US1553452A

US1553452A - Semiautomatic telephone-exchange system

Info

Publication number: US1553452A
Application number: US336401D
Authority: US
Inventors: James L Mcquarrie; Albert M Bullard
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1906-09-27
Filing date: 1906-09-27
Publication date: 1925-09-15
Anticipated expiration: 1942-09-15

Description

Sept. 15, 1925. 1,553,452.

J. L. M=QUARRIE ET AL H1od Sopt. 27, 1906 8 SheetsSheet 6 Sept 15. 1925( J. L. MQUARRIE ET AL SEIIAUTOITIC TLPHONE EXCHANG SYSTEH m.a Sopt. 27 1906 8 SheetsSbeet 1 Sept 15, 1925.

1,553,452 J. L. M QUARRIE ET AL SEIIAUIIATIC TLPHONE EXCHANGE SYSTEM l11od Sept. 27, 1906 8 SheetsSheet 8 Illh ateatcd Sept. l. 1925.

-ninrn i s n nz Pntanr onnaca.

JAMES In. MOQURRE, 0l 0AK PARE, ILLINOIS, AND ALBEBI M. BULLARD, OF NEW "Z0RK, N. Y., ASSIGNORS, BY MESNE ASSIGNMENTS, T0 WESTERN ELECTRIC COM- EANY, NCORPOB'IED, A CORPORATION OF NEW YORK.

SEMIATOMTIC TELEIHONE-EXCHANG SYSTEM.

Apiflicatiom flled Septemoer 27, 1906. Serial No. 336,401.

To all whom it may 00mm:

Be it known that we, JAMES L. MOQUAR- RIE, of Oak Park, in the county of Cook and State of Illinois, and LBERI M. BULLARD, of New York, in the county of New York and State of New York, citizens of the United 'States, have invented a certain new and useful mprovcment in Semiautomatic TelePhone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

urinvention relates to a telephone exchange system Wherein the operator at the central oflice answers the call of a subscriber in the usual way, by uniting her connecting circuit with such subscribers line, and mechanical switching mechanism completcs the connecti on by uniting the connecting circuit with the called line. The ob3ect of our invention is to lessen the labor of the operators and so to decrease the number of operators required in an exchange, t0 render it unnecessary to employ trunking operators, and to make possible great speed and precision in establishing connections.

In our system the operator is provided With a sending apparatus which she may set to determine the operation of the said mechanical switching mechanism, t0 cause the latter to automatically unite her connecting circuit with the proper called line. A number of exchangcs may be provided, at each of which a number of telephone limes are centered, trunk fines extending between the exchanges. The operator, at each ex change is provided with sending apparatus having keys representing the diflerent offices or exchanges, and decimal digit-keys representing the thousands, hundreds. tens and units digits of subscribers limes. The operator at an exchange, after answering a call by uniting her connecting circuit With the calling line by means of a cdnnection switch, operates a key representing the oflice where the line with which connection is desired termiriates, which may be the local or a distant oflice, and also keys representing the digits of the called subscribers line. The oflice key selected brings into service mechanism which automatically unites the operators connecting circuit with an idle trunk line leading to the desired ofiice, and the digit keys thereupon cause the operation of' mechanism at the selectcd oflice for uniting said trunk line with the line o-f the subscriber with whom conversation is desired.

A. feature of the invention consists in the arrangement whereby the stepping or operating magnets of the line switching mechanism are caused to operate With the stepping or operating magnets of the sending apparatus'by Ineans of pulsatin,g current, the sending apparatus being arranged to cut off such pulsating current from its own magnets and the switching mechanism magnets when the desired connectionshave been established. The operation of the sending apparatus is controlled by the manipulation of the ofiice and digit keys referred to, which, when once depressed, are locked in such position under the control of release magnets, circuits for said magnets being automatically completed when the Switching mechanism has completed the connection of the calling line With the desired line, the entire sending apparatus being at this time automatically restored to normal condition.

Another eature of the invention consists in the provision of a test conductor in association with the line connector, the continuity of this conductor being automatically completed when the connector reaches the terminals of the called line. The said conductor includes a relay which is responsive in case the called line is free to complete the continuity of the talking conductors and dis-associate the local apparatus ofthe connec tor therefrom, said relay, in case the caHed line is busy, being unresponsive and serving to enable a locking circuit to be completed for a test relay, which connects a busy test apparatus with the trunk and connecting circuits, t0 notify the operator and calling subscriber that the line of the called party is in use. Said busy test apparatus causes a characteristic tome in the operators telephone. and may also cause a peculiar fiashing of the operators super-- visory lamp.

A further feature of the invention con sists of the arrangement whereby in case the called partys line is busy when tested, the connector used in establishing the connection will be immediately restored t0 normal condition. This may be accomplished by the busy test relay above referred to, which when included in its locking circuit may open the circuit of the retaining magnat of the connector, permitting the restoration of the apparatus thereof to normal condition. The operator upon opening her connection switch in response to the busy signal, elfects the automatic restoration of the remaining switching mechanism to normal condition. If the called line is free and connect1on established therewith, the opcrator, at the termination of the conversation, in response to the display of the supervisory signals, may open her connection switch, thereby effecting the automatic restoration of all the switching mechanism t0 normal condition.

Another feature relates to means for associating the operators sending or controlling device with any one of a plurality of connecting circuits when such connecting circuit is taken for use,

Still another featurc of the invention relates to an arrangement of apparatus and circuits by which the final selector or connector has direct acccss not only to ordinary subscribers lines, but also to trunk lines, such as those leading to private branch excliang0s, and is cnablcd to discriminate betwcen thcsc two classes of lines in making tlxe busy test, and in associated operations. That is to say, the final selector upon testing a busy lino, if it is an ordinary subscrihers lino, Wlll automatically transmit a busy signal, and may also restore itself t0 normal condition; but if the line tested and lound busy is one of a group of trnk lines, the sclcctor will automatically proceed to test in rotation the remaining lines of the group, and seize the first one that 1s froc; or il all are busy, the selector after testing (lux last one of the group will give the busy signal and may restore itself to normal.

\c Wlll describe our invention in detail li rolcrence to the accompanying drawings, which represcnt in diagrammatic form a h.icphone cxchange system embodying our invention, reserving, however, for the appondcd claims a statement of the parts and combinations which -We consider novel with us.

in the drawings Fins. l, 2, 3, 4, 5, 6, and 7 represent an arrangement of circuits and apparatus of a telcphonc cxchange system embodying our invention;

Fig. 8 represents a single-station line leadmg 10 torminals upon the conncctor shown in Fig. 4;

Fig. 9 shows a four-party line with its connecter torminals arrangcd for seloctivc ignnlng; and

Fig. 10 shows a private brunch exchange and its trunk lines and connector terminals.

In tracing the system, the drawings;

should be considered in the order of Figs. 7, 6, 5, l, 2, 3, 4, 8, 9 and 10.

In a system of, for example, 100,000 lines, there may be provided ten offices, at each of which terminate 10,000 lines. At each oflice the lines may be arranged in groups of 300, although groups of any number might be employed. With such an arrangement there Would be 34 groups of 300 lines at each oflice, or to be exact 33 groups of 300 lines and 1 group of 100. Each connector bas a capacity of 300 lines and enough connectors are urnished to handle the calls for each group. The operator in anexclrange answers a call in the usual way by uniting her connecting circuit with the line of the calling subscriber, and after ascertaining the number of the calledparty and the excl1ange where the line of such party terminates, operates her sending apparatus, dcpressing the key thereof which represents the desired office, and the thousands, hundreds,'tens and units digit keys representing the number of the line wanted. An ofiice stepper forms the terminal of the connecting circuit referred to, and is operated by mechanism controlled by the actuatcd ofiicc key to unite the connecting circuit With an idle trunk line leading to the desired office. Said trunk line terminates at the desircd ofiice in a primary selector, Which is a machine adapted to select an idle connector belonging to any one of the thirty-four groups.

A translator is provided in connection with the sending outfit to cause the thonsands and hundreds keys depressed to operate the primary selector and pick ont au idle 'connector of the group desired. The first 300 lines in the exchange are numbered 0000 to 0299. These numbers would be rcached by pressing the naught button of the thousands keys and the 1 or 2 button of the hundreds keys. There is a primary controllcr forming part of-the sending outfit, Which controls the operation of the primary selector, the two bcing operated togcther in scries. The translator is provided with thrcc brushes. The first is associated with the ti1ousands and hundreds keys and arranged to stop the translator at a predetermined point to cause the second brush and the primary controller, which are automaticall v brought into circuit when the transla tor has stoppcd, to advance the primary selcctor into position to connect with the desired connector. The third brush has associatcd therewith an auxiliary controller and said brush, after the operation of the primary controller, automatically brings into play the auxiliary controllcr, which ad vances th brushes of the selected conneotor to the propcr lumdreds zone of the three zones of one hundred lines cach of such connoclor. This automatic advance of the selcctor to the propcr zone in nomdecimal connector to cause the brushes thereof t unite with the terminals of the desired lime J in the selected zone.

.P1BGd upon. the closure of the connection- V and the supervisory lamps V e Will now describe in detail the circuits and apparatus employed in connecting the subscriber NO. 999 shown in Fig. 1, whose lime terminates at oflice A, With the line of the subscriber No. 1132, shown in Fig. 8, whose lime terminates at exchange B.

lihe lime of subscriber No. 999, Fig. 1, extends in two limbs,1, 2 from the substation to the central ofiice A, where the line extends through the usual lime signal apparatus to the poles of a central battery. At the central ofiice, the usual answering jack 3 is provided for the lime, the thimble4 of said jack being connected with a conductor 5 Which leads through the usual out-0E relav to the free pole of a grounded battery 6. The operator is provided with an answering plug 7, with which to umite her connectimg circuit with the calling lime, the plug 7 and jack 3 constituting a manual comnection switch. C

The

link conductors

8, 9 0:15 the operators connecting circuit lead from the tip 10 and ring 11, respectively, of the answering-plug,

' through the windings of the usual repeating coil, between which is bridged a battery 12 in the usual manner, to the line brushes of an office select0r 13, Fig. 2, a supervisory relay being included in link conductor 9 between the battery and the ring of the plug for controlling the usual supervisory signal. The ,sleeve 14 of the amswering plug is connected with a conductor 15 Which leads to earth through the winding of a relay. 16. -Said relay 16, Whose circuit 5, 15, is com* witch, isjprovided. with an armature conected with the,freepole of the battery 17,

'50 the front contact of said-armature beimg connected. witha conductor- 18 leading througH contacts of the superi7isory relays t0 earth. V

A key 19 is provided in association with the

conductors

8, 9 of thebonnecting circuit, adapted, When operated, to connect the operators telephone set with the link conductors of the connecting' circuit, and also to close-a pair of Contacts, 20, 21, which control the placing of the sending apparatus into condition to serve the connecting circu1t. The contact 20 is connected with a conductor 22 which-leads through a resistamcc 23 and springs 24, 25, associated with relay 26, to the free pole of a grounded battery 27, Fig. 5, while the contact 21 is connected with a conductor 28 which leads through the armature 29 and back contact of relay 30, windings of

relays

31 and 26, through the armature 32 and back contact 01 relay 33 to earth. Thus when key 19 is, operated, the

circuit

22, 28 is completed to operate

relays

31 and 26.

Referring first to relay 31, its armature 34 is connected with a conductor 35 which leads through the contacts of a key 36 t0 conductor '18, said.conductor 18 being con-V nected by the armature of relay 16 with the 'free pole of battery 17. The front contact of the armature 34 of relay 31 is connected with a conductor 37 which leadS through r the winding 38 of relay 30 to the armature 29 thereof. .A locking Circuit is mow completed for the

relays

31 and 26 independent of battery 27, said circuit extending from the free po e et battery 17 by way et

conductors

18, 35, -armature 34 and front- Gontact of relay 31, winding 38 of relay 30 t0 conductor 28, thence through the

relays

31 and 26 to earth. The armature 29 of relay 30 is now operated and disconnects the key 1.9 from the circuit of the magnets-3l, 26, so that the operator' may at any subseqent time duiimg the process of establishing the connection, or during the connection, listen in on the circuit without interfering with the sending apparatus. The resistance 23 in conductor 22 is for the purpose of preventing a short-circuit of the relay 30 when the armature 34 of relay 31 closes the branch throgh Winding 38 of relay 30 from battery 17.

The relay 31 is also provided with armatures 39, 40.- The armature 39 is connected V with a common Wire 41 leading to the sending apparatus, and said armature is adapted vvhen attracted to engage the member 42 1 of a pair of normall'y closed springs 42, 43, included in the strand 8 of the connecting circuit, to separate said springs, tlie spring 42 beimgconnected with the portion of the conductor 8 leading to the oifice selector. In like manner, the armature 40 is connected with a common wire 44 leading to the sending .apparatus, said armature being adapted to engage the member 45 of a pair of springs 45, 46, which are hormally 111-.

duded in the ring strand 9 of the connecting" circuit, te; separate said springs, the spring 45 being conriected with the portion of the strand 9 'leadimg to the oflic'e selector. Armatures 39, 40, therefore, in their attractive movement, connect the

strands

8, 9 of the connebting circuit with the common wires '41, 44 leading to the sending apparatus.

The relay 26, Fig. 5, in operating attracts its armature 47, which separates the springs 24, 25, included in conductor 22, said armature 47 engaging the spring 25 which is connected with the free pole of grounded batinstant battery is applied by relay 26 to the eed wire. The sending apparatus is now in operat1ve condition to serve the connect- 1ng c1rcu1t.

Operazfizon of the oyce selector.

The office selector, Fig. 2, is provided with a shaft 50 arranged to have two movementsa rotary movement to select a group of trunk lines leadimg to a particular office, or as in the present case, a group of trunk limes leading to trunk selcctors adapted to select an idle inter-office trunk, and a longitudinal or upward movement to select the first idle trunk line of such group. This shaft carries three brushes, 51, 52, 53, brushes 51 and 52 being connected with the

strands

8, 9 of the connecting circuit, and the brush 53 being the local brush. The shaft 50 is adapted to be rotated by means of the magnet 54 and mechanism comtrolled thereby, and to be moved upward by a magnet 55 and its associated apparatus. Th relay 30, Fig. 1, Wl1en operated, as before described, serves to place the oflice se lector in condition for operation. -The armature 56 of relay 30 is connected with the conductor 57 which leads from conductor 35 and battery 17 through a winding of relay 30, armature 56 and its contact of said relay, contact springs 58, 59 of relay 60 to the office selector, and thence thrOugh the wmding of a rela 61 and through a pair of contacts 62 close by the shaft 50 when in normal position, to earth. A circuit for re lay 61 is thereb provided by way et

conductors

18, 35, 57. The said relay 61 when emergized attracts its

armatures

63, 64 and 65; the armature 63 being connected with earth and when attracted completimg a locking circuit for the relay 61 independent et contacts 62. The armature 65 is connected with the free pole of a grounded battery 67, said armature When attracted engaging its front contact which is connected with a conductor 68 leading to earth through the windimg of the reta1nmg magnet 66 of the shaft 50. The armature 64 of said relay is connected with the free pole of battery 67 and the front contact of this armature is connected with a conductor 69 which leads through the contact springs 70, 71, associated with relay 72, through the winding of relay 73 to earth.

Relay 73 is provided with two

armatures

74, 75, Which with their back contacts are normally included in the

strands

8, 9, of

'a front contact Which is connected With the conductor 76 leading through the rotary stepping magnet 54 of the shaft 50, through the comtact-springs 77, 78, associated with relay 72, to earth.

The armature of relay 73 when attracted is adapted to engage a front contact connected with a conductor 79 which leads through the armature and front contact ot retaining magnet 66, relay 72, to earth. Th office selector is now in condition for operation.

Turning now to the sending apparatus, we will describe the means adapted to be set by the operator t0 actuate theoflice selector and select an idle trunk lime leadimg to the exchange where the called partys lime terminates. In the present cas the selector selects a trunk lime which leads to an idle trumk selector, said selector thereupon operating to pick ont au idle trunk lime leading to the desired ofice.

We will assume that the line of the arty with whom conversation is desired terminates at office B, and that his number at said oflice is 1132. The operator, therefore, after listeming in to ascertain the number of the line desired, depresses the office key B, key I of the thousands keys, key I of the bundreds kcys, key III 015 the tens keys, and key II of the units keys.

The oflice controller, Fig. 7, is provided with a series of keys A, B, etc., which are known as the office keys. Each key comprises a plunger adapted when depressed to be locked in such position under the control of a release magnet 80. Each plunger may carry a latch member, preferably comical in form, adapted when the plumger is depressed to engage the under side of a latch bar to look the plunger in its depressed position, said plunger, when the latch bar is operated by magnet 80 being restored by a suitable spring. Each of said keys, When depressed, forces into electrical contact springs 82, 83, 84. The spring 82 of each key is connected with the eed wire 48 previously referred to, Which is connected by relay 26 with the free pole of battery 27. The spring 88 is connected with a conductor 85 which leads to a terminal of a bank of contacts 86 adapted to be engaged by the contact arm 87. Said arm is provided with a stepping magnet 88, theretaining magnet 89 of said contact arm being operated by current from the feed wire 48, as previously described. Said contact arm 87 is connected with a conduc tor 90 which leads to earth through winding 92 of relay 91.

The third sprimg 84 of each key is connect ed with a conductor 93 which leads through with*a conductor 101 lcading turc 102 of relay 94. The front contact of said armature 102 is connected With a con ductor 103 Which leads 'through the .winding of the stepping magnet 88 of contactarm 87, armature 104 and back contact of relay 91, through the armature 105 and back con- Eact of sluggish re1ay 106 to common Wire ;1.

Assume now that key B has been operated:

' Current will flow from the feed Wire 48 by way of

springs

82, 83, to the contact 86 in the bank 86. Battery Will a1'so be applied from the feed Wire through the

springs

82, 83, 84, to conductor 93 and thence through winding of reay 94, springs 95., 96, of said relay to earth by way of the puisator when spring 98 thereof engagcs its contact. When such contact is made, relay 94 is energized to attract its

armatures

102, 107. Armature 107 is connected to earth and engages contact spring 95, separating the same from its anvi1 96 and completing alocking circuit for relay 94 from the feed Wire independent of the pulsator. Armature 102 in its attracted position connecte the battery contact of the puisator With

conductcrs

101, 103. 1mpulses of current now flow from the free polo of battery 100 over

conductors

101, 103, winding of the stepping magnet 88 of contact arm 87, over common Wire 41, through armature 39 and spring 42 of relay 31, Fig. 1, to the tip-strand 8, armature 74 of relay 73 of the office selector, Fig, 2, conductor 76., through the stepping magnct 54 of the seiector, springs 77, 78 of relay 72 to'earth.

The pulsator 97, as alrady described, when in position to close its grounded contact completes a circuit for the relay 94 whi zh conhects the battery contact of the pu'lsator to the stepping magnets. This provision is made so that the first impulse applied to the stepping magnets will be a full one, that is, when the pulsator is engaging its ground contact it completcs the circuit for reiay 94, so that When it engagcs its battery contact the circuit for the stepping magnet wiil be ready to receive the complete impulse.

The stepping

magnets

88, 54, respond together to the puisating current and rotate the contact arm 87 of the-controiler and the shaft' of the selector, respectively. When the contact arm 87 of the office controller reaches the contact point 86 which is connected through the key B with thefeed-wire, and the shaft 50 has been steppd to the armaaround so as to bring its brushcs in front of the group of terminale ieading to trunk selectors adapted to pick ont trunk fines leading to the desired ofiice, current floWs from the feed wire through the contact springs 82, 83, conductor 85, contact 86 of the bank 86, contact arm 87, conductor 90, through the winding 92 of relay 91 to earth. Relay 91 is thereby energized and attracts its armature 104, removing pulsating current from the stepping

magnets

88, 54. The armature 108 of relay 91 is .connected to earth whiie its front contact is connected with a conductor 109 which leads through the winding 110 of relay 91, winding of sluggish relay 106, to the feed wire. The armature 108 therefore When attracted completes a lookirig circuit for relay 91, and aiso the circuit of the sluggish reiay 106.

A conductor 111 extends from conductor 90 between the arm 87 and relay 91 to the back contact of armature 112 of sluggish relay 106, said armature 112 being connected with common wire 44, and when the arm 87 reaches the point 86 at Which battery is present, animpulse is delivered before the relay 106 has had time to operate, to conductor 44, from the feed wire, by way of key 18,

conductors

85, 90 and 111 and the armature1l2 and back contact of reiay 106. This impulse passes through the armature 40 and its contact 45 of re1ay 31, F1g. 1, strand 9 of the connecting circuit to the ofiice selector, thence through armature 75 of relay 73 and its front contact to condut tor 79, armatureand front contact of retaining magnct66, winding of reiay 72 to earth. Relay 72 is thereupon operated and attracts its

armatures

113, 114, 115. The armature 114 is connected with conductor 79 and is adapted when attracted to engage a contact connected with the conductor 69 which leads to the free polo of battery 67, thereby compieting a locking circuit for the relay 72 from the free poie of 'oattery 67, armature 64 of reiay 61, condnctor 69 to earth Toy way o armature 114 and conductor 79.

The armature 113 of relay 72 is connected With a conductcr 116 which ieads to the front contact of armature 117, of relay 73,

said armature 117 being connected with armature is connected with a conductor which leads through the lifting magnet 55 of the selector, armature 120 and front contact of relay 73, to the battery contact of a pulsator 121. The shaft 50 now begins its upward hunt for a trunk line leading to an idle selector adapted to pick out an idle trunk line leading to the office B. If the first trunk line is busy, battmy will be present upon its local terminal 122, and will maintain relay 73 excited in the path pro- Vided by way of conductor 118, armature 117 of said relay and its front contact conductor 116, armature 113 and front contact of relay 72, conductor 69 to earth; the armature 120 of said relay 73 while attracted maintains the circuit of the stepping magnet 55.

VVhen, however, an idle trunk line is reached by the brushes on the shaft 50, there will be no potential present at the local ter* minal 122 thereof, and the relay 73 will be deprived of current, and will release all its armatures; armature 120 opening the circuit of the lifting magnet 55;

armatures

74, 75,

restoring the continuity of the

strands

8, 9 of the connecting circuit; and the armature 117 breaking the connection of relay 73 with the local brush 53, and connccting at its back contact conductor 118, leading from said brush, with a conductor 123 leading to conductor 69, Which is connected by armature 64 of relay 61 with the free pole of battery 67. The brushes 5l, 52, 53, of shaft 50, now rest in engagement with

contact terminals

124, 125, 122, respectivcly, connected with a trunk line leading to a trunk selector.

It should be borne in mind that the 10W- ermost set of

terminals

122, 125, 124 of the vertical rows forming stopping points for the office selector brushcs lead to automatic trunk selectors, otherwise the relay 73 would fail to hold itself operated, after the impulse which energized relay 72 had spent itself.

' It is also to be assumed that the oflice selector takes at least one rotary step before engagmg the first set:

The trunk selector comprises a shaft 126 having one movement,a rotary movement,said shaft being provided with a stepping magnet 127. The shaft carries three, brushes 128, 129, 130; the brushes 128, 129, being line brushes connected by

conductor

131, 132, with the

contact terminals

124, 125 of the office selector, the

armatures

133, 134, and back contacts of a relay 1.35 being included in said

conductors

131, 132, respectively. The local trunk terminal 122 of the selector is connected With the conductor 137 which leads through the retaining magnet 138 of the trunk selector, contacts 139 closed by the selector shaft 126 when in normal position, winding 140 of relay 135 to earth,

current being delivercd to said conductor 137 from battery 67 when the brush 53 engages said contact 122 and the relay 73 has restored its armature, as previously dc scribed, whereupon the relay 135 and retaining magnet 138 are operated.

The retaining magnet 138 in operating, attracts its armature and completes a looking circuit for itself independent of contacts 139 through its own armature resistance 138 and ground, the function of this resistance being to prevent the short-circuiting of relay 135. Relay 135 in operating attracts its

armatures

133, 134, 141, and 147. T he armatures 133, 134, when attracted, maintain the selector brushes 128, 129 dead during the selection. The armature 141 is connected with a conductor 142 which leads through the Winding 143 of relay 135 to earth. Said armature 141 in its attracted position engages the contact spring 144, and separates the same from its normal contact 145, said spring 144 being connected with a conductor 146 leading to the local brush 130 upon the selector shaft. The armature 147 is connected with a-conductor 148 Which leads to the battery contact of the plusator 149, while the front contact of said armaturc is connected with conductor 150 leading through the winding of the stepping magnet 127 of the trunk selector to earth.

Thus when relay 135 is operatcd, a circuit is completed by armature 147, by way of conductors 148, 150, said circuit including the magnet 127, which is operated to advance the brush 130 on shaft 126 one step, to the terminals of a trunk line leading to the desired oflice. If this trunk line is busy, battery will be present at the local terminal 151 of such line, and current will flow through the local brush 130, conductor 146, spring 144 and armature 141, conductor 142, winding 143 of relay 135 to earth, maintaining the relay 135 energized. The stepping magnct 127 will thus continue to receive current and will advance the brush another step, and so on until an idle trunk line is found, whereupon current will not be present upon the terminal 151, and relay 135 will be deprived of current, releasing its armatures and restoring the continuity of the talking

conductors

131, 132, Which Were broken during selection to prevent dis turbances; opening at armature 147 the circuit of the stepping magnet 127 and breaking at armature 141 the connection of relay 135 With the local brush 130. Spring 145. which now rests in engagement with spring 144, is connected with a conductor 152 lead' ing to conductor 137, which is connected with battery 67, .at the ofiice selector, and a potential is thereby applied by way of

conductors

69, 123, 118, 137, 152, 146, to the contact terminal 151 of the trunk lime upon which the selector brush 130 rsts, t lock ont other trunk selectors from the trunk line selected. The brushes 128, 129 of the trunk selector now rest upon the terminals of the

limbs

152, 153, respectively, ,of a twowi-re trunk lino leading to the ofiice B and the primary selector forming the terminal 01: such trunk line at the said distant oflice.

Opcraiz'on of translatflg machine and primary selector.

As before stated, the line with which connection is desired, is numbered 1132. Therefore the operator depresses key I of the 1000s keys 154-, key I of the 100s keys 155, l;ey III of the s keys 156, and key II of the units kys 157. The 1000s and 100s keys control the operation of the translator shown at theleft in Fig. 6, which operates the primary selector 136, Fig. 3, forming the terminal of the trunk line at the distant oflice to connectthe trunk lines with an idle connector of the group containing the desired number. The shaft 159 of th translator is arranged to have two movements,

one in long steps under the control of step-,

ping magnet 160, and the other in short steps under the control of magnet 161. The shaft carries three brushes, the brush 162 being adapted to cooperate with the de' pressed 1000s and 100S keys, and the bank of contacts 163, to stop the shaft at the proper point tocause the brush 161 ofthe'translator to apply battery t0 a particular contact of theprimary controller 165, and cause the same to operate in series with the primary selector until the contact arm 166 of the primary controller reaches the contact to which battery has been applied by brush 164, and the primary selector reaches the group of trunks leading to the connectors of thgroup wherein is located the called partys line, at which time the primary controller and primary selector are stopped, and the primary selector -caused to locate an idle connector. The third brush 167 of the transalator is provided with a bank of contacts 168, which control the application of battery to a predetermined point upon.the auxiliary controller 169, which is operated after the primary selector has*locatcd the connecter to advance the brushes of such connector into the proper bank of its three banks of 100 lines each.

Describing now more in detail the operation of the translating mechanism and primary selector: The

relays

511 and 172, Fig. 7, control the starting of the translating mechanism, said relays being arranged. to operate when the trunk selector has made connection with an idle trunk line leading to a distant office. Said relay 511 is included in a conductor 170 leading from the front circuit through contact springs- 171 controlled by the armature 173 of relay 172, to the fced.

wire 48, the connection of this conductor at armature 105 of relay 106 with wire 41 being complcted when the ,sluggish relay 106 is operated after the impulse is applied to Wire 44 to start the office selector in its upward hunt for an idle trunk selector. The circuit for relay 511 extends from the feed wire 48 through conductor 170 to conductor 41, thence through contacts 39, 42, of relay 31, to link conductor 8, over trunk wire 131 to the trunk selector, through the contacts closed thereby,to trunk wire 152 leading to the distant oflice, .where the same passes through one winding of a repeatmg coil bridged across the trunk conductors, to a conductor 17 1, which leads through the winding of relay 175, normally closed

contacts

176, 177 of a polarized relay 178, normally closed

contacts

179, 180, of said relay, normally closed

contacts

181, 182, of relay 183, to trunk conductor 153, and thence to the primary selector, through the armature 184 and back contact of relay 185, to a conductor 186 whih leads, through contact springs 1'87 closed by the shaft of the selector while in normal position.

The

relas

511 and 172 of the sending apparatus, Fig. 7, are sluggish in their operation to provide a time interval wherem the primary selector may get into condition for operation. This is accomplished under the control of the relay175 associated with the trunk line at the distant office, Whih is in tl 1e circuit iust traced for the relay 511. Sa1d relay 175 in attracting its armature, completes a circuit for battery 189 by way of conductor 190 which leads through the nor* mally closed contact springs 191, 192 of relay 193, Winding of relay 193, winding of the retaining magnet 194 01: the primary selector, to earth,-through the contact springs closed by the shaft 195 of the primary selector when in normal condition. The relay 193 and retaining magnat 194 are now energized and a locking circuit is completed for said relay and magnet independent of relay 175, said circuit extending from the free pole of grounded battery 196, .conductor 188,

through the contact springs 197, 198 of relay I 183, armature 199 of relay 193, (which is now in engagement with the contact spr'ing 191, separating the samefrom its normal contact 192 and disconnecting battery 189 from the reviously traced therefor) through the win ing of relay 193, and over conductor 190, through the winding of the retainmg magnet and its armature 200 and front contact to earth. The armature 201 of relay 193, Which is connected with the portion et conductor 190 leading to the front contact of the armature of relay 175, in its attracted mary selector,,the contacts 202 being included in said conductor between the repeating coil and the selector.

The repeating coil serves to maintain the inductive continuity of the trunk circuit while maintaining the circuit broken for di' rect current. The two windings of the repeating coi} connected with the portion of the trunk circuit leading back to the trunk selector are included in a bridge of said trunk conductor with a condenser, While the other tWo windings of the repeating coil, which are included in the portion of the trunk circuit leading to the selector, are connected in a bridge of the trunk circuit with a grounded battery 203.

The retaining magnet 194 when energized as previously described, attracts its armature 204, completing a circuit from battery 205 by way of conductor 206, through the contact springs 207, 208 of relay 209, winding of relay 185 to earth, said relay thereu'pon attracting its

armatures

210, 184, 211 and 212.

The armature 210 of relay 185, which with its back contact is normally included in the trunk conductor 152, when attracted engages a front contact connected with the conductor 213 leading through the stepping magnet 214 of the primary selector, contact springs 215 of relay 209 to earth. The magnet 214 is arranged to rotate the shaft 195 in thirty-f0ur steps to pick out the group of trunk limes leading to connectors serving a particular group of 300 lines. The remaining armatures of the relay 185 bring into operatiVe condition apparatus Which Will be hereafter described.

The primary selector is now in condition for operation, and sluggish relay 511 of the scnding apparatus, Fig. 7, has now operated to energize relay 172, which in turn causes the deenergization of relay 511, said relay 172 locking italf up, and the combination of

relays

511 and 172, with the first-mentioned relay inert and the other energized, starts the translating mechanism. Relay 511 is provided with an armature 216 connected With the fecd wire 48, said armature when attracted, completing a circuit for the relay 172. Relay 172, which is also sluggish, at tracts its armature 173, opening the contacts 171 Which are included in the circuit of the relay 511, and by means of said armature 173 and one of the members ofthe contacts 171, locking itself to earth frorn the feed wire. The armature 216 et relay 511, Which is connected With the feed wire, is provided with a back contact connected with a conductor 217 leading through the armature 218 and its front contact of relay 17 2,

to the 1000s keys, and when armature 216 of re1ay 511 is retracted and armature 218 of relay 172 is attracted, current fiows from the feed Wire over conductor 217, through the armature 219 and back contact of relay 220 to the 1000s keys 154, Fig. 6.

Each 1000s key, When operated, is arranged to be locked in its depressed position under the control of a release magnet 221, as described in connection with the office controller; eachkey when depressed forcing into electrical engagement contact springs 222, 223, and 224. Contact-spring 222 is connected with the conductor 217 which is united by the feed wire 48 to the free pole of battery 27, and said spring in engaging its anvil 223 applies battery to a 1000s contact terminal in the bank 163 over Which the brush 162 of the translator sweeps. In the present casecalling line 1132since key 1 is depressed, battery.will be applied to the second 1000s contact point 225 of the bank 163. It Will be understood that the brush 162 normally reste one long step from the first terminalwhich would be 0, or the first 1000s terminal, In the system shown, in order that the brush 162 may reach the sec ond 1000s contact point 225, it is arranged to take three long steps. Between the first and second 1000s contact points there are ten intermediate contacts numbered from 0 to 9 inclusive; and the advance of the brush to any of said intermediate contacts is determined by the 100s keys.

The spring 224 of key I, which is in electrical engagement with

springs

223, 222,

and thereby with battery 27, is connected With a conductor 226 Which extends from all the springs 224 of the 1000s keys, through the winding of relay 227, contact springs 228 associated therewith, to the ground contact of a pulsator 229; and when the ground spring of the pulsator engages said contact a circuit is completed for relay 227 which draWs up its grounded armature 230, said armature engaging the member of springs 228 connected with the winding of relay 227 and completing a locking circuit for said relay independent of the pulsator.

The relay 227 is arranged to start the operation cf stepping magnet 160 of the translator, said relay having an armature 231, which, when attracted, completes the continuity of a conductor 232 leading from the battery contact of a pulsator 233, through the Winding of relay 234, armature 235 and back contact et relay 246 to the conductor 41, which is connected With the tip strand of the connecting circuit, and on through to the primary selector. It Will be noted that the locking circuit for relay 227 is established by the pulsator 229 when in engage ment with its ground contact, so that the circuit of conductor 232 Will be completed l'oefore the pulsator 233 engages its

battery

131, 152, through one winding ofthe repeating coil to conductor 174, thence through relay 175, contacts of

relays

178 and 183, to

trunk conductor 153, through the armature 184, and front contact et relay 185, to conductor 237, through contacts 238 of relay 209 t0 earth throgh theWinding of said relay,

this current being Without efi:'eot upon said relay 209. Relay 175 in the circuit just traced responds to said current, and in attracting its armature applies current from battery 189 to conductor 190, and thence through armature 201 and one of the mem bers of springs 202 of relay 193, to trunk conductor 152, thence through armature 210 and its front'contact of relay 185, conductor 213, rotary stepping magnet 214 of the primary selector, contact springs 215 of relay 209 to earth, whereupon the stepping magnet 214 is operated to rotate the shaft 195 one step. This advance of the primary selector is simply to save time in'the operation of the system.

The relay 234 in the circuit traced from the pulsator 233 responds to the pulsations and applies current from battery 239 through the armature 240 and front contact, of said relay 234, to the long step magnet 160 of the trafislator, Which advances the contact arm of the translator in long steps. The relay 234 has an armature 241 also connected with battery 239, said armature when attracted applying current fro-m said batteryto a conductor 242 which leads to earth thxrough the stepping magnet 243 of the primary controller 165 to advance the arm 166 thereof. V v

It Will thus be seen that the translator arma, the contact arm of the primary con- .troller, and the contact arm of the primary selector, advance together until the brush 162 of the translator reaches the 1000s point 225 of the bank 163 of contacts, at which time each of said arms Will have taken three stepsthe translator arm three long steps and the primary c0ntr0ller and primary selector arms three short stepseach. The holding or retainingmagnets of the translator and primar y controller are permanently connected with the feed Wire and were operated the instant relay 26 applied battery to the feed wire, when the sending-apparatus WaS taken by the connecting circuit for use.

When the brush 162 of the translator reaches the contact 225 it finds current thereon, and said current passes through the brush162 to a conductor 244, which leads through the armature 245 'and backcontact of relay 220, through the winding 246 of relay to earth operating said relay 236, which' opens at its armature 235 and back contact the conductor 232 and the circuit beond intermediate point beyond' point 225 would be supplied with battery in the following man'ner:

Relay 236 when energized, as above described,attracts its armature 247, which is connected with a conductor 248 leading through the relay 220 to the feed Wire 48. The front contact of armature 247 is connected through a'winding of relay 236 to earth; and when said armature 247 is attracted, a circuit is completed for the relay 220 which attracts its

armatures

219, 245. Armature 219 when attracted connects conductor 217 and batter 27 with conductor 249 leading to the sprmgs 250 of the 100s keys 155. The armature 245 of relay 220 in its attractive movement connects conductor 244 leading from brush 162 with a conductor 251 leading through the winding of the relay 252 to earth. Brush 162 -is 110W dead, since battery is removed by armature 219 of relay 220 from the thousands keys and 50 from spring250,

conductors

249, 217, to the sec- 4 ond intermediate contact beyond point 225.\

The third spring 253 applies current by way of the springs 250, 512 and

conductors

249, 217, to conductor 254 leading through wmding of relay 255, to earth; said relay 255 in attratcting its armature completmg the continuity of a circuit 513 whmh =extends from the battery contact of a pulsator- 257, through the winding of the short stop magnet 161 of the translator, through the armature 258 and back contact of relay 252 to earth. The puls-ator 257 applies current through the circuit just traced to operate the-stepping magnet 161 and advance the shatt in two short stops, until the brush 162 of the translator rests upon the second inductor 251, to earth through relay 252, which magnet 161 of the translator, leaving the shaft of the translator three iong stops and two short stops from its normal position.

Pfl'mry controller,

The primary controiier in an exchange such as We are describing, vvhere the 1ines are arranged in groups of 300, Wouid have thirty-our contact points, each point representing a group contact point ci a primary seiector, which in like manner wouid have thirty-four rotary stops to engage thirtytour terminais. Frorn each terminal of the primary controiier a conductor runs to three contact points strapped together, over which the second brush 164 of the translator is arranged t0 svveep, said brush coing adapted after the translator has been brought to a predetermined point under the controi et the 1000s and s keys, to apply battery to a certain group of strapped contacts to stop the controlier and seiector vvhen the se- 1ector is advanced to the group of trunk hnes ieading to the connectors serving the group of iines in which the caed partys line is located. The operation of the primary controiier and seiector is automaticaiiy efiected immediateiy upon the compie tien et the movement of the translator. The reay 252, which was operated the instant the transator brush 162 ianded on the second intermediate point, in attracting its armature 262 applied current from the posit1ve battery 263 to conductor 264; leading to the brush 164, which now rests upon the set 01 strapped contacts connected with 1 the iourth contact 265 in the. bank of contacts of the primary controller 165.

Et should be remembered at this point that the primary controller and primary seiector brushes on the shaft followed the long steps of the translator brush, so that the arm 166 ofth primary controller and the arm 195 of the primary selector noW rest on their third group terminals. This arrangement is simpiy to save time in setting p the connection;

The armature 266 of relay 252, which was operatcd when the transiator completed its movement, serves to start the primary con: troller and selector, said armature 266 being sato-r 267, the front contact of said armature be1ng connected with acbnductor 268 lead- 1ng through contacts 269 and the relay 270 to the feed ,Wire 48. The instant the vround sprmg of the pulsator 267 engagesits con tact, a circuit is completed from battery 27 over the feed wire 48, conductor 268, through relay 270, armature 266 and front contact of re1ay 252, to earth; and the relay 270 m operating attracts its-armature 271, Whlch separates springs 269, engaging one to conductor 4-1, which leads to the tip strand Reiay 275 controis a circuit from. battery 278 through the stepping magnet 243 ci the controller. The puisator 273 appiies current through the reiay 275 and out over conductor 4-1, tip strand 8,

trunk conductors

131, 152, to the distant office, and thence through conductor 17, reia: 175,

contacts

181, 182 of reiay 183 to trunr conductor 153, thence through conductor 237,

and reiay 209, to earth this current, however, not afi"ecting the reiay 209. The relay 175 responds to the impuises in the circuit traced and compietes a circuit irom battery 189 over conductor 190, armature 201 of re iay 193, and one 023 the springs 202 to the trunk conductor 152, thence through the armature 210 of reiay 185, conductor 213, stepping magnet 214 of the primary seiector, contacts 215 of relay 209 to earth. The reiay 275 associated' with the primary con troiler and included in the circuit oit puisator 273 aQbove traced maires and breaks the circuit of the stepping magnet 2413 of the controiler. The stepping magnets 2A3 o:t the controller and 214 or the seiector novv rotate their respective contact arms until the contact arm 166 of the controiler reaches the ourth contact in its path, which is connected by the brush 164: and conductor 264 vvith positive grounded battery 263-, atwhich point current fiovvs from said battery through the arm 166 of the controiler and the conductor 269, ieading from said arm through a winding of relay 277, to earth. Relay 277 now operates' and attracts its armature 276, openihg the circuit fromthe pulsator 273 thro-ugh the rclay 275 of the primary controller and the relay 175 at the distant station, said relay 175 controlling the circuit through the stepping magnet 214 of the rimary slector. Said relay 277 a1so dravvs up its armature 280, completing a" locking circuit for itself which extends from thefeed wire 48 throrigh sluggish relay 281, winding of relay 277 to arth. The brushes on the shaft 195 of the primary. se1ector have now reached the fourth group of trunk lines, which lead to connectors adapted to reach the line With which conversation is desired.-

Aut0matc seZectzdn of idZe trum7c bg selector.

. The attraction of armature 27 6 of relay 277 completed the continuity of a conductor 282 which leads from the conductor 269 between the brush 166 and relay 277,

45 tar Stepping n1agnet 214 with trunk conductor 152, and to engage the grounded conthrough the armature 276 and front contact of relay 277, armature 283 and back contact of sluggish rel.y 281, to conductor turc in a contra-clockwise direction, whereupon spring 177 of said'relay is separated from its anvil 176 and thrown into engage- .adapted to serve the fourth' group of three ment with a contact 287 connected with the free pole of grounded battery 288; current thereupoh fiowing from battery 288 through the

springs

287, 177, conductor 174,

contacts

181, 182 of relay 183, trunk conductor 153, armature 184 and front contact of relay 185, condu'ctor 237, springs 238 ofrelay 209, and winding of said relay to earth;

, Relay 209 is now energized and draws up its

armatures

289, 290, 291. The armature 290 is connected with conductor 206 which leads from the battery 205; and'said armature when attracted separates springs 238, engaging th member thefeof leading directly to earth through relay 209 and completing a locking circuit for said relay independent of relay 17 8, which by this time has been deprived of current, owing to the opcration of the sluggiSh relay 281. Arma ture 291 of. relay 209 is connected with a conductor 292 leadingthrough the lifting magnet 293 of the primary selector, armature 2l2 and front contact of re1ay 185 to the battery contact 01: a p'ulsator 294. And saidarmatuie 291 when attracted is adapted to separate springs 215, breaking the continuity of conductbr 2'13 connecting theTo t,act spririg ofsaidpair of springs 215 to eomplete. a circuit. for the lifting magnet 293 and the pulsator294. Said .magnet 293 is adapted to step the shaft 195 up in search of a trunk line leading to an idle connecter hmidred lines in Which the line desired, Number 1132, is to be found.

The armature 289 of relay 209 is cohnected with a conductor 296 leading through the armature 211 and front contact of relay 185 to the local brush 297 of the primary selector; said armature 289 when attracted is adapted to

separate springs

207, 208 included in the circuit from battery 205, with relay 185, and to engage the spring 208, Which leads directly toearth through relay 185, thereby connecting Said relay 185 through its own armature 211 and front contact with said, local brush 297.

Nd-W when the selector has been given 0ne upward movement to bring its brushes into engagement with the terminals of a trunk line leading to the first connector of the fourth group, if, that cohnector is busy, the local brush 297 of the trunk lime leading to said connector will have potential thereon from the local terminal 298 of such trunk, and current Will flow through the local front contact of relay 185, winding of relay 185 to earth, maintaining relay 185 encrgized( Relayl in turn Will maintain the circuitof the up-stcpping magnat 293: in: tact, and the said magnet293 Will lift the shaft 195 another step,and so on untila trunk lime leading to an idle connector is reached, W en no current W1ll' be found upon the local terminal 298 of such line, and relay 185 Will be deprived of current, releasing its armatures. The armatures 210, 184 in retracting restore the continurty of the

trunk conductors

152, 153; the armature 212 opens the circuit of the upstepping magnet 293, and the armature 211 opens the connection of relay 185 with the local brush 297 and. engags its back contact connected Witl1 a conductor 299 Which leads through armature 204 and front contacts of the retaining magnet 194, to the free pole of battery 205 thereby placing by way of local brush297 a test potential upon the multiples of the local trunk terminal 298.

The lirie brushes of the shaft 195, which form the terminals of

trunk conductors

152, 153, are, now in engagement with tcrminals of the trunk lineleading to an idle connec- .tor adapted to reach line 1132, said brushes engaging terminals connected with conducbrush 297, conductor 296, armature 211 and

tors

300, 301, respectively, while the local by; the shaftxof'the connector When in its.

normal, position, to earth. Tlie retaining ma net 306 thereupon attracts its armatures 30 308, armature 3 07 complet-ing a lockr ing circuit for the retztining magnct 306, independent of the .springs Which are separated While theconnectcr shaft is away from normal position.

The auzlary controleh After the primary selector has selected an idle connector, the third brush 167, Fig. 6, of the translator and mechanism associated therewith, is arranged to operate the con nector to move the brushes on the shaft connecter into association with the third the brush 167 of the tran bank of contacts, in which is located the terminale et lino No. 1132 with which con nection is 00 be established. A conductor 311 leads from the wire 260, Wliich is now sup plied with current from positive battory 263 by way of the primary controller, te lator whicn noW rests upon a second intermediate contact 310 beyond the second contact of the set or bank et contacts 1 3, over Wil1Cl1 thebrush 167 swccps, said second intcrmediato contact coing connected with a conductor 3 12 which leads to the last ce; 0 ct terminal 313 upon the anxiliary contrcller 169, saicl contact 313 bcingg included in a bank oE contacts adapted to be engaged by the contact arm 314 c ne controller.

The inte nediato contact points of the bank i.:e divided into groups of three; the contact of each group, representing the -lirst zone or a connecter, being dead;

the second contact, rcpresenting the second zone, coing connected with conductor 312 to apply battory to the tenth point of the controller, While the third contact of oach group,ropresenting the third zone of a connector is connected with a conductor 312 leading to the twentieth contact of the controller. The auxiliary controller has twenty contacts in its loank, and the contact-arm 314 is arrangod t0 loe moved with the connector brushes to place said connecter brushes into operative connection with the propor bank cf contacts. Thus if the lino wanted were in the first bank 01 contacts, the auxiliary c0ntroller would not operate, since the connector brushes are normally in oporative relation to said first bank and the brush 167 would rest upon a dead contact. However,

if the line desired were in the second ban]: cf contacts, potentialwould be applied by the translat0r brush 167 to the tenth contact of the auxiliary controller, and the con troller brushes wo-uld advance with the connector 'brushes ton stops, when both brushes and controllet arm would be stopped, leaving the connector brushes in operative relation to the second bank. In the present case, 1n calling line 1132, the twentieth contact 313 would have potential applied thereto by the translator brush 167, and the controller brushes and connector brushes Would -be ad-- vanced until the controller arm reached point 313, and the connector brushes were placed in operative relation to the third bank of contacts, When both brushes and controller arm would be stoppod.

Sluggish relay 281 associated 16ith the primary controller, WhoSe circuit was co3n pletcd by the armature 280 et relay after the primary controller and prrm solector have completod their operation, oporating applios current rom negative ba tory 315 through the armature 316, and front contact et relay 281, through conductor 319, tl1ence thr0uglc the winding of relay 317, contact springs 318 thereof, to conductor 41.. '1he circuit et this relay is not compie*ed until the connoctor selectod by the primary selector is in condition for -operation, the circuit oxtending over conductor 41 to the tp strand 8 thcnce over trunlz conducto 131, 152., tlorcu,;,l conductor 174, wind of re1ay 1 5, to trunlr conductor 153, thcnce over conductor 301 to the co' nector, through

springs

320, 321 of a connecting relay 323, to conductor 324, which leads through a resistanco 325 to eartir throdgh the armature 308 and front contact et the rotaining magnet 306, which is now energized. Current in the circuit just traced enorgizes relay 175, which attracts its ar mature, applying current from the free polo of loattery 189 ovor conductor 190, through the armature 201 and one of spmngs 202 of relay 193 to trunk conductor 152, thence through the primary selector lino conductor 300, normally closed contact springs 326, 327 of relay 328, to conductor 329, which leads through the contact spr1ngs 330 of a transfer relay 331, rotary steppmg magnet 332, to conductor 324, and thence to earth through armature 308, said stopping magnet 332 being enorgized to give the shaft et the connecter au idle movoment, which is simply incidental to the operation.

Returning to the auxiliary controllor, Fig. 6, relay 317 is now operated by current from battery 315 in the circuit above traced, and attracts its armature 333 which looks relay 317 to oarth in a circuit from battery 315 independent of the connector. Relay 317 also attracts its armature 334, which applies current from the positive battory' 335 to 'oonductor 336, which leads to the armature 337 of relay 338. Said relay 338 has two windings, one included in a groundediconductor connected with the conductor 312, and the other in a grounded conductor connected with the conductor 312, said relay thereby receiving current from the brush 167, When the same rests on either the second or the third contact of a group. In the present case, the brush 167 is resting upon the second intermediate contact past the second 10s point or the third of a group, and current from battery 263 flows by way of conductor 264, brush 164, fourth group of strapped contacts to the fourth contact 265 upon theprimary controller, thonce by way of arm 166 of the contrller,

conduc tors

269 and 311 to the brush 167 of the translator, thenco by way of conductor 312,