US1324365A - And ralph l - Google Patents

Description

3. B. WELLIAMS, 1a., AND R. L. OUASS.

7 9 Ma E Y SI. U S NL H H DIN E0 uL M TC U P P A Patented Dec. 9,1919.

ISHEETSSHEET 1- In venfars: Samuel B. l/l/il/l'ams J1.

fPa/p/v L. Ouass S. B. WILLIAMS, 1a., AND R. L. QUASS. TELEPHONE SYSTEM.

APPLICATION FILED JULY 24.1317] 1,324,365. Patented Bea 9,1919.

TSHEETS-SHEET 2- K g fi :3:

E- Q E 2:: g g

S. B. WILLIAMS, 1a., AND R. L. QUASS.

TELEPHONE SYSTEM.

APPLICATION FILED JULY 24,19l7.

Patented Dec. 9, 1919.

7 SHEETS-SHEET 3- Samue/ B. VVl/l/ams JK Ralph L Guass A/ry TELEPHONE SYSTEM.

APPLICATION FILED JULY 24.1911.

Patented Dec. 9, 1919.

ISHEETSSHEET 4.

. Quays S. B. WILLIAMS, 1a., AND R. L. QUASS.

TELEPHONE SYSTEM.

APPLICATION FILED JULY 24.1917.

1,324,365. Patented Dec. 9,1919.

S. B. WILLIAMS, 1a., AND R. L. QUASS. TELEPHONE SYSTEM.

APPLICATION FILED JULY 24. I917.

1,324,365. Patented Dec. 9, 1919.

7SHEETS-SHEET 7.

ln ven/ons Samue/b. VVi/l/am: J/r

Far/pk L 0416733 SAMUEL B. VIILLIAEW EAWTHORl TE-Q HEW 3E1 rarest clarion.

53., Q1 BRGGKLYN, NEW YORK, AND RALPH L. QUASS, OF ASSIGNORS T0 "WESTERN ELECTRIC COMPANY,

INCORPORATED, OE NEJT sQEK, N. 53"., 2 GOEE'GEI LCEION 933 NEW YORK,

TELEPHGNE SYSTEM.

To all whom it may concern,-

Be it known that we, SAMUEL B. WIL- LniMs, Jr, and RALPH L, QUAss, citizens of the United States, residing at Brooklyn, in the county of Kings and State of New York, and at Hawthorne, in the county of Passaic and State of New Jersey, respectively, have invented certain new useful Improvements in Telephone Systems, of which the following is a full clear concise and exact description. r r p This invention relates to a telephone system of the call distributing type, in which calling subscribers lines are automatically extended to idle operators positions where the connection of the calling line with the called line is'completed.

In order to secure the greatest flexibility of connection and the maximum efficiency of operatiomth call distributing system of the presentinvention is so organized that each calling subscribers line has access to all of the operators" positions, so that as long as there is any operators position available, the calling line may have its connection extended. Generally stated, the inventio herein set- :forth, contemplates the arrangement of the telephone lines in groups, and the association with each group of a group of call-extending circuits, every one of which circuits has access to all of the telephone lines of the associated group and also to all of the operators positions ofthe exchange. Each operators position is provided with a plurality of connecting circuits, and through the medium of these connecting circuits, to which the call-extending circuits are automatically extended, the operator is enabled to complete the connection of the calling line with any line of the exchange. a

When a subscriber cal s, a particular one of the call-extending circuits of the associated group is automatically started and brought into connection with the terminals of the calling line, the control exercised by the calling lines over the call-extending circuits beingthrough the medium ofa controlling circuit which is common, to all. of the telephone lines of that particular group. Likewise, when the call-extending circuit has been selected and causel to connect with the t: ale of the ealic g line, it selects a particular one of the available operators Specification of Letters Patent.

positions through the medium of another controlling circuit that is common to all 01" the call-extending circuits of the associated group. Inasmuch asthese controlling circuits are common to a number of call-extendin circuits, it follows that anything which affects the operativeness of the common controlling circuits also affects the availability of all of the call-extending circuits which they serve.

It is the particular object of this invention to provide an organization whereby the large group of callexten'dingcircuits over which each group of lines has access to any and all of the operators positions, is divided into a plurality of'sub-groups, each of which-subgroups has its own controlling circuit; and to provide switching-mechal'llSl'D, either automatically or otherwise operated, whereby the sub-greupsof call-extending circuits are normally operated as a single large group, but may be divided into sub-groups either at will, or automatizally when trouble occurs inthe common controlling circuit of either sub-group, and the calls from the subscribers lines directed over the calLeXtending circuits of that subgroup which is in serviceable condition, and excluded from the other sub-group. Other related orsubordinate objects of the invert tion willappear from the description which follows.

The preierred embodiment the invention is illustrated in the accompanying drawings, in which Figure 1 is a graphic representation of the arrangement of the apparatus and scheme of the circuits in a call. distributing system organized in accordance with the invention; and Figs. 2, 3, l, 5, 6 and 7,. taken together and arranged side by side in the manner indicated by the lines extending to the margins of the drawings, illustrate as much of the circuit organization 01" thecomplete system as is necessary for an understanding of the operation of the circuits.

Referring first to 1 this is a conventionalized perspective view of a part of the lay-out of such a system, in which are indi cated some of the switchboard sections, some of the line finder and cord selector frames, groups of call extending circuits betweenthe line finder and cord selector frames with their controlling circuits, the

' Patented Dec. 9, i919. application filed July 24, 1917. Serial No. 182,456.

cables extending from the cord selector frames to the operators positions on the switchboard" sections, and the subscribers line cables extending to the switchboard and to the line finder frames The line finder frames FF and FF are shown interconnected, by means of finder or call-extending circuits F, with corresponding cord selector frames SF SF? Each of the line finder frames FF FF serves as the terminal of a plurality of subscribers lines extending to the frame in the line cables LC, LC rcspectively, and each of the cord selector frames S1 SF serves as the terminal of a pli'zrality of connecting cord circuits, the conductors of which are carried in the cables 0G 06 0C QC to the various operators positions 1, 2 3 41-, etc, on the switch board SE. The line finder frames FF FF 2 and the cord selectorframesSFh, SF with their associated switches; may be of the type which is illustrated in Patent No. 1,1?7f0dl 'to James L. lvlctliuarrie, issued March 28, 1916, to which n'zore particular reference will be madehereinafter.

In the specific embodiment of the invention diagrannnatically represented in Fig. 1,

each ofthe line finder frames FF FF -may' serve as theterminal of five hundred; subscribers lines divided into ten groups of fifty lines each. On each sideior face of the line finder frame, and cooperating with the five hundred line terminals which are multipled to appear on both sides or faces,,there may be thirty elevators or movable switches, each serving as the terminal of an associated finder circuit F. Each of the cord selector frames SF SF- may serv as the'terminal of nineteen groups of connecting cord circuits, eachgroup containing the conductors of twenty-five connecting circuits extending by way of the cables 063 06 etc., from a different operators position. On each side or face of each cord selector frame SF SF there may be thirty elevators or switches, each serving as a terminal of one of the finder circuits F, the other terminal of which is a corresponding elevator on the corresponding linefinder frame FF FF Thus the five hundred telephone lines which ter minate oneach line finder frame FF FF have access by way of sixty finder circuits, arranged in two sub-groups of thirty finder circuits each, to the cord circuits of theentire group of nineteen operators positions, which cord. circuits are also multipled to the other cord selector frames and thus made available to the call-extending or finder circuits served by those frames. 7

Each line cable LC", LU LC etc., carrying conductors: of five hundred lines, terinin ates upon a difierent one of the line finder frames FF FF etc, and also extends to multlple spring iacks accessible to all of the operators at different positions of the switchqoard SB. It will be understood, of course, that only enough of the whole equipment is shown to illustrate the scheme of interconnection.

The finder 'or call-extending circuits F that extend between each finder frame FF and its associated selector frame SF, are divided into two sub-groups G and G The finder circuits of one of these subgroups may terminate upon the elevators upon the front of the two connected frames, and the finder circuits ofcthe other sub-group G may terminate upon the elevators on the back of the said f 'ames. Each finder circuit is provided with a finder sequence switch FSS through the medium of which the movements the associated elevators are controlled. Each line finder frame has starting apparatus SA common to the five hundred lines thereofiand the operative relation of this starting apparatus with thefinder circuits of one or the other, or both, of the subgroups fl and G is determined by-single group apparatus The single group apparatus SGA is represented diagrammatically as two normally closed switches, each of which has an. associated magnet for opening.

the switch. As shown, tue starting apparatus of the frame isn'ormally in operative relation with the finder sequence switches F SS of both sub-groups G and G Associated with each sub-group of finder circuits is an operators selecting apparatus GSA under the control of and controlling.

the finder. sequence switches of, the associated sub-groups, and also under the control of operators positions the'connecting circuits ofwh1ch termmate upon the cord selector frame SF; The'operatofs SGlGCtlIlg apparatus of each sub-group controls the telephone receiver from itshook operates the trip imxgnet TM corresponding with the group of fifty lines in which the calling sub-. scribers line is located. it also actuates the starting apparatusSA in, the common con trolling circuit associated with this line finder frame; and thestarting apparatus in operating appropriates one of the findercircuits F which has been preselected, and starts he line-finding elevator orswitch of that finder circuit hunting fort-he calling line.

If the single group apparatus SSA associated wi h the coi'rtrollinp; circuit of the finder frame FF is in its in all condition, the starting apparatus is in operative relation vrithboth subgroups G" and G of finder or LP, Li etc.

call-extending circuits F, and the elevator of whichever one of the finder circuits F has been preselected tor-taking the next call, is started. That is, the finder circuits of the two sub-groups, G" and G are working together as a single group of circuits, any one of which may extend the call of acalling subscribers line. It the operators selecting apparatus OSA of one of the subgroups is not operating properly, or it it is desired for any reason to throw the circuits of that sub group out of service, the switch of the single group apparatus SGA controlling the connection of the startingapparatus SA with that particular sub-group, is opened, thus operatively dividing the single group into two sub-groups and depriving the starting apparatus of control over the finder sequence switches of the circuits of that particular subgroup. 7

Assuming that the single group apparatus SGA associated with the finder frame F F is in its normal position, as shown, a preselected finder circuit in one or the other of the sub-groups G or G is appropriated and its line finder elevator started and brought into engagement with the terminals of the calling line. l t hen this happens, the finder sequence switch FSS of the finder circuit cooperates with the corresponding operators selecting apparatus USA of the cord selector frame Si to select an unengaged operators position, start the cord selector elevator 01 the appropriated finder circuit, trip the set of brushes corresponding with the selected operators position, and cause the brushes to find the te'rminals'ofan idle cord circuit of that position and make connection with them. The operator at the position selected, having communicated with the calling subscriber and learnedthe number of the line Wanted, completes connection with it by inserting the plug of the chosen connecting cordcircuit at her position into the spring jack of the called subscribers hne.

Referring now to the specific embodiment of the invention as illustrated in 2 to 7 inclusive of the drziwing, this embodiment is represented as comprising telephone lines extending froni'stations ash and A to stationary terminals upon the opposite faces or sides of a line finder frame lll the righthand side or front of the frame being served by a plurality of line finder-switches or elevators LF, LF', etc and the left-hand side or back of the frame being served by a plurality-of line fii'ider switches or elevators Each line has associated with it a: line relay l2 and a cutoff relay 11., and each group of fifty lines on the frame ha associatedwith it a common protective relay 149, and also certain group apparatus designated as LG and LG. The group ap pai'atus is connectedthrough the medium of conductors 57 and 58 with the starting and single group apparatus, which apparatus is common to all of the groups and to the five hundred lines terminating upon the line finder frame, and is shown in Fig. 4:. This common starting and single group apparatus is connected through the medium of the conductors 25, 26, 27, 28, 29, 78, 79 and 80 with the apparatus of the group o'l finder circuits F, F, F etc, associated with the line finder switches or elevators on the front of the frame. and through the medium of the conductors 25 25 26, 27,, '28, 29, 78, 79 and S0 with the apparatus of similar anamcircuits associatcd with the line finder elevators or switches on the back of the frame.

As the finder circuits F, F, F etc, are

alike, only one of them is shown completely. The finder clrcuits F, F, W, etc, terminate in cord selector switches or elevators CS,

7 CS, etc., and through the medium of these,

operating under the control of associated operators selectlng apparatus GSA, the finder circuits are adapted to have their connections extended to any one of the connectas illustrated, and may, terminate in a plug 170 which may be inserted in a multiple springjack 14 of a line extending to a called subscribers station A The multiple connection oi the circuits of the various operatorspositions with difi'erent cord selector frames, which is shown clearly in Fig. 1 of the drawing, is indicated in the circuit diagram by the stub connections shown at SF. These stub-connections be understood to represent connections of the same sort as are shown fully at SF in the circuit dia gram.

As heretofore stated, the line finder switches LF, LF, and the cord selector switches CS; CS, maybe substantially like the switch illustrated and described in Patent 1,177,044 to James L. McQuarr-ie, issued l ta'rch 28, 1916, The line finder and cord selector switches are alike in all substantial respects. Each comprises a longitudinally movable. shaft 1 carrying as many sets of brushes 2 as there are groups of stationary terminals to be engaged. To move the shaft up, an extension at the lower end of the shaft is brought into engagement with the constantly rotating power member 3 by means or" an idler wheel operated by the updrive magnet 32; and to move the shaft down, the extension is lie-ought into engagement with the power member l by means of 1 an idler wheel operated by the down-drive magnet 62. Normally the brushes ofeach of the sets 2 are held apart so as to clear the associated terminals by means of a, separat- I Each one ofthe conlit the timeenergized.

ing cam 5. located between the innermost brushes or the set. The cam. 5 is rotatably mounted, and when rotated in one, direction releases the brushes and permits. them to. .engage the associated terminals. The tripping or releasing or the brushes isjcontrolled by a number of trip magnets, as 16 and 17. Each of these when energized rotates an associated trip rod 6 that extends transversely to the switch shafts 1 and carries as many trip 0 a" yokes 7 as there are finder sw tchesin the group. The trip rod in. rotatingbringsall of its trip yokes 7 into position to operate the brush-controlling cams 5oi:' the corresponding sets of. brushes, on all of the.

switches, so that. Whichever of the finder switches is caused to moveup. has that set of: brushes tripped that corresponds with the particular trip magnet 16', 17 that is. at Whenthefinder switch; that has been in use is returned to its normal position, any of-the. associated controlling cams 5-tl1at has been tripped is engaged and rotated in a reverse direction to separate. its switch springs again and thus render them inactive. Each of theline fiiflfilerand cord selector switches has. associated with it a commutator 8v which comprises a number of stationary commutator segments and a set of movable-brushes carriedat the top of the switch shaft 1 and cocperating with the, stationary segments. This commutator serves to make and break a number oi? the control ling circuits in the various stages of .t-heupward-movement of the switch. shaft.

For controlling the, circuits of the. organiation there are employedv a number of sequence switches which are shown at different points and are designated 100, 200, 300, 500 and 600, respectively. These se quence switches may beef the type disclosed in. Patent 1,127,808, issued February 9, 1915, to Reynolds and Baldwin. Each consists of an electrosmagnetically controlled motor or driving mechanism and a number of associated switch cams. The switch cams associated with each of the. sequence switches 100 are-designated 101 to 103, inclusive; those associated with each of the sequence switches 200' are designated-with numerals between 201, and 228, inclusive; those. associated with each of the sequence switches 300. are designated 301 to 304 in elusive; those associated with the sequence switch 500 are designated 501 to 515 in elusive and those associated with the sequence switch 600 are designated 601 to 617 inclusive. To each of the contacts associated ,with the various sequence switchcams are applied certain numerals. These numerals in the case of the cams 101, 201, 301, 501 and 601 indicate the only positions of the associated sequence switch in which these particular contacts are open, the numerals applied to all of the othercOnQeQtS of each sequence switch indicate the only positions of the particular sequence switch in which the associated contacts are closed.

The sequence switches 100 merely act as timing switches andhave only one resting position. The resting positions of the other sequence switches, and the stagesv of operation with which these positions are associated, areas follows:

Sequence switch 200:

Sequence switch 300.

1. Awaiting. a call. 4... Position vacant. Positionbusy.

Sequence switch '500.

1. Finders in one group. 3. Front of frame shut down. 8. Awalting finders on regrouplng.

Sequence switch 600.

1. Finders in'one group. 3. Back of -frameshutdown. 8. Awaltmg finders on regrou-ping.

Theoperation of the system as illustrated in the accompanying drawings is as follows: When a- SLlbSCIIlOBI" calls, the taking of the telephone receiver from. its hook closes a.

circuit inthe usual way that causes the encrgization of the associated line relay 12 at he'central otlice. The line relay in operating closes a circuit that extends from battery through the winding of relay 19 of the group in which the calling line is located, contacts 103 (18%} to 111) of sequence switch 100 of that group, group conductor 18, and armature and 'front contact of line relay 12 to ground. Relay 19 in operating closes a circuit that extends from battery through the right-hand winding of relay 24, front contact and armature of relay 19, conductor 57, inner back contact and armature of relay 22, and left-hand back contact and armature of relay 23, to. ground. Relay 2a in operating closes a locking circuit for itself in its lefthand contact and armature and in doing so causes the operation of the associated tripping magnets 16 on the front and back of the frame, the energizing path for the tripping magnets and for the left-hand or locking winding of the relay 24: being, by Way of the left-hand front contact and armature of relay 2a, conductor 58, winding of relay 22, and right-hand armature and back consequence switch 100 out of position 1, whereupon the switch continues to rotate, under the control of its governing earn 101, until it completes its cycle and again comes to rest in positionl, the circuit by way of cam 102 (18 to 171;) opening in the meantime as a result of the release of the relay 2e. \Vhile the sequence switch 100 is rotating it maintains open in sequence switch contact 103 (18% to 111-) the connection of the relay 19 with the group conductor 18, so that during this period the relay 19 is not under the control of the line relays 12. During this interval the calling line is found and the line relay 12 deencrgized to remove the ground from conductor 18, as will hereinafter be described.

Included in thecircuit by way of conductor 58 closed upon the initiation of a call, as desr-ribed above, is the winding of the starting relay 22. This relay in operating closes the circuit of the starting conductor 129, and in doing so brings about the movement of a line finder switch in one orthe other of the two divisions or sub-groups of switches LF, L1 LF and LE that have access to the terminals of the five hundred lines in which the line assumed to be calling is located. The two divisions or sub-groups are preferably those on the back and front of the line finder frame, as already indicated; but if desired the switches may be divided into subgroups in any other convenient manner.

Associated with the relay 22 in the control of the finder switch starting operation, are the relays 23 and 33, and thecontrol of the starting operation is exercised through the medium of the conductors 125, 126, 127, 12-8 and 129. The operative relation between these conductors and the circuits and apparatus of the finder switches is under the control of the two grouping sequence switches 500 and 600 forming a part of the single group apparatus. Each of these sequence switches when it is operated serves to oirect the calls into the subgroup of finder switches with which it is associated, and excludecalls from the other sub-group. Thus when the sequence switch 500 is energized to move its cams into position 3, the calls originated in the five hundred lines of the associated frame are taken by the finder switches on the back of the frame and excluded from the finder switches on the front of the frame; when the-sequence switch 600 sequence switches and 600 are is energized to move its cams into position 3, the starting apparatus is operatively assoed with the finder switches on the front the frame to cause these switches to take the calls, while the switches on the back of the frame are cut off. l/Vhen both of the standing in position 1, the starting apparatus, includ ing the relays 22, 23 and 33, is operatively associated with the finder switches on both the front and back of the frame, these switches at such time acting as a single group in taking the calls originated by the associated 500 lines.

The manner in which the two grouping sequence switches 500 and 600 are operated, will be explained later. For the present, only the result of that operation upon the circuits extending from the starting apparatus will be described. When both sequence switches 500 and 600 are standing in position 1, the starting conductor 129 is connected by way of grouping sequence switch contact 612 (1) with all of the sequence switch contacts 206 (2) associated with the sub-group G of finder circuits F, F and F extending to finder switches on the back of the frame and is connected by way of grouping sequence switch contact 512 (1) with all of the sequence switch contacts 206 (2) associated with the sub-group G of finder circuits extending to finder switches on the front of the frame. In like manner, the conductor 12'? of the starting apparatus is connected by way of sequence switch contact 510 (l) with the sequence contacts 203 (3) of all-of the finder circuits on the front of the frame, and is connected by way of sequence switch contact 610 (1) with the sequence switch contacts 203 (3) of all of the finder circuits on the back of the frame. Conductor 126 of the starting apparatus is connected by way of sequence switch contact 514 (1) with the sequence switchcontacts 209 (2%} to 3) of all of the finder circuits on the front of the frame, and is connected by way of sequence switch contacts 61d (1) with the sequence switch contacts 209 to of all of the finder circuits on the back of the frame. Conductor 128 of the starting apparatus is connected by way of sequence switch contact 507 (1) with the sequence switch contacts 211 (3 to 3-1;) of all of the finder circuits on the front of the frame, and is connected by way of sequence switch contact 607 (1) with the sequence switch contacts 211 (3 to 35;) of all of the finder circuits on the back of the frame. Conductor 125 of the starting apparatus, when both sequence switches 500 and 600 are in their normal or 1 position, is c011- nected by way of sequence switch contact 616 (1), sequence switchcontact 515 (1), and sequence switch contact 615 (1) serially through the sequence switch contacts 210 to 1) of all of the tinder circuits on both sides of the frame and to ground at the end of the series.

When sequence switch 600 is operated to move its cams to position 8, sequence switch 500 remaining in position 1, the starting apparatus conductors 126, 127, 128 and 129 are left connected by way oi the cams of sequence switch 500 with trio cams 209, 203, 211 and 206, respectively, of the sequence switches associated with the finder circuits on the front oi the frame, and are cut oil', at the cams of sequence switch 600, from the sequence switch cams 209, 203, 211 and 206' associated with the finder circuits on the back of the tran'ie. In like manner the movement of sequence switch 500 into position 3, sequence switch 600 remaining in position 1, leaves the starting apparatus conductras 126, 127, 128 and connected by way of the contacts of sequence switch 600 with the switch can-is 209, 203, 211 and 206 associated with the finder circuits on the back of the frame, and disconnects them at contacts oi? sequence switrh 500 from the corresponding sequence switch cams of the finder circuits on the front of the frame.

The cutting out of the finder sequence cwitrh cam series 210 of the finder circuits on the back of the frame accomplished when sequence switch 600 moves into psition 3, by the discormecting at contact 615 (1) and 616 (1) of the part of the loop circuit extending through these cams, while at tie same time the conductor 125 is connected at sequence switch contacts 615 directly to the series of sequence switch cams 210 associated with the finder circuits on the front of the frame. The cutting out of the 210 cam series of the finder circuits on the front of the frame is accomplished when sequence switch 500 is moved to position 3, by disconnecting from conductor at sequence switch contact 515 (1) the part of the loop including the series associated with the front of the ilrumc, while at the same time a ground for the 2 cam series of the back or the frame is applied at sequence switch contacts 515 (3).

Thus, while'the conductors of the starting apparatus are opcratively associated with the finder circuits of both the front and hack of the frame when the sequence switches 500 and 600 are standing in position 1, the movement of either oi' these sequence switches to position 3 associates these start ing apparatus COlrCllluljOl'S exclusively with the finder circuits at the side of the frame corresponding with the sequence switch that is operated.

Continuing with the description of the operation of the system, it will be assumed that both of the sequence switches 500 and 600 are in their normal or, 1 position. For reasons that will-hereinafter be explained,

tends from battery through the left-hand winding oi. relay 30, conductor 67, sequence switch contacts 206 (2), conductor 29, se quence switch contact 512 (1), conductor 129, inner front contact and armature of starting relay 22, right-hand armature and back contact of relay 23 to ground. The right-hand winding of relay is at this time also included in parallel with the lefthand winding of the'relay in the energizing circuit, the parallel branch being from battery through resistance coil 56, sequence switch contacts 217 (2 to 9), right-hand winding of relay 30, conductor 241,sequence switch contacts 220 (2) and (1 to 13), thereat'ter joining the conductor that extends from the left-hand winding of relay. 30, and to ground over the circuit already traced. The effect of this is to give the relay 30 the benefit of the energizing action of both windings. Relay 30 in operating closes a locking circuit for itself that ex tends from battery through resistance coil 56, sequence switch contacts 217, (2 to 9), right-hand winding of relay 30, sequence switch contacts 216 (2 to 9), left-hand front contact and armature of relay 30, and armature and back contact of relay 52 to ground. Relay 30 also closes a circuit that extends from battery through the motor magnet and cam 202 (-2) of sequence switch 200, right-hand front contact and armature of relay 30, sequence switch contacts 208 (2 to 7), conductor 70, and segment M of the cord selector commutator and corresponding brush to ground. The closure of this circuit causes sequence switch 200 to move out of position 2 and come to rest in position 3.

In position 8 of the switch, a circuit is closed that extends from battery by way of the up-drive magnet 32 of the corresponding line finder switch LF, conductor 59, sequence switch contact 207 (3 to 1), front contact and right-hand armature of relay 30, sequence switch contact 208 (2 to 7), and to ground by way of segment M of the cord selector commutator. The energization of the up-drive magnet 82 starts the upward movement of the corresponding elevator rod with'its associated sets of brushes. At the outset ot'the upward movement of the elevator rod, all of the brush-trip levers are moved past the corresponding trip yokes. The only trip magnet that is energized in this case is the magnet 16 which corresponds with the group in which the calling line is assumed to be located; and consequently the only trip yoke in position to engage a trip lever on the elevator rod is the one which controls the brushes 40, 11, 42 and -13 that are adapted to engage the terminals of that particular group of lines. This set of brushes, therefore, is released and made operative, and the other sets are held clear of their associated line terminals.

As soon as the set of brushes corresponding with the calling line is tripped, the apparatus by means of which the lines control the brush-tripping and finder-starting operations, may be returned to its normal condition. The first step in this restoring operation is effected by theclosure of a circuit which is completed by way of the K segment of the line finder commutator immediately after the brushes are tripped. This circuit extends from battery in parallel branches through the relays 23 and 33 (see Fig. 4:), conductor 126, contact 51 1- (1) of grouping sequence switch 500, conductor 26, finder sequence switch contacts 209 (2% to 3) of finder circuit F, conductor 68, and to ground by way of ,K segment of the line finder commutator and its associated brush.

The energization of the relay 23 interrupts,

in the right-hand back contact of that relay, the previously described circuit that has up to this time maintained. the energization of the trip magnets 16, the group relay 2 1 and the common starting relay 22. Relay 23, in its left-hand front contact closes a locking circuit for itself and the associated relay 33 thatextends by way of conduct-or 125, contact 616 (1) of grouping sequence switch 600, in series through the sequence switch contacts 210 to 1) of all of the finder circuits of sub-group G associated with the back of the frame, grouping sequence switch contact 515 (1), grouping sequence switch contact 615 (1), and in series through contacts 210 (2% to 1) of all of the finder circuits of sub-group G associated with the front of the frame to ground at the end of the series.

As has already been stated, normally there is only one of the finder circuits of all which serve thisframe that has its sequence switch in position 2 awaiting the :receipt of a call. Nhen the call comes in, this sequence switch is immediately moved tov position 3 by the energization of relay 30 in the manner already described. Therefore, at this stage of the operation the sequence switches of all of the finder circuits, being either in position 1 or in position 3 and beyond, are in position to close their contacts 210. The locking cireuit'for the relays 23 and 33 istherefore heldclosed by way of the 210 cam series until another one of the finder circuits has its sequence switch moved into position 2 to break the locking circuit in the associated cam 210. This is accomfinder circuit F in sub-group associatec -with the back of the frame is in position 1,

and that the sequence switch of finder circuits F and F of sub-group G are in same position between 4 and 17, these finder cir cuits being assumed to be in use, the operation of'the relay 33 completes a circuit from battery through the motor magnet and contact 203 (l) of the sequence switch of finder circuit F of sub-group G2, contacts 211 (1.) of the same sequence switch, contacts 211 (3 to 17) and (4 to 17 of sequence switch 200 of finder circuit F of sub-group G contacts 211 (3 to 17 and (A to 17) of sequence switch 200 of finder circuit F in sub-group G grouping sequence switch contact 505 (l), grouping sequence switch contact 606 (1), contacts 211 (3 to 17) and (3 to 3-1;) of sequence switch 200 of the finder circuit F of sub-group G (the finder circuit that has just been appropriated), grouping sequence switchcontact 507 (l), conductor 128, and

left-hand front contact and armature of relay 33 to ground. This causes the sequence switch of. finder circuit F of sub-group G to move into position 2. At the same" time the sequence switch of finder circuit F is moved out of position 3 by the closure of a circuit that extends from battery through the motor magnet and contacts 203 (3) of the sequence switch of that circuit, conduc tor 27, grouping sequence switch contact 510 (1), conductor 127, and right-hand front contact and armature of relay 33 to ground. As soon as the sequence switch of finder circuit F of sub-group G? moves into position 2, it opens in its contacts 210, the previously described circuit by way of conductor 125, which up to this moment has maintained relays 23 and 33 energized, and these relays thereupon release their armatures, Relay 23 in releasing reconnects to ground the circuit which extends in branches 57 and 58 through thevarious sets of line. group relays LG, LG, thus againgiving the line groups access to the starting circuit.

At this stage of the operation of the system, the sequence switch of the appropriated finder circuit F of sub-group G is in position 1, and the elevator rod of the associated line-finder LF is moving up, with the set of brushes tripped that corresponds with the group in which the calling line is located. As the tripped brushes rise, they come into engagement successively with the sets of contacts corresponding with the different lines of the group. At the instant of engagement of the brush 13 with the terminal 17 of each line, the test relay 52 of the finder circuit is connected with local conductor of that line. This local conductor has two branches, one or the other of which is closed depending upon the condition of the l1ne relay 12 of the associated line. If the line relay is inert, as it is when the line is not calling, or when the line has been connected with and its cut-off relay operated, the local conductor 65 of the line is connected with ground by way of an identifying device 150 and a relatively low potential battery. If the line relay 12 is energized, as it is when the line is calling and is not connected with, the local conductor 65 of the line is eonnected with ground by way of the right-- hand back contact and armature of the protective relay 1 19 connnonto a group of lines, the energizing winding of this relay, and a relatively high potential battery.

Therefore, as the elevator rises and the brush 43 engages the corresponding terminal 47 of each of the lines of the group in which the calling line is located, a circuit is completed as each line terminal is engaged that extends either by way of the low potential battery, the device 150, and the left-hand back contact and armature of relay 12, or by way of the high potential battery, the winding of common relay 149, the right-hand armature and back contact of that relay, and the right-hand front contact and armature of relay 12 to the local conductor 65 of the line; and thence by Way of the line terminal l-7, brush 13, conductor 51, finder sequence switch contacts 215 (1 to 8) and (2%} to 41), and winding of relay 52 to ground.

The relay 52 is so adjusted that it will respond only to the current flow produced in the circuit by the high potential battery, and not to that produced by the low potential battery. As the line relay 12 of the calling line is energized, thus connecting the high potential battery to the associated local conductor 65, the test relay responds when the brush 43 engages the terminal? of the calling line. The response of the relay 52 causes that relay to interrupt in its back contact the previously-traced circuit by way of the left-hand armature and front contact of the relay 30, sequence switch contacts 216, and right-hand winding of relay 30, which circuit had been holding the relay 3O locked up from the moment that the relay was first energized upon the receipt of the call. Relay 30 in releasing its armaturcs breaks its own locking circuit, and also breaks the previously-traced path, including sequence switch contacts 208, right-hand armature and front contact of the relay 30, and sequence switch contact 207, over which current has been flowing to energize the updrive magnet 32 of the'line finder. Therefore, the'operatioir of the relay. 52'upon the finding of the calling line acts to effect the instant deenergization of the Lip-drive magnet 82, and thusto stop the brushes upon the terminals of the calling line.

When the relay 30is de'elnergized, as a result offinding the calling-line, it also completes a circuit hat extends from battery through the motor magnet and contact 202 (-3 to 1) of the vfinder sequence switch, righthand back contact and armature of the relay 30, sequence switch contact 208 (2 to 7), conductor 70, and M segment and corresponding brush of the cord selector CS to ground. The closure of this eircuit'moves the sequence switch out of position 4. V

When finder sequenceswitch reaches position 4%}, it closes a path for theflow of current through the cut-off relay 11 of the eallingline, by way of resistance'coil 6 1, sequence switch contact 212 (4-2- to 12%), conductor 50, brush 42, line terminal 46 and conductor 53. The flow of current in this circuit operates the cut-off relay 11 to disconnect the relay 12 from the circuit, and that relay in releasing its armature disconnects the high potential battery from the local conductor 65 ant disconnects ground from the common conductor 18. The disconnection of ground from conductor 18 occurs before the timing sequence switch 100 has completed its cycle of rotation and reconnected conductor 18 with relay 19.

The brushes of the line finder switch are now at rest in engagement with the terminals of the calling line; the group starting circuit represented by the conductors 57 and 58 and the associated relays 22, 23 and 33 has been released and is in readiness to respond to another calling line, and the sequence switchof another finder circuit has been moved into position 2, and thus brought into operative relation with the starting conductor 129.

The starting of a finder switch and the seizing of a calling line having been de scribed, it may be well at this point to consider the manner in which the shutting down of one side of the frame and the directing of the calls exclusively through the circuits associated with the other side of the frame, is effected.

The shutting down of the front of the frame is effected either by closing the circuit of the conductor 80, in a manner that will hereinafter be described, or by operating the switch or key 143. The shutting down of the hack of the frame is effected either by closing the circuit of the conductor 80, in a manner that will hereinafter be described, or by operating the switch or key 1 14. It will be assumed in the present instance that it is desired to shut down the back of the frame in order, for instance, that repairs may be made upon certain of the switches associatedwith that side of the frame. The key 14% therefore is operated, and as a result a circuit is completed that extends from battery through the winding of the relay 136 and to ground by Way of contacts of the key 1 14. The relay 136 in operating closes a circuit that extends from battery through the winding of the relay 134, single group sequence switch contact 604 (1) single group sequence switch con tact 513 (1), right-hand front contact and armature of relay 136, conductor 140,and outerback contact and armature of starting relay 22 to ground. If at the time in question the starting apparatus is engaged in starting a finder switch, the starting relay 22 will be actuated, and the circuit traced above therefore will be open at the contacts of relay 22; but if the starting apparatus is not acting, the completion of the circuit traced above causesthe operation of relay 134:. When relay 134E operates, it closes a locking circuit for itself that extends from the winding of relay 134 to ground by way of sequence switch contact 60 1 (1) and the right-hand armature and front contact of relay 1341-. Relay 1341 in operating also closes a circuit that extends from battery through the windings of the relays 23 and of the starting apparatus in parallel, conductor 126, and front contact and righthand armature of relay 134 to ground. Re-

lay 23 in operating opens, at its left-hand armature and back contact, the path to ground of the conductors 57 and 58 over which the control of the starting relay 22 by the calling lines is exercised, so that as long as the relay 18 1 is energized the starting apparatus is unresponsive to a calling line. The other connections controlled in the attraction of the armatures of the relays 23 and 33 do not effect any operative change at this time. Furthermore, relay 134; in operating closes a circuit that extends from battery through the winding and contact 602 (1) of single group sequence switch 600, and toground by way of the left-hand front contact and armature of relay 134. Sequence switch 600 thereupon moves its cams to position 3, and in this movement the energizing path for the relay 134 is broken at sequence switch contact 60 1, and relay 134: becomes inert. The movement of single group sequence switch 600 to position 3 disconnects the starting apparatus from the finder circuits F, F and F of sub-group G associated with the back of the frame, and leaves the starting apparatus associated exclusively with the finder circuits of subm group a on the front of the frame, as has hereinbefore been described.

At the time this change is effected. it may happen that the finder circuit next in order to be appropriated by a. calling line, as determined by the standing of its sequence switch 200 in position 2, isin the sub-group to more into position 2 the sequence switch.

200 of one of the finder circuits in sub group G associated with the front of the frame. This is effected through the medium of the 222 cam series of the fin-g er circuits of subgroup G, and the associated relay 13 Under the conditions assumed, all of the sequence switches 200 of the finder circuits of sub-group Gr are either in position 1 or are in position 5 and beyond. A circuit therefore is completed that extends from battery through the winding of relay 138, single group sequence switch contact 505 (1), conductor 7 9, and the contacts 222 (5' to 1) of all of the finder sequence switches of the subgroup G to ground at the end of the series. The relay 138 in operating applies a ground by way of single group sequence switch contact 606 (3) to the loop that includes the sequence switch cams 211 of all of the finder circuits of sub-group G, to move into position 2 one of the sequence switches of this series that is at the time standing in position 1. If it be assumed that finder circuit F of subgroup G is in use,'with its sequence switch therefore standing in some position between 4 and 17, and that the sequence switch or finder circuit F is standing in position 1, when relay 138 operates a circuit cou1- pleted that extends from battery through. the motor magnet and contact 203 (1) of the sequence switch of finder circuit h" of sub-group G, contacts 211 (1) of the same sequence switch, contacts 211 (3 to 17) and (4 to 1'?) of sequence switch 200 of finder circuit F conductor 78, sequence switch contact 606 (3), and front contact and armature of relay 138 to ground. Therefore, as soon as grouping sequence switch 600 moves into position 3, the sequence switch of a finder circuit of the associated subgroup G is moved into position 2, where it stands in readiness to respond to the closure of the starting conductor It may here be pointed out that when both single group sequence switches 500 and 600 are standing in position 1 the sequence switch cams 211 of each sub-group G and G are united with each other in a single series, the associated finder circuits thus operating as a single group. Contact 211 (3 to 17 of one sequence switch is joined to the contact 211 (4 to 17) of thenext sequence switch of the series; the contact 211 (3 to 17) of that sequence switch is joined to the contact 211 (4; to 17) of the next sequcnce switch of the series; and so on to the last 211 sequence switch cam of the group, at which point the contact 211 to 17) of one sub-group is connected by way of cams of the single group sequence switches to the contact 211 (4 a) 17} of the tact 6(5 (1), and the ill. ii

first sequence switch of the other subgroup. lVhen the single group sequence switches 500 and 600 are standing in position 1, and the two sub-groups are thus working as a single group, thee-losing oi? the cam series of both sub-groups at the same time acts to apply a ground to the above do- Sl'l'lbl'll circuit including the 211 cains of all of the sequence switches of: both oi the sub groups, the elieet of this ground being to move the sequence switch 200 01 some one of the finder circuits in the two sub-groiqis l and G that happens to be standing in position 1, out 01 that position and into position 2. Thus when all 02"? the sequence switch canis 222 of the finder circuits of sub-group G are in some position from 5 to 1 inclusive, a circuit is completed for the energization of relay 138, as already described. At the same time it the cams 222 of all o1 the sequence switches 200 sub-group (l are standing in some position from 5 to 1 inclusive, a cir uit is closed that extends from battery through the vindingo't relay 137 single group sequence 1 itch coir 222 cam s of subgroup G to gri'iuiid' at the end of the series. The completion of both oi the above traced circuits e'l'lects the energization of the associated relays 1' 8 and 137, and these relays iiroperating apply a ground to the circuit including the 211 rains of both sub-groups. this path extending from ground by way oi the armature and front contact of rehty 138i right-hand armature and front contact of relay 137, grouping sequence switch contact 608 (1), and grouping sequence switch con tact S The ground path thus upplied is connected over the 211 cani series by way oi single group sequence contact (1), single group sequence switch ceutac, 609 (1), conductor 7 8, and thence throu the 211 to 17) and (3 to 17) contacts of one after the other of the busy sequence switches of the series until a sequence switch standing in position 1 is encountered where the ground becon'ics eliective by way of contact-s 211 (1) and 203 (1) of that sequence switch to energize the motor magnet 01!? the switch. If none of the sequence switches of sub-group G is standing in position 1, then the ground is communicated to the s quence switches of subgroup G by w y oi contact 211 (4: to 17) and (3 to 17) oi? finder circuit ll of sub-group G, single group se quence switch contact (306 (1) and single group sequence switch contact 506 (1). When the single group sequence switch 600 moves to position 3, the 211 cain series-oi? the associated subgroup G is connected at sequence switch contact 617 (3) in a closed loop, with a controlling: path to ground at the contacts of relay 138 byway 01? sequence switch contacts 606 and at the same time the 211 cam series of subgroups G the sub-group G sumiug that the starting relay is connected in a closed and independent loop by way of single group sequence switch contacts (509 (3), with a controlling path from this loop by way of sequence switch contact 605 and the 222 cam series of in an exactly. similar manner, the movement o't single group sequence switch 500 to position 3 connects the 5211 cam series of subgroup in a closed loop at sequence switch contact 508 and the .211 cam series oil sub-group G into a closed loop at sequence switch. contact 509 (C3), the first mentioned loop having a controlling path to ground at the left-hand tlirout contact and armature of relay 137 by way oi sequence switch Contact 506 and the other loop having a controlling path to ground by way of the cain series oi. sub-group (l andsequence LCll contact 505 Thus the effect of moving either of the single group sequence switch es into position 3 is to dir' e into two independent loops the series preseleeting circuitaot the finder circuits of the frame, and provide each of these loop circuits with its own con trolling vpath governed by the series of finder elreuii'is oi the iorresponding rub-group.

llnd r the assumption that the shutting down of the back of the frame and the dircctin gg of the calls through the circuits 'asscciuted with the front of the frame was etl'ec'ted by the throwing of the switch or key 'l-ll, the buck of the fraineniay again be restored. to service, and the sub-groups G and G again operated as a single roup by returning the hey ll t to its normal posi tion. i l hen key 144: is thrown back so to open its left cmtact and close its right contact, the cum mug circuito't the re 136 is lu-oken and the relay releases its llETHLt-IIYO. l his closes a ircuit that extends "from battery through the winding oi: Y 134- 'see'guence switch contact 604- (3 to Sill, back contact ant; armature of relay 13G (*onilu tor 1&0, and outer back contact and armature of starting relay to ground, the control of this circuit in the ing contacts oi? relay being in order that the regrouping operation may not take place while the starting apparatus is a i As- 7 is inert the closure of the aborc traced circuit operates the rela 13-11. This relay in operating closes a locking circuit for itself by w of grouping seipienzie switrh (on ct (3 to l), right-hand front cont ct and arn'iature 3-1 to ground, llelay in opaiso closes a circuit that extends iattery through the motor magnet and t 602 (3) 0'1" iping sequence switch of the l tbhan l rein l ntac or (300, ane to ground by w moves out of position 3 and. comes to rest in position. 8.

The grouping sequence switch 600 is held in position 8 subject to the control of the finder circuits of sub-group G which cirunits will be brought into operative relation with the starting circuit by the movement of sequence switch 600 from position 8 to position 1. It may have been when the large group was divided into two subgroups and sub-group G' rendered inoperative by the movement of sequence switch 600 out of position 1, that the finder circuit preselected to take the next call and with its sequence switch standing in position 2, was one of the finder circuits of sub-group G It the reuniting of the two sub-groups into one large group by the movement of sequence switch 600 from position 3 to position 1, occurs while the sequence switch 01 one of the finder circuits of sub-group G is in the preselected or 2 position, then, inasmuch as the sequence switch of one of the finder circuits of sub-group G is also in position 2, the first call after the two sub-groups have been thrown together again, would result in the starting of two finder switches. There fore sequence switch 600 is held in position 8 until any sequence switch of sub-group G that may be standing in position-2, lSlHGVQCl out of this position. This result is accomplished in the following manner; When grouping sequence switch 600 reaches position 4i in its movement to position 8, a circuit is closed that extends from battery through the windings of a pair of trip magnetssay, the magnets 17, on the associated line finder frame, conductor 130, grouping sequence switch contacts 611 (4 to 8), and resting contacts 01"- he i 144 to ground. At the same time a circuit is closed that extends from battery by way of the left-hand winding of relay 300i the finder circuit of sub-group whose sequence switch is standing in position 2, conductor 67, finder sequence switch contacts 206 (2), grouping sequence switch contact 611 (4 to 8), and to ground by way of the resting contacts of key 144.

The result of the closure of these circuits is that sequence switch 200 of the corresponding finder circuit of sub-group G is moved into position 3, the corresponding line finder elemtor started up, and the set of brushes tripped that is associated with the group controlled the trip magnets 17, all

= in the manner that has hereinbetore been described. As the starting of the line finder elevator is not the result of a call initiated by one of the lines of the group, no circuit is closed for the energization of the test relay 52 as the brush 13 successively engages the terminals at? of the lines 01" the group, but above the last set of line terminals is placed a set of terminals 193, the test terminal of which is connected with a relatively high potential battery by way of the righthand back contact and armature and the winding of a protective relay 14:5. i lien therefore the set of brushes rises to the point where the test circuit thus completed, the test relay 52 is energized, stops the brushes in engagement with the set or terminals and moves the associated sequence switch 200 to position 6 in the manner that has already been described. The sequence switch is moved from pos' ion 6 to position 7 when relay 30 is energized by the completion of a circuit controlled by the operators selecting apparatus and by the 219 cam series of the finder circuit sequence switches, in a manner that will hereinafter be described. \Vhen the sequence switch reaches position 7, a circuit is closed that extends from battery through the motor magnet antL contact 22% (7 to of the finder sequence switch, conductor 120, and to ground by way of mc-nt Z and the corresponding brush of the line finder commutator, this segment being grounded by its brush when the elevator has risen to the point where the line brushes engage the set of terminals 193. The closure of this circuit moves the finder sequence switch 200 through position 15 and allows it to come to rest in position 1". In position 16 a circuit'is closed, as will hereinafter be described, that returns the line finder cle \ator to its normal position, after which another circuit is closed that moves the finder sequence switch 200 to position 1. Thus the movement of the grouping sequence switch 600 out of position 3, in the cess of re turning that switch to its normal position 1, returns to its normal position the apparatus of any finder circuit of subgroup G which may have been preselected to take the next call at the time when the subgroup G was disconnected from the starting apparatus.

As soon as the sequence switch 200 of the preselected finder circuit of sub-group (i has been moved as far as position 5, in the course of the operation described above, all of the sequence switches of the finder circuits of sub-group G are in some one of the positions from 5 to 1 inclusive, and therefore the 222 cam series oi"; sub-groin G is closed. As soon as the series circuit of the cams is closed, a circuit is completed that extends from battery by way of the motor magnet and contact 602 (8) of the grouping quence switch 600., and the 222 cam series of sub-group G to ground at the end of the series. The grouping sequence switch 600 thereupon moves out of position 8, and corn tinues to move under the control of its com 601 until it reaches its normal or 1 position, in which position the starting apparatus is again connected with the finder circuits oi? sub-groups G In moving out of position 8, the grouping sequence switch 600 breaks at its contacts 604i- (3 to 9) and (3 to the energizing paths o'lf 1'elay 134. That relay thereupon releases its armatures, and at its left-hand armature and inner front contact opens the connection of conductor 126 with ground. This ground connection operated while sequence switch 600 was moving from position 3 to position 8, and while it was standing in position 8, to energize relay 2% of the starting apparatus and thus dcprirc the lines of the associated finder frame of control over the starting apparatus.

The foregoing description has been direct ed toward the cooperation of the key 14 1-, the relays 18 i and 136, and the grouping sequence switch 600 in shutting down the back of the frame and directing the calls exclusively into the sub-group G of finder circuits associated with the front of the frame. The key 1 13, the relays 133 and 135, and the grouping sequence switch 500 ccoperate in an exactly similar manner in of fecting the shutting down of the front of the frame and the directing of the calls e3;- clusively into the subgroup G of finder circuits associated with the back of the frame. If it should happen that one side of the f 'aine shut down when conditions arise that would ordinarily lead to the shutting down of the other ide of the frame, in the manner described, the arising of this condition, instead of bringing about the movement to position 3 of the grouping sequence switch that is standing in position 1, brings about the operation of the relay 23 of the starting apparatus to block all calls by opening the path to ground from conductors 57 and 58. Thus, for instance, if the grouping sequence switch 600 has been moved into position 3 to shut down the back of the frame, and a condition arises that causes the energization of relay 135 and would ordinarily lead to the movement of sequence switch 500 to shut down the front of the frame, the ground that this relay applies at its armature and front contact is effective by way of grouping sequence switch contact 618 and conductor 126 to bring about the energization of relay 23,- and that relay in operating opens at its right-hand armature and back contact the path to ground of the conductors 57 and 58, thus keeping all calls blocked as long as this condition continues.

In the foregoing, the keys or switches 1 1- 1 and 143 were described as the means for causing the operation of the grouping sequence switches to bring about a dividing of the large group into sub-groups, and the operative connection of one or the other of these subgroups with the starting circuit. In the system of this illVQlltlOH, the grouping operations are also under the automatic control of operators selecting circuits and apparatus associated with the finder circuits of the two sub-groups G and G this con-- trol being exercised by way of the conductors SO and 80 respectively. In order to make clear the nature of this control, the operation of the system involving the selection of an operators position and of an idle connecting circuit on that position will now be described.

i l 'hen the sequence switch of the lindcr circuit over which the call. is being extended has reached position 6, as hereinbefore described, the finder circuit is brought into operative relation with the operators selecting circuit. lVhen the finder sequence switch reaches position 6, it awaits the closing of a circuit the completion of which is dependent upon the condition of the other finder circuits of the associated sub-group. This circuit extends from battery through the left-hand winding of the relay 30, conductor contact 219 (6) of the appro- 1')11{113Cl circuit sequence switch, contacts 219 (9 to 1-) of the sequence switches of the associated finder circuits of sub-group G preceding it in the series, conductor 76, outer armature and back contact of relay 5st, and right-hand back contact and armature of relay 61 to ground. A. branch path for the energization of the relay 30 also exists at this time, this branch path extending from battery through resistance 56, sequence switch contacts 217 (E2 to 9), right-hand winding of relay 30, conductor 241, sequence switch contacts 220 (6) and (1 to 13), and contact 219 (6) of the appropriated finder circuit sequence switch, from which point it extends to ground at the right-hand back contact and armature of the relay 61 over the path already traced. This circuit for the energization of relay 30 is open either in the cam 219 of a preceding finder sequence switch in the series, or in contacts of the relay 5% or 61 as long as any sequence switch of the series is in positlons i to 9. That is, 1t is open from the tune the line finder switch of any associated finder circuit finds a calling line until the cord finder switch of that circuit has moved far enough to trip the brushes corresponding with. the selected group, as will be described. has occurred will the above-traced circuit of the awaitingfinder circuit be closed. When the circuit is closed, the relay 30 attracts its armatures and completes a circuit that extends from battery through the motor magnet and sequence switch contact 202 (6 to 7) of the sequence switch 200, right-hand front contact and armature of relay 30, se quence switch contact 208 (2 to 7), conductor 70, and segment M and corresponding brush of the cord selector commutator to ground. The completion of this circuit moves finder sequence switch out of position 6.

When the sequence switch 200 reaches no Not until this i sition it closes a circuit that extends from battery by war-, of the Wll'lCllIlg of relay (Fig. conductor Tl, sequence switch contact (6%; to E3), conductor 24-2., ceiiductor 66, and segment M and correspoiuliug brush of the line finder commutator to ground. The operation of the relay applies ground to the conductors 81 extending to all of the operators positions. At each of the positions where the operator is at her station and in readiness to receive a call the associated relay 91 (Fig. 7) is inert, and the operatofs telephone sequence .ll'Cll 5-390 is in its 1 posi .on. Conse yuently -'t each of such positions; a circuit is closed that ex tends from battery, through the winding of the associated relay armature and back contact of relay 91, nequence switch contac 39% '(1), conductor 81, inner armature and front contact of relay to ground. relay 92 of each awaiting position therefore attracts its armature and closes a circuit that extends from battery, through the front Contact and armature of the relay 92 to the conductor 82, and thence to ground by way of the windings of the relays 77 corresponding to operators posit on at the YilllOllS cord selector trainee.

ll hen the finder sequence switch 200:

reaches position T in which position it comes to rest, it closes a circuit that extends from battery through the winding of relay 54., leftdiand back contact and armature of 61, conductor 73, finder so uence 1 contact ('l to 8), conductor 2&2, ctor 6G, and segment M and corresponding brush of the line finder eonnnutator to ground. Relay o-l attracts its armatures and completes a branch of thecircuit traced above. which branch extends rein conductor T3 by way of the left-hand arenas lure 2 nd back contact oi the relay 91, arreature and front contact of relay (33, front contact and inner armature of relay 5%, armature and front contact of relay 77, (which relay is energized, as previously dcscribed as a result of the corresponding operators position being in rez'idiness to receive call), right-hand bacl; con d s "itch spring-of relay 93 of the corresponding; group winding: of associated relay 9-l, winding of relay 93, left-bane itch spring and iodin contact 035 relay 93, conductor Sihleft-hand back contact ant armature of r y 95 at the O operato i"s position to hatte Upon the closure of the above-traced branch circuit group relays 93 and 9d are energized in parallel with the relay 5%. R4 lay 93 in operating disconnects its own ener izing winding and that of relay 9% from the previously traced path to battery by way of the left-hand back contact and armature of relay 95. and connects them in a path which extends to battery by wayoi" conductor S4; and the winding of the relay 95. This causes the relay 95 also to he energized and to interrupt in. its left-lumd armature and back contact the path by Way of conductor 83 over which the relays 93 and 94 were initially energized.

lzlelay 94: in operating closes a circuit from through the ra'inding of the trip magnet 20 corresponding to the selected operatofs position and to ground by way of the right-hand armature and front contact of the relay 9i. This relay also closes a circuit that extends from battery through the winding oi the relay 63 and the lefthand armature and front contact of the relay 94.: to ground. The relay 63 in operating closes a branch. that extends from the con ductor "4'3 (grounded at contact 228 (7 to 8) of the line finder sequence switch) through the armature and front contact of relay 63, conductor 72, sequence switch contacts 220 (7} and (l to 13), and left-hand winding of relay 30 to battery. A branch energizing path :tor relay 30 also extends from conductor F2 by way of sequence switch contacts 220 (7), conductor 2 1-1, right-hand winding of relay 30, sequence switch contacts 217 (2 to 9),a11d resistance 56 to battery. Relay 30 attracts its armatures and closes a circuit that extends from battery through the motor magnet and sequence switch contact 202 (6 to 7), front contact and right-hand armature of relay 30, sequence switch contact 208 (2 to 7), conductor 70, and segment M and corresponding brush of the cord selector commutator to ground. The closure of this circuit moves sequence switch 200 out oi": position 7. rliurtherinorc rela I 80 in o aeratin J 3 1'5 is locked up over a circuit that extends from battery through resistance 56, sequence snitch contacts 217 2 to 9), right-hand winding of relay 30, sequence switch con tacts 216 (7 to 9} and (2 to 9), front contact and left-hand armature of relay 30 and armature and back contact oil relay to ground.

W hen the selpience switch reaches position 8 it closes a circuit that starts the up'=. ard increment of the brush-carrying rod of the cord finder switch, this circuit extending from battery through the up-drive magnet 34: oi the cord finder, conductor 89, sequence switch contact 207 (8 to right-hond front contact and armature of relay 30, sequence switch contact 218 (8 to conductor 66, and segment M and corresponding brusl'i oi the line-finder commutator to ground. At the outset of the upward movement of the cord finder brush red the tripping levers oi" ti o -vai'ious sets of brushes are brought simultaneously into operative position with respect to the corresponding tripping yokes, and that set of brushes is tripped and made operative whose trip magnet is at the time

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