US1000077A - Transmission system. - Google Patents

Description

G. G. CUMMINGS & A. WRAY.

TRANSMISSION SYSTEM.

APPLICATION FILED MAE. s, 1909.

1,000,077. Patented Aug. 8, 1911.

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TRANSMISSION SYSTEM.

APPLICATION FILED MAR. 3, 1909.

Patented Aug. 8, 1911.

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UNITED STATES PATENT OFFICE GEORGE C. CUMMINGS, OF WES"ERN SPRINGS, AND ARCHIBALD WRAY, OF CHICAGO,

ILLINOIS.

TRANSMISSION SYSTEM.

Specification of Letters Patent.

Patented Aug. 8, 1911.

Application filed March 3, 1909. Serial No. 481,100.

To all whom it may concern:

Be it known that we, GEORGE C. CUM- Minos, a citizen of Canada, and a subject of King Edward VII, residing at WVestern Springs, in the county of Cook and State of Illinois, United States of America, and Anonnunn VRAY, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Transmission Systems, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

()ur invention relates to systems of electrical transmission, and has for its general object the provision of improved means for operating electro-magnetic responsive devices located at a series of receiving stations from a central or transmitting station, the invention finding a most important adaptation to party telephone line practice, certain features of the invention relating particularly to party telephone line practice, Where the electro-magnetic responsive devices are employed for signaling purposes, enabling the operator at the transmitting station to signal the party line or receiving stations selectively.

As applied to party telephone lines,our invention has for its further object the provision of means whereby the signal-receiving devices at the various party line or receiving stations may be selected and operated, even though the party line be in use, the equipment being such that the use of the party line for signaling purposes does not interfere with its use for talking purposes.

In carrying out these features of our i11- vention, novel equipment at the transmitting station and at the receiving stations is employed, which renders the system of our invention of especial utility in connection with train dispatchers lines, for, by means of our invention, the train dispatcher may signal all of the receiving or party line stations, one of said stations, or any plurality of said stations, by mechanism which does not interfere with the conversation that may be going on over the line, and by which the use of the line for talking purposes does not interfere with its use for signaling purposes.

In practicing our invention, We employ a transmission system including a line circuitleading from a transmitting to a plurality of recelvmg stations, electro-magnetic responsive apparatus at the receiving stations, one set of instrumentalities distributed among the receiving stations and performing their functions in succession and having partial control of said electro-magnetic responsive apparatus, a second set of instrumentalities distributed among the receiving stations and adapted to complete the control over said responsive apparatus, and means controlled at the transmitting station for causing the operation of one of the said second set of instrumentalities at a selected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to effect the operation of the electromagnetic responsive apparatus thereat.

In practicing our invention, we preferably employ as a transmission system including a line circuit leading from a, transmitting to a plurality of receiving stations, electromagnetic responsive apparatus at the receiving stations, one set of normally restrained self-operating instrumentalities distributed among the receiving stations and, when released, performing their functions in succession and having partial control of said electro-magnetic responsive apparatus, a second set of instrumentalities distributed among the receiving stations adapted to complete the control over said electro-magnetic responsive apparatus, electro-magnetic mechanism at the receiving stations for releasing said set of self-operating instrumentalities and operating the second set of instrumentalities, and means governed at the transmitting station for offecting the substantially simultaneous opera tion of said electro-magnetic mechanism to cause one instrumentality of each set at a selected station jointly to effect the operation of the electro-magnetic responsive apparatus thereat.

We will explain our invent-ion more fully by reference to the accompanying drawings, showing the preferred embodiment thereof, which is particularly adapted to railroad practice, though the invention is not to be restricted to the use to which it is put, Figure 1 showing the transmit-ting station and Fig. 2 a plurality of party line stations.

The circuit illustrated is a metallic circuit having two metallic sides 37, 38, though the cults. The circuit 37, 38 extends from the party line or receiving stations shown in Fig. 2 to the dispatching, sending or central station shown in Fig. 1.

As the invention is embodied 1n a telephone, system in the illustration thereof fun nished by the drawings, there is shown at each receiving or party line station, a switchhook connected with one side of the an cuit (the side 37 a receiver 68 having one terminal connected with the other sideof the circuit (the side 38), the primary winding 73 and a secondary winding 66 of an induction coil 67, a telephone transmitter 71, and a local battery 72, the entire arrangement being such at each party line station that when the telephone receiver is upon its switchhook, the said receiver and transmitter are included in open circuits, the switch-hook serving, when relieved of the weight of the receiver, to close the associate local circuit including the transmitter 71, the battery 72 and primary winding 73, and to complete a connection between the sides 37, 38 of the party line circuit through the switch-hook 70 and the receiver 68, thereby connecting said receiver-in bridge between the sides 37 38 of the party line. Another bridge conductor is provided at each party line or receiving station, in the embodiment of the invention illustrated, which second bridge conductor, instead of being opened 'and closed, as is the conductor containing the telephone receiver, is permanently closed, for the purpose of maintaining constant connection of the electro-magnet 50 at each re ceiving station with the sides 37, 38 of the line circuit. This permanently closed bridge conductor also includes impedance devices 51, 52, so as to prevent the voicecurrents that are to be directed to any party line or receiving station from being shunted from the active telephone receiver at such receiving station and for preventing telephone currents that are to be impressed upon the line by the telephonic apparatus at a receiving station *from being shunted away from the line, which would occur if there were not sufiicient impedance in the elements 50, 51, 52, inasmuch as the bridge conductor portion containing these elements is in parallel relation with the bridge conductor portion containing the associate telephone receiver 68. The telephone bridge conductor portion contains condensers 65, 69, one upon each side of the included telephone receiver 68, so that direct current that is to be impressed upon the line at the transmitting, sending or central station may be forced through the electro-magnets 50 at the receiving stations for purposes that will appear. A third bridge conductor is provided ateach party line or receiving station, which third conductor includes a magneto generator 68, which, when idle, serves to open said third conductor, and, when active, serves to close said thirdbridge conductor, one terminal of the generator 68 being connected or. adapted for circuit connection directly with one side 38 of the line circuit, while the other terminal of the generator 68" is adapted for connection with the other side 37 of the line circuit, through the condenser 65, which is of a capacity that will permit of the current from the generator 68 to pass therethrough to operate a suitable signal appliance 46 atthe central or transmitting station, so that the attendant at each party line station may signal the central or transmitting station. The electro-magnet 50 provided at each party line or receiving station has an armature switch including two terminals 54:, that constitute the normally separated terminals of a local circuit at each party line station, which includes magnet 56 and a local battery 57 VVhcu the operator or dispatcher at the central or dispatching station desires selectively to signal a receiving or party line station, or a number of such stations, such dispatcher or operator will, by means of suitable apparatus to be described, impress direct currcnt upon the sides 37, 38 of the line circuit, thereby to occasion the simultaneous energization of the electro-magnets 50 at the party line stations, thereby simultaneously to effect closure of the local circuits at the party line or receiving stations, which include the magnets 56, said magnets 56, upon being energized, setting into operation suitable circuit-closing or controlling mechanism at the receiving or party line stations, the circuit-controlling mechanism at the different party line or receiving stations being out of step with each other, so that but one of such mechanisms may at a time perform the function for which such mechanism is provided. Each such circuitcontrollingmcchanis; each such receiving or party line station, in the embodiment of the invention illustrated, includes a rotating contact arm 59 operated by any suitable mechanism that is released and permitted to become efi'cctive when the magnet 56 is energized, as will hereinafter more fully be set forth, and a contact button 60, the distances between the arms 59 and their associate buttons 60 differing at the several party line or receiving stations, so that if said arms 59 are rotated synchronously, but one arm 59 can be in engagement with a contact 60 at a given time, inasmuch as the engagement between the elements 59 and 60 is successively effected at the different stations. As has been made plain, the electro-magnets 50 at all of the party line or receiving stations are simultaneously energized so as to set all of the contact arms 59 in motion through the releasing action of the magnets 56. After the arms 59 have thus been set into motion, openings in signal-receiving circuits at the party line stations (which signaling circuits-will hereinafter be described) are successively partially closed at the differcut receiving or party line stations by the engagement of the elements 59, 60. The signal-receiving circuits include each an additional opening that is closed by apparatus governed at the transmitting or central station, which closure is timed to occur with the engagement of the contact elements 59, 60 at the selected station or stations, it being possible in this way to close one signal-receiving circuit of one selected party line station or the signal-receiving circuits or any number of party line or receiving stations, it being possible for the operator at the central station to signal all, one, or any number, of party line stations. In carrying out this feature of the invention, the contacts 5t and 55 at each party line or receiving station, in addition to governing the releasing magnet 56, are also serially related with the contacts 59, G0 in the associated signallng circuit, so that when the electro-magnets 50 are energized during the revolutions of the arms 59, they may, by bringing together the contacts 54 and 55 at all of the party line stations, partially close the signal-receiving circuits at such party line stations, the particular signal-receiving circuit that is completely closed being the one of those whose contacts 59 and 60 are engaged during the engagement of the contacts 54 and 55. While the electro-magnets at the party line stations are employed for the double purpose of effecting the operation of the releasing magnets .)6 and partially to control the signalreceiving circuits at the party line stations, it is to be understood that the invention is not to be limited to relays having these two purposes. Suitable apparatus is preferably employed at the central or transmitting sta tion which is designed automatically to time the energizations of the magnets 56, this being preferably so constructed that it may be set not only to select one party line station, but to select any number of party line stations indiscriminately or such central station apparatus may be further set so as to cause the operation of all of the signal re-' ceivers at all of the party line stations.

Having thus in a general way described the manner of selecting party line stations for the purpose of causing the operation of the signal receivers thereat, we will now describe the preferred form of signal-receiving outfit employed at each party line or receiv ing station and the cotiperat-ive relation thereof with the electro-magnets 50, and will thereafter describe the preferred form of central station equipment that is adapted to cotiperate with the line electro-magnets 50 for the purposes which have herein been set forth.

The signal receiver at each party line is desirably a vibratil'ig bell 63, circuit through which being initially dependent upon the engagement of the contacts 54, 55 at the same time the contacts 59, at the selected station are engaged. Inasmuch as the bell 63- is a vibrating bell whose circuit is intermittently opened and closed, and it being desirable to cause the signal receiver to operate until the attendant at the selected station responds, a holding magnet 61 has a local circuit closed therethrough when the contacts 54, 55, 59 and G0 are in closed cir cuit relation, the magnet 61 retaining its armature in engagement with the contact (32, whereby a local circuit is established for the magnet (31, which is maintained until the push button 6+ is operated by the receiving or party line station attendant to open the circuit of the magnet 61. The vibrating or circuit breaking signal receiver- (33 includes the battery 57 and the contact (32, so that the signal receiver, after having once been set into operation, is continued in operation until the contact (32 is excluded from circuit with the bell 63, which exclusion occurs when the push button 64 is operated to deenergize the magnet 61 to separate the armature of the magnet 61 from its contact 62, where the desired opening in the circuit of the signal 63 occurs.

The mechanism including the wiping contact 59 at each of the receiving stations, is a normally restrained self-operating instrumentality, these instrumentalities at the different party line stations serving, when released, to engage the contacts 59, 60 at the different stations, in succession, as has been explained. Any suitable form of self;opcrating mechanism may be employed to constitute said instrumentality, such, for example, as a spring motor or clock mechanism, which is diagrammatically indicated as having, in addition to the wiping contact 59,'a disk I mounted upon the second hand-shaft of the clock mechanism and car rying the wiper 59, the mechanism of each clock being normally held at rest by means of the finger arms 5, 6 which have projections engaging the disks 1. 2, the arms 5, 3' moving with the armature 8. about a common center, so that when the armature 8 is attracted, the associate clock mechanism is released, such release occuring simultaneously at all receiving stations, owing to the simultaneous energization of the electro-magnets 50 at all receiving stations. Y

It will thus be seen that we have provided a. transmission system (in the embodiment of the invention illustrated, a signaling or telephone system) including a line circuit (37, 38) leading from a transmitting station to a plurality of receiving stations, electro-magnetic responsive apparatus (the elements 61 and 63, for example) at the receiving stations, one set of normally re strained self-operating instrumentalities (the mechanisms including the wiping contacts 59, for example) distributed among the receiving stations, and, when released, operating in succession and having partial control of said electro-magnetic responsive apparatus, preferably by closing normally separated contacts, a second set of instrumentalities (preferably the additional switching devices 54 and 55) distributed among the receiving stations and adapted to complete the control over said responsive apparatus, and means (preferably the electro-inagnets 50) controlled at the transmitting station, for releasing said set of self-operating instrumentalities and cansing the operation of a second set of instrulnentalities, to cause one of said second set of instrumentalities at a selected station to operate together with one of said first set of instrunicntalitics, to effect the operation of the clect'ro-magnetic responsive apparatus at the selected station.

The party line terminates at the central or transmitting station indicated in Fig. 1, in the two normally disengaged contacts of the switch governed by the electro-magnet or relay 23, the signal-receiving device 46 at the transn'iitting station being in bridge of the transmission line 37 and 38, this sig nal device 46 being operable by current produced by the generators 68 at the different party line stations, the bridge circuit for the device 46 including the condenser 32, so that the direct current which is impressed upon both sides 37, 38 of the transmission line is not shunted. The telephonic apparatus at the central or transmitting station includes a telephone receiver which is preferably permanently in bridge, it being the usual duty of the central station attendant to have the receiver 33 constantly at his car, on which account it is not often necessary to operate the generator 68 when a party line station desires communication with the central or trans mitting station, the generators 68 only being used when a calling party line station is not answered when a calling party i1npresses voice-current upon the telephone line 37, 38. The operators telephone re ceiver 33 is in serial relation with the secondary 34 of an induction coil, said receiver and secondary being included in the same bridge between the sides 37 and 38 of the telephone line, said elements 33, 34 being disposed between the condensers 32 and 36 included in the same bridge therewith.

The induction coil includes the primary 42 inductively related with the secondary 34, the primary 42 being included in a local circuit with the transmitter 40 and transmitter battery 41, which local circuit is closed by the switching device 43. A sec- 0nd switching device 44 is also desirably employed, whose contacts, which are normally engaged, constitute terminals of a shunt conductor about the secondary 34 to cut out the opposition to the incoming voice-currents that would otherwise befurnished by the said secondary. The switching devices 43, 44 are desirably simultaneously operable, so that when the central station operator wishes to impress voice-currents upon the line, a simple motion will engage the con tacts of the switching device 43, to close the transmitter circuit 40, 41, 42 and to open the shunt about the secondary 34, it being understood that the switching devices 43, 44 are in their respectively normally opened and closed conditions excepting when the central station operator is impressing voice-currents upon the line. The terminals of the limbs 37 and 38 of the telephone line, that are associated with the electro-magnetic switching device 23, are adapted to be engaged by the movable terminals of the battery 24 when the magnet 23 is energized, whereby the battery 24 is bridged between the sides 37, 38 of the telephone line tosimultaneously operate the electro-magnets 50 for the purposes which have hitherto been set forth. An impedance device 25 is included in serial relation with the battery 24, a part of said device 25 being included on one side of said battery and the balance of said device on the other side of said battery, the impedance, being high, serving to prevent the shunting of voice-currents im pressed upon the telephone line 37 38, the arrangement of the entire system being such that, owing to the impedance 25, the inclusion of the battery 24 in bridge of the circuit 37, 38 does not interfere with the transmission of voice-currents. The use of the condensers 65, 69, 32 and 36 in the telephone bridges, on the other hand, serve to confine the current from battery 24 to the electro-magnets 50, whereby the telephone line 37, 38 may be used for conversational purposes without any interference from the operation of the selecting apparatus of which the electro-magnets 50 form parts and without any interference from the signaling apparatus, inasmuch as the signaling apparatus at the party line stations is included in local or independent circuits. Impedance devices 51 and 52 are preferably employed also to prevent disturbances that might arise due to the operation of the elec tro-magnets 50 from reaching the line or telephone sub-station outfits immediately in association therewith.

It being preferred to control the application of the battery 24 to the telephone line by means of the magnet 23, as has been described, said magnet 23 is given an initial energi'zation which releases all of the selfacting instrumentalities of which the wipers 59 form parts, the said magnet 23 being also thereafter energized during the movements of the arms 59, the latter energizationtof the magnet 23 to occur at just gbout the time the'contacts 59 and eocf a selected station are in engagement, whereby during the engagement of such contacts 59 and (30 at a selected station, the contacts 54 and 55 at said selected station are also closed, whereby the two gaps in the signaling circuit or the circuit of the electro-magnctic responsive device at the selected station are closed, the selected station being the only station at which the two closures at 54, 55, 59 and 60, simultaneously occur, although the contacts 54 and 55 at the remaining party line stations are at the same time engaged, owing to the fact that the elements 59 among the diiferent party line stations, are engaged with respect to each other, successively with their contacts 60. It is apparent that not only may one party line or receiving station be thus selected, but that a number of party line or receiving stations may be selected, or that all may be selected, it only being necessary to energize the magnet 23 at the proper times,those times at which the contacts 59 and 60 of the diiierent stations to be selected'are in engagement or are about to be engaged, this result being due to the fact that the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

The magnet 23 is initially energized when the switch 22 is closed, the circuit occasioning the initial energization of the magnet 23 being traceable from the battery 17, through the winding of the magnet 23, to the battery 17, by way of two engaged contacts of the switch 22. The successive energization or energizations of the magnet 23 which is or are to occur in order that a party line or receiving station or party line or receiving stations may be selected and signaled, desirably occurs automatically after a suitable instrument has been set and adjusted properly to time the energizations of the magnet 23. To this end, there is employed a wiper 3, which may be understood, for example, to rotate in a clockwise direction, connected with one terminal of the battery 17 and a plurality of contact buttons 4 normally separated from the other terminal of the battery 17, but adapted for connection with said other terminal of the battery 17, through the winding of the magnet 23, when the switches (such as 27 28, 29) associated with said buttons 4, are closed, each button 4 having one such switch in serial relation therewith.

Switch-actuating plungers 10, 11, 12 are provided for the switches 27, 28, 29, there being as many such plungers as there are buttons 4, included in a set, the drawing illustrating two sets of buttons 4, the Wiping arm 3 being adapted to rotate a halt revolution each time it is set into motion. wiping arm 3 is caused to have a fixed ratio of speed with respect to the wiping arms 59 at the party line stations, the elements 3 and 59 desirably moving in synchronism and each desirably moving a half revolution in its full range of operation. There are thus two buttons 4, one in each set of buttons, that are in association with one of the switches 27, 28, 29, the wiper 3 moving over said buttons 4 from its state of rest, which may be with the free end of the wiper completely up or fully down, whereby the battery 17 is successively included in circuit with that button or those buttons 4 that are connected with the actuated switch or switches (27, 28, 29) by the wiper 3, a circuit being established through the magnet- 23 each time the wiper 3 encounters a button 4 whose associate controlling switch (27, 28 or 29) is'closed. As there are as many buttons 4 in each of the two sets as there are party line or receiving stations, and. as there are as many switches 27, 28, 29 as there are buttons 4, it is apparent that one or any number or all of the party line stations may have their signal circuits closed, so that the operator at the transmitting station may converse with any receiving or party line station or stations irrespective of the location of such receiving station or stations upon the line, it being further apparent from what has been described, that the cen tral station or transmitting station operator may thus signal various party line stations even though conversation may at the time be in progress. Such a system as this is of especial adaptability in the service of train despatching, as must be very apparent without specific illustration.

As the wiper 3 completes a half revolution, it passes over a contact 21, thereby to include the battery 17 in circuit with the magnet 20, whose armature 19 is thereupon at tracted, to close circuit at 18 through another magnet 16, the engagement between the elements 3 and 21 lasting a sufiicient length of time to permit the magnet 16 to attract its armature, which is in coiiperativc relation with a number of detcnts 13, 14 and 15 associated with the plungers 10, 11 and 12 corresponding to the selected stations, to cause said detents to release those plungers which have been actuated for the purpose of signaling the selected stations, suitable mechanism then coming into play, which need not be described, for restoring said actuated plungers to their normal or idle positions.

The I The wiper 3 is designed to pass ofi fromto occasion the o eration of the signal receivers at selecte party line stations, said plungers may be held in their depressed condltions. Thus all the operator at the central or transmitting station is required to do is first to depress the selected plunger or plungers 10, 11 or 12, etc that correspond to the party line or receiving station or stations to be signaled, whereafter such operator depresses the key 22, primarily to give the magnet 23 its initial energlzation primarily to operate all of the electro-magnets 50, to set the devices 59 into motion, and thereafter to operate all of the electro-magnets 50 when the element 59 at a selected station is in contact with or is about to come into contact with the associate button 60.

The mechanism employed for operating the wiper 3 at the central or transmitting station is desirably the same as is employed to operate the wipers 59 at the party line or receiving stations, the magnet 9 in Fig. 1 performing the releasing function of the magnet 56 in Fig. 2, the elements 1 2, 5, t5, 8 in Fig. 1 each performing a function sumlar to that performed by the elements 1, 2, 5', 6, 8' of Fig. 2.

The metallically continuous bridge conductors that include the electro-magnets 50 and retardation devices 51 and 52 are desirably of very high resistance and retardation, the aggregate retarding effect of the elements 50, 51, 52 having in practice equaled over six hundred thousand ohms to talking current and thirty thousand ohms to sixteen cycle ringing current, and a simple resistance of about fifty-five hundred ohms to direct current. It is obvious that these values may be changed within wide limits without departing from the spirit of our invention. We prefer to employ very high resistance for the metallic bridge conductors containing the elements50, 51, 52, particularly where there are many stations bridged upon the line, as in railroad work, whereby each individual bridge may not receive current materially in excess of the amount necessary to operate the included relay 50.

The battery 24 should be of high voltage, say one hundred ten volts, to compensate for drop in E. M. F., due to resistance of the line wires, the resistance of each metallically continuous bridge being desirably so great in proportion to the resistance of the line wires, that all of the electro-magnets 50 may receive approximately the same current at the same voltage and operate as nearly as possible simultaneously. By placing the eleetro-magnets 50 between the retardation elements 51, 52, such relays are so protected that the signals at the sub-stations or party line stations will not easily be impaired by lightning flashes nor will' the relays so readily burn out.

The signal receiver or bell 46 at the transmitting or despatchers station may have a resistance of twenty-five hundred ohms. The condensers 65 at the receiving or party line stations may each have a capacity of two microfarads so as to insure the passage of strong signaling current from the alternating current generator 68 to the line. The condenser 69 may have a capacity of one microfarad, the condensers 65 and 69 cooperating, as has been stated, to prevent current from the battery 24 from being short circuited from the line relays 50 when party line stations are being selected.

While we show a source of current 57 at each of the receiving stations for the purpose of operating the signal receiver there at, we do not wish to be limited to the location of the sources of current at the receiving stations.

While the invention has been shown as applied to railroad practice, it is, of course, understood that the invention is not to be limited to such practice. It is also to be understood that changes may readily be made in the embodiment of the invention illustrated without departing from the spirit of the invention.

Having thus described the invention,there is claimed as new and is desired to secure by Letters Patent the following 1. A transmission system including a line circuit leading from a transmitting to a plurality of receiving stations, electro-magnetic responsive apparatus atthe receiving stations, one set of instrumentalities distributed among the receiving stations and performing their functions in succession and having partial control of said electro-magnetic responsive apparatus, a second set of instrumentalities distributed among the receiving stations and adapted to further the control over said responsive apparatus, and means controlled at the transmitting station for causing the operation of one of the said second set of instrumentalities at a selected station to have it cotiperate with one of the said first set of instrumentalities located at a selected station to take part in operating the electro-magnetic responsive apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another stat-ion or stations may be then selected by the operation of the second set of instrumentalities.

2. A transmission system including a line circuit leading from a transmitting to a.

plurality of receiving stations, electro-magnetie responsive apparatus at the receiving stations, one set' of instrumentalities distributed among the receiving stations and perform ng their functions in succession and having partial control of said electro-magnetic responsive apparatus, a second set of instrumentalities distributed among the receiving stations adapted to further the control over said electro-niagnetic responsive apparatus, and apparatus governed at the transmitting station for operating the second set of instrumentalities substantially simultaneously to cause one instrumentality of each set at a selected station jointly to take part in operating the electro-magnetic responsive apparatus thereat,- there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated When a station is in selected condition so that another station or stat-ions may be then selected by'the operation of thesecond set of instrumentalities.

3. A transmissionsystem including a line circuit leading from a transmitting to a plurality of receiving stations, electro-magnctic responsive apparatus at the receiving stations, one set of instrumentalities distributed among the receiving stations and performing their functions in succession and having partial control of said electro-magnetic responsive apparatus, a second spt of instrumentalities distributed among the receiving stations adapted to further the control over said electro-magne'tic responsive apparatus, eleetro-magnetic devices .at the receiving stations for operating the second set of instrumentalities, and means governed at the transmitting station, for effecting the substantially simultaneous operation of said electro-magnetic devices to cause one instrumentality of each set at a selected station jointly to take part in operating the electromagnetic rcsponsive apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain 'free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

4. A transmission system including a line circuit leading from a transmitting to a plurality of receiving stations, electro-magnetie responsive apparatus at the receiving stations, one set of normally restrained self-operating instrumentalities distributed among the receiving stations and, when released, performing their funetions in succession and having partial control of said eleetro-magnetie responsive apparatus, a second set of instrumentalities distributed among the receiving stations and adapted to further the control over said responsive apof instrumentalities at a selected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to take part in operating the electromagnetic responsive apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated When a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

5. A transmission system including a line circuit leading from a. transmitting to a plurality of receiving stations, ele'ctro-magnetie responsive apparatus at the receiving stations, one set of normally restrained self-operating instrumentalities distributed among-the receiving stations and, when released, performing their functions in successionand having partial control of said electro-magnetic responsive apparatus, a second set of instrumentalities distributed among the receiving stations adapted to further the control over said electro-magnetic responsive apparatus, and apparatus governed at the transmitting station, for releasing said self-operating instrumentalities and operating the second set of instrumentalities substantially simultaneously to cause one instrumentality of each set at a selected station jointly to take part in operating the electro-magnetic responsive apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be on erated when a station is in selected condition so that another station or stations may be then selected by the operation of theseeond set of instrumentalities.

6. A transmission system including a line circuit leading from a transmitting to a plurality of receiving stations, electro-magnetic responsive apparatus at the receiving stations, one set of normally restrained selfoperating instrumentalities among the receiving stations and, when released, performing their-funetions in suc cession and having partial control of said electro-magnetic responsive apparatus, a second set of instriunentalities distributed among the receiving stations adapted to further the control over said electro-magnetic responsive apparatus, electro -magnetic' mechanism at the receiving stations for releasing said set of self-operating -instrumentalities and operating the second set of instrumentalities, and means governed at the transmitting station for effecting the substantially simultaneous operation of said electro-mag netic mechanism to cause one instrumentaldistributed ity of each set at a selected station jointly to take part in operating the clectro-ma netic responsive apparatus thereat, there eing present means whereby the Instrument-alities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that; another station or stations may be then selected by the operation of the second set of instrulnent'alities.

7. A ransmission system including a line circuit leading from a transmitting to a plurality of receiving stations, electro-mag netic responsive apparatus at the receiving stations, one set. of normally restrained instrumentalities distributed among the receiving stations and, when released, peri'orniing their functions in succession and having partial control of said electro-magnetic responsive apparatus, a second set of instrumciitalities distributed among the reeeiving stations and adapted to further the control over said responsive apparatus, and means controlled at the transmitting station for releasing said first set of instrumen talities and causing the operation of one of the said second set of instrumentalities at a selected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to take part in operating the electro-magnctic responsive apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

A transmission system including a line \lltltli leading from a transmitting to a plurainy of receiving stations, electro-magnetic responsive apparatus at the receiving stations. one. set of normally restrained instrumentalities distributed among the receiving stations and, when released, performing their functions in succession and ha \ing partial control of said electro-magnetic responsive apparatus, a second set of instrumentalities distributed among the receiving stations adapted to further the control over said electro-magnctic responsive apparatus, and apparatus governed at the transmitting station, for releasing said first; set of instrumentalities and operating the second set of instrumentalities substantially simultaneously to cause one instrumentality of each set at a selected station jointly to take part in operating the electro-magnetic responsive apparatus thereat, there being present means whereby the instrumentali ties of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

9. A transmission system including a line circuit leadin from a transmitting to a plurality of receiving stations, electro-magnetic responsive apparatus at the receiving stations, one set of normally restrained instrunientalities distributed among the receiving stations, and, when released, performing their functions in succession and having partial control of said electro-magnetic responsive apparatus, a second set of instrumentalh ties distributed among the receiving stations adapted to further the control over said electro-magnetic responsive apparatus, electro-magnetic mechanism at the receiving stations for releasing said first set of instrumentalities and operating the second set of instrumentalities, and means governed at the transmitting station for efiecting the substantially simultaneous operation of said electro-magnetic mechanism to cause one in strumentality of each set at a selected station jointly to take part in operating the eleetro-magnetic responsive apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be 0perated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

10. A transmission system including a line circuit leading from a transmitting to a plurality of receiving stations, electro-magnetic responsive apparatus at the receiving stations included in independent circuits, one set of instrumentalities distributed among the receiving stations and performing their functions in succession to close one of two breaks normally existing in the circuit of the electromagnetic responsive apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations to close the second of the two breaks normally existing in the circuit of the electro-magnetic responsive apparatus at each receiving station, and means controlled at the transmitting station for causing the operation of one of the said second set of instrumentalities at a selected station to have it cotiperate with one of the said first set of instrumentalities located at a selected station to take part in effecting the closure of the circuit of the electromagnetic responsive apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

11. A transmission system including a line circuit leading from a transmitting to a plurality of receiving stations electro-magnetic responsive apparatus at th tions included in independent circuits, one set of instrumentalities distributed among the receiving stations and performing their functions in succession to close one of two breaks normally existing in the cirpuit of the electro magnetic responsive apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations to close the second of the two breaks normally existing in the circuit of the electro-magnetic responsive apparatus at each receiving station, and apparatus governed at the transmitting station, for operating the second set of instrumentalities substantially simultaneously to cause one instrumentality of each set at a selected station jointly to take part in effecting the closure of the circuit of the electro-magnetic responsive apparatus thereat, there being pres ent means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

12. A transmission system including a line circuit leading from a transmitting to a plurality of receiving stations electro-magnetic responsive apparatus at the receiving stations included in independent circuits, one

set of instrumentalities distributed among the receiving stations and performing their functions in succession to close one of two breaks normally existing in the circuit of the electro magnetic responsive apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations to close the second of the two breaks normally existing in the circuit of the electro-magnetic responsive apparatus at each receiving station, electro-magnetic devices at the receiving stations for operating the second set of instrumentalities, and means governed at the transmitting station, for effecting the substantially simultaneous operation of said electro-magnetic devices to cause one instrumentalit-y of each set at a selected station jointly to take part in eifecting the closure of the circuit of the electro-magnetic responsive apparatus thereat, there being pres ent means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

13. A transmission system including a line circuit leading from a transmitting to a plurality of receiving stations, electromagnetic responsive apparatus at the receiving stations included in independent circuits, one set of normally restrained self-operating instrumentalities distributed e receiving sta amon the receiving stations and, when release performingtheir functions in successlon, to close one of two breaks normally exlstmg in the circuit of the electro-magnetic responsive ap aratus at each receiving station, a secon set of instrumentalities dlstrlbuted among the receiving stations to close the second of the two'breaks normally existing in the circuit of the electromagnetic responsive apparatus at each receivlng station, and means cont-rolled at the transmitting station for releasing said set of self-operating instrumentalities and causing the operation of one of the said secondset of instrumentalities at a selected station to have it cooperate with one of-the said first set of instrumentalities located at a selected station to take part in effecting the closure of the circuit of the electro-ma etic responslve apparatus thereat, there eing present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

14. A transmission system including a line circuit leading from a transmitting to a plurality of receiving stations, electromagnetic responsive apparatus at the receiving stations included in independent circuits, one set of normally restrained self operating instrumentalities distributed among the receiving stations and, when released, performing their functions in succession, to close one of two breaks normally existing in the circuit of the electro-magnet1c responsive apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations to close the second of the two breaks normally existing in the circuit of the electro-magnet-ic responsive apparatus at each receiving station, and apparatus governed at the transmitting station for releasing said set of self-operating instrumentalities and operating the second set of instrumentalities substantially simultaneously to cause one instrumentality of each set at a selected station jointly to take part in effecting the closure of the circuit of the electro-magnetic responsive apparatus thereat there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

15. A transmission system includinga line circuit leading from a transmitting to a plurality of receiving stations, electromagnetic responsive apparatus at the receiving stations included in independent circuits, one set of normally restrained selfoperating instrumentalities distributed among the receiving stations and, when released, performing their functions in succession,ito close one of two breaks normally existing in the circuit of the electro-magnetic responsive apparatus at each receiving station, a second set of inst-rumentalities distributed among the receiving stations, to close the second of the two breaks normally existing in the circuit of the electro-magnetic responsive apparatus at each receiving station, electro-magnetic mechanism at the receiving stations for releasing said set of self-operating instrumentalities and operating the second set of instrumentalities, and means governed at the transmitting station, for effecting the substantially simultaneous operation of said electro-magnetic mechanism to cause one instrumentality of each set at a selected station jointly to take part in effecting the closure of the circuit of the electro-magnetic responsive apparatus thereat there being present means whereby the instrumentalit-ies of the first set at stations remainin unselected remain free to be operated w en a station is in selected condition so that another station or stations maybe then selected by the operation of the second set of instrumentalities.

16. A transmission system including a line circuit leading from a transmitting to a plurality of receiving stations, electromagnetic responsive apparatus at the receiving stations included in independent circuits, one set of normally restrained instrumentalities distributed among the receiving stations and, when released, performing their functions in succession. to close one of two breaks normally existing in the circuit of the electro-magnetic responsive apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations, to close the second of the two breaks normally existing in the circuit of the electro-magnetic responsive apparatus at each receiving station, and means controlled at the transmitting station, for releasing said first set of instrumentalities and causing the operation of one of the said second set of instrumentalities at a selected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to take part in eifecting the closure of the circuit of the electro-magnetie responsive apparatus thereat there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

17. A transmission system including a line circuit leading from a transmitting to a plurality of receiving stations, electro-magnetic responsive apparatus at the receiving stations included in independent circuits, one set of normally restrained instrumentalities distributed among the receiving stations and, when released, performing their functions in succession, to close one of two breaks normally existing in the circuit of the electro -magnetic responsive apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations, to close the second of the two breaks normally existing in the circuit of the electro-magnetic responsive apparatus at each receiving station, and apparatus governed at the transmitting station for releasing said first set of instrumentalities and operating the second set of instrumentalities substantially simultaneously to cause one instrumentality of each set at a selected station jointly to take part in effecting the closure of the circuit of the electromagnetic responsive apparatus thereat, there bein present means whereby the instrumentalitles of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

18. A transmission system including a line circuit leading from a transmitting to a plurality of receiving stations, electro-magnetic responsive apparatus at the receiving stations included in. independent circuits, one set of normally restrained instrumentalities distributed among the receiving stations and, when released, performing their functions in succession, to close one of two breaks normally existing in the circuit of the electro-magnetic responsive apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations, to close the second of the two breaks normally existing in the circuit of the electro-magnetic responsive appara tus at each receiving station, electro-magnetic mechanism at the receiving stations for releasing said set of instrumentalities and operating the second set of instrumentalities, and means governed at the transmitting station, for effecting the substantially simultaneous operation of said electro-magnetic mechanism to cause one instrumentality of each set at a selected station jointly to take part in effecting the closure of the circuit of the electro-magnetic responsive apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

19. A transmission system including a transmission line extending to a transmitting station, a source of current, switching mechanism for includin the same in circuit withthetransmission line, an electro-magnet governing said switching mechanism whose circuit has one terminal in the form of a wiper, the complement of said terminal being in the form of contact buttons engageable by the wiper, manually operable switching devices governed by the operator, -for operatively including a selected contact or contacts in the circuit of said magnet, whereby when said wiper engages a contact or contacts thus operatively included in the circuit of said magnet, said magnet is energized to include the aforesaid source of current in circuit with the line, normally restrained self-operating mechanism for effecting relative movement between the wiper and contacts, electro-magnetic mechanism for releasing said selfoperating mechanism, and a manually operated switching device for closing circuit through said electro-niagnet and said electro-magnetic mechanism.

20. A transmission system including a transmission line extending to a transmitting station, a source of current, switching mechanism for including the same in circuit with the transmission line, an electro-magnet governing said switching mechanism whose circuit has one terminal in the form of a wiper, the complement to said terminal being in the form of contact buttons engageable by the Wiper, manually operable switching devices governed by the operator, for operatively including a selected contact or contacts in the circuit of said magnet, whereby when said wiper engages a contact or contacts thus operatively included in the clrcuit of said magnet, said magnet is energized to include the aforesaid source of current in circuit with the line, the aforesaid manually operable switching devices being provided with detents for holding the same in actu-' ated positions, and eleetro-magnetically operated releasing mechanism for releasing said detents and having in its circuit said viper and a terminal contact engaged by the "iper when finishing its travel.

21. A transmission system including a transmission 11118 extending to a transmittingstation, a source of current, switching mechanism for including the same in circuit with the BIQDSIIIISSIOII line, an electro-magnet governing said switching ,mechanism whose circuit has one terminal'in the form of a Wiper, the complement to said terminal being inthe form of contact buttons engageable by theaviper, manually operable switching devices governed by the operator, for

operatively including a selected contact or contacts in the circuit of said magnet,

whereby when said wiper engages a contact or contacts thus operatively includedin the circuit of said magnet, said magnet is energized to include the aforesaid source of current in circuit with the line, normally re strained self-operating mechanism for effecting relative movement between the wiper and" contacts, electro-magnetic mechanism for releasing said self-operating mechanism, a manually operated switching device for closin circuit through said electro-magnet and said electro-magnetic mechanism, the aforesaid manually operable switching devices being provided with detents for holdingthe same in actuated positions, and electro-magnetically operated releasing mechanism for releasing said detents and having for its circuit said wiper and a terminal contact engaged by the wiper when finishing its travel.

22. A signaling system including a line circuit leading from a transmitting to a plurality of receiving stations, signal'receiving apparatus at the receiving stations, one set of instrumentalities distributed among the receiving stations and performing their functions in succession and having partial control of said signal receiving apparatus,a second set of instrumentalities distributed among the receiving stations and adapted to further the control over said responsive apparatus, and means controlled at the transmitting station for causing the operation of one of the said second set of instrumentali-,

ties at a selected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to take part in operating the signal-receiving appa-v functions in succession and having partial control of said signal receiving apparatus, a

second set of instrumentalities distributed among the receivingstations adapted to further the control over said signal receiving apparatus, and apparatus governed at the transmitting station for operating the see 0nd set of instrumentalities substantially simultaneously to cause one instrumentality of each set at a selected station jointly to take part in operating the signal receiving apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

24. A signaling system including a line circuit leading from a transmitting to a plurality of receiving stations, signal receiving apparatus at the receiving stations, one set of instrumentalities distributed among the receiving stations and performing their functions in succession and having partial control of said signal-receiving apparatus, a second set of instrumentalities distributed among the receiving stations adapted to further the control over said signal-receiving apparatus, electro-magnetio devices at the receiving stations for operating the second set of instrumentalities, and means governed at the transmitting station, for effecting the substantially simultaneous operation of said signal-receiving devices to cause one instrumentality of each set at a selected station jointly to take part in operating thesignalreceiving apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated When a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

25. A signaling system including a line circuit leading from a transmitting to a plurality of receiving stations signal-receiving apparatus at the receiving stations, one set of normally restrained self-operating instrumentalities distributed among the receiving stations and, when released, performing ,their functions in succession and having of normally restrained sel partial control of said signal-receiving apparatus, a second set of instrumentalities distributed among the receiving stations and adapted to further the control over said signal-receiving apparatus, and means controlled at the transmitting station for releasing said set of self-operating instruiuentalities and causing the operation of one of the said second set of instrumentalities at a selected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to take part in operating the signal-receiving apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

26. A signaling system including a line circuit leading from a transmitting to a plurality of receiving stations, signal-receiving apparatus at the receiving stations, one set =operat1ng instrumentalities distributed among the receiving stations and, when released, performing their functions in succession and having partial control of said signal-receiving apparatus, a second set of instrumentalities distributed 'among the receiving stations adapted to further the control over said signal-receiving apparatus, and apparatus governed at the transmitting station, for releasing said self-operating instrumentalities and operating the second setof instrumentalities substantially simultaneously to cause one instrumentalit-y of each set at a selected station jointly to take part in operating the signal-receiving apparatus thereat, there being present means whereby the instrumen- 'mentalities distributed among the receiving stations and, when released, performing their functions in successlon and having partlal control of sa1d signal-receiving apparatus, a second set of instrumentalities distributed among the receiving stations adapted to further the control over said signal-receiving apparatus, electro-magnetic mechanism at the receiving stations for releasing said set of self-operating instrumentalities and operating the second set of instrumentalities, and means governed at the transmitting station for effecting the substantially simultaneous operation of said electro-magnetic mechanismto cause one in-: strumentality of each set at a selected station jointly to take part in operating the signal-receiving apparatus thereat, there being present means whereby the instrumentalities'of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second setof instrumentalities.

28. A signaling system including a line circuit leading from a transmitting to a plurality of receiving stations, signala-eceiving apparatus at the receiving stations, one

set of normally restrained instrumentalitransmltting station for releasing said first set of instrumentalities and causing the operation of one of the said second set of 1n.-

strumentalities at a selected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to take partin operating the signalreceiving apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

29. A signaling system including a line circuit leading from a transmitting to a plurality of receiving stations, signal-receiving apparatus at the receiving stations, one set of normally restrained instrumentalities distributed among the receiving stations and, when released, performing their functions in succession and having partial control of said signal-receiving apparatus, a second set of instrumentalities distributed among the receiving stations adapted to further the control over said signal-receiving apparatus, and apparatus governed at the transmitting station, for releasing said first set of instrumentalities and operating the second set of instrumentalities substantially simultaneously to cause one instrumentality of each set at a selected station jointly to take part in operating the signal-receiving apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

30. A signaling system including a line circuit leading from a transmitting to a plurality of receiving stations, signal-receiving apparatus at the receiving stations, one set of normally restrained instrumentalities distributed among the receiving stations, and, when released, performing their functions in succession and having partial control of said signal-receiving apparatus, a second set of instrumentalities distributed among the receiving stations adapted to further the control over said signal-receiving apparatus, electromagnetic mechanism at the receiving stations for releasing said first setof instrumentalities and operating the second set of instrumentalities, and means governed at the transmitting station for eflecting the substantially simultaneous operationvof said electro-magnetic mechanism to cause one instrumentality of each set at a selected station jointly to take part in operating the signal-receiving apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

31. A signaling system including a line circuit leadin from a transmitting to a plurality of receiving stations, signal-receiving apparatus at the receiving stations includedin independent circuits, one set of instrumentalities distributed among the receiving stations and performing their functions in succession to close one of two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations to close the second of the two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, and means controlled at the transmitting station for causing the operation of one of the said second set of instrumentalities at a selected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to take part in eflecting the closure of the circuit of the signal-receiving apparatus thereat, there being present means whereby the instrumentalities of the first set atstations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

32. A signaling system including a line circuit leading from a transmitting to a plurality of receiving stations, signal-receiving apparatus at the receiving stations included in independent circuits, one set of instrumentalities distributed among the receiving stations and performing their functions in succession to close one of two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving stat-ion, a second set of instrumentalities distributed among the receiving stations to close the second of the two breaks normally existingin the circuit of the signal-receiving apparatus at each receiving station, and apparatus governed at the transmitting station, for operating the second set of instrumentalities substantially simultaneously to cause one instrumentality .of each set at a selected station jointly to take part in effecting the closure of the circuit of the signal-receiving apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to' be operated when a station is in selected condition so that another stat-ion or stations may be then selected by the operation of the second set ofinstrumentalities.

33. A signaling system including a line circuit leading from a transmitting to a plurality of receiving stations, signal-receiving apparatus at the receiving stations included in independent circuits, one set of instrumentalities distributed among the re- :i sriis cciving stations and performing their functions in succession to close one of two breaks normally existing in the circuit of the signal-receiving a iparatus at each receiving station, a second set of instrumcntalitics distributed among the receiving stations to close the second of the two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, electrdmagnctic devices at the receiving stations for operating the second set of instrumentalities, and means governed at the transmitting station, for effecting the substantially simultaneous operation of said electro-magnetic devices to cause one instrumentality of each set at a selected station jointly to take part in effecting the closure of the circuit of the signalreceiving apparatus thcreat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to .ie operated when a station is in selected condition so that an other station or stations may be then selected by the operation of the second set of instrumentalities.

34:. A signaling system including a line circuit leading from a transmitting to a plurality of receiving stations, signal-receiving apparatus at the receiving stations included in independent circuits, one set of normally restrained self-operating instrumentalities distributed among the receiving stations and, when released, performing their functions in succession, to close one of two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations to close the second of the two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, and means controlled at the transmitting station for releasing said set of self-operating instrumentalities and causing the operation of one of the said second set of instrumentalities at a selected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to take part in effecting the closure of the circuit of the signal-receiving apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

35. A signaling system including a line circuit leading from a transmitting to a plurality of receiving stations, signal-receiving apparatus at the receiving stations included in independent circuits, one set of normally restrained self-operating instrumentalities distributed among the receiving stations and, when released, performing their functions in succession, to close one of two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations to close the second of the two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, and apparatus governed at the transmitting station for releasing said set of self-operating instrumentalities and operating the second set of instrumentalities substantially simultaneously to cause one instrumentality of each set at a selected station jointly to take part in efi'ecting the closure of the circuit of the signal-receiving apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated When a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

36. A signaling system including a line circuit leading from a transmit-tin to a plurality of receiving stations, signa -receivin apparatus at the receiving stations included in independent circuits, one set of normally restrained self-operating instrumentalities distributed among the receiving stations and, when released, performing their tunetions in succession, to close one of two breaks normally existing in the circuit of the signail-receiving apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations, to close the second set of the two breaks normally existing in the circuit of the signalreceiving apparatus at each receiving station, electro-magnetic mechanism at the receiving stations for releasing said set of selfoperating instrumentalities and operating the second set of inst-rumentalities, 'and means governed at the transmitting station, for effecting the substantially simultaneous operation of said electro-magnetic mechanism to cause one instrumentality of each set at a selected station jointly to take part in effecting the closure of the circuit of the signal-receiving apparatus thereat, therebeing present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

37. A si aling system including a line circuit leading from a transmitting to a plurality of receiving stations, signal-receiving apparatus at the receiving stations included in independent circuits, one set of normally restrained instrumentalities distributed among the receiving stations and,

- existing in the circuit of the signal-receiving apparatus at each receiving station, and means controlled at thetransmitting station, for releasing said first set of instrumentalities and causing the operation of one of the said second set of instrumentalities at a se-- lected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to take part in effecting the closure of the circuit of the signal-receiving apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

38. A signaling system including a line circuit leading from a transmitting to a plurality of receiving stations, signal-receiving apparatus at the receiving stations included in independent circuits, one set of normally restrained instrumentalities distributed among the receiving stations -and, when released, performing their functions in succession, to close one of two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations, to close the second of the two breaks normally existing in the circuit of the signal-rmeiving apparatus at each receiving station, and

- apparatus governed at the transmitting station for releasing said first set of instrumentalities and operating the second set of instrumentalities substantially simultaneously to cause one instrumentality of each set at a selected station jointly to take part in effecting the closure of the circuit of the signal-receiving apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in'seleeted condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

39. A signaling system including a line circuit leading from a transmitting to a plurality of receiving'stations, signal-receiving apparatus at the receiving stations included in independent circuits, one set of normally restrained instrumentalities distributed among the receiving stations, and, when released, performing their functions in succession, to close one of two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station,

a second set of instrumentalities distributed taneous operation of said electro-magnetic mechanism to cause one instrumentality of each set at a selected station jointly to take part in effecting the closure of the circuit of the signal-receiving apparatus thereat, there being present means whereby the instrumentalities of the first set at stations remaining unselected remain free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities.

40. A party line telephone system including a line circuit leading from a transmit ting to a plurality of receiving stations, each having telephonic apparatus in a telephonically continuous but metallically discontinuous bridge between the sides of the line circuit, signal-receiving apparatus at the receiving stations, one set of instrumentalities distributed among the receiving stations and performing their functions in succession and having partial controlof said signalreceiving apparatus, a second set of. instrumentalities distributed among the 'receiving stations and adapted to further the control over said signal-receiving apparatus, electro-magnets at the receiving stations in metallically continuous bridges between the sides of the party line, and switching mechanism at the transmitting station for operating said electro-magnets to cause the operation of one of the said second set of instrumentalities at a selected station to have it cooperate with one of the said first set of in main free to be operated when a station is in selected condition so that another station or stations may be then selected by the operation of the second set of instrumentalities 41. A party line telephone system ineluding a line'circuit leading from a transmitting to a plurality-of receiving stations, each having telephonic apparatus in a telephonically continuous but metallically discontinuous bridge between the sides of the line circuit. signal-receiving apparatus at the receiving stations, one set of instrumentalities distributed among the receiving stations and 1 will performing their functions in succession and having partial control of said signalrecciving apparatus, a second set of instrulnentalities distributed among the receiving stations and having govermnent exercised from the transmitting station that is independent of government exercised by the first set of'instrumentalities and adapted to further the control over said signarl-receiving apparatus, eleetro-magnets at the receiving stations in metallically continuous bridges between the sides of the party line, and switching mechanism at the transmitting station for operating said electro-magnets to operate the second set of instrumentalities substantially simultaneously to cause one instrumentality of each set at a selected station jointly to take. part in operating the signal-receiving apparatus thereat.

42. A party line telephone system including a line circuit leading from a transmitting to a plurality of receiving stations, each having telephonic apparatus in a telephonically continuous but metallically discontinuous bridge between the sides of the line circuit, signal-receiving apparatus at the receiving stations, one set of instrumentalities distributed among the receiving stations and performing their functions in succession and having partial control of said signal-receiving apparatus. a second set of instrumentalitics distributed among the receiving stations and having government exercised from the transmitting station that is independent of government exercised by the first set of instrumentalities and adapted to further the control over said signal-receiving apparatus, electro-magnetio devices at the receiving stations for operating the second set of instrumentalities, electro-magnets at the receiviug stations in metallically continuous bridges between the sides of the party line, and switching mechanism at the transmitting station for operating said electr0-mag nets to effect the substantially simultaneous operation of said electromagnetic devices to cause one instrumentality of each set at a selected station jointly to take part in op erating the signal-receiving apparatus thereat.

43. A party line telephone system including line circuit leading from a transmitting to a plurality of receiving stations, each having telephonic apparatus in a telephoni cally continuous but metallically discontinuous bridge between the sides of the line circuit, signal-receiving apparatus at the receiving stations, one set of normally restrained self-operating instrumentalities distributed among the receiving stations and, when released, performing their functions in succession and having partial control of said signal-receiving apparatus, a second set of instrumentalities distributed among the receiving stations and having government exerci ed from the transmitting station. that is independent of government exercised by the first set of iustrinnentalities and adapted to further the control over said responsive apparatus, electro-magnets at the receiving stations in metallically continuous bridges between the sides of the party line, and switching mechanism at the transmitting station for operating said electro-magnets to release said set of self-operating instrumentalities and causing the operation of one of the said second set of instrumentalities at a selected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to take part in operating the signal-receiving apparatus thereat.

44. A party line telephone system including a line circuit leading from a transmitting to a plurality of receiving stations, each having telephonic apparatus in a telephonically continuous but metallically discontinuous bridge between the sides of the line circuit, signal-receiving apparatus at the receivil'g stations, one, set of normally restrained self-operating instrumentalities distributed among the receiving stations and,

when released, performing their functions in succession and having partial control of said signal-receiving apparatus, a second set of instrumentalities distributed among the receiving stations and having government exercised from the transmitting station that is independent of government exercised by the first set of instrnmentalities adapted to further the control over said signalreceiving apparatus, electro-magnets at the receiving stations in metallically continuous bridges between the sides of the party line, and switching mechanism at the transmit ting station for operating said electro-magnets to release said self-operating instrumentalities and operating the second set of instrumentalities substantially simultaneously to cause one instrumentality of each set at a selected station jointly to take part in operating the signal-receiving apparatus thereat.

45. A party line telephone system including a line circuit leading from a'transmitting to a plurality of receiving stations, each having telephonic apparatus in a telephonically continuous but metallically discontinuous bridge between the sides of the line circuit, signal-receiving apparatus at the receiving stat-ions, one set of normally restrained self-operating instrumentalities distributed among the receiving stations and, when released, performing their functions in succession and having partial control of said signal-receiving apparatus, a second set of instrumentalities distributed among the receiving stations and having government exercised from the transmitting station that is independent of government exercised by the first set of instrumentalities and adapted to further the control over said signal-re ceiving apparatus, electromagnetic mechanism at the receiving stations for releasing said set of self-operating instrumentalities and operating the second set of instrumentalities, electro-magnets at the receiving stations in metallically continuous bridges between the sides of the party line, and switching mechanism at the transmitting station for operatin said 'electro-magnets to effect the substantially simultaneous operation of said electro-magnetic mechanism .to cause one instrumentality of each set at a selected station jointly to take part in operating the signal-receiving apparatus thereat.

46. A party line telephone system including a line circuit leading from a transmitting to a plurality of recelving stations, each having telephonic apparatus in a telephonically continuous but metallically discontinuous bridge between the sides of the line circuit, signal-receiving apparatus at the receiving stations, one set of normally restrained instrumentalities distributed among the receiving, stations and, when released, performing their functions in succession and having partial control of said signal-receiving apparatus, a second set of instrumentalities distributed among the receiving stations and havinggovernment exercised from the transmitting station that is independent of government exercised by the first set of instrumentalities and adapted to further the control over said responsive apparatus, electro-magnets at the receiving stations in metallically continuous bridges between the sides of the party line, and switching mechanism at the transmitting station for operating said electro-magnets to release said set of instrumentalities and causing the operation of one of the said second set of instrumentalities at a selected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to take part in operating the signal-receiving apparatus thereat.

47. A party line telephone system including a line circuit leading from a transmitting to a plurality of receiving stations, each having telephonic apparatus 1n a telephonically continuous but metallically discontinuous bridge between the sides of the line circuit, signal-receiving apparatus at the receiving stations, one set of normally restrained instrumentalities distributed among the receiving stations and, when released, performing their functions in succession and having partial control of said signal-receiving apparatus, a second set of instrumentalities distributed among the receiving stations and having government exercised from the transmitting station that is independent of government exercised by the first set of instrumentalities and adapted to further the ing said electro-m'agnets to release said instrumentalities and operating the second set 1 of instrumentalities substantially simultaneously to, cause one instrumentality of each set at a selected station jointly to take part in operating the signal-receiving apparatus thereat.

A8. A party line telephone system including a line circuit leading from a transmitting to a plurality of receiving stations, each having telephonic apparatus in a telephonically continuous but metallicall discontinuous bridge between the sides 0 the line circuit,signal-receiving apparatus at the receiving stations, one set of normally restrained instrumentalities distributed among the receiving stations and, when released performing their functions in succession and having partial control of said signal-receiving apparatus, a second set of instrumentalities distributed among the receiving stationsand having government exercised from the transmitting station that is independent of government exercised by the first set of instrumentalities and adapted to further the control over said signal -receiving apparatus, electro-magnetic mechanism at the receiving stations for releasing said set of instrumentalities and operating the second set of instrumentalities, electro-magnets at the receiving stations in metallically continuous bridges between the sides of the party line, and switching mechanism atthe transmitting station for operating said electro-magnets to effect the substantially simultaneous operation of said electro-magnetic mechanism to cause one instrumentality of each set at a selected station jointly to take part in operating the signal-receiving apparatus thereat.

49. A party line telephone system including a line circuit leading from a transmitting to a plurality of receiving stations, each having telephonic apparatus in a telephonically continuous but metallically discontinuous bridge between the sides of the line circuit, signal-receiving apparatus at the receiving stations included in independent circuits, one set of instrumentalities distributed among the receiving stations and per- .-forming their functions in succession to close one of two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations and having government exercised from the transmitting station that is independent of government exercised by the first set of instrumentalities, to close the second of the two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, electro-magnets at the receiving stations in metallically continuous bridges between the sides of the party line, and switching mechanism at the transmitting station for operating sald electro-magnets to cause the operation of one of the said second set of instrumentalities at a selected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to take part. in effecting the closure of the circuit of the signal-receiving apparatus thereat.

50. A party line telephone system including a line circuit leading from a transmittin to a plurality of receiving stations, eaci having telephonic apparatus in telephonically continuous but metallic-ally discontinuous bridge between the sides of the line circuit, signal-receiving apparatus at the receiving stations included in independent circuits, one set of instrumentalities distributed among the receiving stations and performing their functions in succession to close one of two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, a second set of instrumentalities distributed among the re-' ceiving stations and having government exercised from the transmitting station that is independent of government exercised by the first set of instrumentalities, to close the second of the two breaks normally existing in the circuit of the signaLreceiving apparatus at each receiving station, electro-magnets at the receiving stations in metallically continuous bridges between the sides of the party line, and switching mechanism at the transmitting station for operating said electro-magnets to operate the second set of instrumentalities substantially simultaneously to cause one instrumentality of each set at a selected station jointly to take part in elfecting the closure of the circuit of the signal-receiving apparatus thereat.

51. A party" line telephone system including a line circuit leading from a transmitting to a plurality of receiving stations, each having telephonic apparatus in a telephonically continuous but metallically discontinuous bridge between the sides of the line circuit, signal-receiving apparatus at the receiving stations included in independ- 'ent circuits, one set of instrumentalities distributed among the receiving stations and performing their functions in succession to close one of two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, a second set of instrumentalities distributed among the receiving stations and having government exercised from the transmitting station that is independent of government exercised by the first set of instrumentalities, to close the second of the two breaks normally existing in the circuit of the signalreceiving apparatus at each receiving station, electro-inagnetic devices at. the receiving stations for operating the second set of instrumentalities, electrounagncts at the receiving stations in nietallically continuous bridges between the sides of the party line, and switching mechanism at the transmitting station for operating said electro-magnets to effect the substantially simultaneous operation of said electro-magnetic devices to cause one instrumentality of each set at a selected station jointly to take part in effecting the closure of the circuit of the signal-receiving apparatus thereat.

52. A party line telephone system including a line circuit leading from a transmitting to a plurality of receiving stations, each having telephonic apparatus in a telephonically continuous but metallically discontinuous bridge between the sides of the line circuit, signal-receiving apparatus at the receiving stations included in independ ent circuits, one set of normally restrained self-operating instrumentalities distributed among the receiving stations and, when released, performing their functions in succession, to close one of two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, a second set of instrument-alities distributed among the receiving stations and having government exercised from the transmitting station that is independent of government exercised by the first set of instrumentalities, to close the second of the two breaks normally existing in the circuit of the signal-receiving apparatus at each receiving station, electro-ma nets at the receiving stations in metallical y continuous bridges between the sid'es of the party line, and switching mechanism at the transmitting station for operating said electro-magnets to release said set of self-operating instrumentalities and causing the operation of one of the said second set of instrumcntalities at a selected station to have it cooperate with one of the said first set of instrumentalities located at a selected station to take part in effecting the closure of the circuit of the signal-receiving apparatus thereat.

53. A party line telephone system including a line circuit leading from a transmitting to a plurality of receiving stations, each having telephonic apparatus in a telephonically continuous but metallically discontinuous bridge between the sides of the line circuit, signal-receiving apparatus at the re ceiving stations included in independent Cli', cuits, one set of normally restrained self-opcrating instrumentalities distributed among the receiving stations and, when released, performing their functions in succession, to close one of two breaks normally existing in the circuit of the signal-receiving apparatus

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