US1078690A - Automatic telephone system. - Google Patents

Description

'P. NEWPORTH, JR. AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED JAN.17,1912.

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APPLIGATION FILED JAN. 17,1912

Patented Ndv. 18,1913.

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UNITED STATES PATENT OEFFTCE,

FRANK NEWFOBTH, JR., OF CHICAGO, ILLINOIS, ASSIGNOR T0 AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

AUTOMATIC TELEPHONE SYSTEM.

To all cohom 2'25 may concern: Be it known that I, FRANK Nnwron'rn J12, a citizen of the United States of Amer;

My invention relates to an improved telephone system, and more particularly to a system in which automat c selecting andeonnecting switches are employed for establishing a connection between a callingand a called subscribers line. I

Heretofore," in such systems, it has been found advisable and necessary to have the normal eonductorsthat is, the conductors by means of which the connector bank contacts are connected with the line conductorsterminate in normally open contacts In the cut-ofi:' relay of the line switchin stead of being permanently connected with the line conductors. This 'was'necessary for the reason that very often when connection is completed with the line ringing current is projected over' the normals before the cut-off relay. of the line switch has had time to'disconnect the line relay from the line, and if the normals were permanently "connected with the "line, this ringing current would energize the line relay of the line switch of the called line and cause it to operate.

It is one of the objects of my present invention to provide means which will enable the normals to be permanently. connected with the line and yet prevent any possibility of ringing current being projected over the called line before its line relay is diseon N nected therefrom. This is accomplished in the present instance by providing means whereby the connection between the calling and the called lines is not completed until a predetermined interval after the line relay has been disconnected from the called line.

- This new construction is of practical advantage not alone in the saving of a number of I of line switch shown m British springs at each line switch, but likewise in the fart i it saves considerable wire and labor in Specificatidn of Letters Patent. Applicat on filed January 17, 1912. Serial No. 671,692.

b Patented Nov. 18, 1913.

nee-tor. This reversal of battery in the calling line may be used to advantage for operatin ca'll' registers or operators signals, and is liliewise useful for the pur se of insur- REISSUED inga. positive release of the connector in the manner morespeeifically hereinafter pointed out'.

These and other objects and features of my invention will be more clearly understood by reference to the following descripi tion, in which the complete operation Of-a system embodying the features of my invention is particularly described.

In the accompanying drawings Figures 1 and'2 taken together show a complete cir-- euit connection betweenja calling substation A and a called substation A in a system'embodying the principles of'my Invention;

The automatic telephone system represented herein is of theFtvell-known type of system embodying subscribers individual or line switches, selectors {and connectors, the

- connection shown being established through the medium of a line switch C, first selector E, second selector F and connector H, As shown herein, thev substation A comprises the usual receiver 2, transmitter 3,switch book 4, ringer 5 and condenser 6.. Being an automatic substation, it is also provided with anautomatic calling device. This calling device may be of the type shown in British patent to S. G. S. Dicker No.

29,654-of1910; In the drawings, however,

theeallina device is represented diagram matically by .a pair of impulse springs 7 and 8 and a toothed impulse wheel 9, which impulse whe'elmay be controlled by the subscriber through the medium of a dial (not shown) provided with finger holes. The mechanism is'so; arranged that as the dial and impulse wheel are rotatedforward by the subscriber,-the impulse springs are not operated; but as the dial and impulse whee] return to normal position, the springs are separated momentarily a number of times 1 corresponding to the digit called.

The line switch C is of the general type patent to R. \V. James No. 26,301 of 1906, the par-. ticular form shown, however, being similar to that shown in British patent to T. G. Martin No. 1,419 of 1910, with the excep tion that the line relay and operating magnet are made separate instead of being'combined in a single structure. Among other details, the line switch comprises a plunger (not shown) carried upon the end of the plunger arm 107 which is adapted, when the hold the plunger arm 107 down after it has once been operated. The line relay 39 is slow acting that is, slow to deenergize, so that it may keep the operating winding 40 energized for a. short time after the cut-off armature 106- has operated to disconnect said line relay 39 from the line. 'As shown herein, the conductors 123 and 124, by means of which the connector bank contacts are connected with the line, are permanently connected w'vith the line conductors instead of one or both of them being adapted to be connected with the line through normallyopen contacts controlled by the cut- -oif armature 106, as has been the general practice heretofore. r The master switch D is of the general type of master switch disclosed in British patent to R. W. James No. 26,301 of 1906, above referred to, but is of the particular form shown in said'British Patent .No. 1,419 of 1910 to T. G. Martin.

The selector E is of-the general type of selector switches shown in United States Letters Patent No. 815,321, issued to Keith, Erickson and Erickson March 13, 1906, the circuits beingmodified, however, as shown in British Patent No. 1,419 of 1910 above referred to, in order to operate-in a system in which the centralotfice apparatus is controlled by the calling subscriber over the two sides of the line in series.

The second selector F is similar to the first selector E, with the addition "of the sideswitch wiper 10.

As the construction and operation of the line and master switch and selectors are in general well known, and are fully described in the publications above referred to, it is not thought necessary to describe the same in detail herein.

The connector H (Fig.2) is of the general type of connector switches disclosed in United States Letters Patent to Keith, Erickson andEricksohNo. 815,17 6, granted March 13, 1906 the circuits being modified, however, in or er tooperate in a two-wire system. ,As shown herein, the connector is assumed to be provided with a bank of contacts arranged in horizontal 'rows or levels, which contacts are adapted to beengaged by a set of wipers 11, 12 and 13 carried upon I a vertically and rotatably movable shaft which is controlled-by the vertical and ro- V tary operating magnets 14 and 15. The operations of the switch are controlled by the calling subscriber through the mediumof the double-wound relay 16, which relay is connected with the line circuit through the springs of the so-called'back-bridge relay 18. The usual means for releasing the switch shaft to permit it to be restored to normal position are provided in the release magnet 17. The usual-side switch comprising the wipers 21, 22, 23' and 24 is controlled by the private magnet 25 in the usual manner. Three relays 26, 27 and 28 are likewise provided. These relays 26, 27 and 28 are slow-acting relaysthat is, relays which deenergize slowly after their energizing circuits have been broken. The relay 29 is the usual ringing relay for applying ringing current to the called line for signal ing purposes. The talking circuit through the connector is divided into two inductively connected sections by'thecondensers 30 and '31. The springs 19 and 20 are controlled by the switch shaft in such a manner that they are permitted to close only when said shaft is raised one or more steps from its normal position.

At M there is shown a ringing current generator and at S a busy signaling machine is represented for supplying the usual interrupted busy signaling current. At B there is shown a battery having one terminal grounded at G for supplying current for operating the central oflice apparatus and for talking purposes. The line switch C and substation A are in all respects the same as the line switch C and the substation A.

A general description of the apparatus having been given, it will now be explained how the connection is extended from the calling to the called substation.

-Wl'1en the receiver at the substation A is removed from the switch hook preparatory 'to making a call, the engagement of the hook switch springs 37 and 38 completes abridge across the line through the receiver and transmitter at the substation. The closure of thisbridge across the line establishes an energizing circuit for the line relay 39 of the line switch C. The relay 39, upon energizing, operates to closegthe circuit of the operating winding 40 of the magnet 120,

p which, uponenergizing, attracts the plunger arm'107 and cut-off armature 106, whereby the line conductors 41 and 42 are extendf ed through the line switch bank springs 43 and {Hand 45 and 46 to the selector E, and the line relay 39 is disconnectedfr'om. the

line. \Vhen the connection is extended to the selector E, its line relay 47, which is normally bridged across the line circuit fof' the switch inseries with the battery, becomes energized and operates to close the circuit of the relay 48. The relay 48, upon energizing, operates to close the circuit of the holding winding 49 of the line switch before the line relay 39 breaks the circuit I of the operating winding 10, and to extend ductor to the connector tenets of the calling line.

When the substation calling device is op-.

a guarding ground potential over the conprivate bankconerated for the first digit of the called number, which will be assumed to be 2220, the substation impulse springs 7 and 8 are separated twice momentarily, thereby causing the selector line relay 47 to be twice momentarily deenergized. Each time the relay 47 deenergizes, it closes a circuit through the vertical magnet 51. Since the digit called is 2, the vertical magnet 51 operates twice to raise the switch shaft and its wipers two steps, after which the side switch passes to second position and causes the rotary magnet 52 to operate in the usual manner to rotate the shaft wipers onto the contacts of an idle trunk line leading to a second selector F. The

Y side switch thereupon passes to third position and, through the medium of its wipers 53 and 5a, disconnects the line relay 47 from the hue circuit and extends the line conductors through the shaft wipers 55 and 56 and the contacts upon which they have been rotated to the second selector F: The line relay 57 of the second selector thereupon becomes energized in the same manner in which the line relay of the first selector was energized when connection was firstextended to it.

I When the substation calling device is operated for the second digit 2 of the called number, the selector F operates in the same manner as explained for the selector E. in

connection with the previous digit to extendv the connection over the trunk conductors 58 and 59 to an idle connector H which has access to the group of lines to which that of the substation A belongs. When the connection is thus extended to the connector H, its line relay 16, which is normally bridged across the conductors 58 andr59 in series with the battery, becomes energized' The relay 16, upon energizing, closes the circuit of the relay 26. When the calling subscriber oper-' ates his calling device for the third digit 2 of the called number, the circuit of the line relay 16 of the connector is broken twice momentarily. The relay 26 being a slowacting relay does not have timeto deenergize during the momentary interruptions of its circuit by the line relay, and, therefore, each time the relaylG denergizes, a circuit is closed from ground G through the spring 66 and its-back contact, spring 67 and its front contact, relay 27, vertical magnet 14 and side switch wiper 24 to the battery lead 70, and thence through battery B to ground G. Since the digit called is 2, the vertical magnet receives two impulses over this circuit and operates to raise the switch shaft and wipers 11, 12 and 13 two steps. The

relay 27, which is energized in series with the vertical magnet, is a slow-acting relay and, upon being energized by the first impulse, remains in its energized position until after the last impulse is delivered to the vertical magnet. The relay 27, upon energizing, completes a circuit extending from round G through the springs '71 and 72 and private magnet 25 and relay 28 in multiple to the battery lead 70. The relay- 27 deenergizes and breaks the circuitof the pri vate magnet 25 and the relay 28 shortly after the last impulse is delivered to the vertical magnet. The private magnet, upon energizing and .dei nergizing, causes the side switch to pass from first to second position. When the calling subscriber operates his calling device for the last digit 0, the circuit of the line relay 16 is. broken ten times. Since the side switch is'now in second p0sition. each time the line relay deencrgizes a circuit is closed from ground G through the spring 66 and its backcontact, spring 67 and its front contact, relay 27, springs 73, rotary magnet 15 and the side switch wiper 24 to the battery lead 70. The rotary magnet 15 operates in response to the ten impulses rcccived over this circuit-to rotate the switch shaft ten steps to carry the wipers 11,12 and.

liq

tion. The side switch wiper 23, upon reaching third position, completes a circuit ex tending from ground G through said side switch wiper, shaft wi er 11, connector private bank contacts an the cut-oil winding 74 of the switch C to the battery lead 70. The winding 74, upon energizing, attracts 'the annature 75, which operates to disconnect the battery from the line. at the,

switch 0'.

The passage of the side switch wipers 21 and 22 to third position and theclosing of the contacts 716 and 77 by the deenergiza tion of the relay 28 finally completes the connection between the calling and the called linesv The passage of the side switch wiper 21 to third position completes the circuit of the ringing relay 29. This circuit extends from ground Gr through the interruptenTS, relay .79'and the side switch wiper 124-150 the battery lead' 70. The relay 29, upouenergizing, discon-vnects the calling line from the called line and connects the ringing current generator" M with the called-line through the ringing relay springs 82 and 85 and their front contacts, contacts 77 and 76 of the relay 28 and the wipers 13 and 12. The relay 2-8, which controls the contacts 77 and 76, is a slow-acting relay and therefore does not permit its contacts to close until shortly after the side switch has passed to third position and closed'the circuits of the cut-off winding 74 of the line switch C. It will thus seen that by the aid'of therelay 28 it is impossible for ringing current to be applied to the called line until after the cut-ofi" winding 74 has had sufiicient time to energize and disconnect the line relay 125 from the line, thereby preventing any false operation of said relay by the ringing current, notwithstanding the fact that the connector bank contacts are permanently. connected with the line instead of through normally open contacts in the cut-0E relay of the line switch, as has been heretofore necessary. Since the circuit of the ringing relay 29 includes the interrupter 78, said relay is energized only intermittently so as not to ring the called subscriber continuously. When the called subscriber removes his receiver in response to the call, the talking circuit of the called substation is bridged across the line, and as soon thereafter as the ringing relay 29 deenergizes,

said substation IS'PICVldGd with talking current over a circuit extending from ground G at the connector'release rela 26, through the springs 80, right-hand .wi ing of the back-bridge relay 18', side switch wiper 22, ringing relay springs 81 and 82, springs 77, thence to and through the substation A' and back over the line 84, wiper 12, spring 76, springs 85 and 86,"sideswitch. wiper 21 and the left-hand winding of the back-bridge relay 18 to the battery lead 70.

The relay [1.8,fupon energizing, closes the circuit'of the relay 87; This circuit extends from ground G through the side switch wiper 23, springs 88 and relay 8? to the battery lead 70; The relay 87, upon energizing, operates to open the circuit of the ringing relay 29 atthe springs 79 and, by closing contact, between the springs '89, forms a locking circuit for itselfindependent of the relay 18,511 as not to denergize again when'the called subscriber han sup his re ceiver. The shifting of the springs 110 and 112 by the energization of the relay l8 transposes the connection between the windthe line relay 16 and the trunk conductors 58 and 59, whereby the direction of .-the current in the calling line is reversed.

A unereversal of current is often used for "and 4 8 of the selectors'F'and E, respectively.

the purpose of operating-call registers in the manner shown in British patent to S. G. s. Dicker, No. 1,298 of 1910. It ma also be used to operate supervisory or op craters" signals ina manner which is well I known in theart. in the drawings the complete talking circuit between the calling and the called lines is outlined by'heavy conductors.

After the conversation is completed, the entire connection is released by the hanging up of the receiver at the calling substation. During the time the connection is being maintained, the release rclays 90 and 48 of the selectors F and E, respectively, are maintained energized over a circuit extending from ground 'G at the connector through the springs 80, conductor 91, pri-' vate wiper 92 of the selector F, side switch wiper 93 and spring 952, whence the circuit branchesfone branch passing through the relay ,90 to battery, while the other branch passes through the side switch wiper 10 and on to the selector E and through its relay 48 tothe battery lead 70. VJhen the-calling subscriber hangs up his receiver, the circuit of the line relay 16- of the connector is broken. The relay l6,-upon deenergizing, breaksthe circuit of the relay 26. The relay 26, upon denergizin closes the circuit of'therelease magnet 1 said circuit extending from ground G through the spring 66 and its back contact, spring 67 and its back contact, spring 20 and release magnet 17 to the battery lead 70. The magnet 17, upon energizing,immediately restores the shaft and side switch of the connector to normal position, and the switch shaft, upon reaching its lowest position, separates the springs 20, thereby permitting the release magnet to deenergize, The relay 26, upon denergizing, also disconnects ground G from the back-bridge relay 18 and also breaks the holding circuit of the relays 90 The disconnection of ground from the relay 18 permits said relay to deenergize and cause the current in the calling line to be restore to its normal direction, even though thecalled subscriber has not yet hung up his receiver. The breaking of the circuits of the relays 90 and 48 permits the said relays to dener'gize so as to close the circuits of their respective release magnets 95 and 96, which, upon energizing, cause the switches F and E to be restored to normal position. The relay 48, upon deie'nergizing, also breaks the holding circuit of the holding winding 49 of the switch C, causing said'switch to be restored to normal position.

In the foregoing it has been assumed that the line of the substation A was idle when not have completed connection. therewith. 13o

and the calling subscriber would have been given-a busy signal in-the following main ner: Vhenever a line is busy, either on acsaid line through the private wiper 11, side switch wiper 23 (which is then in second position), springs 98 and 99 and relay 100 to the spring 1010f the private'magnet relay 27. When the relay 27 de'e'nergizes' after the last impulse for the lastdigit is delivered, it permits the spring 72 to engage the spring 101 before the springs 72 and 71 separate, whereby the ground potential applied to the spring 101. from the guarded contact of the busy line'provides a holding circuit for the private magnet 25 and does (not permit it to. deenergize, while at the same time the relay 100 becomes energized in series with the private magnet. Since. the

private magnet 25 does not deenergize after the lastldigit is called, the side switch remains locked in second position and no connection is completed between the calling .line and the busy called line. The relay 100,

upon energizing, transfers the locking ground for itself and the private magnet from the guarded private bankcontact of the busy line to the ground G by way of the springs-.19, 102 and 99. The relay 100, upon energizing, also completes a connection from the busy signaling machine S through the springs 103, contact 104 and side switch wiper 22to the calling line to notify the callingsubscriber that the called line is busy. After having called a-busy line, the switches are released by the hanging up of the receiver at the calling substationnn the same manner as if an Idle line had been called. I

In the foregoing description it has been explained how the battery connection with the-calling line through the connector line relay, which is reversed upon the response of the calledsubscriber, is restored to its normal position as a result of the hanging up of the receiver at the calling substationif thecalled subscriber has not yet hung up his receiver. This feature has no particular function .in the connection shown in the drawings, in which theconn'ection is extended from the line switch C to the connector H through the medium of selector switches E and F. In an exchange of a smaller capacity, however, or-in a small branch exchange; in which selector switches are not used-- that is, where the trunk lines to which the line switches a. have access lead directly to connector switches-the trunk conductor 91 (Fig. 2.) would be connected to the line switch bankspring 114. In such a case the holding circuit for the holding winding 49 of the switch C would extend from ground G at the connector through the springs 80, conductor 91, line switch bank springs 114 and 115 and winding 49 to the battery lead 70. Thus the circuit of the winding 49, of the switch C would be broken immediatel upon the de'nergization of the relay 26 of t e connector H when the calling up his receiver and before the connector had time to release. It has been found that sometimes whenthe holding winding 49 of the line switch C deenergizes, the .cut-ofl' armature 106 falls back and permits the line winding 39 and ground G to be connected with the calling line before the plunger arm,

107 has fallen back far enough to permit the plunger {to be withdrawn from the bank sufiiciently to disconnect the line from the connector. If the connector back-bridge relay 18 is controlled entirely by the called subscriber, and the called subscriber has not yet hung up his receiver when this occurs, the ground at the line switch will be connected to the same side of the line which is connected to the non-grounded terminal of the battery through the line relay 16. This will cause said line relay to energize again before the connector has had time to release, and the relay 16, upon energizing, will close the circuit of the relay 26, which in turn will cause the winding49 of the switch C to ens ergize. This will break'the energizing cir- 4 cuit of the connector line relay again and the. entire operation Wlll be repeated over and over without releasing the connection until the called subscriber hangs up his receiver. As shown herein, however, the connector. upon deencrgizing, would open the circuit of the relay 18 at the same time that the circuit of the winding 4:9 was opened, so that the connections between the line and the battery through the connector relay 16 would be restored to their normal direction by the time the battery was restored to the line at the switch C, and there-- fore the same terminal of the battery would be connected to either side of the line in both the switch C and the connector H, and the connector line, relay would not be energized the relay 26 of again, but would permit the connector to release in the usual manner.

While I havejllustrated my invention in connection with a particular typesof automatic telephone system, it will, of course, be

understood that the features of my invention are capable of broader use and that my the va- Y coninvcntion contemplates the use of rious novel features of my inventlo';

nection with an automatic system 01 any known type, or inconnection with a semiautomatic system.

What I claim as my invention isz 1'." In a telephone system, a calling and a called subscribers line, a line relay individual to each line, means for extending a connection between the calling and the called subscribers lines, means for disconnecting said relay from the called line, and

"means whereby the connection between the calling and'the called lines is not completed until a predetermined interval after the line relay has been disconnected from the called line.

2. In a telephone system, a calling and :1 called subscribers line, a non-numerical line switch individual to each subscribers line, a line relay for each switch normally connected with the subscribers line, means for disconnecting said relay from the line when said line is 21 called line, means for extending a connection between the calling and the called subscribers lines, and means whereby the connection is not completed until a predetermined interval after the line relay has been disconnected from the called 11118.

3. #In a telephone system, a callingand a called subscribers line, a line relay individual to each line, meansincluding automatic switches controllable over two sides of a line circuit in series for extending a connection between the calling and the called subscribers lines, means for disconne ting said relay from its line when said lin is a called line, and means whereby the connection between the calling and the called lines is not completed until a predetermined interval aftenthe line relay has been disconnected from the called line.

4. In a telephone system, a calling and a called subscribers line, a non-numerical line switch individual to each subscribers line, a line relay for each switch normally connected with the subscribers line, means for disconnecting said relay from the line when said line is a called line, means including automatic switches controllable over two sides of a line circuit in series for extenddetermined interval after the line relay has been disconnected from the called line.

5. In a telephone system, a calling and a called subscribers line, means including an moving said side switch into its final posi tion after the impulses for the last digit f the called number have been transmitted,

and means for completing the connection between the calling and'the called lines at a predetermined interval. after the side switch has passed to its final position.

'6. Ina telephone system, a calling and a called subscribers line, means including an automatic connector switch for establishing a connection between said lines, a side switch in said connector switch having a plurality of operative" positions, means for \moving said side switch into its final posi--- tion after the impulses for the last digit of the called number have been transmitted, means for completing the connection between the calling and the called lines at a predetermined interval after the side switch nection between said lines, a side switch for said connector switch having a plurality of operative positions, a private magnet for controlling the operation of said side switch, I a re ily connected in parallel with said private magnet, and means controlled by said relay for completing theconnection with the called line.

8. In a telephone system, a calling and a called subscribers line, means including a connector switch for establishing a connection between said lines, a side switch for said com ector switch havinga plurality of operative positions, a private magnet for controlling the operation of said side, switch, a slow-acting relay connected in parallel with said private magnet, means controlled by said slow-acting relayfor completing the connection with the called line at .a

predetermined interval after the side switch has moved to its final position, and means -for controlling the operation of said connector switch over two sides of the line circuit 1n series.

'9. In a telephone system, subscribers lines divided into groups, a line relay individual to each line, means forextending a connection between the calling and-the called subscribers lines, said means including an auto matic switch having motion in one plane to select groups and motion in a plane at rightangles thereto to find a line in a selected group, means for disconnecting said relay from the called line, and means whereby the connection between the calling and the called lines is not completed until a predetermined interval after the line relay has been disconnectedfrom the called line.

10. In a telephone system, subscribers lines divided into groups, a non-numerical line switch individual to each subscribers line, a line relay for each switch normally connected with the subscribers line, means for disconnecting said relay from the line when said line is a called line, means .for extending a connection between the calling and the called subscribers lines-said means;

including an automatic switch having mo tion in one plane to select groups and inotion in' a plane at right-angles thereto to find a line in the selected group, and means whereby the connection is not completed until a predetermined interval after the 'line relay has been disconnected from the called line. i v

11. In a telephone system, subscribers lines divided into groups, a line relay individual to each line, means including automatic switches controllable over two sides of a linecircuit in series for extending a 4 connection between the calling and the called subscribers lines, said automatic switches having motion lIi-OIIB plane to select groups and motion'in' a plane at right-angles thereto to find a line in a selected group, means for disconnecting said relay from its line when said line is a called line, and means whereby the connection between the calling and the called lines is not completed until a predetermined interval after the line relay has been disconnected from the called line.

12. In a telephone system, subscribers,

5 lines divided into groups, a non-numerical line switch individual to each subscribers line, a line relay for each switch normally connected with the subscribers line, means for disconnecting said relay from the line go when said lineis a called line, means including automatic switches controllable over two sides of a line circuit in series for extending a connection between the calling and the called subscribers lines, said automatic ;5 switches having motionin one plane to select groups and motion in a plane at right-v angles thereto to find a line in a selected group, and means whereby the connection is not completed until a predetermined inn terval after the line relay has been disconnected from the called line. &

13; In a telephone system, subscribers lines divided into groups, means including an automatic connector switch for establish- ,5- ing a connection between said lines, said connector switch having motion in one plane to select groups and motion in a plane at right-angles thereto to find a line in a selected group, a side switch in said connector 0 switch having a plurality of operative posi- I tions, means for moving said side switch into itsfinal position after the impulses for.

the last digit of the called number have been transmitted, and means for completing 5 the connection between the calling and the called lines at a predetermined interval after the side, switch has passed to its final position. i 14. In a telephone system, subscribers 9 lines divided into groups, means including an automatic connector switch for establishing a connection between'said lines,said connector switch having motion in one plane to select oups and motion in aplane at s, right-mg es thereto to find a line in a secircuit in series.

- sides of a line circuit in series, a back-bridge transmitted, means for completing the connection between the calling and the called lines at a predetermined interval afterthe side switch has passed to its final position, and means for controlling the operation of said connector switchover two-sides'of the line circuit in series;

15. In a telephone system, subscribers" lines divided into groups, means including a connector switch for establishing a co motion between said lines, said connector switch having motion in one plane to select groups and motion ina' plane at right-angles thereto to find a line in a selected group, a

side switch for said connector switch having-5a plurality. of operative positions, a private magnet for-controlling the operation of said side switch, a,relay connected in parallel with said private magnet, and means controlled by said'relay for completing the connection with the called line. a

16. In a telephone system, subscribers lines divided'into groups, means including a connector switch for establishing a'connection between .said lines, said connector switch having motion in'one plane to select groups and motion in a plane at right-angles thereto to find a line in a selected group, a side switch for said connector switch having a plurality of operative positions, a private magnet for controlling the operation of said side switch, a slow-acting relay connected in parallel with said private magnet, means controlled by said slow-acting relay for completing the connection with the called ,line at; a predetermined interval after th side switch has moved to its final positidn, and means for controlling the operation 'f said connector switch over two sides of the line I Q 17. In a telephone system, a callin and a called subscribers line, means including an automatic switch for establishing a connection between said lines, a back-bridge relay forsaid switch, meansjor denei'gizing said relay by anging up the receiver'atthe calling substation, and means controlled by the denergization of said relay for reversing the battery connection to the calling line.

18. In a telephone system, a calling and a called subscribers line, means including a connector switch for establishing a connection between said lines, means for controlling the operation of said switch over two relay for said connector, and means for deenergizing said back-bridge relay upon hanging up the receiver at the calling station.

19. In a telephone system, subscribers 13 back-bridge relay for said switch, means'for deenergizingsaid relay by hanging up the receiver at-the calling substation,and means controlled by the denergization of said relay for reversing the battery connection to the calling line. i

20. In a telephone system, subscribers lines divided into groups, means including a connectorswitch for establishing a connection between said lines, said connector sw1tch having motion in one plane to select groups and motion in a plane at right-angles thereto to find a line in a selected group, means for controlling the operation of said switch over-two sides of a line circuit in series, a back-bridge relay for said connector, and means for deenergizing said 'bflClI-bl'ltilt) relay upon hanging up the receiver at the calling stat-ion.

1 21. In a telephonesystem, a calling and a called subscribers line, means including a connector switch for establishing a connection between said lines, means for controlling the opcration'ot' said switch over two sides of a line circuit in series a back-bridge relay for said connector, means for deenergizing said back-bridge relay upon hanging up the receiver at the calling station and means controlled by the denergizatidn of said, relay for reversing the battery connection to the calling line.

2211i a telephone system, a calling and a called subscribers line, means including an automatic switch for establishing a connection between said lines, a release relay, a baclcbridge relay connected to ground through springs controlled by said release relay, means for deenergizing said backbridge relay by hanging up the receiver at the calling substation, and means controlled by said deenergization for reversing the battery connecticrrto the calling line.

23. In a telephone system, a calling and a called subscribers line, means including an automatic connector switch for establishing a talking connection between said lines, a

pair of condensers in the talking conductors, a relay bridged across the talking conductors on the called side of said condensers, a release relay for said connector, means controlled by said release relay for controlling the circuit of the bridged relay, and means for dcnergizing said bridged relay when the calling subscriber replaces his receiver upon the hook. a

In a telephone system, a calling and a called subscribers line, means including an automatic connector switch for establishing a connection between said lines, a pair of condensers in opposite sides of said talking connection, a back-bridge relay bridged across the talking conductors at the called side of said condensers, a release relay, means controlled by said release relay for controlling the circuit of'said back-bridge relay; means controlled by the calling subscriber for denergizing said release relay to thereby denergizesaid back-bridgerelay, and means controlled by the deenergization of said back-bridge relay for reversing the hat- .tery connection to the calling line.

25. In a telephone system, a calling and a called subscribers line, a line switch for said calling line, a line relay for said switch normally connected with said line and .wi-th battery, a cut-oil relay for cutting oil said line relay during a connection, means including a connector switch for extending a connection from said line switch to a called subscribers line, means controlled by the calling subscriber in releasing for denergizing said cut-off relay to again connect said line relay and battery to the calling line, and means operated at the same time for reversing the battery connections to the calling line at the connector and thereby prevent said line relay from energizing.

26. In a telephone system, a calling and a called subscribers line, a line switch for said calling line including a line relay normally connected with the line and a cut-oii relay for disconnecting said line relay during the time a connection is established with the called line, means including a connector 100 switch for extending a connection from said line switch to the called line, a relay bridged across the called end of said connector, a release relay controlling the circuit of said bridged relay, means controlled by the call- 27. In a telephone system, subscribers lines divided into groups, means including a connector switch for establishing a connec-- tion between said lines, said connector switch having motion in one plane to select groups and motion in a plane at right-angles there- 12a to to find a line in a selected group, means for controlling the operation of said switch over two sides of a line circuit in series, a" back-bridge relay for said connector, means for denergizing said back-bridge relay upon hanging up the receiver at the calling station, and means controlled by the deeuergization of said relay for reversingthe battery connection to the calling line.

28. In a telephone system, subscribers side of said condensers,

' lishing a connection copies of this patent may be obtained for lines divided into groups, means including an automatic switch for establishing a connection between said lines, said automatic switch having motion in one plane to select groups and motion in a plane at right-angles thereto to find a line in a selected group,.a release relay, a back-bridge relay connected to ground through springs controlled. by said release relay, means for de'elnergizing said back-bridgerelay by hanging up the receiver at the calling substation, and means controlled by said deenergization for reversing the battery connection to the calling line.

29. In .a telephone system, subscribers lines divided into groups, means including an automatic connector switch forestab lishing a talking connection between said lines, said connector switch having motion in one plane to select groups and motion in a plane at right-angles thereto to find a line in a selected group, a pair of condensers in the talking conductors, across the talking conductors on the called a release relay for said connector, means controlled by said release relay for controlling the circuit of the bridged relay, and means for deiinergizing said bridged relay when the calling subscriber replaces his receiver upon the hook.

30. In a telephone system, subscribers Ines divided into groups, means including an automatic connector switch for estabconnector switch having motion in one plane "to select groups andmotion in a plane at right-angles thereto to find a line in a selected group, a pair of condensers in opposite sides of said talking connection, a backbridge relay bridged across the talking conductors at the called side of said condensers, a release relay, means controlled by'said release relay for controlling the circuit of said back-bridge relay, means controlled by the calling subscriber for deenergizing said release relay to thereby detinergize said backbridge relay, and means controlled by the dee-nergization of said back-bridge relay for reversing the battery connection to the calling line.-

31. In a telephone system, subscribers linesldivided into groups, a line switch for said calling line, a line relay for said switch normally connected with said line and with battery, a cut-off relay for cutting off said line relay during a connection, means including a connector switch for extending a connection from said line switch to a called subscribers line, saidconnector switch having motion in one plane to select groups and motion in a plane at right angles thereto to find a line in a selected group, means controlled bythe calling subscriber in rea relay bridged between said lines, saidcents each, by addressing the Washington, D. G.

leasing for deenergizing said cut-0ft relay to again connect said line relay and battery to the calling line, the same time for reversing the battery connections to the calling'line at the connector and thereby prevent said line relay from energizing. 32. In a telephone system, subscribers lines divided into groups, a line switch for said calling line including a mally connected with the line and a cut-ofi relay for disconnecting said line relay during the time a connection the called line, meansflincluding a connector switch for extending a connection from said line switch to the called line, said connector switch having motion in one plane to select groups and motion in a plane at right-angles thereto to find a line in a selected group, a relay bridged across the called end of said connector, a release relay; controlling the circuit of said bridged reiay, means controlled by the callingsubscriber'in releasing for denergizing sai release relay, circuit connections whereby. the deenergization of said release relay denergizes said cut-off relay and said bridged relay, and means ,controlled by the deenergization of said bridged relay for reversing the battery connections to the calling line to thereby prevent said line relay from energizing.

33. In a telephone system, a line, normal conductors permanently connected therewith, a connector switch for connecting with said line through means including a line relay for said line for extending a connection therefrom, means for disconnect-ing said relay from said line when said line is called, means for applying ringing current to said line, and means for preventing ringing current being projected projected over said line before said relay has been disconnected.

Signed by me at Chicago, Cook county,

Illinois, this 27th day of December, 1911.

and means operated at line relay noris established with said normal conductors,

o'ver said line before said relay has been dismeans for preventing ringing current being Flt NK NFAVFORTH, JR.

Witnesses ARTHUR J, RAY, ALBERT Annnusnn.

Commissioner of Patents,

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