US1075260A - Telephony. - Google Patents

Description

M. L. JOHNSON.

TELEPHONY. APPLICATION FILED AUG. 10, 1911. RENEWED JULY 25, 1913.

L@?fi6. I Patented Oct. 7, 1913 IIVVENTOR WITIVE ES: w MORTON L. JOHNSON; O I.

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MORTON I]. JOHNSON, OF'CHICAGO, ILLINOIS, ASSIGNORTO CORWIN TELEPHONE MAN- UIEACTUBING'COMBANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONY.

Specification cfLetters Patent.

Application filed-August 10, 1911, Serial No. 643,341. Renewed July 25, 1913. Serial N0. 781,255.

To all'whom it may concern:

Be it known that I, .MORTON L, Johnson, citizen of theUnited- States, residing at Gill: cago, in the county of Cook and State i Illinois, have invented a certain new and useful Improvement in Telephony, of which thefollow-in'g isarfull, clear, concise, and exactdescription, reference being had to the accompanying drawings, forming a partot this specification. i

My invention relates to telephone exchange systems and has for one of its ole-- jects the. provision of means whereby the stations upon a party line that extends to an .1 exchange may have telephonic communication to the exclusion of the exchange and mechanism controlled at one of the party line stations that serves to prevent the telephone at the remaining party line station from becoming connected with the party line when telephonic connection is established between thefirst party line station and saidparty line.

My invention has for its further object the provision of means whereby apparatus at. an exchange, which is automatically responsive to circuit changes at substations, may be held-in a condition of use dur-mg the time telephonic communication is established between the part line stations to the exclusion of the exc ange, there being means for-removing the influence of the aforesaid means to permit the party line station that appropriates the party line to have operating influence over the exchange equipmerit, V I

I will explain my invention more fully by reference to the-accompanying drawing showing. the preferred embodiment thereof and which-diagrammatically illustrates two minate in a tip line spring 1, and a sleeve line spring 2 of a spring jack.3. The tele-- phone line extending from the party line stations C, D has its sides terminate in a tip line spring 4 and a sleeve line sprin 5 of a spring jack 6, the sprin jacks 3 an 6 being located at the same exaiange A. The

-ployed upon the premiseswhere they equipmentat the exchange A may be of any well known or suitable type and therefore Patented eat. 7, ieis.

does not require description in detail. The

drawing-shows one of a number of manually controlled link circuits, the linkcircuit shown including a calling plug? and an answering plug 8, this link circuit and its com panions being. adapted to connect the station B with the line having the party line stations C and D, the plugs being inserted in the jacks of the respective lines for thispurpose. a

There are features of my present invention that are not only of service in connection with manual exchanges but are also ofservice in connection with those exchanges in which lines are automatically extended. To the extent that the features of my present invention are of service in connection with both general classes of systems, I ge nerically claim the invention herein disclosed. My copending' application Serial No. 643,342, filed August 10, 1911 relates more particularly to systems in which lines are automatically extended.

In the embodiment of the invention illustrated, each line is provided with a cutofi change. and substations in a manner so well understood as to require no description.

My invention more direc concerns the relationship of: the party line-stations with each other and also with the exchange and I will describe the equipment illustrated at each arty line station,- similar characters of re erence being given to similar parts at both the party line stations as the equipments at these stations are identical in construetion, circuit arrangement and function, in the embodiment of the inventien shown.-

,The party line stations C, 1) may be'locate'cl at difierent premises, or they may be 1ocated at the same premise, in which latter case either of the stations may constitute an 'attendants station and the other the princial station. If the stations are 'collocated, hut one signal receiving bell manta emare located, but if the stations are wide y separated each station should be equipped with such a hell. I have shown a. signal receiv' bell 12 in bridge of the arty line at one of the stations 0,1). en two bells are employed the operator at the exchange A may select one or the other for operation, if desired, or both bells maybe caused to respond, the party at either station being privileged to respond and it may be arranged to have one of the parties respond if the bell at his station rings for an unusual length of time, it then being understood that it is the object to have the other party respond when his bell rings at all.

Each station is provided with a telephone receiver switch hook 13 adapted, when relievedlof the weight of the telephone receiver 14, -to connect the telephone receiver and transmitter 15 in a circuit path between the switch springs 16 and 17. Each switch.

hook is provided with a post 18 that is depressed when the associate receiver is upon its switch hook, the limit to which such post 18 may be depressed being determined by a stop 19. The post 18 is providech with a lug 20 that engages the spring 17 and the springs 17 and 16 are mechanically united by a strut 21 of insulating material. By this arrangement the receiver, when placed upon its switch hook, is adapted to bring the springs 16 and 17 into engagement with their normal contacts, and, when the springs 16 and 17 are otherwise free to move, said springs will by their own resilience separate from their normal contacts and engage their alternate contacts. The mechanically united springs 16 and 17 are provided with a commonextension 22 that normally lies beneath the catch 23 carried by the armature of a magnet 24, this catch serving to prevent the springs 16 and 17 from engaging their alternate cont-acts. The lug 20 normally overcomes the resilience of the springs 16 and 17 for the purpose of maintaining them in engagement "with their normal contacts, a slight clearance intervening between the extension 22'and the catch 23 that will permit the post 18 to rise sufficiently, when the catch 23 is in normal position, to efiect engagement between the associate switch hook and the contact located above the same, such movement however being sufliciently restricted by the catch 23, when in normal position, toprevent the springs 16 and 17 from leaving their normal contacts and engaging their alternate contacts when the associate telephone receiver is removed from its switch hook. The manually operated switch 26 controls a gap in the bridge between the sides of the party line, which bridge ineludes the magnet 24 that is desirably of high resistance .say 1,000 ohms. A party line subscriber, in initiating a call for a line terminating at the exchange A will remove his telephone from its switchhook and will also close the contacts atthe switch 26 so as to include the magnet 24 in bridge of the party line to cause said magnet to be supplied with current from the common batferent sides of the party line. '11 signal is displayed at the exchange in the usual way and the wants of the calling party line stations are attended to in a manner well known. If either of the party line stations is a called station, the bell 12 at such called station will be caused to ring by the operator at the exchange and the answering partydine subscriber will repeat the operations which have inst been described, thereby placing the telephone receiver and transmitter at-such answering party line station in bridge of the party line.

If the telephone receiver and .transmitter at one of the party line stations is in bridge of the party line, the other party line station cannot become connected with the party line since the low resistance bridge established through said telephone receiver and transmitter will shunt the magnet 24 of the station seeking the line so that the contact springs 16 and 17-at such seeking station will not be free to engage their alternate contacts as a consequence of which the telephone receiver and transmitter at the seeking station are locked out of circuit with the party line. The fact that the line is busy is indicated to the seeking party line subscriber by the failure of the plunger 27 to rise above the plate 28, the extension 22 forcing this plunger above the plate 28 only when the magnet 24 responds, this magnet 24 responding only when the party line is free for appropriation.

In order to enable the subscribers atthe party line stations to communicate directly with each other I preferably employ a dis.- tinct line between these stations that forms no part of the main party line, though I do not wish to be limited to this arrangement. This distinct line between the party line stations includes a conductor 29 that joins the normal contacts of the springs'17 and a con ductor 30 that joins the normal contacts of the springs 16. A battery 31 is included in one of these conductors for the purpose of supplying battery current to the telephones at the party line stations. When either party line station desires to communicate with the other the. contacts of a switch 32' are closed by the calling party to include a signal receiver 33 of the called party in circuit, the circuit for such a signal receiver being traceable from the battery 31 through the incense signal receiver 33-at the called station, the

tio-ns including the conductors 29 and 30,

the switch springs 16 andl7-and the normal contacts of said switch springs. During the conversation between the party line subscribers, the springs 16 and 17 are held out of 'engagement'with their alternate contacts by means of the catches 23 so that the party lineproper, which extends to the exchange, is maintained out of telephonic relation with the telephone at both of the party line stations during the establishment of telephonic connection between these sta-v tions by way of the conductors 29 and 30, the signal receivers 12 being then amply freeto receive incoming signals, while at the same time the line signal 11 at the exchange is not disturbed by any low resistance shunt at the party line stations. In this we telephonic communication may be held directly between the party line stations independently of the exchange so that this conversation may not be listened into by wayof any line entering the exchange or by the operator at the exchange. Now let it be assumed that the stations C, Dare located in the same .place and that one of these stations, say station G, is presided over by any attendant whose duty it'is to assist the party at the remaining station in governing the connection of the telephone at such remaining station with the party line. As the system;.is organized the'party at either of the stations is adapted to assist the other in the way described but for the sake of illustra tion the station C has been selected as the attendant station, it being understood that I do not limit myself to the equipment whereby each of the party line stations may supplement the other in effecting telephonic association with the party line. If the party at station D desires to call another party, say the party at station B, and wishes the attendant at station C to attend to the details of the call, the party at station I) will operate the signal 33 at station C and have telephonic communication with the party at station 0 in the manner which has been described, whereafter the party at stationD will restore his-telephone to its switch hook to await the signal to be conveyed by his signal device 33 when; the called line has been secured. The attendant at station C will remove his telephone from its switch hook and will operate the switch 26 so as to permit the @rings 16 and 17 to engage their alternate contacts, in the manner which has been descrimd, thereby to include the associate telephone receiver and transmitter in bridge of the party line to occasion the operation of the line signal 11 at the exchange. The operator at the exchange will communicate with the party at station 0 to ascertain the number of the line called for p and will connect thespring jack 6 of the calling party line with the spring jack 3- of the called line by the link connector that includes the plugs 7 and 8, the plug 8 then being inserted in the jack 6 and the plug 7 in the jack 3'. When the called party at station B responds the party at stat on C will inform the called party that the part at station D- desires to communicate with im whereaf-ter the attendant at station C will close the contacts of his switch 34 to include a magnet 35 in bridge of the party line, this magnet serving to close the contacts of a switch 36 that is in parallel with the switch 34 so that the bridge through the -magnet 35 may be maintained at 36 w the contacts of the switch 34 are separated. The bridge established through the magnet 35, this magnet being desirably of high resistance say of 1,000 ohms, aiiords the passage of suflicient current from the common battery of the common battery exchange A through the supervisory relay 37 at the exchange to maintain this supervisory relay in its energized condition. When the attendants switch 34 is operated the telephone 1 receiver and transmitter at the attendants station either has its circuit'opened at its switch hook or is limited to circuit relation with the conductors 29 and 30. When the attendant operates the switch 34 his receiver should be free of itsswitch hook and this too receiver is restored to 'its switchhook while the" switch 34 is closed in orderto preserve the control of the bridge to be established by the relay 35. In the operations that are being traced the called party B has heard such response, this attendant thereupon informing the party at station D that ,the called party at station B-has responded, this information being'secretly conveyed from the attendants station C to the station D through the agencies and in the manner which has been described. The calling party at station D- thereu on closes the contacts of his switch 26 an removes his telephone from its switch hook whereby this telephone becomes connected in bridge of the party line with the result that the bridge established at the magnet 35 is broken and the supervisory signal 37 at the exchange is placed directly within the control of the calling party, at station D The magnet maybe equipped with a signal attachment 35 to inform the operator at the attendant party line station, which ever station this may be, when thevother party line station has taken the party line. v

It will be observed that the party at the attendant station cannot listen in upon the connection that is now established between the calling station D and the called station B since the magnet 24 at the attendant station is shunted by the telephone receiver bridge at the station'D, the catch 23 of the shunted magnet 24 preventing the springs 16 and 17 from leaving their normal andengaging their alternate contacts, which latter contacts have to be engaged by these springs in order to enable the attendant at station C to bridge the telephone at this station across the party line which is now connected with the receiver and'transmitter at station D to the exclusion of the private line 29,30 owing to the separation of the normal contacts at station D from the springs 16 and 17 thereat. In this way, as the invention is specifically embodied, either station C or D may communicate with the other and either of these stations may have connection with the exchange by way of the party line to the exclusion of the other. On the other hand a calling-station whose line terminates at theexchange is totally excluded fromthe telephonic circuit that intervenes directly between the stations C, D by way of the private line 29, 30, a characteristic that is of importance particularly where one of the stations C D is a called station with respect to a line entering the exchange.

The element 18, in the preferred embodiment of the invention, is manually operated through the manipulation of the associate telephone receiver which acts upon the ele ment 18 through the intermediation of the receiver switch hook 13. I do not wish to be limited in all embodiments of my invention to the switch hook control of the element 18.

While I have herein shownand particularly described the preferred embodiment of my invention I do not wish to be limited to the precise details of construction and cirsnit arrangement illustrated, but

Having thus described my invention ,1

claim as new and desire to secure by Letters Patent the following:

1. A telephone exchange system including telephone lines extending from telephone substations to an exchange, one of said lines being a party telephone line extending from a plurality of party line stations to said exchange; circuit connections whereby telephonic communication may be held between the party line stations'to the exclusionof the exchange; switching mechanism for connecting the telephone at one of the party line stations in telephonic circuit with the party line and at that time serving to break the telephonic connect-ion between the party line stations; and mechanism controlled by said switching mechanism serving to prevent the telephone at the party line station companion to that havingsaid. switching mechanism from becoming connected with the party line when the telephonic connea tion between the party line stations s broken. j

2. A telephone exchange system including telephone lines extending from telephone substations to an exchange, one of said lines being a party telephone line extending from a plurality of party line stations to said exchange; circuit connections whereby telephonic communication may be ,heldbetween the party line stations to the exclusion of the exchange; switching mechanism-for connecting the telephone at one of the party line stations in telephonic circuit-with the party line; and mechanism controlled by said switching mechanism serving to prevent the telephone at the remaining party line station from becoming connected with the party line, when said telephonic connection with the party line is established, and preserving such telephonic connection established between party line stations to the exclusion of the exchange.

3. A telephone exchai'ige system including telephone lines extending from: telephone substations to an exchange, one of said lines being a party telephone line extending from a plurality of party line stations to said 'exchange; circuit connections whereby telephonic communication may be held between the party line stations to the exclusion of the exchange; switching mechanism for connectin the telephone at one of the'party line stat-ions in telephonic circuit with the party line; and mechanism serving to prevent the telephcne at the remaining party line station from becoming connected with the party line, when said telephonic connection with the party line is established, and preserving such telephonic connection established between party line stations to the exclusion of the exchange.

4. A. telephone exchange system including telephone lines extending from telephone substations to an exchange, one'of said lines being a party telephone line extending from a plurality of party line stations to said exchange; circuit connections whereby tele-- phonic communication may be held between the party line stations to the exclusion of 'the exchange; switching mechanism at one of the party line stations adapted in one condition of use to take part in establishing the telephonic connection between the party line stations that is independent of the exchange and in another condition of use to permit of the connection of the associate telephone with the partfyQni; means at the station where this switching mechanism is located for preventing that operation of said switching mechanism that will permit the association of theassociate telephone receiver with the party line; and meansat the remaining party line station for goyerninganism at one of the party line stations adapted intone condition of use to take part in establishing the telephonic connection between the party line stations that is independentof the exchange and in another condition of use to permit of the connection of the associate telephone with the party line; means at the station where this, switching mechanism is located for preventing that operation of said switching mechanism that will permitthe association of the associate telephone receiver with the party line; and vmeans at the remaining party line station for governing the operation of the latter means, there being a switch hook at the station where the aforesaid switching mechanism is located which serves to place said switching mechanism in condition to enable theestablishment of telephonic connection between the party line stations that is exelusive of the exchange and which switch hook permits the connection of the associate telephone with the party line when said switching mechanism is free to efiectthis connection' 7 6 A telephone exchange system including telephone lines extending from telephone substations to an exchange, one of said lines being a party telephoneline extending from a plurality of party line stations to said exchange; circuit connect-ions whereby telephonic communication may be held between the part-y line stations to-the exclusion of the exchange; switching mechanism at one of the party line stations adapted in one condition ofuse to take part in establishing the .telephonic connection. between the part line stations that-is independentlofthe exc mange and in another conditionof -use topermit; of the connectionof the. associate telephonewith .theparty line; electro-magnetic means at the station where this switching mecha nismjs located for preventing that operation of-said-switehing mechanism that will; permitthe association oftheassoc ate teleph'on'e receiver with the party line; and;

means at the remaining party line station for governing the operation of the latter means.

7. A telephone exchange system including telephone -'lines extending from telephone substations to an exchange, one of said linesbei-ng a party telephone line extending from a plurality of. party line stations to said exchange; circuit connections whereby telephonic communication may be held between the party line stations to the exclusion'of the exchange; switching mechanism at one of the party line stations adapted'in one condition of use to take part inestablishing the telephonic connection be tween the party .line stations that is inde pendent of theexchange and in another condition of use to permit of the connection of I the associatetelephone with the party line;

,stations that is exclusive of the exchange and which switch hook permits the connection of the associate telephone with the party line when said switching mechanism is free to efi'ect this connection,-

8. A telephone exchange-system including telephone lines extending from telephone substations to an exchange, one of said lines being a party tele hone line ex tending from a plurality of arty line stations to said exchange circuit connections whereby telephonic communication may be held between the party line stations to the exclusion of the exchange; switching mechanism at one of the party line stations adapted in one condition of use to takepart in establishing the telephonic connection between the party line stations that is independent of the exchange and in another condition of use=to permit of the cennection'of the associate telephone with the party line; electro-magnetic means at' the station where this switching mechanism is located for pre-. venting that operation of said switching mechanism that will permit the association of the associate telephone receiver with the party hue; means at the remainlng party line station for governing the operation of the latter means, said electro-magnetic means having a bridge connection for inch ding it across the party line; and asource of current in connection with the party line for energizing said electromagnetic means when connected in bridge of the party line,

bridge connection of the party line that contains the telephone thereat that serves to shunt suiiicient current from said electromagnetic means to prevent the operation thereof, the bridge including said electromagnetic means being of sufiiciently high resistance for the purpose.

9. A "lephone exchange system including telephone lines extending fromtelephone substations to an exchange, one of said lines being a party telephone line extending from a plurality of party line stations to said exchange; circuit connections whereby telephonic communication may be held between the party line stations to'the exclusion of the exchange; switching mechanism at one of the party line stations adapted in one condition of use to take part in establishing the telephonic connection.

between the party line stations that is independent vof the exchange and in another condition of use to permit of the connec tion of the associate telephone with the party line; electro-magnetic ineans at the station where this switching mechanism is located for preventing thatoperation of said switching mechanism that will permit the association of the associate telephone receiver with the party line; means at the remaining party line station for governing the operation of the latter means, there being a switch hook at the station where the aforesaid switching mechanism is located which serves to placesaid switching mechanism in condition to enable the-establishment of telephonic connection between the party line stations that is exclusive of the exchange and which switch hook permits the connection of the associate telephonewith the party line when said switching .mechanism is free to effect this connection,

ing telephone lines extending from tele-- phone substations to an exchange, one of said lines being a party telephone line extending from a plurality of party line stations to said exchange; circuit connections whereby telephonic communication may be held between the party line stations to the:

exclusion of the exchange; switching mechnovaaeo anism at one of the party line stations adapted in one condition of use to take part in establishing the telephonic connection between the party line stations that is independent of the exchange and in another condition of use to permit of the -connection of the associate telephone w" the party line; electromagnetic mean. H -the station where this switching mechanisn'ili gib located for preventing that operation out said switching mechanism that will permit the association of the associate telephone receiver with the party line; means at the remaining party line station for governing the operation of the latter means; and switching mechanism at the station where said electro-magnetic mechanism is located to enable the operation of said. electro-magnetic mechanism to permit of the association of the associate receiver with the party telephone line, this latter switching mechanism being so associated with said electromagnetic mechanism as not to interfere with the control of said electro-magnetic mechanism exercised at the associatefparty line station.

11. A telephone exchange system including telephone lines extending from telephone substations to an exchange, one of said lines being a party telephone line extending from a plurality of party line sta-' tions to said exchange; circuit connections whereby telephonic communication may be held between the party line statiohs to the exclusion of the exchange; switching mechanism atone of the party line stations adapted in one condition of use to take part in establishing the telephonic connection between theparty line stations that is independent of the exchange and in another condition of use to permit of the connection of the associate telephone with the party line; electro-magnetic means at the station where this switching mechanism is located for preventing that operation of said switching mechaijism that will permit the association of the associate telephone receiver with the party line; means at the re v maining party line station for governing the operation of the latter means, there being a switch hook at the station where the aforesaid switching mechanism is located which serves to place said switching mechanism in' condition to enable the establishment of telephonic connection between the party line stations that is exelusive of the exchange and which switch hook permits the connection of the associate telephone with the party line when said switching mechanism is free to effect this connection; and swit hing mechanism at the station wheresaid electro-magnetic mechanism is located to enable the operation .of said electro-magnctic mechanism to permit of the association of the associate reof the associate telephone receiver with the I mechanism is located, to enable the operation 7 intense exclusion of the exchange; switching mechanism, at one of the party line stations adapted in one condition of use to take part in establishing the telephonic connection between the partyline stations that is independent of the exchange and in another condition of use to permit of the connection of the associate telephone with the party line; electro-magnetic means at the station where this switching mechanism is located for preventing that operation of said switching mechanism that will permit the association party line; means at the remaining party line station for governing the operation .of the latter means, said electro-magnetic means having a bridge connection for including it across the party line;-a source of current in connection with the party line for energizing said electro-magnetic means when connested in bridge of the party line, the means for preventing the operation of said electro-lnagnetic means including a bridge connection of the party line that contains the telephone thereat that serves to shunt, suflicient current from said electro-magnetic means to prevent the operation thereof, the bridge including said electro-magnetic means being of sufiiciently high resistance for the purpose; and switching-mechanism at the station where sai electro-magnetic of said electro-magnet-ic mechanism to permit of the association of the associate receiver with the party telephone line, this latbeing a part y telephone line extending from a plurality of party line stations to said exchange; circuit connections whereby telephonic communication may be held between the party line stations to the exclusion of the exchange; switching mechanism at one of the party line stations adapted in one condition of use to take part in establishing the telephonic connectionhetwe'en the party line stations that is independent of the exchange and in another condition of use to permit of the connection of the associate telephone with the {party line; electromagnetic means at the station where this switching mechanism is located for preventing that 'iopcration of said switching mechanism that will permit the association of the associate telephone receiver with the arty line; means at the-remainingpar-ty, inc station for governing the operation of the latter -means,.t-he re being a switch hookatthe station where the aforesaid switching mechanism is located which serves to place said switching mechanism in condition to enable the establishment of telephonic connection between the party line stations "that is ex elusive. of the exchange and whichswitch hook permits the connection of the associate telephone with the party line when said switching mechanism is free to effect this connection, said elcctro-magnetic means having abridge connection for including it across the party line; a source of current 1!) connection with the party line forlenergia ingsaid elect-ro-magnetic means when connected in bridge of the party line, the means for preventing the operation of said electromagnetic means including a bridge connec-' tion of the party line that contains the telephone thereat that serves to shunt suflicient current from said electro-magnetic means to prevent the operation thereof, the bridge including said electro-magnetic means be-.' ing. of sufliciently high resistance for the purpose; and switching mechanism at the station where said .electro-magnetic mechanism is located to enable the operation of said electro-magnetic mechanism to permit of the association of the associate receiver withthe party telephone line, this latter switching mechanism being so associated with said-electromagnetic mechanism as not. to interfere with the control of said electro-magnetic mechanism exercised at the associate party line station.

' 14.'A telephon'e exchange system-in'clitding telephone lines extending from telephone substations to an exchange where a common sourcejof current islo cated, one of said lines being a party telephone line extending from a plurality of party line sta tions to said, exchange; circuit connections whereby telephonic communication may be held between the party line stations to the exclusion of the exchange; switching mechanism for connecting the telephone ati one of the party line stations in telephonic circuit with the party line and at thattime serving to break the telephonic connection between the party line stations; mechanism controlled by said switching mechanism serving to prevent .the telephone at the party line station companion to that having said switching mechanism from becoming connected with the party line when the tele phonic connection between the party line stations is broken; means ior preventing operation at the exchange when telephonic communication is established between party line stations exclusively of the exchange; and meansfor removing the control of-the latter means when telephonic "connection is established betweenthe, telephone at a party line station and the party line.

15. 1%; telephone exchange system including telephone lines extending from tele phone substations to an exchange where a common source of current is located, one of said lines being a party telephone line extending from a plurality of party line stations to said exchange; circuit connections whereby telephonic communication may be held between the party line stations to the exclusion of the exchange; switching mechanism for connecting the telephone at one of the party line stations in telephonic circuit with the'party line; mechanism controlled by said switching mechanism serving to prevent the telephone at the remaining party linestation from becoming connected with the party line when'said telephonic connection with the party line is es tablished; meansfor preventing operation at the exchange when telephonic 'communi cation is established between the party line stations exclusively of the exchange; and

means for removing the control of the latter.

means when telephonic connection is established between the telephone at a party line station and the partv line.

16. A telephone exchange system including telephone lines extending from telephone substations to an exchange where a common source of current is located, one of said lines being a party telephone line extending from a plurality of party line stations to said exchange; circuit connections whereby telephonic communication may be held between the party line stations to the exclusion of the exchange; switching mechanism for connecting the telephone at one of the party line'stations in telephonic circuit with the party line; mechanism serving to prevent the telephone at the remaining party linestation from becoming connected withthe party line when said telephonic connection with the party line is established;

means for preventing operation at the ex change when telephonic comn'iunicatlon 1s vestablished between the party line stations exclusively of the exchange; and means for .removing the control of the latter means when telephonic connection is established between the telephone at a party, line station and the party line.

17. A telephone exchange system including telephone lines extending from telephone substations to an exchange where a common source. of current is located, one of said lines being a party telephoneline exthe associate telephone with the party line;

means at the station where this switching mechanism is located for preventing that operation of said switching mechanism that will permit the association of the associate telephone receiver with the party line; means at the remaining party line station for governing the operation of the latter means; means for preventing operation at the exchange when telephonic communication is'established between the party line stations exclusively of the exchange; and means for removingthe control of the latter means when telephonic connection is established between the telephone at a party line station and the party line. U

18. A telephone exchange system including telephone lines extending from telephone substations to an exchange where a common source of current is located, one of anism at one. of the party line stations adapted in one condition of use to take part in establishing the telephonic connection between the party line stations that is independent of the exchange and in another condition of use to permit of the connection of;

the associate telephone with the party line;

means at the station where this switching mechanism is located for preventing that operation of said switching mechanism that will permit'the association of the associate telephone receiver with the party line;

means at the remaining party line station for governing the operation of the latter means,,there being a switch hook at the station where the aforesaid switching-mechanism is located which serves" to place said switching mechanism in condition to enable the establishment,-'of telephonic connection between the party line stations that is exclusive of the exchange and which switch hook permits the connection of the associate telephone with the party line when said switching mechanism is free to efi'ect thisconnection; means for prevent ng-operation at the exchange when telephomc commumcatmn'ls established between the party line stations exclusively of the exchange; and means for removing the control of the latter means when telephonic connection is established between the telephone at a party line station and the party line.

19. A telephone exchange system including telephone lines extending from telephone substations to an exchange where a common source of current is located, one of said lines being a party telephone line extending from a plurality of party line stations to said exchange; circuit connections whereby telephonic communication may be held between the party line stations to the exclusion of the exchange; Switching mechanism at one of the party line stations adapted in one condition of use to take part in establishing the telephonic connection between the party line stations that is independent of the exchange and in another condition of use to permit of the connection of the associate telephone with the party line; electro-magnetic means at the station where this switching mechanism is located for preventing that operation of said switching mechanism that will permit the association of the associate telephone receiver with the party line;

means at the remaining party line station for governing the operation of the latter means; means for preventing operation at the exchange when telephonic communication is established between the party line stations exclusively of the exchange; and means for removing the control of the latter means when telephonic connection is established' between the telephone at a party line station and the party line.

20. A telephone exchange system including telephone lines extending from telephone substations to an exchange Where a common source of current is located, one of said lines being a party telephone line extending from a plurality of party line stations to said exchange; circuit connections whereby telephonic communication may be held between the party line stations to the exclusion of the exchange; switching mechanism at one of the party line stations adapted in one condition of use to take part in establishing the telephonic connection between the party line stations that is independent of the exchange and in another condition of use to permit of the connection of the associate telephone with the party line; electromagnetic means at the station where this switching mechanism is located for preventing that operation of said switching mechanism that will permit the association of the associate telephone receiver with theparty line; means at the remaining party line station for governing the operation of the latter means, there being a switch hook at the station where the aforesaid switching mechanism is located which serves to place said switching mechanism in condition to enable the establishment of telephonic connection between the party line stations that is exclusive of the exchange and which switch hook permits the connection of the associate telephone with the party line when said switching mechanism is free to efiect this connection; means for preventing operatibn at the exchange when telephonic communication is established between the party line statitons exclusively of the exchange; and means for removing the control of the latter means when telephonic connection is established between the telephone at a part, 1

line station and the party line.

21. A telephone exchange system including telephone lines extending from telephone substations to an exchange where a common source of current is located, one of said lines being a party telephone line extending from a plurality of party line stations to said exchange; circuit connections whereby telephonic communication may be held between the party line stations to the exclusion of the exchange; switching mechanism at one of the party line stations adapted in one condition of use to take part in establishing the telephonic connection between the party line stations that is independent of the'exchange and in another condition of use to permitof the connection of the associate telephone with the party line; electro-magnetic means at the station where this switching mechanism is located for preventing that operation of said switching mechanism that will 'ermit the association of the associate telep 10118 receiver with the party line; means at the remaining party line station for governing the operation of the latter means, said electromagnetic means having a bridge connection for including it across the party line; a source of current in connection with-the party line for energizing said electro-magnetic means when connected in bridge of the party line, the means for preventing the operation of said electro magnetic means including a bridge connection of the party line that contains the telephone thereat that serves to shunt sufficient current from said electro-magnetic means to prevent the operation thereof, the bridge including said electromagnetic means he ingot sufliciently high resistance for the purpose; means for preventing'operation at the exchange when telephonic communi cation is established between the party line stations exclusively of the exchange; and means for removing the control of the latter means when telephonic connection is established between the telephone at a party line station and the party line.

22. A telephone exchange system including telephone lines extending from telephone substations to an exchange where a common source of current is located, one of said lines being a party telephone line extending from a plurality of party line stations to said exchange; circuit connections whereby telephonic" communication may be held between the party line stations to the exclusion of the exchange; switching mechanism at one of the party line stations adapted in one condition of use to take part in establishing the telephonic connection between the party line stations that i inde' pendent of the exchange and in another condition of use to permit-of the connection of the associate telephone with the party line; electro-magnetic means at the station where this switching mechanism is' located for preventing that operation of said switchmg mechanism that will permit the associa tion of the associate telephone receiver with the party line; means at the remaining party line station for governing the operation of the latter means, th'ere beinga switch hook at the station where the aforesaid switching mechanism is located which serves to place said switching mechanism in condition to enable the establishment of telephonic connection between the party line stations that is exclusive of the exchange and which switch hook permits the connec-i tion of the associate telephone with the party line when said switching mechanism is free to effect this connection, said electromagnetic means having a bridge connection for including it across the party line; a source of current in connection with the party line for energizing said electro-magnetic means when connected in bridge of the party line, the means for preventing the operation of said electro-magnetic means including a bridge connection of the party line that contains the telephone thereat that serves to shunt suflicient current from said electro-magnetic means to prevent the operaticnthereof, the bridge including said electro-magnetic means being of sufl'iciently high resistance for the purpose; means for preventing operation at the exchange when telephonic communication is established between the party line stations exclusively of the exchange; and means for removing the control of thelatter means when telephonic connection is established between the telephone at a party line station and the party.

line. Y

- 23. A telephone exchange system including telephone lines extending from tele phone substations to an exchange where a' common source of'current is-located, one of said lines being a party telephone lineextending from a plurality of party line stations to said exchange; circuit connections whereby telephonic communication may be held between the party line stations to ,the exclusion of the exchange; switching mechanism at one of the party line stations adapt.

ed in one cs ndition of use to take part in establishing the telephonic connection between the party line stations that is independent of the exchange and in another con.- dition of useto permit of the connection of the associate telephohe with the party line; electro-magnetic means at the station where this switching mechanismislocatedfor preventing that operation of said switching mechanism that will permit: the association of the associate telephone receiver with the party line; means at the remaining party line station for governing the operation of the latter means; switching mechanism at the station where said electro-magnetic mechanism is located to enable the operation. of said elect-ro-magnetic mechanism to permit of the association of the associate receiver with the party telephone line, this latter switching mechanism being so associated with. said electro-magnetic mechanism as not to interfere with the control of said electro-magnetic mechanism exercised at the associate party line station; means for preventing operation at the exchange when telephonic communication is established between the party line stations exclusively of the exchange; and means for removing the control of the latter means ,when telephonic connection is established between the'tele phone at a party line station and the party 24. A telephone exchange system including telephone lines extending from telephone substations to anexchange Where a common source of current is located, one of said lines being a party telephone line extending from a plurality of party line stacd in one condition of use to take part in establishing the telephonic connection between the party line stations that is independent of the exchange and inanother condition of use to permit of the connection of the associate telephone with the party line; electromagnetic means at the statiomwhere this switching mechanism is located for pre venting that operation of said switching mechanism that will permit the association otthe associate telephone r ceiver with the party, line; means at the remaining party line station for governing the operation of the latter means, there being a switch hook at the station where the aforesaid switching mechanism is located which serves to place said switching mechanism in condition to enable the establishment of telephonic connection between the 'party line station that is exclusive of the exchange and which switch hook permits the connection of the associate telephone with the party line when saidswitching mechanism is free to efiect this connection; switching mechanism at the station where .said electro magnetic mechanism is located to nabl'e the operation of said electro-magnetic mechanism to permit of the association of the associate receiver with the par telephone line, this latter switching mec anism being so associated with said electro-magnetic mechanism as not to interfere with the control of said electro-magneticmechanism exercised at the associate party line station; means for reventing operation at the exchange w en telephonic communication is established between the party line stations exclusively of the exchange; and means for removing the control of the latter means when telephonic connection is established between the telephone at a party line station and the party line.

25. A telephone exchange system'including telephone lines extending from telephone substations to an exchange where a common source of current is located, one of said lines being a party telephone line extending from a plurality of party'line stations to said exchange; circuit connections whereby telephonic communication may be held between the party line stations to the exclusion of the exchange; switching mechanism at one of the party line stations adapted in one condition ofuseto take part in establishing the telephonic connection between the party line stations that is independent of the exchange and in another condition of use to permit of the connection of the associate telephone with the party line; electro-ma'gneticmeans at the station where this switching mechanism is located for preventing that operation of said .switching mechanism that will permit the association of'the associate telephone receiver with the party line; means at the remaining party line station for gov-ernin the operation of the latter means, sai electro magnetic means having a' bridge connection for including it across the party line; a source of current in connection with the party line for energizing said electro-magnetic means when connected in bridge of the party line, the means for preventing the operation of said electro-nragnetic means including a bridge connection of the party line that contains the telephone thereat thatserves to shunt sufficient current from said electromagnetic means to prevent the operation thereof, the brid c including said electromagnetic means eing of sufiiciently high resistance for the purpose; switching mechanism at the station where said electro-magnetic mechanismis located to cnable'the operation of said electro-magnetic mechanism to permit of the association of the associate receiver with the party telephone line, this.

latter switching mechanism being so associated with said electro-magnetlc mechanisin as not to interfere with the control of said electro-inagnetic mechanism exercised at the associate party tine station; means for preventing operation at the exchange when telephonic communication is established between the party line stations exclusively of the'exchange; and means for removing the control of the latter means when telephonic connection is established between the tele phone at a partyline station and the party 26. A telephone exchange system including telephone lines extending from telephone substations to an exchange where a common source of current is located, one of said lines being a party telephone line extending from a plurality of party line stations to said exchange; circuit connections whereby telephonic communication may be held between the party line stations to the exclusion of the exchange; switching mechanism at one of the party line stations adapted in one condition of use to take part in establishing the telephonic connection between the party line stations that is inde-' pendent of the exchange and in another condition of use to permit of the connection of the associate telephone with the party line; electro-magnetic means at the station where this switching mechanism is ldcated for pre venting that operation of Said switching mechanism that will permit the association of the associate telephone receiver with the party line; means at the remaining party line station for governingthe operation of the latter means, there being a switch hook at the station where the aforesaid switching mechanism is located which serves to ,place said switching mechanism in condition to enable the establishment of telephonic connection between the party line and which switch hook permits the connection of the associate telephone with the party line when said switching mechanism is free to effect this connection, said electro-magnetic means having a bridge connection for including it across the party line; a source of current in connection with the party line for energizing said electro-magnetic means when connected in bridge of the party line, the means for preventing the operation of said electro-magnetic ineans including a bridge connection of the party line that contains the telephone thereat that serves to shunt suflicient current from said electro-magnetic means to prevent the operation thereof, the bridge including said electro-magnetic means being of suficiently high resistance for the purpose; switching mechanism at the station where said electro-magnetic mechanism is located to enable the operation of said electro-magnetic mechanism to permit of the association of the associate receiver with the party telephone stations that is exclusive of the exchange 10 removing the control of the latter means when telephonic connection is established between the telephone at a partyline station and the party line.

In witness whereof, I hereunto subscribe my name this 24th day of July A. D., 1911.

MORTQN L. JOHNSON.

Witnesses: (I

E. L. WHITE, G. L. GREGG:

fiopies of this patent may be obtained for five cents each, by addressing the Commissioner of latents,

Washington, D. C.

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