US1008216A - Party-line telephone system. - Google Patents

Description

E STOUT & J. S. KUPKA. PARTY LINE TELEPHONE SYSTENL. APPLICATION FILED JULYIQ, 191o Iii Patented Nov. 7, 1911.

' 1 6 SHEETS-SHEET 1.

WITNESSES:

MJM T INVEA/TGRS Eda/am? Jfoul ATTORNEYS EQSTOUT & J. s. KUPKA.

PARTY LINE TELEPHONE SYSTEM. APPLICATION F'ILED J LY19, 1910.

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E. STOUT & J. s; KUPKA.

PARTY LINE TELEPHONE SYSTEM. APPLICATION FILED JULY 19, 1910 1 ,OO8,21 Patented Nov. 7, 1911.

B'BBEETS-SHEET 3L ATTORNEYS E. STOUT & J. s. KUPKAQ' PARTY LINE TELEPHONE SYSTEM.

APPLICATION FILED JULY 19, 1910.

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B. STOUT & J s. KUPKA. PARTY LINE TELEPHONE SYSTEM. APPLIGAITION FILED JU LY19, i910.

Patented Nov. '7, 1911.

6 SHEETSrSHEET 6-.

' Arman/Era 'EDWARD STOU'IJ'AND JosErE-s. K-UPKA, or MAn'rinsBone, rown.

PARTY- LINE TELEPHONE SYSTEM.

' Specifieationofletters Patent.

Application filedi'uly 19, 1910. .Se'ria1.No. 572,675.

'lfo. all wnomit'may concern:

"Be itlmown that we, EDWAIiD Smir and JOSEPH S. KUPKA, both citizens of the United States, and residents of Martins'biirg, in the countyof Keokuk and State of Iowa, have invented anew andlJTproved Party- .Line Telephone System, of-which the fol- I lowing is a'full, clear, and exact description.

mechanism, whereby when any two or more stations are connected for-talkin all other stations are excluded" interfere with business. beingvtrans'acted over the line.

Our invention contemplates further, the use of a busy signal whereby when the line is busy warningto this effect is given at each station, and also shows at eachstation when I the line is clear, if such is the case. Our invention still further contemplates various improvements inthe mechanism and electrical connections whereby the efliciency' of party line systems of this character is greatly improved.

Our IIIVGIIUOII further comprls'es means wherebya slight change may be made in the mechanism, the resultbeing that the ringers willring selectively as desired and yet-the talking and hearing circuits remain open, as

is the case with ordinary telephones.

Our invention may be employed in connection with ordinary telephone lines in instances where it is desirable to change the same,.so as to employ selective ringers, a minimum of change in the COIIStIUCtlJD being necessary for this purpose.

Our invention also contemplates a connec tion of party lines with a. central oflice, in

such manner as to' attain a number of advantages, as hereinafter descrlbed.

and are una le to 15 extends throug Reference is to b'ehad to the. accompany- PatentedNovQ 7, 1911.

ing drawings forming a part of this specifi. cation, Whi'chsimilar characters of refer:

figures.

' Figure 1 is a fragmentary section taken 'ence indicate corresponding partsfin all the on the line 11 of Fig. 3, looking in the direction of the arrow and showing part of the mechanism employed in our improved selective switch; Fig. 2 is a reduced elevation showing complete ounselective switch,

on'eof which is employed at each station;-

Fig. 3 is a section on the line 33 of Fig. 4, looking inthe direction of the arrow and showingmo're particularly the electricallyoperated contact mechanism forming part" of the switchand controlling various circuits Fig. 4: is a'section onlthe line 44 of Fig. 3, I I

looking inthe direction of the arrow; Fig. 5

1 is a section on the line'5 5of Rig. 4., looking in the direction of the "arrow and showing a portion of the time-controlled selective con-v tact mechanism; Fig. 6 isa diagram ofthelwiring and electrical connections at one of I thestations; and Fig. 7 is a diagram show-. r

ing the wiring'at threestation's, two of which are temporarily connected up for ringingand talking.

At each station is a casing 8 pr'ovided with a wall board 9 and containing a switch mechanism which is controllable electrically from afdistance. Mounted upon the outside of the casing Sis a d'ial '10 and below this dial are binding posts 11 to facilitate making the electrical, connections.

At 12 is'a winding stem for winding theclockwork, as hereinafter described.

. At 13- is an el'ectricalbell which is conveniently placed upon the top ofthe casing.

A revoluble hand 141s mounted rigidly upon one eiid ofa'revoluble shaft 15, the

latter'ezrtend'ing thrbugh a-motor 16'and be- I ing driven by the gearing-.17 of said motor.

This motor iswound'by aid of the winding stem 12 and consists merely of ordinar clockworkso arranged as to turn the she 15 at the rate. of,say,'one revolution per minute, the rate, however, being dependent: upon the motor. One end of the shaft 15 is engaged by aleaf-spring 18, which being of metal is also an electrical conductor. The casing 8 is provided with a partition 19 havingan openin 20' through it. The shaft this opening, and mounted rigidly upon the shaft 15 are three cranks 21, 22, 23 for shifting various movable parts, as hereinafter described. Supported upon the partition 19 is a contact ring 24 made of copper or other suitable metal. A con tact arm 25 and a stop arm 26 are mounted rigidly upon the shaft 15, the stop arm 26 being provided with a pin 27, this stop arm and pin being used, as hereinafter described, for starting and stopping movements of the shaft 15.

Disposed centrally within the casing 8 is a supporting plate 28 and mounted upon the latter is a magnet 29. This magnet is provided with an armature lever 30 which is mounted upon pivots 31 and carries a rest Two arms 33, 34 are mounted upon the armature lever 30 by aid of pivots 30" and are bent backward over the magnet 29 and adapted to engage the rest 32, as will be understood from Figs. 1 and 3. The arms 33, 34 carry barbs 35, 36, and over these arms extends a beam 37 of insulating material which serves as a limiting stop and prevents excessive travel of these arms, as will be understood from Fig. 3.

A1338 is a push pin and connected with the same, inside of thecasing, is a leaf spring 39 which tends to maintain the push pin in its normal position that is, extend ing outwardly from the casing. v Journaled within the casing and disposed adjacent to the inner end of the push pin 38 is an arm 40, and connected with the same is a ten,- sile spring 41. The arm 40 carries a plate 42 of insulating material against which the push pin 38 presses. The arm 40 is provided with an extending portion 43 having a finger 44 integral therewith, and is further provided with a portion 45 bent'slightly in relation to the portion 43 and extending through the opening 20, as will be understood from Fig. 1.

* When the push pin is pressed in, the portion 45 engages a lever 46 which is mounted upon a pin 47 andgis provided with a portion 48 disposed adjacent to the contact ring 24, as shown in Fig. 5. A contact bar 49 is provided with a rounded portion 50 and is-secured upon the partition 19 by aid of a screw 51 which also serves the purk pose of an electrical connection. Engaging the lever 46 is a hook 52. Adjustably but rigidly mounted upon the contact ring 24 are contact springs 55, 56.

At the difierent stations (see 7) the cont-act springs 55 are placed in .diflere'nt angular positions relatively 'to the contact ring 24. At the several stations, however,

the contact springs 56 all have the same relative position. The purpose of this arrangeme'nt is that when at the various stations the several motors are started into action, so that the. several contact arms 25 start to travel, thesecontact arms will allengage their-respective contact springs 56 at the same 'moment, but at. the different stations thevarious contact arms 25 will reach their corresponding contact springs 55 at different moments. Connected with the coni tact ring 24 is a binding post 57 for facilitating electrical connections. The bell 13 is also provided with binding posts 58.

Pivotally connected with the hook 52 isan armature lever 59'integral with an arma- 5 turc 60, and adjacent to this armature is a magnet 61. Because of the oflice of this magnet we designate it as a starting mag net. The arm 59 extends through a slot 59 1 and is engaged by a leaf spring 59 which 89 normally presses it downward, as will be understood from Fig. 5.

Mounted upon the'board 28 are binding posts 62, and stationary contact members .63, 64 connected respectively with binding as the contact members 67, 68 out of engagementwith their mating contact members 63, 64.

Whenever the magnet 29 is energized so as to lift the arms 33, 34, as above described, the barbs 35 and 36 disengagethe plates 69, 70 (or'either of them which happens to be in engagement) and by allowing the swinging contact members 67 68 (or either of them) to fall, cause them to engage with their respective stationary contact members 63, '64. The 'swinging contact members 67 68 are mounted respectively upon pivots 71, 72, the latter being in metallic communica tion with binding posts 73, 74, as will be understood from Fig. 3.

A magneto which may be of ordinary construction, is shown at 75, and is provided with a contact 76 controllable by pressure upon the actuating crank 77, asvwill be understood from Fig. 6. At 78 is a telephonic receiver which normally rests upon a switch hook'7 9. Below this switch hook are four contact springs s0, s1, s2, '83 arranged is indicated in Fig. (3. A. transmitter is shown at 84 and is con- 1 20 veniently mounted upon a stand 84.

At 85 is an induction coil which is provided with the usual primary winding 86. and secondary winding 87. s

' Each station is provided with a. battery 88 and from the latter extends a wire 8 which is connected with a wire 90 leading the transmitter. wire 91 is connect d with the wires 89, 90 and leads to the swinging contact member .68. Awire92 is con- 13-) v the casing. This pllggx tact ring 24 except when the arm is over the contact springs 56, 55. T 7

above explained, are so located that shortlyafter the motors are all thrown into action,

- tion; thehole.117 is for 'nected with the transmitter 84 and with the primary winding 87. Connected with this primary winding is a wire 93 which leads to a wire94, the latter being connected with the contact spring 81.- The contact spring is connected by a wire 95 with wires 96, 97, the wire 96 leading-to the battery 88 and the wire 97 to the'bell 13. A wire 98 is connected with the contact spring 82 and with the wires 99, 101. The. wire 99 leads to the" ground 100, the wire 101 being connected with the generator 75, as shown more particularly in Fig. 7. A wirel02 leads from the contact spring 83 to a wire 104, the latter being connected l with the starting magnet 61. A wire 103 leads to the magnet 29 which, because of its ofiice, we designate as thedrop magnet. A. wire 105 leads from the starting magnet 61 to the contact bar 49. A wire 106'1s'connectedwith the binding'post 57 and with the'drop' magnet 29. v A wire 107 is connected with the leaf spring 109, thewire 111. and with the contact 76 and the ma neto,

l8 and also with two wires 108, wire 108 being connected with a and the wire ,109 being connected wit the line wire which is shown at 110 and'extends from station to station. The wire 111. extends from the contact 7 6 to the receiver 78,

and a wire 112 is connected with the receiver and also with the stationary member 63. A wire 11B is connected with the swinging contact membr '67. and also with the secondary winding86 of theinduction coil 85. This secondary winding is connected by a wire 114* with the wires 93, 94.- A wire 114 extends fromthe bell 13 to the statiom' until the party has lodges against the portion 48 of the-lever- 46 at that station,'and this normally prevents themotor from running. When the various movable parts occupy their respec tive normal positions,'the contact arm 25 extends directly upward. When the motors are running, each arm 25- has no metallic communicationwith its corresponding con easing the various arms'25 engagethe' respective contact springs 56, this being done 'simultaneously; but as the motors continue run the arm 25 of each selectlve switch is upp most, and at each station'the' in 27 is lodg- -arm 43 to extend under the arm,

' the usua connecting, it to ese, as-

ning', each arm 25 reaches its particular contact spring 55 at a moment of time difiering from the moment at which other similar. arms located at other stations reach their respective contact springs 55.

As in other systems, Whenever a receiver 7 8 rests upon itsswitch. hook 79, the switch hook occupies its lowermost position, as in dicated in Fig. 6. w Theoperation of our device is as follows: \Ve will assume that at all the stations the movable parts are in normal position. In this event, each magnet 29 remains denergized, the arms 33, 34, are in engagement with the plates 69, 70, the swinging contact members 67 68 are out of engagement with the respective stationary contacts 63, 64, BI"

ing against theportion 48 0 the lever- 46.

Suppose, now, that the central operator, 'or a particular subscriber, wishes to send out I what we designate as a general call; that is,

he wishes to attract the attention of all the otherstations on the line. To do this, he proceeds by first pressing the push pin 38 inward. This causes the portion 44-of the 34 (see Fig. 4). the lever 46, and with the same impulse that starts the motor" will cause the arm 34 .to rise'as indicated in Fig. 7, so that contact The portion 45, however, .passesover 1 is made (at the calling subscribers station only) betweenthe-swingingcontact member 67 and the fixed contact memberi63. While pushing in on the push 88, the operator now grasps the handle manner, seas to'jclose the contact 76, he. turns the handle and throws the impulse into the linethat releases the motors and lifts the arm 34 of the callin gized -.by the-generator: ground 100, wires 99, 101, generatorflti, contact 76, wires'108, 109, to l1ne110; this circuit is continued at each of the other stations on theline, as

7 of his generator j pressing this handle to the left in station v I as just described. At the calling su scribers station the following circuit is thus 'ener-..

followstline 110, wires 109, 107, leaf spring 18, shaft 15, cont-act arm 25 (now extending 11 5 7 directly upward in its (normal position of idleness), contact bar 49,-.wire .105, magnet.

61 wires 104, 102,

contact springs 83, 82 (t se springs being new in engagement), ;wires 98,99, ground 100. This energizes; the

magnet 61 and causes a movement of its releasing the stop pin 27, which rests against the point of. the armature lever 59 m'all motors, when in normal position.'- This frees themotor mechanismv and as the'move-- other stations, all of the motors start "to work simult-aneously. I Consequently the "armature'BO to raise the ari'nature59, thus. I.

. ments. described take place at each of the A varions-hands14 (see Fig. 2) start to travel 180 over the ordinals representing the various stations. There is, however, no station num bored 2, and at the point where the hand 14 shown in Fig. 2, reaches the ordinal 2 in said figure, all of the contact arms 25 at the other stations rest respectively upon the contact springs 58. Each of the, several call stations remains connected with the line by virtue of the contact arm 25 at each station resting upon the contact spring-56 at that station, as just stated. This b't-nnection is simultaneous at all of the call stations, for

the reason that at each station the contact spring 56'has the same relative position.

The calling operator, watching the hand 14 of the switch at his station and noting the instant when this hancl-comes to the ordinal 2 in Fig. 2 (representing the in "wire 106, drop magnet 29, wires 103,102,

contact springs 83, '82, wires 98, 99, to ground 1.00, thence back through ground to the starting point. This circuit energizes the drop magnet 29 at each station, thereby swinging the armature 30 and raising the arms 33, 34 at each of the called stations, the result being that at each called station the swingingcontact members 67, 68 now drop down upon the respective fixed con tact members 63, G4. The dropping of each swinging contact 68 complet-es 'a teach of the called stations the following circuit: battery 88, wires 89, 9L, swinging contact member (38, fixed contact member 64, wire 114,

continuous ring bell 13, wires 97, 96, back to- By virtue of this circuit an' alarm is sounded at eachvof the several,

battery 88.

called stations. The called subscribers hearing the respective alarms take down their receivers 78. If any one or more of the subscribers fail to do this, it matters not those who fail *simply do 'not open their respective talking vcircuits. Those who do remove their receivers, however," by so doing place their receiversin connection with the line. At the calling subscribers station a local-circuit through the primary winding of the induction coil may be traced as follows: 'loat tery 88, Wires 89, 90, transmitter 84, wire 92, primary winding '87 of induction coil 85,

wires 93,94, contact springs 81, 80, wires 95,

' '96, backto battery 88. This circuit causes the primary winding 87 to'act inductively upon the secondary winding 86, so that at the calling subscribers' station a part of a talking circuit is completed as follows: ground. 100, wires 99, 98, contact springs 82, 81, wires 94, 114 secondary winding 80, wire 113, contact members 67, '63, wire 112, receiver 78, Wires 111, 108, .109, toline 110; at each ofthe called stations the circuit thus partially traced as continued as follows line "110, wires 109, 108, 111, receiver 78,wire 112, contact members 63, 67, wire 113, secondary winding 86 of induction coil 85, wires 114, 94, contact springs 81, 82, wires 98, 99, to ground 100, thence back to the starting point. The various subscribers thus called, or at least such of them as care to listen, now hear any conversation uttered at the calling station. It will be noted, however, that although the connections are made as described at the beginning of the conversations, the motors are all in action. Consequently, at each station the shaft 15 is turn ing. This continues unti the stop pin 27 lodges against the portion .48 of the lover -10, which brings all of the motors to rest. They continue at rest so long as the talking continues, or at least untilsome subscriber rings oil. During the time that the line is being used, and the hand 14 shows the line to be in use, it is impossible for any one to disconnect the parties who are holding their receivers off the hook, as it will be noted that the circuit is-broken with the ground between 82, 83. The plug 118 placed in the hole 116 will hold the hand 14 to the"linc busy position, until the party is ready to give up the line, and even if the motor has beenreleased it can not operate until the plug 118 is removed.

Suppose, now, that the calling subscriber, having finished his conversation, rings 0th. He does this by grasping the handle 77 of his generator and pressing this handle to the left "in the usual manner actuates the generator and throws an impulse into the line.

A circuit is thus partially completed as follows: ground100, wires' 99, 101,.generator 75, contact 76, wines 108,109, t'o'line; =this circuit is continued at each 'subscribers sta-. tion as follows: line 110, wires 109,107,;contact spring 18, shaft v.15, contactarm v25-, contact bar 49, wire-1'05, magnet '81, wires 104, 102,-contact springs83, S2,vv wires 98,

' 99, ground 100, thence back to source at the calling'station. This energizes the magnet.

61 andby causingthe armature lever '59: and hook 52 to tilt the lever 46, causes the portion 48 of said'lever' to release the pin 27.,

The motors are thus all released and being thus set in motion they run until the movable parts are in normal position, the various hands 14 at the respective stat-ions indieating that the lineis clear, by now standinga't zero, and the stop pin ,27 will nowbe resting against the-portion 48 of the lever 46 ready to be. released for another round tact member .67 and the fixed contact member any number of subscribers p with the ordinary telephone, but the ringing fails to hang his reee1ver-back on the hook' .while the other stations are in glghe act of of service. It will be noted that the turning of the shaft 15 under the action of the motors, sooner or later carries the various cranks 21,22, 23 around. The crank 21 is. employed to replace the swinging contact 67 while the motors are. passing from line busy position to normal position; the crank 22 is-used for the purpose of replacing the swinging contact 68, when the gen-' eral call is given at station No. 2 or the number assigned; and. the crank 23 acts to replace the swinging contact 68 when' a private call is given. The crank 21 at the proper point of its rotation therefore trips. the plate 69 and causes the arm 34 to hold this plate in itsvertical position, 'so as to break engagement between the movable con- 63. This opens the talking circuit-that is, thr'ough the receiver 78. The crank 22 will stop the bell Whenthe ring is given at thegeneral call number 2, and the crank 23 Will do likewise at the private or selective number. Similarly the crank 23 trips the plate. 70' upward, so thatthis plate is now held the arm 33. This'lifts the contact member 68 out of engagement with the contact member 64 and opens the ringing circuit. It will' also be noticed that the opening of the ringing circuit takes-place at a very early period during the revolution of the shaft 15. y The ringing circuit thus being opened, it is obvious that no alarm can be sounded at any station while the line is being restored. By moving the crank arm 21 so as to render it inoperative, the system may be employed under conditions ,where privacy is not desired; consequently the line will always be open for talking and hearing, as is the case will remain selective as before outlined. It can be so arranged in a case where thetalking and hearing circuit is always made, that the dial will show line busy. or clear, as the case may be, or if this is not wanted, by moving the point 48 in such a way that the stop pin 27 will not ,conie in contact with it, the motors will-make a complete revolution each time that the stop pin 27 lodges against the lever 59.

.If after using the line, it happens that have their receivers off the hooks, andpne of the subscribers before the ring-off impulse is given, the movable patrts at the station where this happens will remain for-themoment in a false position; that is to say, the negligence .of a subscriber in failing to hang up his receiver in time will cause his station to be left out when the other stations affected are restored to normal condition. If the-subscriber in question happens to hang his receiver back on the hook during any PBJ'tOIlJthQ time this is a matter of the step by being restored and will operate his genera-. tor, this will release the moving parts at his station and they will be .restored to'normal condition. They will be a little later than the correspondin parts-at the other stations in arriving-at t eir normal condition,-but little or no consequence. Suppose again that a called subscriber fails to hang his receiver on the hook until after all of the other call stations have been restored to normal condition. The subscriber whose station is thus at the particular stat-ion left out can easily restore his station to normal condition by pursuing the following course :He operates his generator which starts into action the motor mechanism at two .or more of the stations, or at all of the stations as the case may be. The subscriber in question now watches his indicator until step movement brings his apparatus apparently into normal position. He then quickly presses- :his push-button 38. This stops the moto mechanism and throws into circuit the tal ing connections; He now operates his gen rator again. This releases his motor mechanism and the latter soon arrives in such position as to indicate that the line is. busy, though the station under consideration is a little later than bther' stations in arriving in theso called busy position. If, however, sufiicient time be allowed, this makes no difl'erence, all of the stations now being in the condition generally known as busy. The subscriber whose station is more consideration now rings 01f. This clears the entire line including his station. .All of the stations are thus restored to\normal co dition..

It may sometimes happen t at a subpart-icularly' under 'scriber in restoring his station n normal condition may accidentally ring up some other subscriber, but when this 0 curs he simplyexplains to the other subscri er that he isqinerely restoring his station to ormal condition.

Suppose, now, that it be desired to use the system for selectivity. Reference is here made to Figs. '6, 7, showing the diagram. The calling subscriber, we will say, wishes to call up a particular subscribersay Number 9-and starts with the various partsin their respective normal positions. He presses upon the push pin 38, as; before, thereby causing the portion 44' of thearm 43 to extend beneath the arm 34, the portion 45 being now placed across the-lever 46, and while holding this pushbutton in he next actuates his impulse into the line energizes all'of the various magnets 61, thus starting all the mo tors into action, as described. The same im--. pulse that started the motor of the calling station will, by the ortion 45 being pushed over the lever 46, lift the arm 34 and release generator and by throwing an hand 14, asdesired.

' variety of relations.

net 29 of the station called, as described.

Since the various contact springs 55 are disposed in different relative positions around the contact ring 24, it follows that the contact arms 25, moving exactly alike at all of the stations, make contact with their respec-' tive contact springs at different moments for different stations. At station numbered 4;, for instance, the-contact arm 25 engages the contact spring 55 at one interval of time,

whereas at station 6 the contact arm engages the contact spring 55 a little later. The operator watches the hand 1%, as above stated, until it points to the ordinal indicating the station hewishes to call (say, for instance, station 9). Then upon actuating the gen orator again, a circuit is partially completed at this station as follows ground 100, wires 99, 101, generator 75, contact 7 6, wires 108,

109, to line 110; thence, at station numbered 9 only tthis being the only station where the arm 25 is in engagement with its contact spring 55) the circuit is completed as follows: line 110, wires 109, 107, leaf spring 18, shaft 15, contact arm 25, contact spring 55, contact ring 24-, binding post 57, wire 106, drop magnet 29, wires 103, 102, contact springs 83, 82, (now in engagement), wires 98, 99, round 100, thence back to point of beginning. This energizes the drop 29 at station 9 only. The arms 33, 84: being raised by action of the armature'30, the movable swinging contact members 67, '68, are dropped upon the fixed contact members 63, 64'. The engagement of the contact members 68, 64. causes the bell to ring, the cir cuit being the same as above described for ringing the bell when a number of subscribers are called. The engagement of the contact members 67, 63, together with the removal of the receiver 78 from the switch hook 7 9 at the station 9, completes the talkevery station, for the reason that at each station the operator notices the position of the hand 14. The ringing oil is accomblished in the manner above described with reference to ringing olf at other stations. The plug 118 may, if desired, be inserted in the ole 116, for the purpose of stopping'the Our system may be used in an -immense With comparatively little'alteration our system may be employed in connection with ordinaryjtelephones with crank.

out molesting the communicatingparties, and enable any one on the line to select any other party and ring that station alone, or by using the general call number anyone can call all stations at the same turn of the generator Its chief use is on-lines where so lect-ivity is desired. It is highly beneficial,

too, in relations where it be desired to call up and talk to a considerable number of subscribers, the, general action of the system being for this purpose rendered inde pendent of whether any single, subscriber, or any number'of subscribers, answer the call.

Under our system unless a station generates on the number assigned to the central ofiice, the line drop does not fall there. lit also prevents molesting the night alarm at the central oiiice, should any one on the line wish to talk'to a station on the line at night.

On the other hand, any stat-ion that has 00- casion may ring the night alarm at the cen tral office at night, and not molest any other station by causing the bells to ring. :The central otfice will have aprivate number just the same as any other party on the line. This system will, when it is desired, allow the central operator to hear at all times on any line, by plugging in as in ordinary cases. This makes it possible toclear the lineby the central operator, should anyone carelessly leave the system showingf line busy Or the ringer at the central oilice can be arrangedas all others and not be allowed tohear any conversations on the line unless that office has been called. This can be done by moving the crank 21 over so that it will replace the drop arm 34: over the swinging contact 67.

Havingthus described our invention, we claim as new and desire to secure by Letters Patent:

1. A selector switch, comprising a ringing circuit, a talking circuit, a contact for opening and closing said ringing circuit, a contact for opening and closing said talking circuit, a revoluble member provided with cranks for opening said contacts, means bperated electrically from a distance for controlling said revoluble member, and means including magnetic mechanism controllable fronna distance for closing said contacts.

2. In a selector switch, the co:nbination .6f a motor, a revoluble shaft connected therewith and turned thereby, a contact ring, a contact member mounted thereupon, an arm carriedby'said shaft and adapted to engage and disengage said contact member for the purpose of opening and closing an electric circuit, another arm mounted upon said shaft. a lever provided with a portion disposed partially within the path of travel. of said last-mentioned arm for the purpose of arresting the rotation of said shaft, and means controllableelectrically from a dis v tance for actuating, said lever, thereby libcrating said arm and allowing said motor dition of said magnet. 5. In a selector switch,- the combination 4. v In a selector switch, the combination of a drop magnet, a contact controllable there'- by for closing a ringing circuit, another contact controllable by said drop magnet for closing a talking circuit, and means controllable at will for temporarily closing one of saidcontacts independently of the conof a motor, gearing including g1. revoluble shaft to be turned by said motor, an arm mounted upon said revoluble shaft, a movable lever provided with a portion for temporarily holding said arm, thereby rendering the motor inactive, mechanism controllable electrically froma distance for actuating said lever in order to release said arm, selective contact mechanism controllable by the rotation of said shaft for throwing circuits into and out of action, and means controllable at the will of the subscriber :tor.

temporarily preventing the movement of said arm.

6. A selector switch, comprising a motor, a revoluble shaft connected with said motor and driven thereby, selectivecontact mechanism controllable by rotation of said revolu- J ble member for opening and closing circuits,,'

a motor circuit provided with means for stopping and starting said motor, means controllable electrically from a distance for opening said motor circuit when said motor is in action, and mechanism controllable by a subscriber for temporarily preventing said irevoluble shaft from turning.

7. In a selector switch, the combinationof a contact ring, contact members mounted thereupon, one of said contact member's being fixed and another being movable, and a' movable contact member for engaging and disengaging said contact members, a' plurality of circuits connected with said contact members, and means controllable alternately at"the will of the operator for employing said circuits either for a general call or for a particular selective call, as desired.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

EDWARD STOUT. JOSEPH s. KUPKA.

Witnesses HERMAN O. WOLFERT,

W. J. CRAIG.

Copies of this patent may be obtained for ive cents each, by addressing the Commissioner otlatents,

Washington, D. O.

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