Likewise, the operation of relay To, as already noted, will remore the other of the normal grounds from the winding of relay S'IP1. Consequently, the winding of relay STP1 will be connected in series with the fundamental circuit FD1 through the path provided by the lower inner armature and back contact of relay RVE, the lower make-before-break Contact of relay RV, conductors FR11 and FR1, the fundamental circuit FD1, conductors FT1 and FIn, the upper make-befcre-break contact oi relay RV, the upper `inner back contact and armature or relay RVE, .the make-before-break contact of rrelay FC, the

upper back contact of relay PR, the winding of relay L, to battery and ground. Relay STP1 will now operate.

The operation of relay STP1 will then operate relay GR. Relay GR will now act to short-circuit the relays STP@ and STP1. The short-circuiting path now established extends from ground through the upper make contact and armature-of relay GR, the upper inner armature and back contact of relay RVE, the upper makebefore-break contact of relay RV, conductors FT11 and FTi to the fundamental circuit FDi, which has already been traced and found to be in series with the winding of relay STP1. Relays STPo and STP1 will therefore release. The ground established bythe upper armature of relay GR will hold relay L operated. The closure of the lower make contact of relay GR will cause relay FC to operate. Relay FC will be locked, the locking circuit including, in addition to the battery and winding of relay FC, the back contact .and armature of relay F01, the lower inner make contact and armature of relay FC, the upper inner make contact and varmature of relayON and ground. Relay FC changes the holding circuit for relay L which may now be traced from ground at the upper make contact and armature of relay GR, the upper inner make contact and armature of relay FC, the upper make contact and armature of relay L1, the winding of relay L, battery and ground. The release of relay STP@ will remove the short circuit around the counting relay W3', whereupon the Awindings of relays W3` and W3' will be connected 'in series relationship. Consequently, vrelay Wa Awill then operate. The release of relay STP1Will then release relay GR.` The release of relay GR will then remove the shunt path from the winding of relay STP@ which is in the fundamental circuit FD1, as well as from the Winding o f'relay STP1. The release of relay GR also causes a short circuit to be established for the winding of relay SIPi, this short circuit being established throughthe make-before-break contact of relay GR and the'lower outer .armature and make contact of relay FC. Thus, the release of 'relay GR will cause relay STPo to be reoperated in a circuit which may be traced to include the fundamental circuit AFD1 and the winding of relay L. The latter .circuit includes battery, the winding of relay L, the upper armature and make contact of relay L1, the upper inner armature and make contact of relay FC, the inner upper armature and back contact of relay RVE, the upper Imake-before-'break contact of relay RV, conductors FTn and FT1, the fundamental circuit FD1,rconductors FR1 and FRn, the lower make-beiorefbreak contactof relay RV, the lowerV inner back contact and armature of relay RVE, the lower outer make contact and armature of relay FC, the makebefore-break contact of relay GR and ground.

A In response to the reoperation of relay STPo, counting relay W2 will then be operated .over a circuit which may be traced from groundat the contacts of relay STPO, conductor TV1, cross point Xs, terminals K1 and Kas, the armature and make contact of relay W31', the armature and back con- `tact of relay W2', the winding of relay W2, battery and ground. Y The operation of relay W2 then short-circuits the winding of relay W2 in va manner similar to that already described for the short-circuiting of the winding of relay W3. At

Athe same time relay FC will be locked, as previously shown. The relay FC is employed to control the second fundamental circuit FB2 which extends between the trunk circuit of Fig. 2 and the terminating circuits of Fig. 3. Thelterminating omce of Fig. 3 is illustrated as of the crossbar type, but the operation of this terminating ofticeimay be similar to that which would take place in a panel subscriber oiiice or a tandem oiiice, or a panel distant office selector.

The operation of relay FC establishes a bridge across the trunk conductors T2, R2. This bridge includes conductor T2, conductors FT2 and F'Im, the upper outer armature and make contact of relay FC, the armature and back contact of relay B01, the winding of relay STPz, the windingof relay CF1, conductors FR12 and FRz to conductor R2. The completion of this bridge circuit causes relay A3 of the incoming trunk circuit ITC of Fig. 3 to operate. Battery vis connected `through the left winding of relay A3 to conductor T2 through the upper backcontact and armature of relay T3 while ground i-s connected through the lower outer back contact and armature of relay D3 to conductor R2 through the lower back contact and armature of relay T3. The operation of relay A3 causes the conductors T2 and R2 to be connected respectively to the upper armature and lower inner armature of relay ON1, the connecting circuit being shown schematically as including the cross-points of the primary link switch PLK and the secondary link switch SLK of the terminating sender link TSL. The terminating sender link TSL, when operated, provides a ground path for the conductor F, through the lower back contact and armature of relay RV2,

f winding of relay RV3 and battery, operating RVs.

.and armature of relay T3.

aseav'ee make contact `of krelay. RVs, the. upper makef1 before-breaky Contact of relayRVr to the upper make Contact and armature of relay ON1,`which is connectedto` conductor Tathrough the switches PLK and SLK. The remainder of thefunda-y mental circuit -FDz isconnected to conductor R2 and includes switches PLK and SLK,l the lower inner armature and make contact of relay ON1, the upper armatureA and back contact vof relay RVz to ground over either of two paths. One of .theseground` paths-includes the lower inner back contact and armaturejofvrelayLx and the other ground path includes the upper backcontact and armature of relay L4. Itwill be observed thatground through the lower outer back` contact and'armature of relay D3 is also connected to ,conductor R2 through the lower back contact The fundamental circuit FDa just described being now connected to the-bridge circuit of Figs. 2 and 4 previously described, will cause the operation of relay L2 of the fundamental .cijrcuitFDa and the relay S'IPz of the bridge circuit. The terminating sender TS of Fig. 3 is now ready to start incoming brush selection. v

From the foregoing it will be seen that upon the seizure of repeater circuit of Fig. 4, one revertve pulse is returned to the originating sender of Fig. land is counted and. recorded in the counting relay apparatus by an advance in the countingrelays 'as already described. This revertive `pulse-is returned to the originating office independently of any operation of the circuits of the terminating office' of Fig. 3 and'without any control whateverbyV the apparatus of the terminating oflice. It will be observed also that 'the closure of -the-l fundamental circuit FD2 is completed lafter the-transmission ofV the rst revertive pulse to` the voriginating'oiiice of' Fig. l. These are important factors of this invention and will be referred to later.

' The operation of the relay STPz of. Fig. 4, as already described, `will operate relayPR.- Relay PR thenv isflocked throughits lower inner make contact and armature, the back contact and armature ofrelay F01, the-lower inner make contactA and armature of relay FC and upper inner make contact andfarmature' ofrelay ON and ground. Ati thel same time the: operation of the relay La at the terminating foflicerof Fig.. 3 causes relay La to operatefwhich in 'turn will cause relay L4 to operate. Moreover, the terminatingvsender link TSL will apply'ground tothe conductor COO tov cause relay T3 to operata VTheioperation of relay Tawill then disconnectl the windings of relay Aa from the bridge circuit: previously described, whereupon relay-A3 will release. With relays T3, La and L4. operatechshort circuits are then removed lfrom thejwinding of relay STPS, thereby allowing the winding of S'IPz to be connected in series with the fundamental circuit FDa through the upper backcontact an'd armature of relay RVz. Relay SIPa then operates yand in turn causes relay GRi to operate. Relay GRi produces a groundpulse to bel transmitted to the windings of relays SIPz and STP'a to llSethe latter relays to 'be released. l The graundpulsjais transmitted over 'the circuit which includes the'zu'pp'er' armature and rInake'contact of relay'I GRi', the upper. armature and make `contact of "relay RV3, `the upper' make-beforel-break"contact ofyrelay RVi, 'the v'upper make vcontact and armature `of relay ONr, then through the switches ySALK and PLK' to` conductor Tannen sverconductors Fra, Fira, the upper outer 'armature and make 'contact of relay FC', ythe armature and backc'ontact of relay B01, the .winding of relay' ,STPa tliewinding lof relay CFL, conductors FRia and FRaconductor Rz then through switches PLKQand'SLK'to' 'the [lower inner armature and'make 'contactfof relay'ONi, the upper armature and backfcont'act of' relay Rvz to the winding of relay STP; 'and ground; 4.es

battery is'l absentfrom the' circuit ju'Stltrac'ed. both relaysSTPa and STPS' therefore release, while relay La is' held operated through the'upper'make contactand arnria'ture` of relay '(LrRr. The release of relay STPa of Fig.' 4Q 'connects ground lto the be 'traced from 'the armaturean'dback contact .a of relay STPa, the lower outer armature 'and' make contact of relayrPR,` the'low'er inner armature and make contact of relay' the 'inner 'upper armature andv make contact; frel'ayFC, the inner upper armaturejandfback v tact of relay RVF., the `upper make-before'breakj contact of relay RV, conductors FT11 and F'Ii; conductor Ti, then through the fundamentalcircuit FDi, then back' over conductor R1. conductors FR;` and FR1`1`, the lower make-before-break contact of relay RV, the lower inner rback contact and` armature of relay RVE, the lowerouter vmake contact and armature of relay FC, "the lmake-before-break contact of relay `GrR toground. Relay STP() of the fundamentall circuit FD1 therefore releases. RelayL of the repeater is held operated by ythe ground at the yarmature and back contact of relay STPz, through the lower outer armature and make contact of relay PR, the lower inner armature.

and .make Contact of relay v;I.l1',ftheupper make contact and armature of yrelay L1, the winding of relay L, battery and ground. The release of relay STPo then allows thewinding of relay Wa' to beconnected for a brief intervalthrough'its lower armature and make contactto the pulse counting relay apparatus PCR forcounting this pulse as already been described and therefore neednot be.

repeated. The reoperation of relayv STPz removes the shortcircuiting ground from the fundamental circuit FD1 previously described, whereupon the relay S'IPo of the: latter fundamental circuit is reoperated. The operation of relay STPo in' turn causes the counting relay Wlto operate and at thev same time short-circuitfthelrelay Wr".

Itis thereforeinoted that after the original pulse wasjsent tothe originating sender of Fig'. 1, upon" seizure ofthe repeater of Fig. V4 (regardless of the operations ofthe terminating circuitgpf Fig. 3), theflrst pulse actually returned from the terminating oflice' of Fig" l3 will be directly repeated by the repeater of` Fig. 4 to the' originating oce of Fig'. 1. t. The rstpulse returnedv by the terminating ofce of Fig. 3 will be the second pulse received by the" originating officeof Fig. 1 through the repeater of Fig. 4.V 'Later the second pulse returned v,from the'terminatingoice of Fig. 3 will be repeated by'the'repeater of Fig. 4 to the o'riginating cnice ofFig; 1 as the third pulse received by the originating office.' This procedure'will continue with. eachfsubsequent pulse from the terminating o'ice of Fig. 3 (except the last pulse) Thes'epulses will be repeated until the originating cnice is fully satisfied. When the satisfying pulse is" receivedgfrelays BO and FOV of the originating ofl'ce" will be operatedjupon the release of relay S'I'Pi` and'provide the completion signalto the terminating oic'e.' .The fundamental circuit-.FE1 will be `'opened at the back` contact and'armature of 'relay BO.` Theopening of the fundamental circuit FD1'will cause relay'v L vef Fig. 4 'tobe" re.

leased at the conclusion of the pulse, which in turn will release relay Li; At this time one pulse is yet to' be received'from the terminating cnice of Fig. A3, but thisv lastpul'sefwill not affect the originatin'goiflcefofFig.v 1', as will be explained.

For the case' in whichthe subscriber dialsnumber 6200 it was pointedoutthat four 'pulses are required for 'incoming brush selection and that these four pulses have" already been received by theforiginatingsender. However, onlythree of thejv necessary four pulses" have been returned bythe terminating sender of Fig. 3 .to the fundamental circuit FD1 Lof' Fig. 1', but the fourth pulse from' theterminating sender will be receivedby the repeating apparatus of Fig. 4,y andwill serve to open the fundamental circuit FDz. This fourth pulse fromtheierminating equipment will not reach the originating oice. This fourth orlast pulse, in releasing'relayS'IPzv of Fig. 4in the manner already described, will operate relayBOr'and relay F01 over :apath'which includes ground at the armatureand back contact of relay STP2,'the lower outer armature and make contactv of relay PR, the Vlowerinner armature and back contact of relay L1 and parallelpaths provided by the windingsof relays B01 and F01to battery and ground. Relay F01 locks over a path fromI the winding of relay'FOr and its make contact and armature, the lower inner make contact and armature of'relay FC, the upper inner make contact and armature oi'frelay ON and ground. Of course,frelay B01 will holdin parallel with relay F01. lTheoperationof FOrreleases relays PR and FC.. When relay FC releases, it will cause Vrelays BO1 .and F01 tolrelease. It is to be observed that the operation of relay BO1'will openv the fundamental circuit FDz at the contacts of relay B01 while the release of relay FC will also open the .fundamental circuitFD2 at another point in the circuit, namely, at the outer upper make contact `of relay FC. Therefore, the fundamental circuit will lbeheld open evenithough relay B01 is .subsequently.released.- Hence, at the end of the last ypulse, relay GR1-beingthen released, the relay L2 ofFig. 3 will'be released, in turn releasingrelays le 'and-Laffhisaction in the Iterminating sender of Fig; 3 will cause the pulse counting relays'PCR andthe register switch RS to record the. vcount foi-.the incoming. brush selection communicated .to the termnatingoiice of.1Fig.

by theoriginating oice of Fig, l. The terminating cnice Will now be prepared for the next selection, namely, the incoming group selection.

The originating sender of Fig. 1 may also be advanced for the incoming group selection by the operation of its relay FO upon receipt of the last or satisfying pulse, as already described. The sequence relays will change the connections Vto the dialjregister DR and thereby prepare it for the group selection. This will also cause the re- 1 lease of the counting relays previously operated.

The incoming group selection now takes place in a manner similar to that already described for incoming brush selection. For the case where the number dialed is 6200, the incoming group selection will correspond to the number 0 which, as willA be understood, requires but one revertive pulse. The fundamental circuit FD1 will be closed as before, operating relay L of the repeate1` of Fig. 4 and relay S'IPo of the originating sender of Fig, 1, The ground at the contact of relay S'I'Po will now be closed through the sequence relays for the incoming group selection apparatus 1G82 to the vertical conductor HV1 of the hundreds register and its Contact at cross point XXz, the vertical conductor TVz of the thousands register and its cross point at -Xa contacts Ko and Koo, then through the winding of counting relay Wo to bat,

tery and ground. The operation of relay Wo will cause the windings of relays BO and FO to be short circuited. At the repeater station of Fig. 4, the operation of relay L will cause relay L1 to operate, thereby removing the short circuit from the Winding of relay STP1. Consequently, relay STP1 will operate and in turn will operate relay GR. The operation of relay GR will produce a ground pulse which will be returned to the originating sender of Fig. 1 in the manner already described. As only one ground pulse is required for the incoming group selection, closure of this pulse will releaserelay S'IPo of the fundamental circuit FD1 and in turn allow relays BO and FO to become operated. The operation of relay BO will open the fundamental circuit FD1, thereby releasing relay L of the repeater of Fig. 4 and in turn relay L1 upon the release of relay GR. The operation of relay FO will cause the originating sender to advance for the next selection which will be the iinal brush selection vas is well under- 1 stood in the art.

It is pointed out that the pulse required for the incoming group selection is returned to the originating sender by the operation of apparatus in the repeater .circuit of Fig.,4, and that the apparatus of the repeater circuit will cause the operation of apparatus at theterminating ofce so as to start pulsing.` VInasmuch as the selection completion signal `has already been recorded in the repeater by the release of relays L and L1, the terminatingfoffice will returnonly one pulse in the manner already described and this pulse will be employed to record the count for the group selection at the terminating cnice. However, although the operation of the fundamental circuit FDZ is dependent upon the operation of the fundamental circuit'FD1, the single pulse emanating fromthe terminating sender will ynot be repeated into the fundamental circuit FD1 as was the case for incoming brush selection; I' It is not' believed necessary -to repeat the circuit operations which are required to relay the single ground pulse from the .terminating circuit to the repeater circuit, as this has already been fully described. At the conclusion jof Athe incoming group selection, the terminating sender. will advance for` the next selection which will be the iinal brush selection and at the same time release the relays no longer required for this operation. The final brush selection will be followed by the tens selection and then by the units selection. After the units selection has been completed, the originating and terminating senders will close the incoming advance loop. The incoming advance signal is a reversal of polarity of the battery 'applied to the fundamental circuit of the terminating office, and it will indicate to the originating oice that all selections have been completed. The closure of this loop is brought about by operation of the sequence relays already referred to, causing relay L of the repeater circuit to operate as well as relay STP@ of the fundamental circuit FD1. the operation of relay L will in turn cause relays L1, STP1, GR and FC to operate. Relay GR will short-circuit and therefore release relays STPo and STP1. The release of relay STP will be ineffective at this time, because none of the counting relays have been operated. The release of relay STP1 will release relay GR andallow relay SI'Po to reoperate.

The Operation of relay FC again closes the fundamental circuit FB2 at the make contact of its upper outer armature, and in turn causes the relay L2 of the terminating sender to operate in series with relay STP2. The operation of relay STP2 again operates relay PR which will be locked as before. The operation of relay L2 will again operate relays La and L4. With the final units hold magnetFU operated due to the completion of the nnal units selection, the operation of relay L4 will cause relay RV1 to be operated, the operating path including the lower armature and make contact of relay L4 and the upper make contact and armature of magnet FU. The operation of relay RV1 in turn will operate relay RV2. When both relays RVi and RV2 are operated, the bat-l tery connected to the winding of relay L2 will now be connected to conductor R2 to which the fundae mental circuit is connected, this pathbeing tracearmature of relay ON1, and switches SLK and PLK. This reversal of polarity applied to the conductors T2 and R2 then operates relay CF1 at the repeater of Fig. 4, this relay being of the polar type. Ground at the upper inner armature and maken' contact of relay ON is now connected through the armature and make contact of relay OF1- to thewinding of relay RV, causing relay RV to be operated. Relay RV then'locks through its upper outer make contact and armature to ground at the make contact of the upper inner armature of relay ON. Relay RV then reverses the polarity of the potential applied to the fundamental circuit F131. Battery at the winding of relay L is now being connected to the conductor R1 which isconnected to the fundamental circuit F131- over a path which may be traced through the winding of relay L, the upper armature and make contact of -relay L1, the upper inner' armature and makecontact of relay FC, the upper inner armature and back contact f relay RVE,` the lower inner armature and'make contact of relay RV,

conductors FRn and FR1 to conductor R19 At Briefly,

, vention, they serve to advance the originatingv 4U the same time the conductor T1-which is con# nected to the fundamental circuit FDi--willy be connected .to ground over a path. which includes conductors FT1 and FI'n, the upper inner make contact and armature of relay RV, the lowerinner back Contact and armature of relay RVE, the lower outer make contact and armature of relai7 FC, the make-before-break contacts of relay GR and ground. The reversal of polarity will, therefore, operate relay OF of the fundamental circuit FD1, which is alsoof the polar type.

The operation of relay RV2 at the terminating. oiilce will release relay RVs. Relay RVs-is, however, of the slow release type and it will not clisconnect battery and ground from conductors R2 and T2 until av sufcient interval of `time has elapsed. The release of relay RVs will thereafter release relays L2, L3 and L4, andat the same time disconnect battery and ground from conductors R2 and T2. Subsequently, ground will be removed from conductor COO, releasing relay T3, and thereafter ground will' be connected to conductor lDD1, causing relay D3 to operate in the usual manner. The release of relay RV3, in opening the fundamental circuit FDz, will release relays STP2 and OF1 of the repeater circuit. v The release of relay OF1 will connect groundl atA the upper inner armature and make contact of relay ON and through the armature and back contact of relay O-F1, lower outer armature and make contact of relay RV to the winding of relay RVE, thereby operating the latter relay. Relay RVE will inV turn disconnect battery and ground from the fundamental circuit FD1, thereby releasingr relays SI'Pn and OF of the originating sender.

Although the various circuits controlled by relays STPO and OF are not shown because they are not required for an understanding of the present insender in a well-known manner, and at the same time apply ground to the conductor TR to operate the relay TK of the district junctor DJ. The relay TK will then be locked through its lower outer make contact and armature and the connection of the district junctor DJ to the originating sender by way of the sender link SL will be broken.

The operation of relay RVE will also release relay L1, 'which then will cause relay L to release. The release of relay L1 with relay STP2 normal is accompanied by the operation of relays B01 and F011 in parallel, the operating circuits for which are completed through the lower outer armature and the make contact of relay PR and the lower inner armature andV back contact of relay L1. The operation of relayFO1 releases relays PR and FC, after which relays B01 and F01 release. The operation of relay RVEl will also release the relay PLS, this relay being of the slow release type so as to prevent interference with the, advance of the circuits-ofthe originating sender. The release of relay PLS will cause relay To to release, but it will causerelay y D0 to become operated. The operatingl path for relay Do includes battery, the winding of relay Do, conductors D1 and D11, the winding of relay TC, resistor R2, the lower back contact arid armature of relay PLS, the lower outer make contact and armature of relay RVE and ground. Relay TC is ofthe polar type and will not operate even though its winding is included in the operating Ipath for relay D0.

The operation of relay TK in the district junctor yDJ performs the trunk closure func tion. The.. operation of relay TK connects the winding or the polar relay CS yof thev district junctor DJ through the upper armature and lower inner armature of relay TK across the conductors T1 and R1. Consequently, relay Ao of Fig. 2 will become opera-ted.` Relay Ao repeats the trunk closure function by operating relay BDi, the operating path for relay BDl traversing the lower inner armature and make contact ofA relay Do. Relay BD1 locks in a path from battery through its upper winding, upper inner make contact and armature, lower outer make Ao and the subsequent operation of relay BD1 will causerelay D0 to be locked in its operated position, the locking path for relay Dt including the lower inner armature and make contact of relay BD1, the lower inner make contact and armature of relay Dn, the make Contact and armature of relay An and ground. The same ground will be connected through conductors D1 and D11 to the winding of relay TC, resistor R3, battery and ground, thereby operating relay TC. The operation of relay TC will then release both the relay ON and the hold magnet HMQ. The release of the hold magnet will open the cross-point CPQQ of the link circuit CBLC. Relay TC will release when the hold magnet contacts and the cross-point CPss are opened. The release of relay ON will release both relays RV and RVE. The simultaneous release of relays RVE and ON will render the repeater circuit of Fig. 4 available for subsequent seizure by another originating sender, the availability of the repeater ybeing evidenced by the connection of battery through resistor R1, the upper outermost armature andback contact of relay RVE, the upper outer armature and back contact of relay ON to conductor N, which terminates in the link circuit CBLC. The operation of relay A3 at the terminating oflilce connects ground to the winding of relay D2 through the lower innermost armature and make contact of relay D3 to lock relay D3. This will signal the terminating sender to summon a marker v(not shown) by applying ground to lead DD1 which extends into the terminating sender linkY TSL. After the marker has caused thel connection of the called line to be completed, the terminating sender will release relayl ON1 and the connection through the switches PLK and SLK of the terminating sender link TSL.` Relays RVi and RV2 and any other relays and magnets that may be operated release and the terminating sender is now returned to normal.

i When the called subscriber answers in response to the application of ringing current to his line, the originating circuit, the trunk circuit and the terminating circuit will then be ready to transmit speech currents thereover. The connection of the called partys line to the terminating circuit will cause relay S1 of the incoming trunk circuit ITC to operate, thereby operating T3. Relay T3 will reverse the polarity of the voltage applied to the conductors T2 and R2.

That is, lbattery will now be connected through lin relay T3 to conductor R2.'

the left winding of relay A3, the upper outer armature and make contact of relay Da, the A upper inner make contact and armature of relay D3 and the lower make contact and armature of At the same time ground will be connected through the right winding of relay Aa, the lower outermost armatureand make Contact and the lower intermediate make contact and armature of relay D3, the upper make contact and armature of relay T3 to conductor T2. This reversal of polarity applied to conductors T2 and R2 will not interfere with the previously operated condition of relay A3, but polar relay S at the repeater station will now be operated. Relay S will then cause relay To to operate, the operating path for which is completed through they upper inner armature and make contact of relay Do. 'Ihe operation of relay To also reverses the polarity of the voltage appliedk to conductors T1 and R1. This reversal of polarity now causes battery to be connected to conductor R1 over a path through the left winding of relay A0, the upper left portion of the repeat coil RC, the upper intermediate make contact and armature of relay D0 and the lower make contact and armature of relay Tu. Ground will be simultaneously connected to the conductor T1 over a path which includes the right winding of relay Ao, the lower left portion of the repeat coil RC, the upper outermost armature and make contact of relay Du and the upper make contact and armature of relay To. The operated condition of relay Ao will not be aiected .by this reversal of polarity, but the polar relay CS of the district junctor DJ will 'become operated. Relay CS controls message register apparatus (not shown) for charging the call to the calling subscriber. When the called subscriber disconnects, relays S1y T3, S, To and CS will release in the orde1` mentioned. Moreover, when the calling subscriber disconnects, relays TK, A'o, Du, BDi, A3 and Dsk will release. All of the apparatus will therefore be restored to normal.

The revertive pulse repeater shown specically in Figni is connected to the originating sender of Fig. l and the terminating sender of Fig. 3, through the trunk circuit of Fig. 2, so as to increase the range of revertive pulse control from about 30 miles to about 60 miles. Of course, two or more such repeaters may be connected intandern to correspondingly increase the pulsing range to about 90 miles vor more, as may be desired. Moreover, the repeater equipment need not be spaced by 30 miles from either the originating oiiice or the terminating olce, for this distance may be substantially less than 30 miles when conditions warrant a smaller'spacing. If a repeater is connected to an oice which is substantially less than, let us say, 30 miles away, an artificial line in the form of a T-pad, or a vr-pad, or of any other'form, may be inserted between the repeater circuit and either the originating oiiice or the terminating ofce, or both, to introduce the required time delay factor which is important in the practice of this invention. AObviously the artificial line network just referred to may be part of the repeater of Fig. 4 or, if desired,` it may be bridged across conductors Ti and R1 if the originating sender of Fig. 1 is spaced less than the predetermined distance of, for example, 30 miles from the repeater of Fig. 4; or it-may be bridged across conductors T2 and R2 where additional delay `is required between the repeater of Fig. 4 and the terminating oii'ice of F'ig. 3.' The insertion of such an artificial line ornetwo'rk will allow all of the revertive pulses to be returned to the originating oicein regular order. y 1

It will be further understood that the repeater circuit of Fig.. 4 may be included asa part of a part' of' a tandem sender, permitting such a sender to repeat pulses rather thanrecord. the digits which represent these pulses. i

While l this invention has been shown and described in certain patent arrangements merely for illustrative purposes, it will` be understood that the general principles lof this invention may be applied to other andwidely variedy organizations lwithout departing from the spirit` of` the invention and. the scope of the appended claims.. What is .claimed is: y y l. In a signaling'system, they combination of a selector,- means .for producing pulsesv to control said selector, means for seizing said selector, said seizing means including means for producing one pulse and at thelsame time for starting said pulse producing means, pulse counting means, means controlled by saidp'ulse counting means for interrupting the pulse producing means after a predetermined number of pulses have been counted by said counting means, said interrupting .means causing saidv pulse producing means toproduce. oneadditional pulse thereafter, and

means to prevent the transmission of said additional pulse-to said pulse' counting means.

2, vIn a signaling system, ther combination of a'- saidisecond station being relayed by said repeater tofsaid :firstl station to be counted by-said counting apparatus, means to signal the repeater afterl a predeterminedv number ofl pulses have been counted by said counting apparatus, and means responsive to said signal received by said repeater tocausel said source to produce one additional pulse and then to interrupt said source.

v 3.=.In a signaling system, the combination of a pulse controlleddevice, a source of pulsesconnectedfto said device to control said device, apparatus for counting pulses, meansresponsive to the connection of said apparatus to said device to produce a pulse to be counted by said apparatus and to start the source of pulses connected to said device, and means responsive to the reception by said apparatus of .a predetermined number of pulses from said source to cause said source to produce one additional pulse and then to interrupt the production of pulses by said source.

4. In an automatic telephone system, the combination of a first telephone ofce having pulsecounting apparatus, a second telephone oiilce having a pulse-controlled selector and a source of pulses therefor, a repeater interposed between said rst and second telephone offices, means responsive to the connection of the rst office to said repeater to produce a pulse to be transmitted to the rst oii'ice to be counted by said apparatus, means for thereafter establishing a path between said repeater and said second oiilce and for starting said' source of pulses, the pulses emanating from said source being relayed byfsaid repeater to the counting apparatus ofthe first station, means responsive to the reception of a predetermined number of pulses by said counting apparatus to signal the repeater to interrupt the 'source of pulses, and means controlled by said signal to vinterrupt said source of` signals after said sourcehas produced one additional pulse.

5. In an automatic telephone system, the combination of a first telephone ofce having pulsecounting apparatus, a second telephone oice having a pulse-controlled selector and a source of pulses associated with said selector, a repeater `interposed between said rst and second telephone onices, means responsive to the connection of the first oice to said repeater to produce av pulse to be transmitted to the iirst office to be counted by said apparatus, means for thereafter, establishing a path between said repeater and,v

said second oiiice and for startingv said source of pulses, the pulses emanating from said source being relayed by said repeater to the counting apparatus of the iirst station, means responsive to theV reception of a predetermined number of pulses by said counting apparatus to signal the repeater to interrupt the source of pulses, meansv l second oflice having a pulse-controlled selector and a source of pulses associated with said selector, a trunk circuit interposed between said first and second oioes, a. repeater associated with said trunkv circuit, means responsive to the connection of said iirst oflice to said repeater through said trunk circuit to produce apulse for transmission over said trunk circuit `to the counting apparatus of said rst oice, vmeans for thereafter starting the production of pulses by said source at said second oiiice, the pulses ,emanating from said. source at said second office being relayed through thel trunk circuit to thel repeater and back over the trunk circuit to the, counting apparatus of the first oiiice, means responsive to the reception of a predetermined Inumber of pulses by said counting apparatus to signal said repeater to interrupt the transmission of pulses to said' first oiiice, means 'controlled by said signal tol interrupt the sourceof'pulses at the second oilice after one additional pulse has been produced by said source.

'7. In a telephone system, the combination of a iirst oice having pulse-counting apparatus, a second office having a pulse-controlled selector and a sourceof pulses associated with said selector, a trunk circuit interposed between said iirst and second oices, a repeater associated with said trunk circuit, means responsive to the connection of said first oice to said repeater through said trunk circuit to produce a pulse for transmission over said trunk circuit to the counting apparatus of said iirst office, means for thereafter starting the production of pulses by said source at said second office, the pulses emanating from said source at said second oiiice being relayed through the trunk circuit to the repeater and back over the trunk circuit to the counting apparatus of the first office, means responsive to the reception of a predetermined number oi pulses by said counting apparatus to signal said repeater to interrupt the transmission of pulses to said rst oiiice, means controlled b-y said signal to interrupt the source offpulses at lthe second oliice after oneadditionalipulse has-beenlproduced by said source, Y. and means lcontrolled by.

' sai-d additionalpulse to disconnecttherepeaterl pulses to signal the repeater to cease returning pulses to said sender, and means responsive to y said signaly at said repeater to 'cease the production of pulses by said terminating olice after-an additional pulse is received by said repeater 4from said terminating oilce. -v Y 9. In an' automatic telephonesystem, thecornbination of a rst office having relays for counting receivedpulses, a second oilice having selector apparatus to be controlled .by pulses, means at the second office to `produce pulses for con-` trolling said selector apparatus, a repeaterwhich may interconnect said-first and second oflices, means responsive to the connection of said Iirst oiiice to said repeater to cause lsaid repeater to transmit alfirst pulse to said rst olce to be counted by said relays, the repeater relaying the pulses received from the second office to said first oilice to be counted by said relays, means responsive to a predetermined number of pulses -received by said relays to preventthe repeater from' relaying additional pulses to said first oice, and means controlled bythe latter means to ystop the production of pulses atfsaid second-cnice after second oflice. c Y f one additional pulse'r has been produced at said' 10, In an automatic telephone system, -the combination'of a first office having relays for counting received pulses,A a. second olce having selector apparatus toV be Vcontrolled by pulses, means at the second ofticeto produce pulses for controlling said selector apparatus,y a repeater which may interconnect said` first and second oiices, means responsive to the connection of said first office to said repeater to cause said re-A accepte,

peater to-ltransmit a iirst pulse to said first oflice to be counted by said relays, the repeater relaying the pulses received from the second office to said rst'ofliceto be counted byfsaidrelays, means responsive ,toay predeterminednumber of pulses receivedby-saidrelays to preventl the repeater from' relaying additional 'pulses-to said rst office, means controlled by the latter means to stop the production .of pulses at said. second oice after one additionalvpulse has been produced at said second cnice, :andmeans controlled vby said additional pulseftoj disconnect saidA repeater from said first and'fsecondofces. l

, 11.1111 a signaling systemthe combination of a pulse-controlled selector, algenerator of pulses to control said selector, nieansresponsive to the seizuregof; saidselector toproduce a pulse,y said means fals'ogstarting `said .generator to produce pulses,-pulse receiving-means, a and means controlledbysaid pulse receiving means to signal said generator to stop its production of pulses, said generatorproducing an additional pulse after the transmission of said signal. f

`12. In a signaling system, the combination of @pulse-controlled selecting device, a generator ofy pulses connected to said device to control its operation,a'pulse counterfmeans for connecting said pulsecounter to said generator to start the production of 4pulses by said generator for transmission to'said counter,"said 'starting means including means .to generate a rst'pulse for transmissionito said counter, and means controlled by said counter to transmit 'a signal'to said generator Ato stopsaid generator, said generator producing only one additional pulse after thestopping signal has been received. y

13. In a signaling system, thev combination of a pulse-controlledselecting device', a generator of pulses vconnected to said device to control its-operation,v La' pulse counter, meansl for connecting said pulse. counter tosaid generatorI to start the production of pulses by said generator for transmissionitoy said counter, said: 'starting means including means to generate' a'iirst pulse for transmissionto'said counter, means controlled by said counter vto .transmita signal to said generator to stop A:said generator; l `said generator producing oneza'dditional pulse after saidsignal has been received, and means controlled by said additional pulse toldisconnect s'aidpulse counter `from said generator. y

:ROBERT cAMPBmL AVERY.v A