US1153352A - Telephony. - Google Patents

Description

A. W. -STEINKE.

TELEPHONY.

APPLICATION FILED ocT.2|. 19M.

Patented $0M. M, 1915;

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AWN/ST W STEM/[E y/Z f ATTORNEY A. W. STEINKE.

TELEPHONY.

APPLICATION FILED cT.2|. 1914.

Lwwm Patented Sept. 14, 1915.

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E w :5 r 10* INVENTUR ADE UST WI STEINKE BV/K M i m name PATJENUF omeo AUGUST w. sTnINKE, or FORT DODGE, IowA, ASSIGNOR To MQNABCH TELEPHONE, MANUFACTURING COMPANY, or FORT D DGE, I WA, A CORPORATION OF IOWA.

TELEPHQINY.

asses.

Specification of Letters I atent.

' Application filed October 21, 1914. Serial No. 867,895.

To all whom it may concern:

Be it known that I, AUCUsT W. STEINKE, citizen of the United States, residing at Fort Dodge, in the county of Webster and State of Iowa, have invented a certain new and usefullmprovement in Telephony, 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. I

My invention relates to telephony and has for its general object the provision of improved exchange equipment whereby link connectors which .I standardize may be employed for connecting commonbattery lines with each other; magneto telephone lines with each other; and whereby common battery telephone lines, whether calling or called, may be connected with magneto telephone lines, whether calling or called. By means of myinvention the clearing outor supervisory signaling apparatus pertaining to thelink connectors or cord circuits may be placed under the control of the lines, whethercommon battery or magneto, with which they may happen to be associated.

The various features and advantages of my invention, as it is preferably embodied, will be fully described in connection with the accompanying drawings showing the preferred embodiment of the invention and in which- Figure 1 is a diagrammatic illustration of a magneto telephone line and a common battery telephone line together with a cord circuit adapted to unite the same for conversation; Fig. 2 is a simplified diagram of the circuit existing between the stations of Fig. lwhe'n they are connected for conversation"; Fig. 3 is a simplified diagram of the circuit existing between two magneto lines connected for conversation; Fig. 4 is a simplified diagram of the circuit existing between a common battery calling line and'a called magneto line connected for Conversation; and Fig. 5 is a simplified diagram of the circuit existing between two common battery lines connected for conversation.

Like parts are indicated by similar characters of reference throughout the difl'erent figures.

In Fig. 1 I have illustrated a magneto telephone station 90 having its line 1 and 2 of the switch book serves to close the' local transmitter circuit, when the receiver" is removed from the switch hook, this transmitter circuit including the primarywinding 8, transmitter battery 9 and the telephone transmitter 10. The upper of the two alternate contacts of the switch hook serves to close the line through the secondary 11 and the receiver 7. Themagneto generator 12 is in normally open bridge ofthe line, this generator being arranged to close this bridge when the generator is to be operated to transmit signaling current from the station. Assuming that the station 90 is a calling station, the calling subscriber will operate his generator 12 to include it in bridge of Patented Sept. 14, 1915.

its llne, current from this generator being traceable from the generator spring 12 to the'alternate contact of this spring, the side of the line connected with this alternate Contact, theleft hand winding of the line relay 13, the left hand armature switch of this relay, the contact of this armature switch, the left hand armature switch of the cutofl relay 14, the Contact of this armature switch, thence to the other side of the line and the generator 12 connected therewith. I When the line relay 13 is energized consequent upon the passage of magneto current I through its left hand winding, a locking circuit is established for this line relay which is traceable from the common battery 15, through the right hand winding (the lockin winding) of the line relay 13, the right hand armature of the line relay 13 and its Contact, the right hand armature of the out 01f relay 14 and its Contact, thence back to the battery 15. The line lamp 16 is now included in a circuit which is traceable from the battery 15, the right hand armature switch of cutofi' relay 14, the contact of this armature switch, the right hand armature switch of line relay 13, the Contact of this switch, the line lamp 16, the pilot relay 17 preferably of the arrangement illustrated, many of the parts shown being similar to the parts described in connection with the magneto telephone line extending from station 90 and similar parts of the magneto and common battery lines are given similar characters of reference. The common battery substation has less equipment, ob-

viously, than the magneto substation but the bell bridge includes a condenser 6 to obstruct the flow of direct current. The line signal of the common battery line, when such line is a calling line, is displayed by the line lamp 16 whose circuit is established at the left hand armature switch of the line relay 13 when this line relay is energized upon the removal of the telephone receiver 7 at the calling common battery line station. The circuit established for the line relay 13 is traceable from the common battery 15, the two windings of the line relay 13 in parallel, one side of the common battery line, the transmitter, receiver and switch hook at the calling station, the right hand armature switch of'the cutoff relay 14 back to the battery 15. The circuit for the lamp 16 of the calling common battery line is traceable from the common battery 15, through the pilot relay 17 common to a pluralit of common battery lines, the lamp 16, the left hand armature switch of line relay 13 the left hand armature switch of the cutoff relay l4 and its contact, thence back to the battery 15. When an answering plug 18 is inserted in the jack of a calling common battery line or a connecting plug 21 is inserted in the jack of a called common battery line,

] circuit is established for the cutofl' relay 14 which is traceable from the grounded battery 19 through the resistance 20, the heel of the inserted plug, the jack engaging this heel, the winding of the cutofi' relay 14 to ground. The armature switches of the out off relay are attracted to open the circuits of the line relay l3 and the associate lamp 16 if the line having these elements is a calling line and serving to prevent the closure of these circuits, if the common battery line is a called line, when the called partyremoves his telephone from its switch hook.

The operator at the exchange, in response to the signal conveyed by the signal lamp 16, inserts the answering plug 18 in the answering jack 3 that is individual to the calling line, which is now considered to be the line 90 for the sake of explanation, whereb circuit is established through the cutoff relay 14 that is traceable from the grounded battery 19, the 500 ohm resistance 20, the heel of the answering plug 18, the thimble of the answering jack that has received this plug, the winding of the cutoff relay 14, to ground. The cutoff relay is now energized to attract its armature switches, the

circuit for the energizing winding of the line relay 13 being further broken at the left hand armature switch of the cutoif relay 14 while the locking circuit of the line relay 13 is broken at the right hand armature switch of the cutoff relay 14, the circuit of the line lamp 16 being also broken at this latter armature switch. The line signal attracted by the lamp 16 is thus efi'aced when the operator responds by inserting an answering plug into the answering jack. In order to remove the control of the line relay and line signal from the station of a magneto called line, the connecting plug 21 has a heel portion which has connection with the battery 19 that is similar to the connection of the heel portion of the answering plug 18 with such battery so that when the connecting plug is inserted within a multiple jack of a called magneto line the cutoff relay 14 pertaining to such called line is energized. The operator may test the condition of the called line by applying the tip of the connecting plug to the thimble of the multiple jack of the called line appearing at her position, any suitable testing circuit being of service for this purpose and as testing circuits are well known a description of one that may be employed in the system of my invention need not be furnished.

Assuming that the answering and connecting plugs have been inserted respectively in the answering jack of the calling magneto line 90 and the accessible multiple jack of the called common battery line 120 the circuit condition illustrated by the simple diagram in Fig. 2 will result, the tip and sleeve strands of the cord circuit being rendered telephonically continuous respectively through condensers 22, 23 which prevent the flow of battery current between the two halves of the cord circuit for the purpose of making one-half individual to a calling line and the other half individual to :1. called line whereby there may be calling and called line supervision, though the invention is not to be limited to this double supervision. The equipments upon both sides of the condensers 22 and 23 are substantially similar so "far as through circuit conditions are conkey is operated constitute terminals of the operators talking set 28. The inner lower spring of the listening key 27 is individual to the right hand winding of the supervisory' or disconnect-relay or magnet 29, which relay is individual to the answering end of the cord circuitand which is't'o be governed by the calling-subscriber, in clearing out or disconnecting. The inner upper spring of the'listening key'27 is individual to the left hand winding of the: supervisory or disconnect relay or magnet 30 which-relay is individual to the connecting end of the cord circuit and which is to be governed by the called subsccriber in clearing out or disconnecting. The relays 31' and 32, which are unresponsive to "wave" form current produced by'the magneto generator 12, are respectively individual to'the answering and connecting'ends of'the cord circuit. \Vhen either of such relays isjbrought into association with amagneto line it remains inert although it is in bridge of the cord circuit, this inert condition of the relay being maintainedowing to the fact that it will not respond to the alternating current emanating from'the magneto generator of the line associated therewith. When the relay 31 is connected with a calling magneto line, as illustrated in Figs. 2 and 3', the associate resistances 3.3 and 34: :(e ach being desirably of 400 ohms ohmic resistance) are included in series with the winding'of relay 31 (which is preferably of 100 ohms resistance) and also with the left hand winding of the associate supervisory relay 29, this latter winding being also of 100 ohms resistance. That is, therelay 31, byremaining inert when associated with av calling magneto line, inaintains the bridge between the sides of the cord circuit that is traceable from the strand or the cord circuit, the left 'hand winding ofthesup'ervisory relay 29, the-left hand armature switch of the relay 31, the n'ormal jcontact ofthis armature switch, the resistance33, the resistance' 34, the winding of? the relay 31, to the sleeve strand of the cord circuit. When the relay 32 is connected with. a called magneto line, as illustrated in Figs. 3 and 4, the associate resistances 35 and 36 (each being desirably of 100 ohms ohmic resistance) are included in series with the winding of relay 32 (which is preferably of 100 ohms resistance) and also with the right hand winding of the associ'ate su pervisory relay 30, this latter winding being also of 100 ohms resistance. That is, the relay 32, byremaining inert when associated with a called magnetoline, maintains a bridge between the sides'of the cord circuit that is traceable from the tip strand of the cord circuit, the/right hand winding of the supervisory relay 30, the right hand armature switch of the relay 32, the normal contact of this armature switch, the resistance 35, the resistance 36,the winding "of the relay 32, to the sleeve strand of the cord circuit. "Whenever the relays 31 and 32 are associated-one' with a calling magneto line or the other with a called magneto line -th e supervisory relays 29 and 30 respectively associated therewith would. be energized by the passage of magneto current through the en ergizing windings thereof that are thus in bridge of the cord'circuit, this magneto-"current being furnished at the corresponding magneto substation.

When a calling magneto subscribers supervisory or disconnect signal is conveyed his supervisory relay 29 is energized by clearing out magneto current to enable its armature to establish a circuit that includes the right hand (locking) winding of this relay, and which circuit is traceable from the grounded'battery .19, the winding of the supervisory pilot relay 37 (common to a number of cord circuits), the lower inner spring of the listening key 27 and its con-' tact that normally engages the same, the supervisory lamp 38 individual to the relay 29, the armature switch'of relay 29,,the alright hand (locking) winding of the relay 29, the right hand armature switch of relay 31 and its normal contact, to ground. When a called magneto subscribers supervisory or disconnect signalis'conveyed'his supervisory relay'30 is energized by clearing out magneto current to enable its armature to establish a circuit that includes the left hand (locking) winding of this relay, and which circuit is traceable from the grounded battery 19, the upper inner spring of .the listening key 27 and its contact that normally engages the same, the supervisory lamp 39 individual to the relay 30, the armature switch of relay 30, the alternate contact of this armature switch, the lefthand (locking) winding of the relay 30, the left hand armature switch of relay. 32 and its normal contact, to ground. The operator will efface a clearing out signal thus conveyed by depressing her listening key 27 to open the locking circuit of the supervisory relay or relays'thus operated by clearing out magneto current, the locking circuits then being broken at the inner contact springs of said key. When a calling magneto line and a called common battery line are connected as indicated in Fig. 2, the commonbattery 15 is in common; battery relation to the called line. When two magneto lines are connected as indicated in Fig. 3, the common battery is excluded from the line circuits. When a calling common battery line is connectedwith a called magneto line the common battery is'in the usual common battery relation with the calling line, as indicated in Fig. 4. When two common'battery lines are connected, as in' Fig. 5, the common battery is in the usual common battery relation te'rnate contact of this armature switch, the

with both lines. The relays 31 and 32,

which may be constructed similarly to slug- &

to prevent the insertion of common battery in circuit with magneto telephone lines. When a common battery line is connected with another line the relay 31 or 32 then associated therewith, being responsive to direct current from the common battery 15, is energized to bring the common battery into usual common battery relation with such common battery line, such relay also then operating to exclude one of the associate resistances (33 or 35) from circuit with the line to improve the passage of current from the common battery to the common battery line, as is made clear by certain of the diagrams. When clearing out magneto current is sent over a magneto line to-the exchange the relay (31 or 32) then individual to such line will not respond but a clearing out signal will be conveyed by the energization of the associate clearing out relay 29 or 30 as previously set forth. Clearing out signals are caused at the substations of common battery lines by the location of the receivers upon the switch hooks at such stations which opens the lines thereat, circuit having been previously maintained at the switch hook of a common battery station when the receiver is removed therefrom through the energizing winding of the associate rela 29 or 30 (being respectively the left hand and right hand windings of such relays). The circuit for such energizing winding of such relay 29 or 30 is traceable from the grounded alternate contact of the associate relay 31 or 32, the armature switch corresponding to such grounded contact, such energizing winding, the tip strand of the cord circuit,

- the tip side of the common battery line, the

, When the operator removes this plug from switch hook, telephone receiver and telephone transmitter at the common battery station, the sleeve side of the common battery line, the relay 13 of such line, to the grounded battery 15. When the circuit just traced is broken by'the location of the receiver upon its switch hook at the common battery station the armature switch of the relay (29 or 30) is released to close circuit, by way of its normal contact and the armature switch of the relay 31 or 32 then connected with such normal contact, through the associate supervisory signal 38 or 39, it-

being understood that the relays 31 and 32 are in a local circuit, when associated with common battery lines, as indicated clearly in Figs. 2, 4 and 5, such local circuit including the plug individual to the relay 31 or 32 and the jack then receiving the same.

such jack she opens the circuit of the associate relay 31 or 32 to release the armature switches of such relay and open the circuit of the associate supervisory signal 38 or 39. The circuits thus established for the signals 38 and 39 include resistances 40 and 41 which are desirably of 75 ohms whereby the clearing out lamps are caused to glow with more or different brilliance than when such lamps are included in the circuits established by calling magneto lines through the locking windings of the relays 29 and 30 which are preferably of 125 ohms resistance. The operator is thus enabled to know whether the clearing out signals are conyeyed by common battery lines or magneto mes.

In order to prevent the diversion of too much current from the battery 15 through the relays 31 and 32 when such relays are coupled with common battery lines and are included in the local circuits just mentioned, the resistance 34 and 36 are in permanent serial relation with such relays so as to be included in such local circuits with the common battery 15 when these relays are coupled with common battery lines. When these relays are coupled with magneto lines the extra resistance 33 or 35 is placed in series with the aforesaid resistance 34 or 36 whereby the magneto line, which is grounded at 42 at the juncture of these re sistances, is balanced.

While I have herein shown and particularly described the preferred embodiment of my invention I do not wish to be limited to the precise details of construction and circuit arrangement shown as changes may readily be made without departing from the spirit of my invention, but

Having thus described my invention I claim as new and desire to secure by Letters Patent the following 1. A telephone exchange system including a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection with said jacks; two serially related resistances normally in bridge of the cord circuit; a ground connection between said resistances; a clearing out magnet connected between the ground and one side of the cordclrcuit; a relay, which is responsive to direct current but is unresponsive to magneto current, connected between said ground and the other side of the cord circuit, this relay having armature switching mechanism serving, when idle, to bring the aforesaid resistances into serial relation and, when actuated, to exclude the resistance that is included between said battery lines and having a ground complemental to the aforesaid ground; and a local circuit including the grounded common battery, the engaging contacts ofthe jack of an employed common battery line and the plug received by this jack, the aforesaid relay, and the resistance .that is connected with that side of the cord circuit with which the relay is connected, upon the establishment of which local circuit said relay is energized.

2. A telephone exchange system including a plurality of telephone lines extending from substations to an exchange, said sub-' stations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection with said jacks; two serially related resistances normally in bridge of the cordcircuit; a ground connection between saidresistances; a clearing out magnet connected between the ground and one side of the cord circuit; a relay, which is responsive to direct current but is unresponsive to magneto current, connected between said ground and the other side of the cord circuit, this relay having armature switching mechanism serving, when idle, to bring the aforesaid resistances into serial relation and, when actuated, to exclude the resistance that is included between said ground and the side .of the cord circuit opposite that with which the relay is' connected; a common battery for the'common battery lines and having a ground complemental to the aforesaid ground; and a local circuit including the grounded common battery, the engaging contacts of the jack of an employed common battery line and the plug received by this jack, the aforesaid relay, and the resistance that is connected with that side of the cord circuit with which the relay is connected, upon the establishment of which local circuit said relay is energized, the relay, when inert, serving to exclude the common battery from a magneto line to which the relay has become individual.

3. A telephone exchange system including a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection with said jacks;'twi,o serially related resistances normally in bridge of the cord circuit; a ground connection between said res1stances;-a clearing out magnet connected between the ground and oneljside of the cord circu t; a relay, which s responsive serving, whenidle, to bring the aforesaid resistances' into serial relation and, when actuated, to exclude the resistance that is included between said ground and the side of the cord circuit opposite that with which the relay is connected; a common battery for the common battery lines and having a ground complemental to the aforesaid ground; a local circuit including the grounded common battery, the engaging contacts of the jack of an employed common battery line and the plug received by this jack, the aforesaid relay, and the resistance that is connected with that side of the cord circuit with which the relay is connected, upon the establishment of which local circuit said relay is energized; and line relays for the may be established in conjunction with its common battery line. I

4. A telephone exchange system including a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines: jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween: a cord circuit provided with plugs at its ends for connection with said iacks: two serially related resistances normally in bridge of the cord circuit; a ground connection between said resistances: a clearing out magnet connected between the ground and one side'of to direct. current but is unresponsive to ma 2- neto current. connected between said ground and the other side of the'cord circuit. this relav having armature switching mechanism serving, when idle, to bring the aforesaid resistances into serial relation and, when actuated, to exclude the resistance that is included between said ground and the side of the cord circuit opposite that with which the-relay is connected; a common battery for the common hatterv lines and having a ground complemental to the aforesaid ground: a local circuit including the grounded common battery, the engaging contacts of the jack of an employed common battery line and the plug received by this'jack. the aforesaid relay, and the resistance that is connected with that side of the cord circuit with which the relay is connected, upon the llth v battery line.

5. A telephone exchange system including a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks atthe exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection with said jacks; two serially related resistances normally in bridge of the cord circuit; a ground connection between said resistances; a clearing out magnet connected between the ground and one side of the cord circuit; a relay, which is responsive to direct current but is unresponsive to magneto current, connected between said ground and the other side of the cord circuit, this relay having armature switching mechanism serving, when idle. to bring the aforesaid resistances into serial relation and, when actuated, to exclude the resistance that is included between said ground and the side of the cord circuit opposite that with which the relay is connected, said magnet and relay being in serial relation with each other and with saidresistances: a common battery for the common battery lines and having a ground complemental to the aforesaid ground; anda local circuit including the grounded common battery, the engaging contacts of the jack of an employed common battery line and the plug received by this jack, the aforesaid relay, and the resistance that is connected with that side of the cord circuitwith which the relay is connected, upon the establishment of which local circuit said relay is ener 'zed. j

6. A telephone exc ange system including a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over'such telephone lines to the exchange; a plurality of common bat-.

tery telephone lines; jacks at the exchange provided for said telephone lines toenable the establishment of connection therebetween; a cord circuit providedwith plugs at its ends for connection with said jacks; two serially related resistances normally in bridge of the cord circuit; a ground connection' between said resistances; a clearing out magnet coted between the ground and one side of the cord circuit; a relay, which is responsive to direct current but is unresponsive to magneto current, connected between said ground and the other side of the cord circuit, this relay having armature switching mechanism serving, when idle, to bring the aforesaid resistances into serial relation and, when actuated, to exclude the resistance that is included between said ground and the side of the cord circuit opposite that with which the relay is connected, said magnet and relay being in serial relation with each other and with said resistances: a common battery for the common battery lines and having a ground complemental to the aforesaid ground; and a localcircuit including the grounded common battery, the engaging contacts of the jack of an employed common battery line and the plug received by this jack, the aforesaid relay, and the resistance that is connected with that side of the cord circuit with which the relay is connected, upon the establishment of which local circuit said relay is energized, the relay, when inert, serving to exclude the common battery from a magneto line to which the relay has become individual. j 1

7. A telephone exchange system including a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit-provided with plugs at its ends for connection with said jacks; two serially related resistances normally in bridge of the cord circuit; a ground ,connection between said resistances; a clearing out magnet connected between the ground and one side of the cord circuit; a relay which is responsive to direct current but is unresponsive to magneto current, connected between said ground and the other side of the cord circuit, this relay having armature switching mechanism serving, when idle, to bring the aforesaid resistances into serial relation and, when actuated, to exclude the resistance that is included between said ground and the side of the cord circuit opposite that with which the relay is connected, said magnet and relay being in sereal relation with each other and with said resistances; a common battery for the common battery lines and having a ground complemental to the aforesaid ground; a local circuit including the grounded common battery, the engaging contacts of the jack of an employed common battery line and the plug received by this jack, the aforesaid relay, and the resistance that 'is connected t'wsaw 4- with that side of the cord circuit with which tilt ergized; and "line relays for the common battery lines which are also adapted for inclusion each in the local circuit that maybe established in conjunction with its common battery line. 7

8. A telephone exchange system'including a plurality of telephone lines extending from substations to an exchange, said substations being provided wlth magnetowave form current generators for transmittingsignaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection with said jacks; two serially related resistances normally in bridge of the cord circuit; a ground connection-between said resistances; a clearing out magnet connected between the ground and one side of the cord circuit; a relay, which is responsive to direct current but is unresponsive to magneto current, connected between said ground and the other side of the cord circuit, this relay having armature switching mechanism serving, when idle, to

bring the aforesaid resistances into serial re lation and, when actuated to exclude the resistance that is included between said ground and the side of the cord circuit opposite that with which the relay is connected, said magnet and relay being in serial relation with each other and with said resistances; a common battery for the common battery lines and having a ground complemental to the aforesaid ground; a local cir cuit including the. grounded common battery, the engaging contacts of the jack of an einployed common battery line and the plug received by this jack, the aforesaid relay, and the resistance thatis connected with that side of the cord circuit with which the relay is connected, upon the establishment of which local circuit said relay is energized, the relay when inert, serving to exclude the common battery from a magneto line to which the relay has become individual; and line relays for the common battery lines which are also adapted for inclusion each in the local circuit that may be established in conjunction with its common battery line.

9. A telephone exchange system including a plurality of telephone lines'extending from substationsto an exchange,said substations being provided with magneto wave form current generators for transmitting slgnaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks atthe exchange provided for said telephone lines to enable the establishment of connection therebetween a: cord circuit provided with plugs at its ends for connection with said ljacks; two serially related resistances individual to each end of the cord circuit and normally in bridge of the cord circuit; a ground -connection between said resistances; a supervisory magnet individual to each end or the cord circuit and connected between the ground of its associate resistances and one side ofthe cord circuit; a relay individual to each end of the cord circuit and which is responsive to direct current but is unresponsive to magneto current, connected between the ground of its associate resistances and the other side of the cord circuit, each relay having armature switching mechanism serving, when idle, to bring the aforesaid resistances to which the relay is individual into serial relation and, when'actuated, to exclude the associate resistance that is included between its ground and the? side of the cord circuit opposite that with which the relay is connected; a common battery for the common battery lines and having a ground complemental to theaforesaidground; and

a local circuit including the grounded com-, mon battery, the engaging contacts of the jack of an employed common battery line and the plug received by this jack, the relay individual to such plug, and the resistance individual to the relay and that is connected with that side of the cord circuit with which the relay is connected, upon the establishment of which local circuit said relay 'is energized.

10. A telephone exchange system including a plurality of telephone lines extending from substations to an exchange, said substations. being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection with said jacks; two seriallyrelated resistances individual to each end of the cord circuit and normally in bridge of the cord circuit; a ground connection between said resistances; a supervisory magnet individual to each end of the cord circuit and connected between the ground of its associates resistances and one side of the cord circuit; a relay individual to each end of the cord circuit and which is responsive to directcurrent but is unrespon-. sive to magneto current, connected between the'ground of its associate resistances and the other side of the cord circuit, each relay having armature switching mechanism serving, when idle, to bring the aforesaid resistances to which the relay is individual into serial relation and, when actuated, to exclude the associate resistance that is It t) included between its ground and the side of the cord circuit opposite that with which the relay is connected; a common battery for the common battery lines and having a ground complemental to the aforesaid ground; and a local circuit including the grounded common battery, the engaging contacts of the jack of an employed common battery line and the plug received by this jack, the relay individual to such plug, and the resistance individual to the relay and that is connected with that side of the cord circuit with which the relay is connected, upon the establishment of which local circuit said relay is energized, each relay, when inert, serving to exclude the common battery from a magneto line to which the relay has become individual.

11. A telephone exchange system including a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection with said jacks; two serially related resistances individual to each end of the cord circuit and normally in bridge of the cord circuit; a ground connection between said resistances; a supervisory magnet individual to each end of the cord circuit and connected between the ground of its associate resistances and one side of the cord circuit; a relay individual to each end of the cord circuit and which is responsive to direct current but is unresponsive to magneto current, connected between the ground of its associate resistances and the other side of the cord circuit, each I relay having armature switching mechanism serving, when idle, to bring the aforesaid resistances to which the relay is individual into serial relation and, when actuated, to exclude the associate resistance that is included between its'ground and the side of the cord circuit opposite that with which the' relay is connected; a common battery for the common battery lines and having a ground complemental to the aforesaid ground; a local circuit including the \grounded common battery, the engaging contacts of the jacks of an employed common battery line and the plug received by this jack, the relay individual to such plug, and the resistance individual to the relay and that is connected with that side of the cord circuit with which the relay is connected, upon the establishment of which local circuit said relay is energized; and line \relays for the common battery lines which are also adapted for inclusion each in the local ciring a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection wtih said jacks; two serially related resistances individual to each end of the cord circuit and normally in bridge of the cord circuit; a ground connection between said resistances; a supervisory magnet individual to each end of the 09rd circuit and connected between the ground of its associate resistances and one side of the cord circuit; .a relay individual to each end of the cord circuit and which is responsive to direct current but is unresponsive to magneto current, connected between the ground of its associate resistances and the other side of the cord circuit, each relay having armature switching mechanism serving, when idle. to bring the aforesaid resistances to which the relay is individual into serialrelation and, when actuated, to exclude the associate resistance that is included between its ground and the side of the cord circuit opposite that with which the relay is connected; a common battery for the common battery lines and having a ground complemental to the aforesaid ground; a local circuit including the grounded common battery, the engaging contacts of the jack of an employed common battery line and the plug received by this jack, the relay individual to each plug, and the resistance individual to the relay and that is connected with that side of the cord circuit with which the relay is connected, upon the establishment of which local circuit said relay is energized, each relay, when inert, serving to exclude the common battery from a magneto line to which the relay has become individual; and line relays for the common battery lines which are also adapted for inclusion each in the local circuit that may be established in conjunction with its common battery line.

13. A telephone exchange system including a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines: jacks at the extoo ltd

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aitaata plugs at its ends for connection with said jacks; two serially related resistances individual to each end of the cord circuit and normally in bridge of the cord circuit; a ground connection between said resistances; a supervisory magnet individual to each end of the cord circuit and connected between the ground of its associate resistances and one side ofthe cord circuit; a relay individual to each end of the cord circuit and which is responsive to direct current but. is unresponsive to magneto current, connected between the ground of its associate resistances and the other side of the cord circuit, each relay having armature switching mechanism serving, when idle, to bring the aforesaid resistances to which the relay is individual into serial relation and, when actuated, to exclude the associate resistance that is included between its ground and the side of the cord circuit opposite that with which the relay is connected; a common battery forthe common battery lines and having a ground complemental to the aforesaid ground; and a local circuit including the grounded common battery, the engaging contacts of the jack of an employed common batterv line and the plug received by this jack, the relay individual to such plug, and the resistance individual to the relav and that is connected with that side of the cord circuit with which the relay is connected, upon the establishment of which local circuit said relay is energized, the supervisorv magnet, resistances, and relay individual to each end of the cord circuit being normally in serial relation.

14. A telephone exchange svstem including a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection with said lines; two serially related resistances individual to each end of the cord circuit and normally in bridge of the cord circuit; a ground connection between said resistances; a supervisory magnet individual a to each end of the cord circuit and connected between the ground of its associate resistances and one side of the cord circuit; a relay individual to each end of the cord circuit and which is responsive to direct current but is unresponsive to magneto current, connected between the ground of its associate resistances and the other side of the cord 1 circuit, each relay having armature switchthat is included between its ground and the side of the cord circuit opposite that with which the relay is connected; a common battery for the common battery lines and having a ground complemental to the aforesaid ground; and a local circuit including the grounded common battery, the engaging contacts of the jack of an employed common battery line and the plug received by this jack, the relay individual to such plug, and the resistance individual to the relay and that is connected with that side of the cord circuit with which the relay is connected, upon the establishment of which local circuit said relay is energized, each relay, when inert, serving to exclude the common battery from a magneto line to which the relay has become individual, the supervisory magnet, resistances, and relay individual to each end of the cord circuit being normally in serial relation.

15. A telephone exchange system includ-- ing a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection with said jacks; two serially related resistances individual to each end of the cord circuit and normally in bridge of the cord circuit; a ground connection between said resistances; a supervisory magnet individual to each end of the cord circuit and connected-between the ground of its associate resistances and one side of the cord circuit; a relay individual to each end of the cord circuit and which is responsive to direct current but is unresponsive to magneto current, connected between the ground of its associate resistances and the other side of the cord circuit, each relay having armature switching mechanism serving, when idle, to bring the aforesaid resistances to which the relay is individual into serial relation and, when actuated, to exclude the associate resistance that is included between its ground and the side of the cord circuit plug received by this jack, the relay indiwill vidual to such plug, and the resistance individual to the relay and that is connected with that side of the cord circuit with which the relay is connected, upon the establishment of which local circuit said relay is enltd ergized; and line relays for the common battery lines which are also adapted for inclusion each in the local circuit that may be established in conjunction with its common battery line, the supervisory magnet, resistances,.vand relay individual to eachend of the cord circuit being normally in serial relation.

16. A telephone exchange system including a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection with said jacks; two serially related resistances individual to each end of the cord circuit and normally in bridge of the cord circuit; a ground connection between said resistances; a supervisory magnet individual to each end of the cord circuit and connected between the ground of its associate resistances and one side of the cord circuit; a relay individual to each end of the cord circuit and which is responsive to direct current but is unresponsive to magneto current, connected between the ground of its associate resistances and the other side of the cord circuit, each relay having armature switching mechanism serving, when idle, to bring the aforesaid resistances to which the relay is individual into serial relation and, when actuated, to exclude the associate resistance that is included between its ground and the side of the cord circuit opposite that with which the relay is connected; a common battery for the common battery lines and having a ground complemental to the aforesaid ground; a local circuit including the grounded common battery, the engaging contacts of the jack of an employed common battery line and the plug received by this jack, the relay individual to each plug, and the resistance individual to the relay and that is connected with that side of the cord circuit with which the relay is connected, upon the establishment of which local circuit said relay is energized, each relay, when inert, serving to exclude the common battery from a magneto line to p which the relay has become individual; and

line relays for the common battery lines which are also adapted for inclusion each in the local circuit that may be established in conjunction with its common battery line, the supervisory magnet, resistances, and relay individual to each end of the cord circuit being normally in serial relation.

17. A telephone exchange system including a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines: jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection with said jacks; two serially related resistances; a ground connection between said resistances; a common battery for the common battery lines and having a ground complemental to the aforesaid ground; a local circuit including the grounded common battery, the engagin contacts of the jack of an employed common battery line and the plug received by this jack, and one of the aforesaid resistances; and a relay for including the other of the aforesaid resistances in series with the first resistance and, together with the first resistance, in bridge of the cord circuit, there being circuit connections whereby the relay will enable these resistances to be thus connected in bridge when the relay is associated with a magneto line and will serve to exclude the second resistance when the relay is associated with a common battery line.

18. A telephone exchange system including a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection with said jacks; two serially related resistances individual to each end of the cord circuit;a ground connection between the resistances of each pair: a common but tery for the common battery lines and having a ground complemental to the aforesaid ground connections; a local circuit including the grounded common battery, the engaging contacts of the jack of an employed common battery line and the plug received by this jack. and one of the aforesaid resistances individual to such plug; and a relay individual to each plug for including the other of the associate resistances individual to the plug that is in the local circuit in series with the first resistance and, together with the first resistance. in bridge of the cord circuit. there being circuit connections whereby the relay individual to the plug in the local circuit will enable these resistances to be thus connected in bridge when such relay is associated with a magneto line and will serve to exclude the second resistance when such relay is associated with a common battery line.

19. A telephone exchange system includmtaata ing a plurality of telephone lines extending from substations to an exchange, said substations being provided with magneto wave form current generators for transmitting signaling current over such telephone lines to the exchange; a plurality of common battery telephone lines; jacks at the exchange provided for said telephone lines to enable the establishment of connection therebetween; a cord circuit provided with plugs at its ends for connection with said acks; two serially related resistances; a ground connection between said resistances; a common battery for the common battery lines and having a ground complemental to the aforesaid ground; a local circuit including the grounded common battery, the engaging contacts of the jack of an employed common battery line and the plug received by this jack, and one of the aforesaid resistances; and means for including the other of the aforesaid resistances in series with the first resistance and, together with the first resistance, in bridge of the cord circuit, there being circuit connections whereby said means will enable these resistances to be thus connected in bridge when such means is associated with a magneto line and will serve to exclude the second resistance when such means is associated with a common battery line.

In witness whereof, I hereunto subscribe my name this tenth day of Sept, A. D. 1914.

AUGUST W. STEINKE.

Witnesses:

WALTER H. TRIMM, L. Q. TRUMBULL.

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