US1189862A

US1189862A - Ringing-current interrupter.

Info

Publication number: US1189862A
Application number: US69890012A
Authority: US
Inventors: Herbert F Obergfell
Original assignee: Automatic Electric Co
Current assignee: Automatic Electric Co
Priority date: 1912-05-22
Filing date: 1912-05-22
Publication date: 1916-07-04
Anticipated expiration: 1933-07-04

Description

H. F. OBERGFELL. RINGING CURRENT INTERRUPTER. APPLICATION man MAY 22, m2.

Patented July 4, 1916;

3 SHEETS-$HEET 1.

M/I'TNESSES H. F. OBERGFELL. RINGING CURRENT INTERRUPTERL APPLICATION FILED MAY 22. 912. 1 ,1 89,862. Patented July 4, 1916.

3 SHEETS-SHEET 2.

Q Q N \mmlhhH & A WIT/V5555? 74/; pi/

. .9 w Q25 W I a/ a 4 wfifuw H F. OBEFEGFELL.

meme CURRENT IN'YERRUPTER.

APPLICATIQN HLED MA 22;?912. 1,189,862. Patented July 4, 1916.

3 SHEETS-SHEET 3- 'rEs PATENT OFFICE.

HERIEER'I' 013E GFELL, or CHICAGO, ILLINOIS, ASSIGNOR T AUTOMATIC ELECTRIC To all whom -uia g concern I Bent known .t at I, Hnunsn'r F. OBERG- rni t acitigen qtf t e United States of America andfre identlofgchicego, in the county of Cook, in th'e State f Illinois, have invented certain -new and; 1' etul Improvements in Ringing-Qui'i'elihInterrupters, of which the My invention reLa't'es to ringing current interruptersjonuse in connection with telephone systems. In telephone exchanges in which automatic ringing is employed it is desirable to liavethe ringing current inter- 1 nect somefipeiin to theseditlerent groups in, rotation, it will in g.

be seen that thegmount of ringing current drawn .from the ringing current generator will belessf than.ifringing current were. sup plied to all .tl roups in the exchange at i.. same tiine.- th such an arrangelnentthat is, sn 'jply ng,ringing current to the different groups; in rotationit possible to use ,a rin ing caua ent generator of much smaller CRQI ity than would otherwise be. the case, i

i.- IIeretof' reeit li;as, been customary to employ. ,(u'(1inar) otary alternating currentgeneiators fou upplying ringingcurrent, which generatortware continuously operati\ -nu1'nbei; ofcommutators or. interrupter wheels were geared up with the shaft of the generator. which.interrupter .ivheels were soarrangeda to,supply; tur -ent only one section xyt th This arrangement. wa,

ever, as thegenerators,a v generally operating continuous v were there fore-l inetlicient r nd espet lna smalllc xeliangea.i ltshas. eeu pro to eni ploy a: wibi ti r g ,polmel anger as a ringing" current generator, together with an interrupter in connection with such a Specification of Letters Patent.

omam, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

RINGING-CURR'ENT 'INTERRUPTER.

Patented July 4, 1916.

Application filed May 22, 1912. Serial No. 698,900.

pole changer, which is arranged to operate only when it is desired to supply ringing current to a called line. Heretofore this interrupter, however, interrupted the ringing current for the whole exchange at one time.

The object of my presentinvention is to provide a simple and eflicient interrupter which will embody both the features of the above types. I provide an interrupt-er which is normally at rest and which supplies ring ing current to only one section of the exchange at a time and operates only when some connector is in ringing position,

These and other objects of my invention will be more readily understood by reference able form of automatic system could be employed. I have also illustrated my invention in connection with a ma lal system in which it is but necessary to substitute an ordinary cord circuit for the automatic connector.

Throughout the drawings similar reference characters illustrate similar parts.

Figure 1 is an elevation of my improved interrupter device. portion of an automatic telephone system in connection with which I have chosen to'illus- [rate my invention. Fig. -i shows a portion of a manual system with which I 'have chosen to illustrate my invention.

The interrupter proper, as illustrated in Fig. 1, comprises, among other details, a solenoid 2 the plunger of which isconnected through the medium of a link 3 with the piston rod l of a dash-pot. The dash-pot comprises a cylinder 5 in which the piston works. The cylinder 5 is inclo'sed in a cup 7 which is partly filled with oil or soiue other suitable. liquid. The bottom of the cylinder is closed. except for a ball valve 8 and a small openingfl; When theso-lenoid is energized,its-plan e "and thej pistonffi :ilve' 8 and z to their lower positions, the valie '8 closes Figs. 2 and 3 show a and the'only exit for tli'e liq iiid from'the cylinder is through the small opening 9, so

that the movement of the piston is retarded and it falls only slowly. Carried by the link' 3, but insulated therefrom, there is a brush or wiper 10 one end of which bears upon along contact strip 11, while the other. end brushes over andmakes contact with a number of short contact pieces 12 which are insulated from each other. Back of the link 3 there is a group of interrupter springs On the-rear of the link 3 there are two

insula'ting pins

16 and 17 which strike the springs 14 and 15, respectively, when the plunger of t-hesolenoid isin its lower and upper positions, respectively. As shown in Fig. 1, the plunger is in its lowest position and the spring 13 is bowed downward in contact with the spring 15. As the plunger .nears the .limit of its upward movement when the solenoid is energized, the pin 17 strikes the spring 15 and torces both it and the spring 13 upward until the latter spring slightly passes its mid position, when, of its own accord, it springs to its extreme'iipper position and into'contact with the spring H and out of contact with the spring 15. As the plunger nears its lowest position when the solenoid is dei nergized, the pin 16 in likemanner forces the spring 13 back to its original position in contact with the spring 15 and out of contact with the spring 11. In Figs. 2 and 3 are represented a connector switch A, a called subscribers sub station C and an individual switch I). This indi 'idual switch is described in British patcut to S. (i. S. Dicker, No. 1298 of 1910.

The connector switch comprises among other details a set of wipers 20,21 and 2'3 carried upon a shaft (not shown) having a vertical motion controlled by the vertical magnet and a rotary motion controlled by the rotary magnet The usual side switch, comprising the wipers '25, IQ-2T and 28, is controlled by the private magnet 30 in a well-known manner. The relays 31 and are slow acting relays that is, they dei nergize slowly after their energizing circuits have been broken. The relay 37 is the ringing relaythat is, "the relay which operates after connection between the callingand called lines has been completed to momentarily sever the connection and apply ringing current to the called line to signal the called subscriber. All of the connectors in an exchange may be sup- 'plied with ringing current by a single ringing current generator 33, and a single interrupter device'of the character shown in Fig. 1 and represented diagrammatically at L in Fig. 2 may be employed to properly control the supply of ringing current to. the con nectors. With respect to the ringing current generatoiythe connectors are divided "into aplurality of groups,= each group being supplied "with ringing current over a separate pair of

leads

38 and 39, and to each group of'conn'ectors a group of

relays

31, 35 and 36 is allotted. The upper and lower. contacts of the group 12 of the interrupter L are preferably dead contacts and serve only as supports for the wiper 10 when it is In its upper and lower positions. Between the upperand lower contacts there are as many contacts as there are groups of connectors, each contact being connectedito the

relays

34 and 35 of some particular group. The other terminals of the relays 31 and 35 are connected to the battery B. The relay 36 is included in a permanent ground connection of the ringing relay 37 of all the connectors of its group. The springs of the relay 36 control a battery connection to one terminal of the solenoid '2. The other terminal of the solenoid is connected to the spring 15. The spring 13 is connected to the grounded terminal of the battery 13 and the. contact 14 is connected to the strip 11.

Having given a general description of the apparatus, it will now be explained how connection is completed with a called line through the medium ofthe connector switch shown, and how the supply of ringing "current to the called line is controlled through the medium offihe interrupting apparatus described herein. \Vhen the connection reaches the connector over the conductors it) and i1 from the calling substation, the connector line relay 42 becomes energized by reason of the closed bridge across the line at the calling substation. The relay 12, upon energizing, closes the circuit of the relay 32. 'hen the calling subscriber operates his calling device for the nextdigit of the oallcd number, the circuit'of the line relay 42 is momentarily broken a number of times corresponding to the digit called. The relay 212 being a slow acting relay does not have time to decnergize during the momentary interruptions of its circuit by the relay 12, and, therefore, each time the line relay dei nergizes, a circuit is closed extending from ground G through the spring 43' and its back contact, spring 14 and its front contact, vertical magnet 23, side switch wiper 28 and the relay 31 to the battery lead 15, and thence through battery B to ground G. The vcrtiral magnet operates in response to the impulses transmitted over this circuit. to raise the shaft wipers 2t), 21 and 22 a number of steps to a position opposite the row or level of bank. contacts corresponding to the digit called. The relay 31, which is included in the energizing circuit or the vertical magnet. is energized by the first impulse, but being a slow acting relay does not deiinergizc until after the last impulse is delivered. The relay 31, in its energized position, closes a. circuit extei'iding from ground G through the springs 46 and 47 and the pr vate ma not 30 to the battery lead 45. This "Eli! broken when the relay 2} decnoi at a; the last impulse is delivered to tnc verticai magnet, and the private magnet, upon dcenergizing. porn, ts the side switch to p :4: from first to second position. v The Sb switch wiper 28, is passing from first to an, end position,"transfers the battery connection from the, vertical, magnet 23 to the rotary magnet lg so that when the calling suhscrihei' operateshis calling device for the last digit of the called number, the line relay 42 operates to transmit a series of impulses through the rotary ,magnet 24. and the relay 31. The rotary magnet operates in response to these impulses torotate the switch wipers onto the contacts of the called line. The re lay 31 operates in response to the impulses for this digit in the same manner as for the previous digit to cause the private magnet to advance the side switch one more step that is, from second to third )OSltl0li 2lf t8l' the last impulse is delivered. The side switch ipers 35 and '26, upon reaching third position, conrpleteltlie connection from the calling line through the wipers 20 and 21 to theconductors L5 and 49 which lead to the called substation. he contact intl c talking circuit at the switch. D (Fig, 3) closed hv the energization of the winding 71, the ('iHllit of which extends from ground (i at the rouncctor through the side switch wiper '37, private wiper and theuv nding T1 to the battery lead 45. The winding Tl is not strong enough to operate the plunger arm ,72. The side switch wiper upon reaching third position, completes a circuit extending: fronr ground ii through the group relay tit}, ringing relay 3? of the con: ncctor, springs 51, side switch wiper iii and the relay 31 to the battery lead lo. The relay 36 is energized in this circuit, hut it has a comparatively high resistance and pre vents the relays 37 and 31 from being opera tively energized, The relay 36, upon energizing, completes a circuit extending from ground (t at the interrupter L through the springs l? and 1:3 (assuming that the solenoid is dei nergized and the plunger at rest in its lowest position), solenoid 2 and the springs 53 to the llattery lead t5. The solenoid, upon energizing, immediately. draws its plunger to itsex treme upward Pt "i'tion; whereuponthe'pin 17 moves the sp'r n 1? out of engagement with the spring cloand into confact witli the spring 14. c The ration of the springs '13 and 15 hreahs the circuit of the Solenoid 2, 'whereuponits plunger begins to fall slowlyunderthe control of the dash-pot.

Vfheri the wiper 10 reaches the second con line until the called subscriber enaiv an id G through the springs ii 11, wiper 10 and the relays A triple to the battery lead inning current generator 33 rings at and 55 mm connector iv The relay 35, upon enerto short-circuit the relay 36,,

' ierehy increas A connector ringing relay argumennuy tqcau'se 5 it to he operatively energiz edQ Tillie?relay 37, upon energizing, operates to fdisc'onnectf the calling line from the called line 1nd to connect the ringing curren generator" 39 ing, disconnect-s the ringing ct rrentgenra 00' tor 33 from the called line s'hontfcircuits the line through the 'sp1-ing s5 6 aiid 57 for a purpose which will herei'nafter beLde-- scribed The relay 35, upon ,denerg zingr permits the ringing relayf3'i'"tO'LdenrgiZeQ which disconnects the generatOiiladS'B S and 2&9 from the called line and. restores the' con nection with the calledv line; The wiper "1Q of the interrupter device" continues its open energizing, oper to 70 ing the current through they;

downward movement and, in passing'tdi er 160 each of the remainingcontacts 112, causes any coni'ieotors in the remaining groups which are in ringing position to operafte' to" su pply ringing current "to the lines" which they have called in the inzinneriiabo'veexs plained. When the pliinger of "the; inter rupter device reaches its lowest position {the spring 13 is forced baclbiiit'ocontactivith the spring 15, and if th ca'llet 's' ubsci'iber has not answered nor the callin hung up his receiverfthe s ol nold 'fl 'W again he energized and th e above o en p repeated. In this mannerriiigiiig current will be periodically suppliedloithe ,a'lled' receiver. When this mars a brid'g is: closed across the. linethrough'th a'lking" circuit in the usual manner a'nd' as; soon as" the ringing relay 3'? deehergizes; "if it hapsi'ibs'ci-iber no his xiii pens to he energized at the tin1e,-the connector hack-bridge rel'ay'57is energiiedover a Cat-mi. moi-(nag from ground n g through the snrin (3B, =1f aver-wi naing-3 of "thefrelayf 'ingin relay springs"'58" and 59j side switch 'wi per 26, shaft "wipe-r '21,"conductor 13 thence to and through' theea'l'iedsubsta tion and back dyer the other :side of th l'irie over the conductor 48, "ivip'ers 20 and 25, springs 61 and "60' andth upperwiiiding of the relay 57 to the battery lad45. The

energize.

relay 57, upon energizing, closes a circuit extending from ground G through the side switch wiper 27, springs 63 and the relay G4 to the battery lead. The relay 64, upon In the above description it will be seen that when the back-bridge relay energizes.

and causes the relay 64 to energize to finally out out the ringing relay 37, the relay (ll becomes locked up and cannot de'nergize to close the ringing relay circuit again when the called subscriber hangs up his receiver and allows the back-bridge relay 57 to de- At theisubstation there is a con-- denser 73 included in the circuit of the ringer 74 to furnish a path for ringing currentwhich is impassableto'battery current.

.Vhen ringing current is disconnected from the line, this-condenser may be left in a charged condition. If the ringing relay 37 were to deiinergize and connect the backbridge relay. 57 with the line while the condenser was thus charged, it would discharge through the back-bridge relay and might cause it to be momentarily energized to cause the relay 64 to break the circuit of the ringing relay before the called subscriber had'answered. As described. however, the relay 34, after cutting off the ringing current, short-circuits the line and thereby causes the substation condenser.to be discharged before the relay permits the relay 37 to dei nergille. and thus the possibility of the ringing relay being prematurely cut out is entirely avoided.

It will be seen from the above description that the connector shown, as well as all other connectors belonging to the same group and to which the

relays

34, 35 and 36 are allotted, can operate to supply ringing current to the lines which are called through them only while the wiper 10 is passing over the second contact. \Vhile the wiper 10 is passing over the. third, fourth, 'fifth and sixth contacts, the connectors of the remaining groups are rendered operative for supplying ringing current to the called line with which they. happen to be connected.

It will thus be seen that if two connectors in different groups are in ringlng position atthe same time, they will not be able to actually draw ringing current from the generatiir 33 simultaneously. It will also be seen that the interrupter device L is noro mally at rest and that it begins to operate The hanging up of the receiver permits the relay 42 to denergize, which Breaks the circuit of the relay 32.. The relay 32, upon deenergizlng, closes the circuit of the release magnet 66, said circuit extending from ground (1? through the spring 43 and its back contact, spring -14 and its back contact, magnet 66 and the springs 67 to the battery lead 45. The magnet 66, upon energizing, restores the switch shaft and side switch, and the switch shaft, upon reaching its lowest position, separates the springs ,67 to permit the release magnet to deenergize.

In case the called line is already in use when the connector attempts to make connection therewith, the connection is not completed, but the side switch remains. locked in second position and the. calling subscriber is given the busy signal from the busy signaling device M in a wcll-known manner,

. which it is not thought necessary to describe herein.

In Fig 4 there is shown a mannual telephone line and the calling end of a cord circuit which is adapted for automatic ringing, the supply of ringing current being controlled by an interrupter similar to that hereinbet'ore described. The various parts of the interrupter and the. controlling relays are designated by thc'same reference uumerals as in Fig. The cord circuit represented is a simple form of circuit which, in addition to the usual supervism'y relay 73 and the lamp 77. is provided with a ringing relay 75 and a lock-out relay H. The functions of these two latter relays are similar to those of the relays 37 and (H, respectively, in the automatic connector switch.

The operation of the manual apparatus is as follows: Upon the insertion of the plug P into the jack J of the called line, a circuit is closed from ground through the cut-off relay 76, sleeve of -the jack J and the plug 1 and the relay 78 to the battery B. The'relay 78, upon energizing'closes the circuit of the supervisory lamp 77, connects the battery with the relay 74 and closes a circuit extending from battery through contacts. 79 and SO and the relays 75 and 36 to ground. The relay 36 being of a high resistance is itself operatively energized, but

. connect signal, but the relay 74 remains locked up through its contact 84 and pre- I 'vents the ringing relay 75 from again becoming operative. The relay 7- resumes its normal position when the plug P is removed from-the jack J, whereby the relay 78 is permitted to deinergize.

\Vhen the interrupter device is used in connection with manual cord circuits, the same arrangement is employed as in an a utomatic systemthat is, the cords are divided into a number of groups, the ringing relays of, the, difi'eent groups being controlled through different contacts of the interrupter.

very eflicient interrupting device, one which is normally at rest and operates only when it is desired to supply ringing current to a called line. Likewise, ringing current is supplied to but a few lines at any one time, .whereby the momentary consumption of current is greatly reduced, thus making it possible to employ a ringing generator of smaller capacity.

While I have illustrated and described certain particular embodiments of my invention, it is to be understood that I do not wish to be limited to the exact constructions shown and described.

What I claim as my invention is:-

1. In a telephone system, a plurality of groups of subscribers lines, means for antomatically supplying ringing current to said lines, a distributing interrupter common to said groups, said interrupter being normally at rest, and means for bringing said interrupter into use when it is desired to apply ringing current to a ine to suecessively interrupt the ringing current in the different groups of subscribers lines.

2.. In a telephone system. a plurality of subscribers lines divided into groups, means for establishing a connection with one of said lines, means for applying ringing current to said line when connection has been established therewith, an interrupter common to said groups of lines normally at rest, means for bringing said interrupter into operation when connection is made with the line, and means controlled by said interrupter for successively interrupting the ringing current supplied to the different groups of subscribers llnes.

' It will thus be seen that I have devised a,

In a telephone system, a plurality of groups of subscribers lines, means for antomatically supplying ringing current to said lines, a distributing interrupter common to a plurality of said. groups, said interrupter comprising a magnet, a wiper carried by the plunger of said magnet, and a bank of contacts successively engaged by sald wiper, said contacts belonging to different groups of said subscribers lines, whereby the ringing current supplied to said groupsis successively interrupted.

4. In a telephone system, a plurality of subscribers lines divided into groups, means for automatically supplying ringing current to said lines, an interrupter common to a' plurality of said groups for interrupting said ringing current, said interrupter comprising a magnet, a plunger controlled thereby for controlling a series of contacts, whereby the ringing current supplied to the different groups of subscribers lines is successively interrupted, and a dash-pot for controlling the operation of said plunger.

5. In a telephone system, a plurality of 90 subscribers lines divided into groups, means for automatically supplying ringing current to said lines, an interruptingdevice common to a plurality of said groups for interrupting said ringing current, said interrupter comprising a magnet, means for energizing said magnet when connection is made with a subscribers line, means for automatically breaking said energizing circuit, and means controlled by the return of the plun- 100 ger of said magnet to normal position to successively interrupt the supply of ringing current to the different groups of said subscribers lines.

6. In a telephone system. a plurality of 105 subscribers lines divided into groups, means for automatically supplying ringing current to said lines, an interrupting device common to a plurality of said groups for interruptsaid magnet when connection is made with a subscr1bei"s line, means for automatically .breaking said energizing circuit. means controlled by the return of the plunger of said magnet to normal position to successively interrupt the supply of ringing current to the different groups of said, subscribers lines, and a dash-pot for controlling the r turn movement of said plunger.

7. In a telephone system, a plurality of subscribers lines, means divided into groups for automatically supplying ringing current to said lines, a distributing interrupter common to a plurality of said groups, said in- 125 terrupter being normally at rest, and means for bringing said interrupter into use when it is desired to apply ringing current to a line to successively interrupt the ringing current in the different groups.

8. In a telephone system a'pluralit of subscribers lines, means or cstablis ing connection witfrsaid means divided intooups for applying ringing current to said ilies when connectlon has been established therewith, an interrupter common to a plurality of said groups normally at rest, means'for bringing said interrupter into operation when connection is made with a line, and means controlled by the interrupter for successively interrupting the ringing current supplied to the subscribers lines.

9. In a telephone system, a plurality of subscribers lines, means divided into groups for automatically supplying ringing current to said lines,a distributinginterrupter common to a plurality of said groups, said interrupter comprising a solenoid magnet, a wiper carried by the plunger of said solenoid, and a bank of contacts successively engaged by said wiper, said contacts belonging to different groups of said automatic ringing means, whereby the ringing current supplied to said groupsis successively interrupted.

10. Ina telephone system, a plurality of subscribers lines, means divided into groups for automatically supplying ringing current to said lines, an interrupting device common to a plurality of said groups for interruping said ringing current, said interrupter comprising a solenoid magnet, means for energizing said magnet when connection is made with a subscribers line, means for a u tomatically breaking said energizing circuit, and means controlled by the return of the plunger of said solenoid to normal position to successively interrupt the supply of ringing current from the different groups of ringing means to said subscribers lines.

11. In a telephone system, a plurality of subscribers lines, means for automatically supplying ringing currentto said lines, an

interrupting device common to a plurality of said groups for interrupting said ring ing current, said interrupting device comprising a solenoid magnet, means for energizing said magnet when connection is made with a subscribers line, means for automatically breaking said energizing circuit, means controlled by the return of the plunger of said solenoid to normal position to successi-vely interrupt the supply of rin ing current from the different 'oups .o r nging mechanism to said subscribers lines, and a dash-pot for controlling the return movement of said solenoid.

12'. In a telephone system, a' series of lines divided into groups, means for each group for connecting two lines, ringing means comprising a generator for signaling when the connection is made, said ringing means also comprising equipment normally at rest and common to sald groups, and equipment individual to said groups, the common equipment controlling the individual equip ment.

13. In a telephone system, a series of lines divided into groups, means for each groupfor connecting lines, ringing means comprising a generator for signaling when the connection is made, said ringing'means also comprising equipment common. to. said groups and electromagnetic equlpment individual to sald groups, said common equip 'ment controlling said individual equipment.

14. In a telephone system, a series of lines divided 'into groups, means for each group for connecting lines, ringing means comprising a generator for signaling whenthe connection is made, said ringing means also' comprising equipment common to said groupsand electromagnetic equipment individual to said groups, said common equipment controlling said individual equipment to render the individual equipments operative consecutively.

15. In a telephone system, a series of lines divided into groups, automatic switches for each group for connecting lines, ringing means for signaling when the connection is made, said means comprising equipment common to said groups, equipment individual to said groups and equipment individual to each switch in each group, said common equipment controlling the individual group equipment and the individu'al switch equipment.

16. In a telephone system, a series of linesdivided into groups, automatic switches for each group for connecting lines, ringing means for slgnahng when the connectionas made, said means comprising, electromagnet-ic equipment common to said groups, equipment individual to said groups an" equipment individual to each switch in each group, said common equipment controlling the individual group equipment and the'ilb dividual switch equipment.

171 In a telephone system, a series of lines divided into groups, automatic switches for each group or connecting lines, ringing means for signaling when the connection is made, said means comprising equipment common to said groups, electromagnetic equipment individual to said groups'and equipment individual to each switch in each group, said common equipment controlling the individual group equipment andthe-im.

dividual switch equipment.

18. In a telephone system, a series of.

lines divided into groups, automatic switches for each group fouconnecting lines, ringing means for signaling when the connection; is made, said means C0mpIlSlIlg equipment common to said; groups, equipment indi vidual'to said groups and electromagnetic equipment individual to each switch ineach group, said common equipment controlling the individual group equipment and the individual switch equipment.

19. In a telephone system, a series of lines divided into groups, automatic switches for each group for connecting lines, ringing means for signaling when the connection is made, said means comprising electromagnetic equipment common to said groups, electromagnetic equipment individual to said groups and electromagnetic equipment individual to each switch in each group, said common equipment controlling the individual group equipment and the individual switch equipment.

20. In a telephone system, a series of lines divided into groups, automatic progressively movable switches for each group for connecting lines, a circuit controller, ringing means for signaling when the connection is made, said means comprising equipment common to said groups, equipment individual to said groups and equipment individual to each switch in each group, said common equipment controlling the individual groupequipment and the individual switch equipment through the medium of said circuit controller.

21. In a telephone system, a series of lines divided into groups, automatic progressivelymovable switches for each group for connecting lines, a circuit controller, ringing means for signaling when the connection is made, said means comprising equipment common to said groups, equipment individual to said groups and equipment individual to each switch in each group, said common equipment controlling the individual group equipment and the individual switch equipment through the medium of said circuit controller, said circuit controller having a bank with a series of contacts, one for each group, and a wiper for moving over said contacts.

22. In a telephone system, a series of lines divided into groups, automatic switches for each group for connecting lines, ringing means for signaling when the connection is made, said means comprising equipment common to said groups, equipment individual to said groups and equipment individual to each switch in each group, said common equipment provided with means for rendering one individual group equipment and its associated switch equipments operative while another individual group equipment is maintained inoperative.

23. In a telephone system, a series oflines divided into groups, automatic switches for each group for connecting lines, ringing means for signaling when the connection is made, said means comprising electromagnetic equipment common to sald groups, equipment individual to sald groups and equipment individual to each switch in each group, said common equipment provided with means for rendering. one individual group equipment and its associated switch equipments operative while another individual group equipment is maintained inoperative.

24. In a telephone system, a series of lines divided into groups, automatic switches for each group for connecting lines, ringing means for signaling when the connection is made, said means comprising equipment common to said groups, electromagnetic equipment individual to said groups and equipment individual. to each switch in each group, said common equipment provided with means for rendering one individual group equipment and its associated switch equipments operative while another individual group equipment is maintained inoperative.

25. In a telephone system, a series of lines divided into groups, automatic switches for each group for connecting lines, ringing means for signaling when the connection is made, said means comprising equipment common to said groups, equipment individual to said groups and electromagnetic equipment individual to each switch in each group, said common equipment provided with means for rendering one individual group equipment and its associated switch equipments operative while another individual group equipment is maintained inoperative.

26. In a telephone system, a series oflines divided into groups, automatic switches for each group for connecting lines, ringing means for signaling when the connection is made, said means comprising electromag netic equipment common to said groups, electromagnetic equipment individual to said groups and electromagnetic equipment individual to each switch in each group, said common equipment provided with means for rendering one individual group equipment and its associated switch equipments operative While another individual group equipment is maintained inoperative.

27. In a telephone system, a series of lines divided into groups, automatic progressively movable switches for each group for.

connecting lines, a circuit controller, ringing means for signaling when the connection is made, said means comprlsmg equipment common to said groups, equipment individual to said groups and equipment individual to each switch in each group, said common equipment through the medium of said circuit controller for rendering one individual group equipment and its associated switch equipments operative while another individual group equipment is maintained inoperative.

28. In a telephone system, a series of lines divided into groups, automatic progressively movable switches for each group for connecting lines, a circuit controller, ringing means for signaling when the connection is made, said means comprising equipment common to said groups, equipment individual to said groups and equipment individual to each switch in each group, said common equipment controlling the individual group equipment and the individual switch equipment through the medium of said circuit controller, said'circuit controller having a bank with a series of contacts, ofie for each group, and a wiper for moving over said contacts to render one individual group equipment operative at a time.

29. In a telephone system, a series of lines divided into groups, means for each group for connecting lines, a circuit controller, ringing means for signaling when the connection is made, said means comprising equipment common to said groups and individual to said groups, said common equipment controlling said, individual equipment through the medium of said circuit c0ntroller, said circuit controller having a bank with a series of contacts, one for each group, and a wiper for moving over said contacts, said equipments being all automatic.

30. In a telephone system, a series of lines divided into groups, automatic switches for each group for connecting lines, ringii'lg means for signaling when the connection is made, said means comprising equipment common to said groups, equipment individual to said groups and equipment individual to each switch in each group, said common equipment controlling the individual group equipment and the individual switch equipment, said equipments being all automatic.

31. In a telephone system, a series of lines divided into groups, automatic switches for each group for connecting lines, ringing means for signaling when the connection is made, said means comprising electromagnetic equipment common to said groups, equipment individual to said groups and equipment individual to each switch In each group, said common equipment controlling the individual group equipment and the 111- dividual switch equipment, said equipments being all automatic.

In a telephone system, a series of lines divided into groups, automatic switches for each group for connecting lines, ringing means for signaling when the connection is made, said means comprising equipment common to said groups, electromagnetic equipment individual to said groups and equipment individual to each swltch in each group, said common equ pment controlling the individual group equipment and the mdividual switch equipment, said equipments being all automatic.

In a telephone system, a series of lines divided into roups, automatic switches for each group or connecting llnes, ringing means for signaling when the connection is;

made, saidmeans comprising equipment common to said groups, equipment individual to said groups and electromagnetic equip-- ment individual to each switch in each group, said common equipment controlling the individual group equipment and the individual switch equipment, said equipments being all automatic.

' 34. In a telephone system, a series of lines divided into grou s, automatic switches for each group for. connecting lines, ringing means for signaling when the connection is made, said means comprising electromagnetic equipment common to said groups, electromagnetic equipment individual to said groups and electromagnetic equipment individual to each switch in each group, said common equipment controlling the individual group equipment and the individual switch equipment, said equipments being all automatic.

3:). In a telephone system, a series of lines divided into groups, automatic progressively movable switches for each group for connecting lines, a circuit controller, ringing means forsignaling when the connection is made, said means comprising equipment common to said groups, equipment individual to said groupsand equipments individual to each switch in each group, said common equipment controlling the individual group equipment and the individual switch equipment through the medium of said cireuitcontroller, said equipments being all automatic.

3(3. In a telephone system, a series of lines divided into groups, automatic progressively movable switches for each group for connecting lines, a circuit controller, ringing means for signaling when the connection is made, said means comprising equipmentcommon to said groups, equipment individual to said groups and equipment individual to each switch in each group, said common equipmentcontrolling the individual group equipment and the individual switch equipment through the medium of said circuit controller, said circuit controller having a bank with a series ofcontacts, one for each group, and a wiper for moving over said contacts, said equipments being all automatic.

37. In a telephone system, a series of lines divided into groups, automatic switches for each group for connecting lines, ringing means for signaling when the connection is made, said means comprising equipment common to said groups, equipment individual to said groups and equipment individual to each switch in each group, said common equipment provided with means for means for signaling when the connection is made, said means comprising electromag- 1161110 equipment common to said groups,

equipment individual to said groups and equipment individual to each switch in each group, said common equipment provided with means for rendering oneindividual group equipment and its associated"switch equipments operative while another individual group equipment is maintained inoperative, said equipments being all automatic.

39. In a telephone system, a series oflines divided into groups, automatic switches for each group for connecting lines, ringing means for signaling when the connection is made, said means comprising equipment common to said groups, electromagnetic equipment individual to said groups and equipment individual to each switch in each group, said common equipment provided 'With means for rendering one individual group equipment and its associated switch equipments operative while another individual group equipment, is maintained inoperative, said equipments being all automatic.

40. In a telephone system, a series of lines divided into groups, automatic switches for each group for connecting lines, ringing means'for signaling when the connection is made, said means comprising equipment common to said groups, equipment individual to said groups and electromagnetic equipment individual to each switch in each group, said common equipment provided with means for rendering one individual group .equipment'and its associated switch equipments operative while another indi- --vidual group equipment is maintained inmatic.

41. In a telephone system, a series of lines divided into group automatic switches for g ringing means for signaling when the connection is made, said means comprising electromagnetic equipment common to said groups, electromagnetic equipment individual to said groups and electromagnetic equipment individual to each switch in each group, said common equipment provided with means for rendering one individualgroup equipment and its associated switch equipments operaoperative, said equipments being all auto tive while another individual group equipment is maintained inoperative, said equipments being all automatic.

42. In a telephone system, a series of lines divided into groups, automatic progressively movable switches for each group for connecting lines, a circuit controller, ringing means for signaling when the connection is made, said means comprising equipment common to said groups, equipment individual to said groups and equipment individual to each switch in each group, said common equipment through the medium of said circuit controller for rendering one individual group equipment and its associated switch equipments operative while another individual group equipment is maintained inoperative, said equipments being all automatic.

43. In a telephone system, a series of lines divided into groups, automatic progressively movable switches for each group for connecting lines, a circuit controller, ringing means for signaling when the connection is made, said means comprising equipment common to said groups, equipment individual to said groups and equipment individual to each switch in each group, said common equipment controlling the individual group equipment and the individual switch equipment through the medium of said circuit controller, said circuit controller having a bank with a series of conta cts, one for each group, and a wiper for moving over said contacts to render one individual group equipment operative at a time, said equipments being all automatic.

44. In a telephone system, a plurality of subscribers lines divided into groups, connectors for each group for connecting a calling and a called line, automatic ringing means comprising equipment common to said groups and equipment individual to each group for ringing the called line, and means in the common equipment for rendering the indi vidual equipments inoperative.

45. In a telephone system, a plurality of subscribers lines, groups of switches ,for connecting a calling and a called line, automatic ringing means comprising equipment common and individual to said groups of switches" for ringing a ca led line, and means in the common equipment for rendering the individual equipment inoperative.

Signed by me at Chicago, Cook county, Illinois, this 18th day of May, 1912.

HERBERT F. OBERGFELL.

Vitnesses:

ARTHUR J. RAY, ALBERT ANDnRsnN.