US1145659A - Automatic selecting multiparty-telephone system. - Google Patents

Description

0. ASMUSSEN. AUTOMATIC SELECTING MULTIPARTY TELEPHONE SYSTEM, APPLICATION FILED MAR. 2|. I9I 3- RENEWED IIIAY 25. I915.

1,145,659. A I Patented July 6, 1915.

7 SHEETS-SHEET I. 3

0. ASMUSSEN.

AUTOMATIC SELECTING MULTIPARTY TELEPHONE SYSTEM.

APPLICATION FILED MAR.2I. 1913. RENEWED MAY 25,1915.

1,145,659. Patented July 6, 1915.

7 SHEETS-SHEET 2.

Y .0. ASMUSSEN. AUTOMATIC SELECTING MULTIPARTY TELEPHONE,SYSTEM.

' APPLICATION FILED MAILZI, I913- RENEWED MAY 25,1915.

1,145,659; Patented Julyfi, 1915.

7 SHEETS-SHEET 3.

257 Line 1 Nor'ih 24b 0. ASMUSSEN. AUTOMATIC SELECTING MULTIPARTY TELEPHONE SYSTEM. APPLICATION FlLED mm. 21, 1313. RENEWED 'MAY 25. 1915. 1,145, 59, Patented July 6,1915.

, I SHEETS-SHEET 4- 2 H 1 4 I W 15 WITNESSES: INVENTOR ATTORNEY:

0. ASMUSSEN.

AUTOMATIC SELECTING MULTIPARTY TELEPHONE SYSTEM.

APPLICATION FLLED MAR IN, I913- RENEWED MAY 25,1915- Patented July 6, 1915.

7 SHEETS-SHEET 5.

INVENTOR WITNESSES:

O. ASMUSSEN..

AUTOMATIC SELECT-m6 MULTIPARTY TELEPHONE SYSTEM. APPLICATION FIL ED MAR.21,1913. RENEWED MAY 25,1915.

1,145,659.- Patented July 6, 1915.

7 SHEETS-SHEET 6- H0 I B g Z0 /Z3 /Z5 /Z525 A33 ATTORNEYS 0. ASMUSSEN.

AUTOMATIC SELECTING MULTIPARTY TELEPHONE SYSTEM. APPLICATION FILED MAR. 21, 1913. RENEWED MAY 25,1915.

1,145,659. Patented July 6, 1915. 725 127 730 7SHEETSSHEETI- r EE 3/ 120' iii, I, 55 /Z-- 71a T* 11% I "r r 9 12 110. T}

um y) I a 611mm;-

.nected and served on an line system. Such small cities and rural districts are provided with circular lishedfor which only very UNrT-ED STATES PATENT omen Y OTTO ASMUSSEN, OF BROOKLYN NEW YORK.

v.AUTOllllIA'lIC SELECTING M ULTIPARTY-TELEP HONE SYSTEM.

T0 aZZ whom it may concern Be it known'that I, OTTO AsMUssnX, a subject of the King of Denmark, residing at Brooklyn, Kings county, and State of New York, have invented and discovered certain new and useful Improvements in Automatic Selecting MultipartyTelephone Systems, of which the following is a specification.

The object of my telephone system is to provide a very economical plant, substituting for manual help reliable automatic operation, which at the same time responds to all the advantages that any telephone system offers the public, and with that aim in view this system has been contrived for the establishment of a mutual automatic interconnecting or exchange system between the subscribers in towns, cities and rural districts on a single metallic circuit svstem with additional earth connection, with the advantage that none of the intermediary stations or subscribers can either hear the calling, the ensuing conversation, or be able to interrupt connected-parties, or take the line.

Small cities and rural districts can be coninterurban trunk and terminal-lines and the subscribers make their own local connections mutually by means of the automatic selecting apparatus, while a central oifice performs the interurban or long-distance exchange connections, connecting automatically, and at a far distant point, the subscribers individually on one system with parties on another, carrying most adaggregated number of sysvan-tageously an tems on one metallic trunk circuit.

In large cities a central office is establimited help is required, or if an-automatic switching or exchange system be adopted, my system will in connection with such an automatic exchange system greatlyreduce the expense of the costly switching apparatusin common USE.

Long terminal and trunk or main lines are constructed so as to establish two telephone speaking circuits through above metallic circuit and earth connection, with the pur-v pose of maintaining a quick service-system. One circuit is used for ordering connections with subscribers, and this circuit will stand open for such shortcommunications to the central office at all times. The ringing on this circuit will not be heard by anybody; except by the central office. Connection between two parties is established at the first moment the lines are. free, and the waiting party, who has ordered the connection, and the selected party, are both called up at the same time by thecentral ofiice. and when the communicating parties unhook their receivers they are in communication together on the circuit reserved for conversation purposes, and nobody can, as per above, overhear the conversation, not even the switchboard operator.

As subscribers on circular systems and on some terminal lines in towns and small cities connect themselves mutually they do not request the central oflice for connections. except when connections over trunk lines. or an interurban exchange are required, and in that case the operator at the central office enters with his current the nearest system. sets the calling subscribers apparatus in position for communication, leaves that system, and connects with the other city's sys tem, where he sets the selected subscribers apparatus in the same position, whereupon he rings both parties up at the same time,

leaving all the other intermediary stations matic apparatus combination on circular lines, works to both systems and terminal 'sides,- establishing connections back-ward justas well as ahead, so that many pairs of parties can speak together on the same line at the same time. The same system is an excellent vehicle for long distance telephone use, as it closes out every one not wanted on the line, excluding every possibility for any body to disturb or intervene, and even the operator at the central ofiice can be cut out.

A signal (not shown) on the apparatus at the subscribers station will indicate when the line is free or occupied.

Three diiif'erent line systems will be used in' connection with this telephone plan, trunk lines, circular lines and terminal lines.

cation of power to the auxiliary switching Trunk lines are established for interurban' connections, and will "connect anumber of city systems automatically on one circuit. Circular lines are installed in small cities in an endless continuation, or the ends are brought together in an interconnecting installation, so that they can be bridged over and form an endless circular circuit, and the ends can in this case be cut off at convenience. Terminal lines are established in cities radiating to all sides from a central office and connecting a large number of subscribers through each circuit with that ofiice.

Circular and terminal systems are provided with the automatic, subscriber, selecting apparatus, when no central office exists in the system. Subscribers on terminal lines in larger cities either connect themselves with one another-,or they ask for connection from the'central office.

This invention therefore consists in the structure of parts and in their combination and association in electric circuits and systerms to the attainment of the above object,

substantially as hereinafter .set forth and claimed.

In the accompanying drawings, which form a part of this specification, the various apparatus have, in the main, been shown coupled up in the system and yet have been'given captions as though sepa- "nately illustrated. This it is believed will simplify thedisclosure of the invention, in-

much asthe illustration of conjointly operating apparatus of one station is neces.

8 and 9 a specially constructed set of inter'-.-

changing apparatus; Fig. 10 a set of modi lied bridging relays; Fig. 11a circular line system; Figs. 12, 13, 14, 15, 1'6, 17, and 17 details of the automatic selecting apparatus:

Fig. 18a telephone switch connection at a station; Fig. 19 a modification in the appliapparatus; and Figs. 20 and 21 detail views e 1 depicts-an automatic selecting automatic, selecting apparatus is contrived for central station purposes. It is used .in circular .systems, in all the subscribers places, and sometimes on terminal lines. It' consists of an electrical driving motor, Fig. 1, M, two connecting wheels, 20 and 21, and a. numerated'selecting disk, 22, this last being provided with numbered holes for insertion of a- -connecting plug, 113,,

"which serves the purpose ofsetting the se-' lected'subscribers apparatus for communication. All three wheels are fixed on an axis, and. are carried around together by the motor, which is fed by a local current from battery .23, forming its circuit through the retaining arrangement, 13%, collecting brush 25, over stopping pm 128, wire28, and

back over wire 29. Through the special contact or connecting system used in this-selectingapparatus it is possible to reverse the current pulsations in a circuit alterna- 'tively. and automatically.

The normalposition of the collecting or connecting brushes 120 and 125, Fig. 1, is

always resting on insulated plates, and the. spring contacts 118 and 123 are always arranged so that the first station, which is consequently the operating partys, is set for conversation Without it being necessary.

to put inanother plug for the setting of that instrument, so the plugfor setting the selected partys apparatus for conversation is generally the only one to-be inserted in v the numbered hole in the selecting disk,

corresponding to the selected partys numher. I

The line changingapparatus, Fig. 2, is a specially constructed electro-magnet with an arch-shaped attachment, 30. It is designed for changing the lines from the se- 'leeting apparatus sothat they shall cooperate either with the line ahead of, or on illustrating features of construction and arrangement on an enlarged scale. I

In order that the cooperation of these several instruments may be better understood in the operation of this system, a detailed description thereof will first be given.

. The apparatus used for the local connect-' ing and interurban exchange operations are the following: The specially constructed the line backof, the operating station. This instrument is not reset until all the other apparatus on the line have been reset after a telephone conversation has taken place,

exceptin stations where somebody has tried -to take the line While. it was busy. Theresetting apparatus. Fig. 3, consists of a smaller motor M, a resetting wheel 31, and a plug supporting rack, 32, which serves as a connecting and disconnecting arrangement.

The auxiliary apparatus of and 6, are electro-magne'tic switches. The two coils of each instrument are bothdouble wound for the purpose vof 'diiferently and momentarily energizing the polarized armatures 33, 34:, and .35, which'are represented small polarized annatures 36, 37, 38, 39 10, and 41, accompanying ,-.the magnets of these switches. 1 The armature levers of these relays are momentarily attracted atr .the moment a current passes those coils,

in their resting or normal position. Six 13.

I scribers places.

i 33, 34, and

. armatures from against contact posts which keep them from adhering magnetically to the armatures, or they release according to the or deenergization of said magnets. These instruments 'are' installed in all the sub- Arch switching attachments are built on'the polarized arniatures 35 and they rock over with the the -resting position R, to the operating position 0, and vice versa. Yhen rocking over to'the one or the other side, the'connecting or conducting sleeves on 'up or down between,

I on both sides ot the the arch, insulation, are thrown or away from, the roller contacts, signified by the small eyes arches, thus forming them, or cutting the 'conseparated by connection with --n'ection between same, every time the armaf 'coils, thereby preventing the current "I 60, before the contact contact screw 65, wire 56,

auxiliary a ppara tus, Fig. 4' or ture shifts. The armature 40 interrupts line 1 every time it .is attached, viz.: time a current passes through the magnet pulsa tion from going out on the line to disturb the position of the next stations instrument, it the le er 49 of the bridging relay, Fig. 7. should fall back on its resting screw Wheels 20 and 21, ,Fig. 1, have finished their contact pulsation. These levers keep the line interrupted as long as the current pulsation lasts. The armature 36 interrupts the linein the same way, but on the section back of the operating station.

The set of bridging relays, Fig. 7, consists of-two bridging relay coils, 44 and 45, four bridging levers, 46, 47, 48 and 49, two local current relays. 50 and 51, with relay levers and 53. hen the armatures 33 and 35, Figs. 4 and 6,, are in resting position a local circuit is maintained through the coils 44 and 45, Fig. 7. from gravity battery 54, Fig. 7, emanating from the carbon pole, flowing over. wire 56, union 66. Fig. 4. armature 33, union 68, Fig. 6,

armature 35, contact screw 1-89. wire 56", through bridging-relay coil 44, Fig.7, over wire 56,througlrbridging relay coil 45 and back overv wii' said battcry.-.

over to positio (In this circuit is interrupted and all the foul" levers, 46, Fig. 7, fall back ORV-H1811 restingscrews 57,

through one Ofllifl coils At certain operations it fi's necessary to- 1 have'the levers 46 and 49. Fig.

energizationevery levels 46, 47

36W to the zinc pole of Ivervy tune anyone of the; 16, as rocked 47, 48, and. 49,

position. this is atthe operating station,

or on the line back, which will be called the southern section from the operating station) and it is only then rocked over simultaneously with one of the armatures 33, Fig. 4 or 35, Fig. 6. At the moment these two rockings or shiftings of the armatures have taken place a local circuit is closed over same, the current flowing from the carbon pole of gravity battery 55, over wire 61, roller contacts 72, Fig. 5, connecting sleeve 73, roller contact 74, (the armature 34 is supposed to have rocked over to position 0, so connecting sleeve 73 has advanced up between roller contacts .72 and 74 and forms connection with them) over wire 61, roller contacts and conducting sleeve 75,- 76, and 77, Fig. 6, (supposing it is that auxiliary pparatus that has rocked over, conducting sleeve 75 forms therefore contact between 7 6 and 77) over'wire 61". through coil of local current relay 51, Fig. hand back over wire 61 to the zinc pole of. said battery. This sustains lever 49 in upright position until the apparatus are reset, whereafter it is upheld in the afore described way through localv circuit current from battery 54. Had it been the armature 33, Fig. 4, that had rocked over to position 0, this current emanating from battery would partly have taken the same way over wire 61, roller contacts and con ducting sleeve 72, 73, and 74, Fig. 5, wire 61, but from union 78 it would flow over wire 79 toroller contacts and connecting sleeve 81, 80 and 82, Fig. 4, (conducting sleeveSl is supposed to be thrown up between contacts 80 and 82) over wire 79, through coil of local current relay 50, over wire 79 and back to the zinc pole of battery 55. This shows that if the ar1nature35. Fig. 6, is thrown over, the lever 49. Fig. 7. is sustained in upright position, and the other and 48 will fall back, but if the other armature Fig. ,4, is thrown over, the lever 46 is upheld and the other levers 47, 48 and 49 fall back, whereas, if armature 34, Fig. 5, is not thrown over, no levers are sustained in upright position, as the circuit through roller contacts 72 and 74. Fig. IS 'lHOlKGD throughan nsulating sleeve when'in normal"pps'ition, as shown in the (lcsign.,:"The' rocking'over of either one of these armature-s, Fig. 4 for 6, makes all the four bridging relay levers 46, 47, 4S, and 4-9, Fig. 7, fall back and thus lock the stations "out of connection everywhere this operationis performed.

The specially constructed set of changing apparatus of Figs. 8 and 9 is another set of electromagnetic switches. with arch switching attachments. 33 and 64. builton the polarized armatures 85 and 36. Four small armatures 87, pany the operating magnets and their object will be explained below. The set of bridging relays, Fig. 10, has twocoils 91 and 92,

i ntcr- S3, 89, and 90 accomtwo levers 93' and 94,- and a Meal current relay95, which sustains the lever 94 in upright position by means of battery 96, which is in circuit through it, when the armature 85, Fig. 8, has rocked over to position 0, over wire 98, roller contacts and conducting sleeve 99, 100, and 101, (the armature issup- '31111313111885, contact screw 103, wire 102,

through coil 91, Fig. 10, over wire 102" and back to the zinc pole of battery 97. The other circuit isover the same wire 102, union '105, where it parts from the first described path, over wire 106, union 107, Fig. 9, armature 86, screw contact 108, wire'106',through coil 92, Fig. 10, over wire 106" and back to the zinc pole of said battery. This keepsthe levers 93 and 94, Fig. 10, attracted to The circular-line system, 85

contact posts 109 and 1 10, when the arma tures 85 and 86 are in resting position; The bridging relays 91 and 92, Fig. 10, have each their separate circuit.

, typified in Fig. 11, represents a'number of stations (three) with an extra line-L93, for trunk line service. This extra line is not necessary in making interurban connections, but may be very above, I end, and'has noother path than to the cenconyenient". (Itflis only used in citiesand towns lwhere ai'larger number of subscribers are connected,butnoton the trunk linesL. 2 is always insulated at the extreme ends on trunk and terminal lines, andja breach can also be made in circular systems, but this makes no difference in thatsystem, so when a subscriber on a circular, terminal or trunk line calls'up the central oflice, tion with .some interurban subscriber, he depresses the'key 112, Fig. 11 and Fig. 6, and

he rings-the usual call bell, (not shown).

This key connects his telephone with 'L. 2.

and'earthwith the central oflice, (as per L. 2 is interrupted at the extreme tral stations). The connection with .L.1 is

interrupted in the switching attachment .of

the auxiliary apparatus Figs. 4 ancl 6, which will'be seen later on, so the operatingparty. sends his message to the central ofiice while I depressing that key all the time he speaks. After thatthe subscriber releases his key.

' Then thecentral oflice sets-for communication both his apparatus and that. of the party in the other city tov whom he wants to speak, and both are rung upat thesame ordering connectime, and the conversationis carried over L. 1 and earth. In cities where said extra wire or line is used, each subscriber has two extra auxiliary apparatus'installed, like those represented in Figs. 4 and 5, or 5 and 6, for the extra interurban connecting purposes, but'no extra selectingpr resetting apparatus required. The telephones and auxiliary apparatus are represented in 11'. p

The sectional cut or view, Fig. 12,' is of the back side 20 of connecting wheel 20, showing a series of radial spring contacts Compared with' sectional cuts, Figs. land 16, it will be seen that when the plug 113 only graphically is inserted in the contactwheels, the radial spring 114 is pushed out, this interrupts the- L. 1 south, but it leaves the L. 1 connected to the north gThis is arrangedwith the object of s ammin the connection of the circular line, always out station, so ahto give the emanating currents the right direction over the one'or the other at the operating section. L. 1 southis connectedlwith the underlying connecting. plates 115, Figs. 12 and 1 6,Iand L. 1 north to the set of radial springs 114, at connecting screw 301, Fig. 1. When both sewer thesev radial springs are in normal position .the connection between the two sections of line 1 is established, but as soon-as one of the radial springs I is pushed out, thisconnection is broken to the southern section.

, The sectional view, Fig. 13, is of the front side 20 of contact wheel 20, showing the spring contacts 117 and the series of contact plates 118, see Fig.16. These contact plates are connected with a conduction rail 119,

117 are'all connected together with L. 1,

Fig. 13. As the series of contact springs 117 are. standing out from the connecting rail 119, the connection from battery 121 to L. 1 is interrupted when in normal position,

whereas connection is established as soon as.

one of those spring contacts is pushed back against the rail 119 by the insertion of the plug 113. The contact plates 118 have insulating spaces between them, Fig. 13. @When the said plates come successively in contact with connecting brush 120, current" pulsaapparatus, Fig. 4 or Fig. 6, on the line,

locking all intermediary stations out of. connection, as all the plates representing the number of intermediary stations are all brought in contact successively with brush.-

-c0ntact 120.

tions flow from battery 121 out'on L. 1. There-is one spring contact 117 and one con- 120' nectimg plate 118 for eachsubscriber, or sta- 5 The sectional view, Fig. 14, is of theback j 128, as soon as the motor revolves. the wheels remain in their stationary 'piug causes the sto ping. and all wherewith side, 21 of connecting wheel 21, Iand it shows a series of radial spring contacts, 123, each with its contact plate 12% on top. These plates are set with di-electric spaces or with insulating plates between the connecting plates, and all are connected with earth, Figs. 1 and 14. lVhen the plugis inserted it pushes out one of these spring con-' tacts 123, as shown in Figs. 1 and 16, and with the rotary movement of the wheels, the contactplate 12%, Fig. 14, comes in touch with connecting brush 125,-this connects the battery 122 with earth over connecting platev 121, Fig. 14. and connecting screw 126,- Fig. 1. There is in wheel 21 a radial spring with its contact plate for each station on the line.

The sectional side 21" of contact wheel 21. This cut, together with the design of Fig. 1 and the cut of Fig. 16, illustrates the connections and circuit for the local motor battery 23. The contact plates 127 are to be put as close together as the movement back and forward willallow.

part of the series of springs 123, each of them is connectedwith a circular wire 129, Fig. 15, and this is con nected with the local battery 23. I these springs are in normal position their contact plates.127 touch connecting brush 25, Fig- 15, a '16, wherewith the motpr circuit is closec through the stoppingpm When position this local circuit is interrupted by the retaining pin 26, as will be described below.

lVhen plug 113 is inserted in the hole bearmg the number of the subscriber who is to be called, it pushes the corresponding contact 123 out, lrigs. l and 16, leaving an Jay space, 130, Fig. 16, in the wheel. l ln'ough plug 113 is 111:: vet. *ound with them, and it comes acror" the stopping pm 128, Figs. 1 a l 16, (w ich pm is always in ilKEd position, :18 are the co art brushes 120 and 125) and that stops the movement of the wheels. .12, the mom a the wheels stop, the contact brush 25 slip into the empty space 130, Fi 16, and breaks therewith the local moto1 curren: This is aw-mined in order not to waste use essl the cur-rant while conversation is going on. The pushed out spring of series 123, Fig. 1. t the selected statior. for con ers'eion at the moment the the other intermediary nlrlii-f-719 have then been locked out through ci'.:-rent pulsations over contact 118, Figs. 1 and 13. =Ths is now the pos ion u' tl19 selecting apparatu when the operating party can call up. Win-n the ccuwusiiion is finished Jul the plug is taken out, the pushed out spring 123 falls back on contact brush Figs 1 and 16,

the local motor circrii is estabview, Fig. 15, is of the front retaining clip 134:, to stop the wheels, and at They form a series of contact plates on the front- When "taining clip 13%,

the wheels and s'tationarypoint. This stationary place rethe rotary movement of the wheels,

motor moves until it is stopped bythe retaining pin 26, Figs. 1, 17 and 17*. At the moment this plug is taken out, the spring contact 117, Figs. 1,

lished again and the 18 and 16, stands out from its connecting rail 119, Figs. 1 and 13, and from battery 121with L. 1 and when the wheel moves till it reaches its stationary then without pulsating any current into the main line. There are none of the radial contact springs 123, igs. 1 and 16, pushed out to cause current pulsations from battery 122, so this movement does not perform any operation on the main lines at all. Retaining pin 26, Figs. 1 and 16, stops the wheels, interrupting the local current, and keeping the motor in its stationary position.

The selecting disk 22, Figs. 17 and 17 is provided with a circular connecting or conducting rail or strip, 133, which has a Figs. 1, 17 and 17*, made the same time to interrupt the local ,motor current circuit. This conducting strip ends in aspring con tact tongue, 132, Figs. 17 and 17*, which closes the circuit when raised against the reand interrupts it when the retaining pin 26. This connection farther around place, it moves pressed down by .pin remains always in a fixed position, while the retaining clip is carried around with comes across saldpin at the sponds to the. subscription number of the operating party. If subscriber number 10 has finished conversation, the Wheels'will stop at number 10, and if subscribed numher 50 has operated connection with somebody, his wheels will stop at his number. Fig. 1- gives a general view of the local battery wires, passing bver the retaining arrangement, 134:, from there it passes to the conducting plates 127, Fig. 15, over contact brush25, stopping pin 128 to the motor from there back to the zinc pole. 'This explains that there are two stops of the wheels in each rotation, the first when the plug1l3 comes across stopping pin 128, and the next is at thestationary place, and interruptions in the loca current are caused as shown at 130,Fig. 16, and 12%, Figs. 17 and 17 To put the motor in rotary movement the retaining pin 26 is pulled out an instant, wherewith the-contact tongue 132, Figs. 17

and 17 is released and comes in contact.

tongue 132 can be rephwed by a hoolelike spring similar to spring this is 223, Fig. :5, lifted from its cont-act plu en the wheel is finishing its rotation, 21; he hook-shaped spring retains it, so when the plug, or in this case the retaining s ,a. is interrupted,

clamp 231 by the I pin, is pulled out the spring drops down on itsv contact clamp and the pin can. thus be dropped immediately after having beenpulled out without causing it to drop on any -retaining-.- arrangement before the wheels start moving.

1 The telephone, Fig. 18, is installed in connection with the auxiliary apparatus and the key 112, Fig. 6, is for use in calling up the central oflices on the trunk lines. Another key. 137 may be installed for the purpose ot excluding the central oilice from overhearing 'the conversations, and the subscriber .'nearest the central ofllce depresses. that key,

interrupting the line to that side.

The combination, represent d g iscontrived with the object of augmenting 'the magnetic force of the auxiliary apparatus, if that shouldlbe required on long distance lines for the. shifting of the armature and the arch switching-arrangement. For

this purpose thepolarized armature, 138, isf provided at its ends with twovfixed short local circuit from battery 148, through that set of roller contacts and conducting sleeve which is ready in the switchingarrangement for it." If the magnet-is-in resting position R, the roller conta'cts'and conducting sleeve 149, 150 and 151 aref'the' ones forming the path-for it. The current flows from carbon pole of battery 148, .over wire- 152, relay lever 1-53, wire 1'55, relay lever 145 which is attracted) stop 147, wire 155, through solenoid 142, roller contacts and conducting sleeve 149, 1 50 and 151,,back to the zinc pole over wire 156. This helps the main current (whose path is not indicated in the design) to rock the magnet over into position 0.. Supposing the switching attachment is in position 0, and it is the resetting current that comes in through the coils, then the insulating sleeve 158 has been thrown down between the contacts 149 and 150, so this v .tacts and conducting sleeve 174, 175 and f path is interrupted, but another over roller contacts and conductingsleeve l-fi, 160 and 161 is formed. The current "li ows conse-- quently, at the moment the levers 144 and v 145 have been attracted, from the carbon pole of battery 148 over wire 162, relay lever 154, wire 163, relay lever 144 (which isattracted) stop 146, wire 164, through solenoid 141, over roller contacts and conducting sleeve 159, 160 and 161 (conducting sleeve has by the magnets rocking over been in Fig; 19,

. local motor circuit is closed and the selecting said battery. This will greatly strengthen the magnetic forces. Otherwise a local cur- ;arent can more simply be let through the magnet coils 143 a'nd 143 in the same direction as the main line currents.

.The. practical use of the system is the following: Suppose a station, '10 for instance, in a system wherethe subscribers make their own connections, wants to communicate witha station 50, the operating subscriber takes the plug 113, Fig. 1, from the supporting rack 32, Fig. 3, and puts it into hole number 50 of the selecting disk 22, Figs. 1 and 1.6..

This establishes the above described connec tions. The spring contact corresponding to number 50in the series 123 is pushed out by I the plug, whichvis provided with shoulders for the object of pushing back simultaneously the spring contact 117 and spring 114,

Fig. 1. Spring contact 117 comes therewith in contact with conductingf rail 119. When a pull is made on the retaining pin 26-, the

apparatus revolves.

' As the first'station to be set for communication is the operating partys in all cases, the respective contaet 118 and spring 123 arepermanently set so that ,they c'ausethe setting of that firstvstation without needing the. insertion of a plug (contact 118 of station 10 is to that end connected directly with. the introduction wire to line 1, that is to say to wire. 167, and spring 123 in this station does not leave any empty space 130, Fig.' 16,'this is filled 0ut to breakthe local current), and as per above, contact brushes 120 and 125 are resting in normal. position on insulated plates, whichadlnits this permanent arrangement. The first cur rent'pulsation's fiow from both batteries 121 and 122, Fig. 1, at the same time forthe setting purposes of station 10. That from bat tery 121 flows over contact brush.120-, conducting rail 119, spring contact 117, union 302, wire 171, (it cannot go backward over";

wire 171 as'the path is interrupted at roller.

45 connecting post 172, wire 173, rol r concontacts 278 and 279) fartherahead. over;

' wire 171, Fig. 7,lever49 of bridging relayg' z 176, Fig. 6, through first winding of magnet coils 17.7 and 178, wire 179, union and Y back over line 2 to the zinc pole ofbattery 121. At the moment the current passed coils 177 and 178, the armature 35, Fig. 6,.-

rocked over to position 0, and the arch" switching attachment changed the connec tions, and in the above described way tl 1e.-'v

local current from battery 54', Fig; 7 ,having its circuit over'wire 56, union 66, Fig.f 4,,

simultaneously through coils which is thrown ary station while the line i:-

armature 33, contact screw 65, wire 56, union 68, Fig. 6, contact screw 189,- wire 56", coils 44 and 45 of the bridging relay,-Fig. 7, and back to the zinc pole of said battery, was interrupted at contact screw 189, F ig; 6. and all th levers 46, 47, and 48, Fig. 7, fell back. The lever 49 gets no time to fall back as will be seen in the following. At the same time that battery 121 sends current over L. 1,. another current pulsation flows down through earth from battery 122, Fig. 1, over contact series 123, union 126, through earth, up over wire 180, Fig. 6, (the only path open for it) over relay lever 41, (which is at that moment attracted against stop 181 by main current from battery 121 flowing 177 and 178) over wire 182, roller contacts and connecting sleeve 183, 184 and 185, Fig. 5, through first winding of magnet coils 186 and 187, over wire 188, union 189 and back to Zinc pole of battery 122 over L. 2. At the moment this current-passed the coils 186 and 187 the magnet 34 with its switching attachment was thrown over to position 0, a local circuit from battery was closed over wire 61, roller contacts and conducting sleeve 72, 73 and 74, Fig. 5, (sleeve 73 has now been thrown up between contacts 72 and 74, forming connection) over wire 61, roller contacts and conducting sleeve 75, 76 and 77, Fig. 6, (sleeve 75 is up between contacts 76 and 77) over wire '61, through local current relay coil 51, Fig. 7, and baclnto zinc pole of battery 55 over wire 61'. This local current sustainsthe lever 49, Fig. '7, attracted in vertical position until the instruments are reset. I

The small relay 191, Fig. 7, is installed with the intention to interrupt in all the intermediary stations locked out,,the connection from these stations selecting apparatus with line 1, which is lead in through wire 218 and Fig. 4, to insure that nobody can take the line, or be able to make any disturbances when other stations are in com munication. At the moment the auxiliary apparatus, Fig. 6, rocked over. a path was formed for the local current through relay 101, Fig. 7. (which breaks said connection) from battery 54. over wire 56. union 191 wire 1 3, roller contacts and connecting sleeve 194, 105 and 196, Fig. 5, wire 197, contact screw 1 Fig. 6, armature 35, over in position 0 and therefore resting on said screw; union 68, Fig. 6. roller contacts and conducting sleeve 19 200 and 201. (conducting sR-cvc 200 is 'tln-n down between contacts 109'and. 201) wiri- Z102. through ('oil 191, T ig. to zinr pole of bat er}? 54. Th 15 1 m" relay 101 nection over wire position, of

and back KOPPS lever g the con- 5 would be the at relay 101 in an intermedioccupied, but in 212 and 213) over down between those contacts and that conthen interrupted there. so

necting link is relay 191, Fig. is not affected. This describes the setting for communication of the first station. and the next 48 stations have now to be locked out of connection. The next following current pulsation on its way to the second station on the. northern section flows through theoperating sthtion from battery 121, Fig. 1, lowed this time by any pulsation from battery until the pushed out contact 123 for station 50 reaches the contact brush 125) out over wire 167, contact posts and sleeve 168, 169'and 170, wire union 302, wire 171, Fig.2, as already described, wire 171, Fig. 7, lever 49. contact post 172, wire 173, roller contact 174, F ig.. 6, but as the insulating sleeve 204 has been thrown down between contact 174 and 176, the current flows (this is not folup to roller contacts and conducting sleeve wire 211,"- roller con-. tacts and conducting sleeve 212,213 and" 214, (conducting sleeve 214 is up between union 215, union 21-7, union217. wire 218,- Figs. 4, wire 218 Fig. 2, over roller contacts and conducting sleeve 219, 220 and 221, over wire 222, Fig. 2. wire 222, Figs. 4, 5, 6, and 7, and out at 280 Fig. 4, on line 1 to said second station. The said second station is also represented graphically in the same Figs. 4, 5, 6, 7, 1, 2. and 3, but it must be remembered the various apparatus are now to be considered in normal position. The pulsations enter the second station as coming from the south, L. 1 over roller-contacts and conducting sleeve 294. 205 and 296. Fig. 2, wire 278, contact plate 115, contact spring 114, (which is not pushed out in the intermediary stations and therefore forms contact with plates 115) union 301. vi-l e 300.

6, and 7,-

union 299, wire 171, xvii-e171, Fig. 7,

lever 49, post 172, wire 173. roller contacts and connecting sleeve 1'74, and 176. Fig. 6. through magnet coils first winding 177 and 178. union 180 and back over L. 2 to zinc pole of battery 121. This operation shifted the armature over to position through the A whercwith the local current bridging relay COllS 44 and 45. Fig. 7, is interrupted, and the levers 46, 47, 48 and 49,

- fall back all of them, and as auxiliary apsover contacts and conducting sleeve 194, 195

' armature 35, (this armature rests on screw.

' over the same described way, taking its and 196, Fig. 5, wire 197 screw 198,. 6,

198) roller-contacts and conducting sleeve 199, 200 and 201, wire 202, through coil 191, 'Fi l 7, and back to ZlIlC'POlQ, attracts lever 19 until the resetting of all the apparatus takes place. This second station on the northern section from the operating station is now locked out andjthe next current'pulsatioil designed for the third station flows course over last locked out stations lever 49, Fig. 7, contact post 60, (as lever 49 has fallen back on that post) and'outover L. 1, to the next station, and this same operation is repeated 4 8 times, but all in such quick succession that it does not take half a second to have both communicating station's setand the 49 locked out. The 50th is now set just in the same way as described for station 10, -;but in this case the connecting wheels 20, 21 and 22, Fig. 1, stop as the plug- 113 now comes across the stopping pin 128, contact brush 25 .Fig. 1, slips into the cavity 130, Fig. 16, and breaks the local motor current, and the desired party is called up. If the connection had been made by a central office both the communicating parties would now be rung up at the same time, and the party nearest the central otlice could depress key 137, Fig. 18, so that the central office would hear nothing of the conversation.

lVhere central oflices operate the connections the subscribers need no selecting apparatus, and only two auxiliary apparatus would be required, like those represented in Figs. 5 and 6, withbridging-relavs, Fig. 7, the same as is the case withthe afore-mentioned installations on the extra third line I in circular systems for interurban communication. i

After finishing aconversation the plug 113 is taken out of the selecting apparatus, Fig. 1, and this puts the motor in movement. automatically,,the connections for outgoing currents are cut off, all in the afore-described I 55 Way. The motor is stopped an instant after at its stationary place, as above described. Plug 113 is now inserted in the resetting apparatus, Fig. 3, it drops just back of the spring contact 223, and it establishes a local motor and a. main line current circuit at the same time, from batteries 224 and 225, over contact screw 226, supporting rack arm 227, cent al piece of plug 228, supporting rack arm 229, contact screw 230, contact 231, spring contact 223, and here at union 233 the said currents part, the'local current from its path over L. 1 and back'throughearthwire 171, Fig. 7, bridging relay lever"49..v

battery 224 flows througli'the motor and back to the zinc .pole, starting the motor.

The main line, or resetting, current makes It continues from union 233'overwire 234 roller contacts and conducting sleeve gi- ifg 236 and 237 of the line changing ap araais, Fig. 2, over union 302, wire 171, Fig.1; 2,2

down that lever, through core-of relay Fig. 7, over spiral wire to lever'238, as'this" is attracted against post 239 in the stations set for communication, it flows over thatpost, wire 241, roller contacts and conduct ing SlQEX'G 62, 63 and 64, Fig. 5, (conducting sleeve 64 is :up between-=62 and 63) down through second winding of magnet coils 186 i and 187 and to earth: This operation throws thearmature34, Fig. 5, back into resting position R, and it interrupts the local current through small relay coil 51, Fig. 7 which causes the lever-238 to fall back on post 240, and the resettingcurrent, (which is flowing out constantly without cessation till all the instruments have been reset) flows now over contact post 240, wire-242, lever 48',

post- 59, wire 243 Fig. 7, roller contacts and conducting sleeve 69, 7 O and 71, Fig. 6, throughsecond winding of magnet coils 177 and 178 to'earth. This operation rocks the armature 35-, Fig. 6, back again in its resting position and it reestablishes the local circuit through the bridging relay coils 44 and 45,

Fig. 7, which attract the levers 46, 47, 48, and 49, lifting them into their upright posi-' tion.

hen the auxiliary apparatus, Figi.. 5,is I reset, :1 small fraction of the currentmay I take its wayfor an instant over lever 49, post 172, wire 173, roller contacts and con.- ducting sleeve 205,: 206 and 207, Fig. 6, wire 208, key 137 ,Fig. 18, telephone contact 209, wire 210, lever 38,. F ig. 5, wire 211, contacts and conducting-sleeve 212, 213 and' 2f4, union 215, union 217 and outon the line to the next station, but this-is scarcely an' instant, and it is only to meet greater resistance over a longer path and-through another bridging 'relay, and magnet coils to earth (if that following station be set or locked out) .but thispath is cut off at the' first following station in normal position, so the greatest part of the current flows through the-coils, 186 and 187, Fig. 5, to earth, attracting the armature 38, this inter over lever 49, Fig. 7, post 172, wire 173,-,;. roller contacts and conducting sleeve 174, 1-3'6' 1 20", rupts the path forthis insignificant stray 175, and 176, Fig. 6, through magnet coils 177 and 178 to L. 2, but the way designed for it, namely, at the moment the bridging next following 48 are locked out stations and the bridging levers 4G, 4", 48and 49, Fig. 7. are resting on their back stops, the current Will come in over lever 49, Fig. 7, down that lever, over post 245, union 247, Wire 242, lever 48, post 59, wire 243 roller contacts and conducting sleeve 69, and 71, F ig. 6. through second Winding of coils 177 and 178 to earth, shifting the armature 35 over to position R, reestablishing the local current and raising the bridging levers again. The small part of the resetting current escaping over lever 49, Fig. 7, post 60, and out on L. 1, is instantaneously checked as the current passes the coils 177 and 178, Fig. 6, attracting the lever 40, which interrupts the L. 1', that is lead dOWIl to that relay with that object, and this makes the full force of the current pass the designed Way,

through coils 177 and 178. This same operation is repeated until all stations are reset,

station 50 is resetin the same way as above described for station 10.

The at'oredcscribed Way of establishing connection by the subscribers themselves, and doing the resetting quite imperceptibly and automatically, demonstrates the operation one way only, which is ahead, or over the northern section from the operating station, but connections can also be made in the other dir ction, or over the southern section from the operating station. A subscriber on a circular or terminal. line system can perceive when the line is taken ahead of him by some other subscriber, for when he reaches the operating subscriber-s selecting apparatus, the line is interrupted, he can notice it upon ringing up that the line is out somewhere, and with an extra little battery and a sounder, whichcould be constantly kept'in use, or switched in, in order to test the line, and by counting the times the sounder sounds, any operator can know exactly which station has taken the line, or where the line is interrupted, and if he does not Want towait till the line .is free, he can make connections over thesection back of him, and it just for such purposes that the extra line changing apparatus, Fig. 2, and the extra'auxiliary apparatus, Fig. 4, have been installed. The selecting disk 22, Figs. 1 and 17, will to that end have the ilug holes numerated shore with the num- Y r be s to take when Working '1, spring 114,

ahead and below with the numbers that must be used when working over the back or southern section. The normal position of this line changing apparatus, Fig. 2, must be described preliminarily. The through connection for an operating current over that, in reference toan intermediary station before it is locked out, is for a current coming in from the southern section over roller contacts and conducting sleeve 294, 295, and 296, Fig. 2, xvire 278 connecting plate 115, Fig. 1, (plug 113 in intermediary station isnot inserted and plates 115 and contact springs 114 are inconnect-ion) over spring 114, union 301, Wli' 300, union 299, Wire 171, Figs. 2 and 7, and here the current enters the auxiliary apparatus on its operating mission as already described.

The through connection for an operating current in reference to an intermediary station before locked out over the same instrument'andjrom the northern section, is over L. 1, Fig. 4, over union 280 and -Vl16 222, Figs. 4-7, Wire 22-2, Figs. 1 and 2. roller contacts and conducting sleeve 219,, 220, and 221, Fig. 2, Wire 218, Figs. 47, entering the auxiliary apparatus over union 259 and lever 46, Fig. 7, on its Way of operation. The through connection for an operating or telephone current fi'om the southern section after such an intermediary station has been. locked out, is the same as just described for a station before it was locked out, Wlllle the description for the current pulsations from the northern section after a station has been locked out is as locked out and the relay 191, Fig. 7, is enerized by a local current through that rclays coil, Which has been already described,-and the relay levers 304 and 191, Fig. 7, have been attracted, a path opens torthe current on its course through the stations. coming in over union 280, Fig. 4, Wire 222, Figs. 44', union 308, Fig. 7, Wire 306, lever 304 of relay 191, connecting post 303, Wire 307, ivire 171", union 258, \vire 218, union 217. L. 1, union 246. Fig. '7. post 244, lever 48, Wire 242, post 240 of relay 51, through core of same relay, lever \vire 171, Figs. 7 and 2,- union 299, ivire 300, union 301. Fig. connecting plate 115, \vire 278, roller contacts and conducting sleeve 294, 295 and 290. and out over the southern section. The same current can partly take its path over Wire Fig. 7, roller con-. tacts and conducting sleeve 219, 220, and 221-, and back over Wire 218. joining the other part on the same course, this division in this case makes no difference in the operation.

Another function of the line changing ap-' paratus, Fig. and the small relay 191, Fig. 7, is to completely prevent interniediate stations from taking the line when it is occupied, disregarding the sign indicating follows: After a station is 7 "that the line is busy. When a subscriber therefore untimely inserts his plug 113 in his selecting apparatus, Fig. 1, the relay 191, Fig. 7, is at such an occasion energized (which is the case in all locked out stations but not in stations set for, communication) and lever 191 is attracted, so when spring 114, Fig. 1, is pushed out, a local circuit is established from battery 225, Fig. 3, at union 309, over wire 310, union 312, wire 171, Figs. 1 and 7, lever 191 of relay 191, connecting post 313, wire 311, Fig. 1, connectingscrew 314, spring 114, (this spring combines two conductors insulated from one anbthcr-by a sheet 'of insulating material) contact bracket 315, wire 316, roller contacts somebody is trying to take the line, they interruption caused is of a lightnings brevity, and it would scarce be noticed in the telephone as a tick. nother path is instantaneously substituted for the through current, instead of flowing through the selecting apparatus, Fig. 1, as above described,

it flows, after such a shifting, over wire 171,

. Fig. 2, roller contacts and conducting sleeve 278, 279 and 220 and out on L. 1, or vice versa. The other paths over union 299 and wire 300, or over union 302 and wire 293, are at the same time interrupted, as will be seen following the wires and having in mind that the magnet has been rocked over to po sition 0. A current passing over wire 222 and 218, Figs. 4-7 and Fig. 2, is now interrupted at roller contacts 219 and 221, Fig. 2, as an insulating sleeve has been thrown down between them, and will flow over union 308, Fig. 7,. wire 306, lever 304, post 303, wire 307, wire 171", union 258, and over Wire 218 to its destination.

If the subscriber who tries to take the line when itvis occupied goes further and puts his machine in movement, the paths for the current pulsations from battery 121 are cut off, the one at roller contacts 168 and 170, Fig. 2, as insulating sleeve 255' has been thrown up between them. The other path over roller contacts and conducting sleeve 256, 257 and 324, Fig. 2, and over wire 171 is cut in relay 191, Fig. 7, as the relay lever 191 is attracted against post 313; As only the battery current from battery 121 on its way of operation over L. 1, opens paths for the current from battery 122,

through earth, no pulsation can flow out from that either, so it is absolutely im-' possible for any intermediary station to interrupt any communicating parties, orvany, operating subscriber. who has been the first, only by 'one instant, to take the line, andno intermediary station can know what parties are'in communication, and no casual parties talk can take place in this system by trying to break in on an establis ed connection. When this line changing appar, ratus has been thrown over untimely by somebody, it will be reset as soon as the subscriber discovers his mistake and puts the plug back again in its resting place, the, rack in the resetting apparatus. How the resetting is performed automatically has already been described. In. establishing connection backward, or over the southern section from the operating station, this line changing apparatus gives the wire 171, Figs. 7 and 2, a direct connection over roller contacts and conducting sleeve 278,279 and 220 out -on L. 1, southern sectiomat the moment the armature 254 has been thrown over to position 0. The current from batandconnecting sleeve 168,169 and 170, so

that instead of flowing overth'ose and up over wire 171, it flows over roller contacts and conducting sleeve 2'56,- 257, and-324, over wire 171. The operation is the following: Key 248, Fig. 2, is depressed an instant wherewithv a current pulsation {flows tery 121v over Wire 167, Fig. 2, is also changed in this apparatus at roller contacts thrown upbetween roller contacts 168 and 170 and the conducting sleeve 1 69 up between contacts 256 and 257, the current takes I I that last said path over wire171, Figs. 2 and 7, lever 191 of relay 191, (this lever is not attracted and will not be as the first sta tion to be set is always the operating station, and statlons set for communication keep the' local circuit over relay 191 cut, as already described) wire 171, union 258, wire 218, Figs. 47, union 217, over L. 1 to union 259, Fig. 7, over that and wire 260, lever 46,

post 261, wire 262, roller contacts and conducting sleeve 263, 264 and 265, Fig. 4, through first winding of magnet coils 266- and 267 and down to union 268 andback over line 2. This operation throws armature 33.0ver to position 0, and the loca1 current maintaining the-four'fleyer s of the interrupted, making from battery 12:2, through earth, ascending over wire 268, stop 269, Fig. 4, relay lever 36. (which is at that moment attracted by the core of coils 266 and 267 by the passing current from battery 121) wire 270, roller contacts and conducting sleeve 183. 184 and 185. Fig. 5, through magnet coils 186 and 187. over union 189, and back over L. 2. This operation throws the armature 3-1. Fig. 5, over to posit on 0. and establishes a local current through small relay 50, Fig. 7, from battery 55. over wire 61. roller contacts and conducting sleeve 72. T3 and 4, Fig. 5. (the conducting sleeve being now between 72 and 7-1) wire 61' to union 78. where it takes its path over wire 79, roller contacts and conducting sleeve 80. 81 and 82. Fig. a, wire 79.

through coil of relay 50. Fig. 7, and back. This station is now set for communication and the next current pulsation from battery 121 is through this set station, and as the following current pulsations are meant for looking out purposes, they flow in over same path-asthe above described from same battery to union 259, L. 1, Fig. 7, over wire 260. lever 46, (which is in upright position) wire 262, roller contacts and conducting sleeve 271, 272 and 273, over wire 27%, Fig. 4, telephone contact 209, Fig. 18. over wire 21D. lever 38, Fig. 5. wire 5211, roller contacts and conducting sleeve 212, 213 and 214',

(conducting sleeve 21a is now between 212 and 213) wire 274, union 275, Fig. 7. wire 276, union 27? contact post 60, (iever 49 is now resting on that post while lever 46 is maintained upright) lever 49. wire171, Figs. 7 and 2, union 299. wire 300. Fig. 2. union 301. F ig. 1, spring 114. (which is in normal position and not pushed out) connecting plate 115. wire 2 78 roller contacts and conducting slee e J94, 2 15 and 296 and out over L. 1 to the next station. the second station on this backward operation. This last described current cannot take the path from wire 171, Fig. 2. over union 302 and wire 2 3, as this is interrupted at the spring contact 117, Fig. 1, and wire 171. Fig. 2. is interrupted at contact 27* and 279 in the switching atta hm nt.

Continuing the liar-i: operation over the southern section, the secod station islocked outby the currrnt orni in over L. 1. Taking for this second ..on, to the rear, the apparatus at the statron cailing, comprised ll; Figs. 1-7. thecurrent entering by line 1. i oion zhdhiiows over wire 2:22. contacts and conducting sleeve 219, .220 and 221, Fig. :Lwire 21 Figs. 4T. union 217:. Fig. 4. union 25!), Fig/ wire 126i). lever to of bridg ng relay 4%. c act 1903 261, wire 262; roller contacts and conducting sleeve 263,264 and 265, Fig. throiigh magnet except lever 46. This the operat roller coils 266 and 267, union 268 and h-ver L. 2 back. The passing of this current pulsation through the said magnet coils throws the magnet over into position 0, Wherewith all the levers 46, 4?, i8 and 49 of bridg ing relays 4+1 and -15, Fig. 7, are released and fall back, as the local circuitcurrent maintaining them in upright position is broken at the moment this magnet opened the gap between screw and armature 33, Fig. 4:. A local current through relay 191, Fig. 7, is established in the same Way as before described, at the moment the auxiliary apparatus, Fig. l3, operates the locking out of connections. his operation locked that second back station out and the next current pulsation will come in through this second back station over L. 1, union 259, Fig. 7, lever 46, contact post 57, union 275, wire 276, union 27?, contact post 60, lever 49. wire 1T1, Figs. 7 and 2., union 299, wire 30! union 301, Fig. 1, spring 114, (which is not pushed out) contact plates 115, wire 27S,

rollercontact and conducting sleeve 29%,

295 and 296, Fig. 2, and out over L. 1. south and to the third back station. The following stations are all locked out in the same way, and the selected station is also set in the same way as above described.

The resetting of the stations back or over the southern section from the operating party is the same as already described for the northern section, but the resettingot the line changing apparatus, not take place until all, the other stations from the same operating stations apparatus to the selected partys are reset. A moment before the wheel 31, Fig. finishes its rotation and the hook-like spring contact 223. grasps around the ping and stops the movement, the spring contact on wheel 31, (or bracket contact) touches the plug and a current pulsation flows trgin battery over supporting arm 3, Fig. 3, over the plug to bracket contact 336, (the resetting current L. 1 and earth, has already ceased to flow as the resetting'is finished before the wheel comes sonear the plug. and as soon as all the stations are reset no currentflows out matwithstanding that the resetting wheel may not have finished its rotation) over wire 33" through second winding of magnet coils 1:51 and 252, Fig. 2, and back over wire 253 to zinc pole. \vlierewith this apparatus is reset. The arrangement of this automatic line changing apparatus relieves ing party from any trouble due to forget-ting to switch back, if a switch were used instead.

If during the resetting of the stations back over a southern section current comes in over line 1, from the northern section.

1." 11g. 2, does .that point-,it is in order to avoid describing detailed paths each time-the passage of ourrents'should have taken that way. The wires 338 and 339, Fig. 4, are the conductors to that breach, leading to the interrupting relay 37 Fig. ,4. The interchanging installa-' tion is destinedfor interconnection from trunk lines to-city or rural systems in connection with a central station, which may connect a number of city systems.

Selecting apparatus are used just as above for setting and looking out of stations and with the same object, but a central station needs no auxiliary apparatus or bridging relays, a telephone connected with L. 2, and which can be switched into connection with L. -1, when required,: is all that is needed. The operation in the central 'ofiice for the selection of the subscribers is the same as before described for the subscribers. on circular or terminal lines,'except that there v are no first auxiliary apparatus to be set for communication, and that two plugs will generally be used, a smaller plug in the se-- lecting disks smaller holes, Fig. 17, below the series of larger holes.

Thisis inserted in the hole bearing the subscribers number who is nearest the central oilice,'and the larger plug, 113, Fig. 1, is inserted in the hole corresponding to the subscriber who is farthest out on the line. The smaller plu'g will cause the first station to be set just in the small plug pushes the spring contact 123, Fig. 1, out in touch with the connecting or contact brush 125, just as the large plug does it, thoughnot so far out but to the same eifect and therewith causingthe current pulsations from battery 122 to flow out and set the stations'in whose number holes the plugs have been inserted.

A third line is generally used for interurban connections, notj'on'the trunk lines,

. but in cities and rural districts, except in small places where there are only a limited numberior si bscriber's on the system. Interchanging stations are locked out or set for] of the in q tion with another subscriber in another city, three small plugs and; a larger one are required and same are inserted in the disks in the central station.

sets the first interchanging installation (or;

The first small plug interurbanexchanging switches), the second the subscribers station in the first city; the

third willset the second interchanging installations switch, and'the fourth, the large plug, will set the called partys apparatus in the farthest away station and stop the I movement of the connecting,wheels when coming across the stoppingpm 128, and connections are then established-and both connectlng parties are rung up. Fi 20 gives a sectlonal viewof. the positions 0 the plugs and the radial spring contact, which for interurban exchange purposes is a double spring 117 and 117 the large plug, which is put in for the last station to be set for communication, pushesboth thpsesprings out protuberantly, wherewith cohtact plate 127 on the radial spring 117 is pushed back from connection with connecting brush 25, leaving an empty space, 130, which said connecting brush slipsinto and thus interrupting the local motor current, at the same time.

as the stopping pin 128 stops the movement of the wheels. The small-plu s do not push the second radial spring 117 out, as holes are made in those springs where those plugs areinserted, so large that the 'sm'all plugs slip through and leaves it in its resting place, forming uninterrupted connection with the series of those plates and brush contact 25. Thelarger plug engages both said radial springsll? and 117 with its.

shoulders and pushesthem out both with itswider circumference,

Fig. 21 is a front view of the connecting dISk, and shows in a more detailed way the position of the plugs as inserted for an in-' te'rurban connection. Suppose that station or subscriber 4 on local city or rural system a wants connection with subscriber 36 on city system C, the first small plug is inserted in the small plug hole A, which sets the interurban exchange switch at city. A; the next .small plug is inserted in plug hole 4, which sets the corresponding subscribers appara,

tus 1n position for communication; the, third small plug is inserted in small plug hole C, which sets that interurban exchanging switch at city C, and the fourth'pliig, the

. I g large one, making thestop, 1s insertedin.

the large plug hole 36,- whereafter the'wheels are put into rotary movement and j'whn are halted at their initial station or apparatus to be set, so the connecting wheels can be used for further operations on lines, as interurban lines, con necting a large number of subscribers and interurban exchange places, every time they stopping places, making them revolve a second or several times, withholding the large plug to be inserted in the last subscribers large plug h'ole, effecting the stop at that subs'cribers comes in over L.

,. union 107, Fig. 9,

number, after all the locking out and setting of stations according to the use of the small plugs, successively inserted in the holes, corresponding to the above indication for setting the selector, and according to the re peated series of nunieration shown on the connecting disk, Fig. 21.

\Yhen an interchanging installation is set for interconnecting purposes the current 1, lever 94, Fig. 10, connecting post 110, wire 341, roller contacts and conducting sleeve 342, 343 and 344, Fig. 9, through magnet coils 345 and 346 to L. 2 and back to zinc pole or" battery 121,

Fig. 1. The passing of this current through said magnet coils throws theIarmat-uie 86' over to position 0, and the rocking over of that interrupted at 108, Fig. 9, the local circuit from battery 97, Fig. 10, which forms its circuit over wire 102,.union 105, wire 106, armature 86, contact screw over wire 106, through coil 92, Fig. 10, wire 106 and back to zinc pole. Lever 94 of bridging relay 92 would new fall back from battery 1...., Fig. 1 wire 347, Fig. 9, over lev r 90, (this is attracted against post 348 while the other current from battery 121 passes the coils 345, and 346} ove1 wire 349, roller contacts and conducting sleeve 350 through earth and up through and 351 and Fig. 8, througi magnet coils 353 and 354 to L. 2 and'bac to zinc pole ofbattery 122, which throws the armatufie85 over into position '0 and establishes a local. current that sustains the lever 94 in upright position, the following: The armature 85, Fig. 8,is therewith thrown over to position 0. T is interrupts at 103, Fig. 8, the local cur nt which makes its circuit from battery 97, Fig. 10, over wire 102, union 104,Fig. 8, armature 85, connecting screw 103, wire102, coil 91, Fig. 10, wire 102 to the zinc pole, and the lever 93, Fig. 10, falls back where done in the same in the way as described in' it remains till'the apparatus are reset. A local current is established from battery 96, Fig. 10, wire 98, roller contacts and conducting sleeve 99, 100 and 101, Fig. 100 is thrown up between 99 and 101) wire 98, through coils of local current relay 95, Fig. 10, over wire 98" and back to zinc pole. Last said relay sustains lever 94, Fig. 10, in upright. position. This installation is now set for interchanging purposes and the next current pulsation goes to operate the locking out or the setting of the next station in the city system, Fig. 11. comes in as before, over lever 94, and post 110, Fig. 10, wire 341, as the insulating sleeve 358, Fig. 9, has been throwndown between roller contacts 342 and 344, thecurrent flows over roller contacts and conducting sleeve 355, 356 and 357, over wire 358', lever 89, wire 359, over L. 3, locking out the stations and'setting the one selected, looking out the other stations on that same system to the opening of the circular system,

ascending over wire 360, over roller. contacts and conducting sleeve 361, 362 and 363, Fig. 9, (conducting sleeve 363 is now up between contacts 361 and 363) wire 364, lever 87 ,wire 373, lever 93 of bridging relay 91-, Fig. '10, over post 377, ing position) wire 3T4, union 375 and out on 1 to operate the looking out of other sta-. tions on the trunk line and city systems. lVhere no setting for communication inthis system, Fig. 11, has to be done, the interchanging installation is locked out justas another station, only armature 86, Fig. 9, is rocked over, the lever 94, Fig. 10, falls back on post ,376 and the circuit current takes its path over that and out over L. 1. The resetting is done just in the same way as the other set or locked out stations, and is.

course of'operation together with those.

L. 2 is always reserved for all the subscribers for the purpose of delivering the central office orders for connecting them with interurban parties. If a party is not in coiqnmunication over L. 1, that is to say, if his auxiliary apparatus, Fig. 5, is not set for communication, he can call the central station 'up any time, over wire 210, lever 38,

Fig. 5, wire 211, roller contacts and conduct ing sleeve 365, 366

and 367, (this path is closed when a station is set for communication over L. 1) Wire 378, key 112, wire 380. union 379 and over L. 2. The magneto bell current cannot flow out any other way, if the operating party s'station is in normal position, because the line 274 from telephone contact 209, Fig. 18,. is interrupted. at roller contacts 271 and 272,.aFig. 4, and-the wire 208 from same contact, interrupted at roller contacts 204 and 205,; ig. 6, or if any of these auxiliary apparatus locked out,"

8, (sleeve The current (lever 93 is in rest-

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