US1147390A - Switches and circuits for automatic telephone-exchanges. - Google Patents

Description

c. L. GQODRUM. SWITCHES AND CIRCUITS FOR AUTOMATIC TELEPHONE; EXCHANGES PatentedvJuly 20, 1915." f

7 SHEETS-SHE?! I.

- APPLICATION FILED MAY5|190 9.v

E c. L. GOODRUM. SWITCHES AND CIRCUITS FOR AUTOMATIC TELEPHONE EXCHANGES.

Patented July 20, 1915.-

7 SHEETSTSHEET 2.

APPLICATION FILED MAY 5 1909.

I c. LIGOODRUMI I SWITCHES AND CIRCUITS FOR AUTOMATIC TELEPHONE EXCHANGES- 1,142,390.

1915. 7SHEETS-SHEEI3wI APPLICATION FILED MAY 5, I909.

- Patented July 20,

vwentor,

attouwgd c. L. GOOD RUM. K SWITCHES AND CIRCUITSFOR'AUTOMATI C TELEPHONE EXCHANGES.

- 'LIQZSUB APPLICATION HLED MAY. 5; 1.909.

- .Patented July 20, 1915:

I SHEETS-SHEET 4.

Hlllll I Witneoou G. Ll GQODRUM. SWITCHES AND CIRCUITSFOR AUTOMATIC TELEPHONE EXCHANGES.

- 7 APPLICATION FILED MAY 5.1909. 4 1,147,390 Patented. July 20,1915.

7 SHEETS-SHEET 5.

C. L. GOODRUM.

SWITCHES AND CIRCUITS FOR AUTOMATIC TELEPHONE EXCHANGES.

APPLICATION FILED MAY 5. 1909.

Y Patented July 20, 1915.

. L. (3000mm.

. C SWITCHES AND CIRCUITS FOR AUTOMATIC 'TEL EPHONE EXCHANGES APPLICATION -FILED M AY 5,1909. 1,147,390. Patented July 20, 1915.

7 SHEETS-SHEET 7.

CHARLES L. 'coonncm, or panama, OHIO, Assreno'n, BY MESNE Assreimnnrs, To I wnsrnnn ELECTRIC COMPANY, or new YonK,-1v. Y., A coaronarron orrnmno s.

swrrcnns AND CIRCUITS FOB AUTOMATIC mnnnrnonn-nxcrranens.

changes, of whichthe following is a specification. I

My present invention relates to automatic telephony in which the connections between subscribers" telephone instrument circuits are effected by electromechanic switching devices located at the central ofiice or eX change and it has for its primary object to simplify this mechanism and increaseits efficiency.

ing line from -llIl6S, said swltch in its operation and requiring no act on To this end my invention comprehends. employing in the first instance a switching operating upon the central of telephony in which the mechanism energy principle wipers are. adapted to move both in. a Ver tical and a rotary direction to select particular contacts in the bank of terminals with which they cooperate and to employ finder to select the line contacts or terminals of a particular incombeing entirely automatic the part of a calling subscriber to actuate it after the subscriber has removed his receiver from the hook. My invention includes the providing vices for men to all the incoming lines leading thereto, whereby it maybe automatically started, arrested and released by current impulses despatched by any one of a number of subscribers. I e

In connection with the finder switching mechanism I have also provided means whereby the incoming lines may be divided into groups and'each group served by one of seyeral such switches in case another or others are in use.

My invention hasfor its further object to provide for use in conjunction with the finder switch a connector switch by means of which the line selected by the former may be automatically connected to any one of a plurality of outgoing telephone instrument In the drawings: Figure 1 is two instrument circuits those of a plurality of suchof operating and controllingde the finder switch which are corn- Specification of Letters Patent. Patented J 1113 20, 1915. Application filed May 5,1909. Serial No. 494m i l circuits and to apply to. each connector a novel arrangement of the operating and'con-' trolling mechanism whereby its functions maybe all performed by impulses of current transmitted over a full'metallic circuit.

As a further object my invention provides anovel arrangement of parts for supplying current for talking purposes to the called line and for automatically releasing the connector switch in the event the line selected by it is otherwise in 'use to restore said switch to its normal position and supply the calling line, seeking the connection, with the busy-signal. I

. To these and other ends the invention consists in certain improvements and combinations of parts allas will be hereinafter more fully described, the novel features being pointed-out in the claims at the end of thespecificatiOn.

a diagrammatic view illustrating generically. the line connections as they may be effected between by means of the finder and connector switches, the operating afinder switch. for serving 'mechanism thereof being. omitted. Fig. 2" J lity view illustrating the method of associating said switches with. the diflerent groups of instrument circuits for independent opera tlon 1n response to calls originating on any line of a group-Sand also showing the manner of connecting the finder switches to facilitate thedistribution of traffic when two .or more subscribers in any group-desire to I Fig. 7 is establish successive connections. a diagrammatic perspective view of a switching mechanism illustrating the various banks of contacts and the wipers cooperating therewith, together withthe side switch mechanism;

Similar reference numerals in the several figures lndlcate slmilar parts.

In a telephone exchange system embodying this invention the connections between difierent telephone-lines are automatlcally set up, or effected, by apparatus arranged at the central oflice or exchange, andthe telephone lines or circuits leading thereto;

are divided into two classes comprising, first, incoming lines, or those on which calls are originated by subscribers who desire to establish communication with other parties and, secondly, outgoing lines over which the calls are despatched-to signal said called parties. Each line may, at. different times, be of either class and it will, therefore, be

- understood when these lines are referred to in the following description, that an incoming line or calling circuit 'is, one leading from asubscribers telephone or station over which impulses of current are sent to connect said line to an outgoing line and that the latter is the c'alledcircuit on which the i -sign-aling devices are actuated, when the connectionhas been set up or completed be tween the telephone instruments of the call ing and the called subscribers.

In the system embodying the present infvention it ispossible to connect by means of .30

. performs the function of selecting an incoming line on which a call has been originated, and the connector switch, associated therewith, performs a similar function in selecting the outgoing line leading to a particular telephone instrument, or subscribers station, with which the called subscriber'desires to communicate. The movable elements or wipers of the finder switch and its associaterconnector switch are tied together when the respective switch mechanisms have performed their functions and have operated the shafts carrying the wipers to position the latter in engagement with the selected line terminals so that the talking circuit from the incoming to the outgoing line is extended through the wipers and may. be

retained until one of the two commun1cating subscribers desires to effect a disconnection of said lines.

The mechanical details of these switches are not shown in this application, as they may be of the well known Strowger type of apparatus in which the switch wipers are mounted upon a longitudinally movable and revoluble shaft arranged at the center of an. arcuate bank containing contacts arranged in horizontal rows and in vertical tiers. The operating mechanism of the switch comprises mechanism for adjusting the shaft longitudinally" to position the brushes thereon in alinement' with one or another of the rows orcontact levels, as they are called, and also means for rotating the shaft to position the wipers in engagement with any particular set of contacts in I the row or level selected.

'In Fig. l a single finder and connector.

switch of this character has been shown diagrammatically to illustrate the manner of connecting two or more telephone instrument circuits indicated generally by A; B, D and E, the finder switch F and the connector --switch Obeing shown with the respective contact elements or wipers in operated position establishing a connectlon between 1nstruments A and B and in dotted lines these strument circuits, while B. and D respectively are the outgoing or called instrument circuits. I

The telephone instruments may be of the usual or any preferred construction comprising generally a transmitter 1, a receiver 2,

and the signaling devices orbells 8, all of which are arranged in the circuit of the line wires AA of instrument A, and B B of instrument .B. The instrument circuits are normally open at each subscribers sta-,. t1on at the contacts A" 3 which are controlled by the receiver hook and are closed when the latter is released by the subscriber removing his receiver therefrom. Each pair of wires constituting the circuits of the telephone instruments is extended to the aforementioned switches located at'the central oifice and terminate in immutable con tacts located thereon, those of the wires A"-A being located on'the switch F, as indicated by A A the corresponding contacts on the switch C being indicated by A -A said contacts being tied together" by conductors A -A the similar contacts of the-wires B'-l3 on the switch F are indicated by B B and on the'switch C by B B said pairs of contacts being also tied together by wires B -B The operating mechanisms controlling the movable elements or wipers of the two switches have been omitted from these illustrations, as well as the side switches employed for cutting the. operating mechanism into'and out of the operating circuits and cutting the lines through from one switch to another, but as will appear more fully-hereinafter, this mechanism is designed to cause such switches to move progressively both vertically and horizontally while their respective brushes engage contacts or terminals representing a large number of telephone lines. The wipers of the switch F are indi seen that the complete circuitbetween theinstruments A and B may be tracedas follows: Instrument A, wire A, contact A wiper F, wire a, wiper C, contact B wire B, instrument B, wire 13, contact B, wiper 'C ,'wire 5, wiper F contact A, wire A instrument A. The foregoing is predicated upon the fact that the call originated at the instrument A and the mechanism of the finder switch operated to pick up the con- Instrument tarts of'the incoming circuit AA after which the switch G was actuated to connect said circuit with the terminals of the outgoing line B'B Supposing -a. reverse operation to be effected in a like manner. The movable elementsof the finder switch F traverse its bank of contacts, or terminals, until reaching the terminals B ,-B of the line BB then the connector switch C operates to pick up the terminals A A of the line A'A The circuit struments will then be traced as follows: B, wires B B contact B wiper F wire 5, wiper C contact A, wires A, A instrument A, wires A, A, contact A, wiper C, wire 4, wiper F contact B wires E -B, instrument B.

The instrument circuits 1) and E, indicated in Fig. 1, comprise the component parts described in the corresponding circuits A and B and these circuits are shown to illustrate the longitudinal movement of the switch shafts which may be adjusted vertically to position the wipers thereon in alinement with the contacts or terminals of a particular row or level when they may be rotated to effect the connection illustrated by the dotted'lines, the brushes F and F of the finder switch connecting the terminals of the incoming line E and the corresponding brushes C and C of the connector switch engagingqthe terminals of the outgoing line D. j

The switchea-The general arrangement of theessential elements of the switching mechanism is best shown inskeleton form in Fig. 7, in which the vertical rotary shaft, indicated by 10, is provided with a plurality of wipers 11, 1'2, and 13, of which'a greater or less number may be employedas occasion At the upper end of the shaft is requires. a drum 15 provided with longitudinally extending ratchet teeth with which cooperates a pawl 16 'on an arm 17- a'daptedto be at tracted whenever the rotary magnet 18 is energized. The shaft is held in its adjusted rotary position'by means of the detent 19. Surmounting the drum is a ratchet member 20 having annular teeth with which cotip-v erates a pawl 21 on an armature lever 22 between the two telephone in-' adapted to be attracted by the vertical magnet whenever the latter is energized for the purpose'of'raising the shaft 10' one or more steps in a vertical direction in which position it is held by a detent 24c. The shaft is normally rotated in one direction to carry the several brushes or wipers thereon beyond the ends of the rows of contacts by means of the spring 25 having one end attached to the shaft and the other team arm which projects laterally from the shaft and bears against a post rigidly mounted on the supporting frame of the switch mechanism which has been omitted from this illustration.

Movable vertically with'the shaft of the finder switch but not partaking of its rotarymovement is a wiper 28 which may be con- 1 vertical distance through which the shaft may be adjusted.

The several Wlpers 11 12 and 13 ay erate with separate rows of csntacts and are adapted to simultaneously engage in the different rows, terminals dedicated to particular instrument circuits. For instance, the brushes 11 and 12 corresponding to'the brushes F and F- of thefinder switch F are adapted to engage with the terminals 11 and 12 of the line wires of incoming circuits and thebrush 13 cooperates with contact 13 .which are apportioned to saidcircuits for purposes to be presently described. All of the aforementioned contacts are shown in Fig. 7, as arranged upon the first level so that they will bet-simultaneously engaged by the respective brushes upon maybe accommodated upon asingle switch.

In switches of this character, the mechathe first upward movement of the shaft 10 and the first rotary movement nism for operating them comprising the ver- I tical, rotary and releasemagnets, are controlled by means of a side switch indicated by S in Fig. 7, comprising the wipers 30, 31, 32, 33 and 34, each of which engages a separate row of three corresponding contacts over which they are stepped by means of an escapement mechanisms controlled by a private magnet P which operates in conjunction with the vertical and rotary magnets 23 and 18 in thewell known manner. The release magnet-indicated by- 35, performs a dual function of disengaging the detents 19 and 24, .to permit the switch shaft 10 to be rotated into its normal position by the spring g nie'zgeeo 25 and to descend to its normal position, and also to restore the side switch S to,its normal position. 1 v

The finder and connector switches arejactuated by electromagnetic devices peculiar to each, those of the finder switch being automatically set into operation, and controlled by secondary circuits, which' are established when an instrument circuit is closed at the subscribers station, and the mechanism of the connector switch is rendered operative when the finder switch has picked up the incoming or. calling circuit and is controlled prising wires AA-, is extended, as indi by impulses of current which may be despatched by 'a suitable form of impulse transmitten-located at the subscribers station, to select a given outgoing line, or called circuit. Accordingly the instrument circuit, comcatedat A, A Figs. 1, 2 and 3 .to normally closed contacts A -4X one of which is mounted upon a spring finger provided with a projection 46 adapted to co-iiperate with contacts on an impulse transmitter A to thereby. transmit or send over the operating circu t one or more impulses of current-when the circuit is closed at the hook contacts A 5 When the line has been extended through the finder, and connector switches the calling subscriber causes the bells or signaling devices of the called'instrument circuit to be operated and to this end each instrument circuit isprovid'ed with a push button A, (Fig. 3) operating a contact spring a" connected to earth as shown and adapted to engage the line contact spring a lhe latter engages a contact a and is retracted out of engagement therewith at a to open the calling instrument circuit after one side thereof has been ,grounded, .these parts being arj ranged inthismanner to establish and main- 'tain a ground on one'side of the calling instrument circuit to prevent the release of the switches during. the ringing period which would otherwise occur when the instrument circuit is destroyed, all as will appear morefully hereinafter. I

- The electromagneticmechanismfor causing the gvarious switches toperform their respective-functions, are all adapted. to be operated-from a. common battery, but in qorderto facilitate the description and illustration, and render a more comprehensive understanding of the various circuits to be had, these are shown in the various diagrammatic views as receiving current from different sources or sets of batteries Z-Z etc. Torender the circuits easy totrace they are shown with the conventional ground connections but it will be understood that whenthe term ground is employed and shown, it refers to a connection leading directly to one side of the mainvbattery, so that a telephone system embgdying this in-' vention, when installed in. working order, is entirely free of the so-called grounds em ployed for actuating the switching parts of the apparatus, thereby eliminating line disturbances orother tr'eubles, attributable to thiscause. is I The finder switch.To enable a comprehensive understanding to be had of the ari ous features of the invention, it will be ad vantageous and facilitate an understanding of the system to first take up the various steps performed in connecting two instrument circuits over a single group of switches, it being understood at the outset that this operation is precisely the same on each group. In order to-illustrate this feature of the invention 1 have shown in Fig. 2 the manner of grouping incoming telephone lines and their connections with a single finder switch. iln Fig. 5 three of such switches have been shown to illustrate particularly thev multipling of the instrument circuits on the various finder switches and also the multipling of the groups in which these lines are divided, on said switches.

Fig. 6 shows the method of wiring or con i The finder switches are further interconnected so that when a switch is actuated by a particular instrument circuit in its group,

another is automatically connected to said group in readiness to respond to a second callv originating in the same group of instrument circuits Similarly the second switch joins a third to the same group and so on with the result that all the instrument circuits of a particular group may establish connections over an equal number of? der switches, each of which is primarily i. tended to only serve the instrument circuits in the group to which it is assigned.

As many separate instrument circuits may be brought together in a single group, as good practice or business conditions may determ-inc. This grouping of the lines being usually arranged upon a ten per cent. basis,

cuits for four subscribers lines have been shown, the first threeof which are arranged 1n one group, whilethe last illustrates 1. second group. With each subscribers line is associated the individual line actuated relays A,-B J and H respectively, which are arranged at the central office and are adapted'to be energized when their respecfive-instrument circuits are close to ener gize the'circuit of a group actuate or re r l. 5 1' ii relays as there are groups. Each of these the starting circuit which energizes its respective finder switch.

relays is adapted to close 7' Also associated with each line is a cut-off relay, tioned being indicated by A, B, J and H, the function of which is to restore their corresponding actuated relays A, etc., to norma position when a finder switch has picked up the terminals of its corresponding instrument circuit. In Fig. 2 the single finder switch illustrated therein, which is typical of all of these switches, is shown'provided with contacts for the line wires, the cut-off relay and the all of which are for convenment circuits,

shown in this figure mice, in illustration,

spective banks of terminals. It will be noticed in 2 that the four and in Fig. 7 the three'last mentioned terminals Tof each line appearing in the different banks and constituting a set dedicated to any particularline are simultaneously engaged by all of the brushes or :in the second levels or horizontal rows, then the coordinate terminals of the cut-off and test circuits will be foundin the second "levels of their respective banks, etc.

. strument circuit A the other and that cut-off terminal f and the test wire'termi- I nal 7 with which cooperate the brushes- Multiple terminals of each line with the multiples of its cut-off and test circuits appear in the same position in front of, each finder switch as shown in Fig. 5, but as this method of trunking is well known, further description thereof is deemed unnecessary;

Referring now particularly to Fig. 2, it-

the line terminals of inare'located one beneath beneath these appear the will be seen that "and. res' ectively. Leading from the terminal f is a wire A leading td theicutoff relay A, the other terminal thereof be- "battery Z leads from'the tact a, with which thearma-ture a? ing supplied contact 7 to a back conof the individual line actuated relay A DOImally.

' engages-said armature being connectedby a wire'c fto the groundfsideof the"battery'- Z which is connected tothe group actuated master relay G arranged in a circuit includ-v forW-ard,

ing the wire g terminating in a I contact" g "engagedby the armature a when the latter :is "attracted; One iend of the coil,

of the line actuated relay of the instrument circuit by those corresponding to thelines men- 1 which has a grounded connection 2 test wire of all of the instru I are arranged in vertical ,alinement so that the respective contacts the relay A at times with current from the The line finding test wire A ceiv erfromits hook I group in which said line'is'included, will be-- the battery Z is connected by the 'wire a to the back con-v tact a. with which normally engages the armature a of the associated cut-ofi relay, said armature being connected with one side joined to the line wire A A ture controlled by the cut-off 'relay, indi cated by a is connected by the wirev a joined to the other line wire A. This armature normally engages a back contact a Fig. 8).

In order to remove the control of the line from the subscriber after a call has been switch and until'the latter has picked up the terminals of said incoming line I arrange therein a normally open bridge which is the wire a? v second arma- (See A is connected to the other extremity of which started during the ope-ration of the finder closed'by the closing of the subscribers strument' circuit to shunt out the telephone I instrument. 'In Fig. 3 this bridge is shown.

comprising the wires a and a leading from the Wires Av and- A respectively one being connected to a forward contact a and the other to anarmature a cooperating therewith and arranged on the line actuated .relay A The latter being energized by the closing of the instrument circuit at the hook contacts A attracts and holds the armature a in engagement with the contact a. until the relayr-rl is cut offby the operation of controlled by the finder switch. Primarily this shunt prevents the opening of the circuit of thegroup actuated or master relay should the calling subscriber inadvertently abandon the call while the finder switch was moving either verticallyor-ln a circuit, it will be seen causes a. switch, whenv it has. been started to actually complete its search for the terminalsof the callingline.

The corresponding parts-to those just described in, connection withinstrument circuit A are found illustrated inconnection with the remaining instrument circuits, said parts being indicated by priate exponents, reference to made hereinafter in explaining which will be tention is called to the fact that the master relay, such as G of each group',-is arranged in a compound circuit which is adapted to be closed by the attraction of any ofthe armatures a b or 9' of the individual line actuated relays of the lines;

group and from this arrangement of the .p'arts it will be seen that by. closing any inby the removal of the restrument circuit them-aster relay of-the.

actuated.

The decimal oncommutator I the use of letters B, .and H, and b, j and h, with the appro-' I the operation of certain parts of the apparatus. At-

constituting the I to control the yertical movement of the switch shafts, said circuits being adapted to 7 be opened by the operation-or" their respective master relays to arrest the upward movement of said shafts to position the wipers thereon in alinement with the horizontal rows or-levels in which appear the different terminals of a line oi any group on which a call has been originated. The lowermost contact ofth'e strip, indicated by f, is .a' home orstartingpoint and is normally grounded, as, indicated at .2 (Figs. 2 and 3). From the first contact on the decimal strip'29 leads the wire 9 terminating in the back contact 9 which normally engages the armature g of the master relay G of the first group, said armature having a grounded connection 2 Likewise leading from contact No. 2 is the wire 9 terminat ing in the back contact 9 of the armature 9 of the master relay G of the second group, sald armature being grounded as 1ndicated at e (FigiQ). From. the remaining contacts of the -stripf extend similar wires, as indicated by 9' and g whichlead to similar contacts of the armatures otthe master relays of additional groups of lines, not shown, said wires 9 9 etc being each grounded when all the instrument clrcuits in their respective groups are idle.

In Fi 3 a single telephone instrument circuit has been illustrated showing its line and cut-off relays, the group actuated or.

master relay and the finder switch with its operating mechanism and in order to facilitate the description the sets of terminals of this line are shown in the switch banks as being arranged in the third level and the third group. i

In the operation of a switch of this character, the first actuation effected is the vertical movement of the switch Shaft F the required number of steps, by the successive impulses of current supplied to the vertical magnet F Then the rotary movement of the shaft is caused by successively energizing the rotary magnet F When the switch "mechanism is in its normal position, the

vertical magnet is in the normal open starting circuit extending through the side switch arm f which together with other arms of the side switch, is allowed to escapeand take one step, when the impulses transmitted to the vertical magnet have ceased. This disconnects the latter and connects in the rotary magnet and upon the cessation of impulses through the latter, s. i switch takes its, second step the third position to disccn magnet and set the arms f the callinginstrument circi.

u. u 1 m l this memes the wires 4 and 5 leading to the connector switch, at which time the arms 7 and 7 respectively engage the contacts f and f of the wires f," and 7' leading from the switch wipers F and F The side switch arm f is normally con nected to round, as indicated ate and in its normal positiom'shown in Fig. 8, rests in engagement with a or tact forming the terminal of the wire 7 9, hich is connected to one end of the coil of the vertical magnet F In its'second positionthe'arm 7 engages. the contact which is the terminal of the wire f connected to one end of the coil of the rotary magnet F and in its third position said arm contacts with the terminal 7 joined by the wire 7 to the wiper 7 which latter cooperates with the terminals of the cut-ofi relay circuits grouped .on this switch. The arm f engagesthe contact 7 and normally closes the holding circuit of the vertical magnet which includes the wire f leading from the brush 7 over which the holding circuit is energized during the verticalmovement of the switch shaft dur-- ing the timesaid brush receives current by reason of its successive engagement with the -magnets is the private magnet I, which as before explained, controls .the escapement mechanism of the side switch. This magnet is adapted to be energized by the impulse of current transmitted to it over the booster line or starting wire which is energized whenever the master relay of the group of instrument circuits. to which the finder switch is dedicated is energized, providing this particular finder switch is in its nor mal position otherwise some other finder switch will be actuated by this impulse of current. The booster circuit comprises thev wire 7) terminating in the forward contact 9 of the armature of the group actuated master relay G and extending to the side switch arm f which latter when in its normal position connects it to the private magnet P. I

Each master relay controls one of these booster lines or starting circuits which leads directly to the side switch arm of its particular finder switch. In Fig. 2 this circult of the second group indicated by p and in Fig. 5, it is shown connected to the side switch arm F and in this figure said circuit of the third group indicated by y) is shown connected to the side switch arm 7 of the third finder switch. Fig. 6 shows method of associating the finder switches with their respective groups oi lines. more extensi\'ely,'thc sidc switch arms of ten different switches being shown and l indicated by f (of the first group) f 7. etc, to 7'9 (of the tenth group) each of which is connected. with its respective booster line or starting wire 32', 79 .72 etc.

A greater or less number of finder switches 1 net F is normally may be employed as occasion requires, and in order to render other finder switches available, in the event two or more subscribers' in any particular group desire to make successive calls, I interconnect the switches in such a manner that when any of them have been operated they will 'automatically connect in another, or others, which will respond to another call from a subscriber -whose particular group switch has been previously operated. To accomplish this object I provide contacts which are engaged by the side switch arms f, f etc., whenever the latter are moved into the third position, which are joined or tapped onto the starting wires of the adjacent finder switch; tacts' are designated by p 22 etc., to p The contact p of the first switch is con-- nected to the starting wire of the last switch in the series by a wire .1), that of the sec ond switch is connected to the starting wire of the first switch by a wire p and the re mainder are likewise connected, each with the adjacent switch as shown in Fig. 6. The booster lines or starting wires are-normally connected with the private magnets of their respective finder switch operating mechanisms by the side switch arms 7', f etc. when the latter engage the contacts h h etc. by the wires h, 71., 'h, etc. (Fig. 6); However, in order to disconnect said magnets from the boosters or starting wires, after the latter have set the switches in motion, each of the wires, h, h", h, etc. have a .set of contacts interposed in them which are closed when the! switch shafts are in normal position. called the off-normal contacts and comprise springs h h, it, etc. joined to the terminals, k, 7?, h and adapted to close against the back contacts 7t, h, h, etc, of the Wires it, h, it etc. Another advantage -obtained by interconnecting the finder switches and automatically bridging the line in the manner described is found in connection with their'operation to be that if the one which is started originally skips or fails to find the line its. side switch arm such as f, will automatically connect another switch to the starting circuit, causing thesecond switch to be actuated and this without the knowledge or the performance of any act on the part of the calling subscriber.

The operating of the finder switches.- Referring to Fig; 3 it will be seen that the private magnet Pot each finder switch re-v ceives current from the batteryZ and controls an-armature i, connected to the wire 13 leading. from theside switch wiper f.

These are Dill'llOSt. Ol' Zlll InFigs. 5 and 6 these con. i

' tively quick the spring which 'When this imagnet is energized the armature 2' is attractedinto engagement with the contact '6 connected by the wire i with one a continuously operating interrupting ma-.

chine,such as is sometimes employed for this n intermittently operating relay Z which latter torm'ot' interrupter 1 prefer touse, as it may beoperated only when a call is originated and arrestedwhen one or more of the tinder switches has performed its function. This single interrupter may be used forv supplying battery current to a plurality of finder switches and in its preferred form I arrange this relay in an independent starting circuit y which is adapted .to be energized whenever any of the group act ted master relays are energized. Consequently this circuit leads to a plurality of forward contacts j, j j, etc, of armatures or contact springs j, j, j, etc. .(Figs. 5 and 6). The starting wire 1" is connected to one end of the winding of relay Z the other extremity of which receives current from the battery Z over the armature j which is held in engagement with the back Contact 1 and the wire j.

The relay Z is piut'erablymade sluggish in its action, while the armature isretracted by arelatively heavy spring which is adjusted to such a tension as to require the magnetic strength of the relay to rise to nearly its maximum point, so that the armature issomewhat slow in pulling up while in releasing its action is comparaon account of the strength of retracts the armature as soon as the circuit of the relay has been broken and before-the magnetism has been entirely discharged from. its core; In its attracted position the armature 11 engages the contact a ot the wire i oined to the which at difi'erent times is employed for operating the vertical and rotaryunagnets.

andfi the wire-z isshown ex-' 'wire. 2' 'and supplies an impulse of current the other brushes or wipers are unoccupied through the individual line actuated relay ground a. The starting impulse of current row or level of the bank traversed by the .brush 7", which are indicated by f. in

the circuit through the group actuated mas iaaeeo is connected to the wire 5, by the ing circuit of the private magnet by the atwirez'fl traction of the armature 'i-which then receives an impulse of current from the battery Z, the side switch arm F then being in the normal position and the switch shaft F also being in its lowermost position with the contact arm f in engagement with the contact 7". grounded at 2 The impulse of current traversing the following path: Battery Z wire 71?, magnet P, wire i contact 2' armature 2', wire 2' side switch arm f, conlhe release magnet F is connected to one side of the battery Z by the wire f and by the wire 7' to the last contact in each Fi 8. The contacts are extra ones and those of the banks corresponding thereto and 1n the same tier, which are traversed by or dead. These contacts f are not i11- volved in the usual release operations but serve to supply theimpulse of current to release the switch and permit the shaft to rotate in its retrograde movement on whatever level it may have been operated and to restore it to its normal position in theevent the wipers skip or fail to pick up-the terminals of a calling line for any cause. The ordinary full release operation can not be conveniently described except in conjunction with the mechanism of the connector switch so that the description of the operation of this magnet which occurs when a calling party hangs up his receiver, niuch'loe deferred until the details of the connector switch have been set forth.

The operation of the finder switch will now be readily understood by considering the successive movements which occur from the moment a calling subscriber closes his telephone instrument circuit by the removal of his receiver 2 from its supporting hook and until the terminal cont-acts of the line are picked up by the switch wipers. The closing of the subscribers instrument cir-- cuit at the point A causes current to flow 2 retains the private magnet energized in addition to the impulse of current received over the starting wire it. The booster line or starting circuit causes the magnet P to close the circuit of the vertical relay and the circuit last described closes the holding circuit of the private magnet before the vertical relay takes its first step to open the off-normal contacts 72, h. The vertical magnet F then receives interrupted current each time the armature j is attracted over the following circuit: Battery Z armature j contact 21*, wires 2'", 2', contact 71, armature 5*, wire 7;, vertical magnet F wiref contact 7, side switch arm f, ground 2 Each energization of the vertical magnet causes the switch shaft F to move upwardly one; step, advancing the wiper f successively into engagement with the group terminals on the decimal strip which continues until said wiper engages the contact of an open branch circuit, such as g inFig'. 3. Whereupon the holding circuit of the private magnet P is opened, allowing the armatures '1; and 71 to be retracted, the latter opening the circuit of the vertical magnet F, at the pame instant the decnergization of the private magnet permits the side switch to escape intothe second position to connect in the rotary mag net E The first step of the side switch movesall of its arms into the second position and the arm F cuts out the vertical magnet F and cuts in the rotary magnet F when said arm engages the. contact 7? to close the'following circuit: ground 2, arm f contact f wire f9, magnet F wires 2' i contact 2' armaturej battery Z current from the latter being intermittently supplied as the previously described circuit of the interrupting relay Z is still maintained. Arranged on the rotary magnet is an armature 7 which is attracted by said magnet into engagement with a forward contact r to close the circuit formed by the wires r and 7' which are joined respectively to the wires it and i to energize the private magnet? A over the following circuit: Battery Z relay A wire a, contact a armature a, wire a; substation A, wire a, armature a contact of, ground The attraction of the armature a which then occurs, closes ter relay G over the following circuit: Battery Z relay G, wire 17, contact 9, armature a", wire 2 The last mentioned relay attracts its armaturcs and j; the former closing the circuit of the private magnet P of the finder switch allotted to -the group of lines in which instrument circuit A appears over the following path: Battery Z wire 72*, magnet l, wire it, contact-7i, spring if, contact 7t, side switch arm i starting wire 7), contact g, armature g,

was also applied at the same instant to the relay Z by the armature j which closed the following circuit: ground .2 armature j, contart 7'1 wir relay if: Wire j', coir upon the first actuation of the rotary magtact (uni idiL-fefi/ Z i l to set the sent mechanism in lne our) o l releasedas soon i, magnet P, which and ms current received closes the l tact 7, wire 7", wiper f contact f, ground overthe brush f is broken for the purpose of allowing the side switch to take a second step to disconnect the circuit of the rotary fbrush 7' so that during the rotary move- -ergized while the third impulse of current ment ofthe switch said wiper successively engages the termlnals, such as 7, of the line finding test wires, such as A, all of which,

with the exception of the one corresponding to the calling instrument clrcult, are closedj/ to ground or to the grounded side of thief battery, so that current is retained in the private magnet P during the rotary movement of the switch until the wiper engages the terminal of the line finding test wire of the'calling line, which is open at the point a, as shown in Fig. 3, whereupon the side switch is allowed to take its second step and move into the third position. This control of the rotary movement of the finder switch automatically, will be understood-y more clearly by reference to Fig. 2, from which it will be seen that the set of contacts dedicated to instrument circuit A are arranged inthe same position in reference to the sets of contacts dedicated to circuits B and J, as they occupy in Fig. 3, that is, they are shown in the third tier so that the switch wipers are rotated three steps before coming in contact. with the set of terminals of instrument circuit A. In Fig. 2 the line finding test wires of instruments B and J are indicated by B and J 15 terminating in the second and first contacts respectively, indicated by 161 and 162 appearing in front of the contact 7 in reference to the direction of rotation of the switch wiper of the test-wire A Upon the first rotary movement of the finder switch the brush f completes the following circuit: battery Z wire 71?, magnet P, wire 2' contact 2' armature 17, wire 2', .side switch arm 7", contact f wire f, wiper f, contact 162, wire J, to ground. This impulse of current holds the private magnet P energized whilethe second impulse of'current is applied to the rotary magnet F completing the second similar holding circuit over terminal 161 of wire 13"", again holding the magnet P enis applied to the rotary magnet. Vhen the wiper f picks up the contact f the private magnet P is allowed to become deenergized because the line finding test wire A is open at the point a, as before described,

and the escapement mechanism being re leased allows the side switch arms to jump into the third position thereby discontinuing the rotary magnet of the switch and ar-- resting it in the operated position with the wipers F and F in engagement with the line terminals A and A of the wires A and A The instant the side switch moves into its third position the arm 7* thereof applies the ground to the circuit of the wiper f to -energit Ye the cut- -relay of the calling line, \\l11c}1 111 turn denergizes thev individual line, actuated 1; ayand the group actuated relay and opei vs'the shunt in. the instrument ci i cuit cuttin /the latter through to the calltag subscribers instrument and placing the 'circuit under his control, so that the connector sw'tch may be operated or the finder switch 1' leased and restored to its normal positiomf h The, 'omplete circuit of the cuto:lf. relay contact f, side switch arm f, ground The energizing of relay A attracts ienergizatiori of the relay- A The latter allowsi'the armatures a and n to be retracted, the former opening the circuit of the group actuated master relay G and the :mayg/oe traced on Fig. 3, illustrating the' vire A terminal ff, wiper f wire matures afand o with the consequent de&

latter opening the shunt in the line circuit. f

The armatures g and 7' being restored to their normal position the movement of the current interrupter Z is arrested' and the multiple contacts on the variousdecimal strips or combs joined by the wires 9 and g are connected to ground to permit any other switch which may happen to engage said strip contact to, continue its vertical movement and pass beyond it.

The connector switch.-The connector switch comprises apparatus common to all the incoming lines which is rendered operative as soon as the finder switch has selected the particular line on which'a call has been originated. The-movement of this switch is controlled by mechanism which is actuated by impulses of current despatched in an suitable manner, but preferably by an impulse transmitter, such as that indicated by.

A located atthe subscribers station. This mechanism has for its primary\-object to control the operation of the movable contact elements or wipers C, C to permit their adjustment into engagement with the terminal contacts of any instrument circuit ou said switch, .and' further, to render the swered in he may destroy the connection and =.ablish another connection over a different group of switches with a third subscribers line. These additional devices also include 'means for automatically despatching to a.

- ,calling subscriber, what is termed a busy "i-signal in case the line of the party with whom he desires to communicate is other- 'wise inuse. p

Among those persons versed in this art it iscu'stomary to designates the two conductors of the telephonecircuit (such as A, A

"l hfoand 4 as the lineand mate wires to the switch C it will be seen that the line,

and as these expressions will serve to elucidate further description, this nomenclature will. be adopted. I

In-tracing thecirouit from the switch F and mate wires 4 and 5 leading from the brushes F. and F (Fig. 3), are extended as indicated by 4:, 5,4 and 5%. (Fig. 4) to the [wipers Cf and C": of the switch and have I interposed therein; condensers 4:7 and 48,

'- The line and mate conductors 4 and 5, 4

and 5 form the tie between the finder and .connectorswitches and leading "from these. conductorsare branches 40 and each of which-ris connected respectively to one end of. the coil of the-line and mate relays 41 and 51 s aid coils being arranged in tandem, thereby serving to balance the line.

.The other ends of the coils of these relays are connected to opposite sides of the bate tery. Z, the .current from which causes both the ,-li-ne,,and mate relays to be energized when the brushes F and F of the finder "switch F are. in cobper'ative engagement a-withuthe,terniinals. of the. incoming line.

5. Associated with the line and mate relay 35 tandem coils 41 and-51 is the holding over or, slow operating relay L, one end of the coil of which is connected by the wire Z to one of the poles of battery Z and to one end of the coil 41*; the other extremity of the A0-v winding of; relay L is extended by the 'lineZ' to the forward contact Z of a normally open :warmature Z ofthe-line and mate relay. The

relayl L is'preferably-made slow or sluggish --in its action by surrounding its core with a copper j-acketxorotherwise constructing it, so-that whenit has once been energized by v theattraction of the armature l which 00'- curs when the callingline is'cut through to the connector switch, it will retain the magnetism in'its core during the vibrationof the (armature Z while the latter. is vibrated by current impulses in-the line and mate relay which maybe transmitted thereto succesis operated vertically and rotated, by sepa sively'at-regular intervals of time, for purposes as will presently appear. p

' The connector switch is similar to the finder'switch previously described in'that it ratemagnets designed for this purpose -which are automatically brought into circuit by a side switch controlled by a private marred turning to the calling party the tone or busy signal in the event the line of the party withwhom a subscriberis endeavoring to establish a connection, is otherwise in use.

In Fig. 4 a single connector switch and the operating mechanism therefor is illus trated diagrammatically, the switch shaft being indicated by C onwhich is mounted thewipers C, C and c. The side switch of the connector comprises four connected arms a, 0?, c 0 the first two of which are inter- .posed in the tie wires 4* and 5 leading from the finder switch and are adapted to gage the contact 0 and in its third position said arm rests upon the contact a grounded as indicated at 2- The side switch arm a is connected by the wire 0 to aback contact 0 of the armature Z which is grounded as indicated ate, and theremaining portion of the circuit of the vertical relay C is formed by the wire 0" connected to the armature c arranged on the slow relay L and by the latter attracted into engagement with the forward contact 0 forming the terminal of the battery Z, and as the latter serves tofsupply currentfor operating the rotary magnet C one end of the latter is con nected to the wire a by a tap 0 The calling instrument circuit A may be traced over the following path: instrument A, line wire A, contact A, wiper F, wire f contact f, side switch arm f, wire i, wire 40', one coil of line relay 41 one coil of' relay 51 battery Z, other coil of relay 51, the other coil of relay 41 line 50*, mate 5, side switch arm f; contact f wire 7 wiper F contact A, mate wire A en the circuit just described is connected through, it is energized from the battery Z,

causing the armature, F, to be attracted to close the circuit of the relay L, which is retained energized during the successivevibrations of the armature Z The last. mentioned relay attracts and by reason of its sluggish operation hblds attracted the armature 0 Now, suppose the instrument cir-.

cuit with which it is desired to effect a connection, is that represented by B in Fig. 4,

the terminals B and B of which are arranged in the second levels and the third tier of contacts in the terminal banks. The calling subscriber then despatches two impulses of current in regular succession by the. operation of his impulse transmitter, such as A. 'Each time the circuit is broken the armature Z of the line and'materelay lse ' coils is allowed to fall back-into engagement closes a circuit through a private magnet.

C, as follows: froiii ground at a, armature Z contactc, wire 0, wire 0, private magnet C, wire-0 wire 0, contact 0, switch spring 0 wireo, through the release magnet (F, to battery Z, and ground atfz The private magnet, C is thus energized. It will be noticed that the above-described circuit also includes the release i'nagnet, C, but the resistance of the private magnet is such that, while it will be properly energized-through the release magnet, C to perform its functions, the said release mag- 7 "net will notreceive sufficient current to become operatively energized.

The privatema et, O fi is a slow magnet or relay and holds over while the armature, Z vibrates in response to impulses through the line relay, 51*. When the impulses cease the armature, Z remains held up and breaks the circuit of the privatemagnet, (Pfl'at the 'contact, 0 thus deenergizing the 'private magnet and 'allowsthe side switch arms, 0 ,0 c and c, to move to sec ond position. 'The switch arm, c ymovingto second position contacts with the terminal, c, of wire, 0, which leads to the rotaryanagnet, 0 The rotary magnet is now ready to receive impulses sent over the line and through the line relay, 51 through the following circuit: from battery Z, wire Z,

-co'ntact c armature 0, wire 0", wire 0 rotary magnet C :Wire c ter minal 0 switch arm 0 wire 0, contact 0 armature Z and ground at a. The. rotary magn'et responds to the vibrations of the armature, Z as often as the same-is vibrated by the impulses passing through the line relay,

' 51*, which, in this case, would be three.

' Thiscauses the wipers, C, C and c, to move over as many contacts in the respective banks as there are impulse s.- As soon as the armature, Z drops back by the first interruption of the current passing through the magnet 51", the-private magnet, C is ener gized over. the .same circuit, as izeforede scribed, and, being a 'slow' magnet. holds up during the interruption and untilthe switc shaft .has been rotated a nu'rnber of steps correspondingto the impulses, after which the private magnet is deenergized by the breaking of its circuit at contact 0 by the drawing up'of'the armature, Z toward the line relay 51 this allows the side switch arms, 0 ,0 c and 0*, to pass to the third position, which extends the line 4 and 5 through ="the side switch arms, '0 0 the wipers,,C and C terminals, B B to'the lines B B of subscribers, station B.

The lines are now connected ready to receive signaling currents which are supplied as follows: The closing of the push button, A

puts ground on one side of the line and opens the other side ofthe line. Grounding this side of the line allows the relay-51 to hold up through one of its windings, but

- grounding one side of the line and breaking .the other side causes the differential relay 41 to be energized throughone of its windings and thiis includes the enerator, ]c,.in a circuit through contacts armature kt, contact'7c and armature 70 thus putting generator current on the lilies 4 5 which are connected to armatures-K and K1.-

WVhen the connector switch, C, rotates to bring the wipers, C and G on the contacts,

' B B thus extending the talking circuit or subscribers'line to station B, wiper c on said switch, C, drops onto contact a", and

thus closes a circuit through the cut-off relay B, as follows: from ground atl, 2

through terminal 0, switch arm a which has moved to third position, wire con- Z, and ground. This puts ground on the terminal a.

relay, B, would have been operated by some other switch putting ground onto the contact 0 which would operate the busy relay C". This would occur immediately tact 0 armature 0 wire 0, to-wiper 0. contact 0 wire 0, cut-ofi' relay B, battery In case the subscriber B-is busy, then the upon the wiper, c, contacting withterminal 0 which would be prior to the time that the side switch arms move to the third 'position' after the private magnet had dropped back.' The circuit through which this busy relay,. C is energized, being, as. follows: from ground'at 0 wipen'; wire 0, arm a ture 0 contact 0 wire-r2 (switch arm 0, contact 01 wire'c through-on the-differential relay- C \\'i{'ne.(i ?1, armature 0 contact c ,'wire Z, battery Z, to ground;

erwinding of- The*energizing of the differential relay,

vQ would release the connector switch, G, as follows: fromground at a, armature 0 contact 0 wire 0-, wire Q25, off-normalcontact 0, switch spring 0 wire a, re lease magnet C battery Z, to ground at 2". permits it to return. The relay, C in becoming energized, locks itself in energized position, as followspground z line 0 primary side of tone coil, wire 0 contact 0 armature 0*", line 0, wire wire 0 armature 0 contact b lin e Z, battery Z, to'

This releases the connector switch and ground. This sends a busy signal back from induced currents on the primary of the tone coil through wire armature 0*", wire 0,

wire a, through the condenser 48 onto the line 5, thus disturbing the balance of the line and-giving a busy signal to the calling subscriber. H 7

When subscriber A is talking to, subscriber B the source of battery supply of' subscriber A would be from battery Z, through, relays 51 and Alt, but the condensers 47 and 48 would prevent the flow of this battery through coils 51 and 41 to subscriber B and batter is supplied to subscriber B through/coll 0", as follows: ground, battery Z, wire Z, contacts 0, arm-a,- ture a, wire 0 3', one coil C wire 0 wire 0, contact 70 armature 70 and to one side of the line'5 From ground at 2 through coil C wire a, contact is, armature k, to other side of line 4;*.-- It will be understood, however, that relay- C is a diflerential relay and'will not be energized by the flow of batterv to subscriber B.

It should be noted that if subscriber A I gets the busy signal he would have to hang up, which would deenergize the line relay, 51 which in turn, breaks the circuit of the vslow relay, L, which, in turn, breaks the the parts to return to their normal position.

two-movement switch comprising a Having thus described my invention, I claim;

1. A series of subscribers circuits ar ranged in groups, a series of switches less in number than the number of*subscribers circuits, said switches each having different levels corresponding in number to the number of groups, a certain one of said series of switches being normally allotted to each group, means for preselecting anidle one of said series of switches it the normally allotted switch. is busy, a master relay for each'group and means for energizing said master relay upon the initiation of a call, said relay operating to cause said preselected switch to select the group of lines represented by said relay.

2. In an automatic telephone system, a brush supporting shaft capable of, longitudinal and rotary movement, a vertical magnet for moving said shaft longitudinally, a rotary magnet for moving said shaft rotatively,

bank contacts arranged in different levels corresponding to the number of vertical steps of said switch, and a commutator having contacts also corresponding to'the number of levels of said switch, and a wiper adapted to successively engage said commutator, and a connection from said wiper to supply current to the vertical magnet, and means for connecting said current supply to said vertical magnet whenever the switch is moved off-normal and so long as a circuit is established through said commutator.

3. A series of subscribers stations arranged in groups, and a series of switches having different bank contacts arranged in diiferent levels, one level for each group, a

master relay for each group of subscribers,

a series of switches corresponding to the number of groups of subscribers, multiple connections of the subscribers circuits to each of the switches, means including branch operating circuits controlled by said master relays for moving said switches vertically when started by the operati'onpf the mas-' ter relay, and for continuing said movement.

until the level corresponding to the operated relay is reached.

4. In an automatic telephone exchange system, a fin der switch having a vertical and rotary movement, a vertical magnet,'a rotary magnet, a side switch, a private magnet for operating said side switch, a commutator having a series of contacts equal to the numberof vertical steps in said switch,.and a wiper on' the switch shaft adapted to successively engage said contacts as said,

switch is moved vertically, and a connection from said wiper through said side switch to the private magnet whereby said private vertical magnet to cause the switch to step up so long as current is supplied through said commutator to said private'magnet.

5.- A series of subscribers circuits arranged in groups, a series of switches less in number than and common to said subscribers circuits, each group of circuits having a certain one of said switches normally allotted thereto, a starting circuit for each of said switches, and means operated when a v switch is taken for use for extending said starting circuit to an idle switch of said 6. A series of subscribers circuits arranged in groups, a series of switches less in number than the number of subscribers circuits, common thereto, each group having a-certain switchof said series normally allotted thereto, said switches each having diflerent levels corresponding in number to the number of said groups, a master relay for each group, starting wires, one for each I master relay, means for maintaining said starting wires extended to an idle switch,

105 magnet is held energized and controls the initiation of a call, and contacts operated by 4 said relay for completing a starting circuit,

whereby an idle switch will becaused'to hunt for the level corresponding to the calling line.

T. In a telephonesystem, groups of incoming lines, a plurality of switches common to said lines, each group having a certain switch normally allotted thereto, means actuated whena switch normally allotted to a group of lines-is taken for use for selecting an idle switch and definitely associating it with said group of lines, and means whereby the preselected switch will be operated to selectthe terminals of a line in said group upon which a call is initiated.

8. In an automatic switchjhaving a vernet and a rotary magnet-and a private magnet for supplying operating current to said vertical and rotary magnets, a starter wire leading tosaid private magnet. having a make-and-break contact adapted to be opened on the first movement of the switch, a wiperon said switch, contacts equal innu'mber tothe vertical steps of said switch adapted to be engaged by said wiper,-

p as

means for supplying current through each the same to continue its vertical, movement until it has moved to the level corresponding to said group.

101 In an automatic telephone exchange, a

series of subscribers? lines arranged in groups, and a master relay for each group,

an automatic switch having a vertical and rotary movement, each of said lines being the lines of each group on a diflierentllevel in said switch, means in each of said lines for operating the master relay of the group,

a commutator having a series. of sections connected to terminals. in said switch with corresponding to the number of levels in said switch, each-of which is connected to'a circuit closing device adapted to be operated by saidmaster relay, a wiper on said switch adapted to successively engage the tical and rotary movenientya vertical magof said contacts, and a connection from said Wiper to said private magnet to cause current to be supplied to said private magnet through said contacts, and thus operate the vertical magnetunti'lsaid current supply is broken at one of'sa-id wiper contacts, and

a side-switch adapted to be operated by,

said private, magnet to change the operating current from, said vertical magnet to said rotary magnet when said switch has reached the limit of its upward movement as de-,-

termined by the current said wiper contacts. v

9. The combination with a vertical and rotary switch, a series of subscribers telephonellines, each having line relays and each connected to said switch in groupscorresponding to the different levels to. which saidswitch moves, a master relay for each group, a commutator having sections corresupplied through sponding to the number of difi'erentlevels,

each of said sections being normally grounded through a circuit breaker operated by said master relay, a wiper on said switch, an

electrically-operated current supply control- T ling? dev-ice having a connection to said wipers, and acircuit closing device also o'p erated by said master relay to close the aircuit through said electrically operated current controllingdevice when said'masterie: Jay is operated, a circuitbreaker in said lastmentioned circuit adapted to be opened at the I first movement of said switch whereby the closing of any of s 1d subscribers lines will energize the master relay pertaining to that contacts on said commutator, an electricallyoperated device connected to said wiper for controlling the current supplied tothe operating mechanism for said 'switch,.a starting wire common-to all the groups also connected to said electrically-operated controlling means, and a circuit breaker in said starting wire adapted to be broken on the first movement of said switch, and a source of current supply for said starting wire and also to the, circuits including the commutator sections whereby the closing of the line in any group will cause the switch to *automatically start and, mo pied-by that line.

ve to the level occu 11. Thecombination with a series oi sub scribers lines arranged in groups, a master relay for .jea'ch groupfavertical and rotary movable switch having a series of groups of contacts arranged in different levels'corresponding to the number of groups of subscribers lines, each of said subscribers lines be ngconnected to one of the termlnals in one of said groups, a master relay one for eachgroup, means for operating said'master relay upon the closing ofthe subscribersiv line in said group, a commutator having-a series of contacts adapted to be-supplied with current when said master relay is not switch vertically A; and rotatiyely, --and ;a private magnet for controlling the current supplied to said operatingfmea'ns, and aconlnection from said wiper to said private magnet whereby current is supplied; to said private magnetsjo long as the wiper engages" the contact to' which currentis supplied, a

starter wire alsofconnectedrto said private magnet, and means supplying current-- for said starter wire adapted to lee-operated uporrthe closingof any subscriber s line connected to sa d switch, a circuit breaker in group-andthus start said switch and cause said starter wire'adaptedfto break said cir cuit upon the first movementof-the switch,

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