US1235301A - Measured-service telephone system. - Google Patents

Description

J. ERICKSON. MEASURED SERVICE TELEPHONE SYSTEM;

APPLlCATlON FILED MAR. 30. 1909. RENEWED NOV. 13' I916.

Patented July 81, 1917.

4 SHEETS-SHEET I.

Om\ \M KN llllllllwwll l. ERXCKSON.

MEASURED'SERVICE TELEPHONE SYSTEM.

LED MAR- 30, 1909- RENEWED NOV. 18.196-

Patent-ed July 31, 1917.

4 SHEETS SHEET 2.

APPLlCATlON Fl 1. EFHCKSON. MEASURED SERVICE TELEPHONE SYSTEM. APPLICATION HLED MAR. 30. 1909. RENEWED NOV. 18.1916.

1 235 ,391 Patented July 31, 1917.

4 SHEET$-SHEET 3- mama jmfenim 0)? 21/ 6 vicfi m,

J. ERICKSON.

MEASURED SERVICE TELEPHONE SYSTEM. APPLICATION FILED MAR. 30, 1909. RENEWED NOV. 18, 1916.

LQ35,301 Patented July 31, 1917.

4 SHEETS-SHEET 4.

Jofin grin/gm, I, 1.?

JOHS ERIGKSON, OF CHICAGO-,QILLINOIS;

.ASSIGNOB TO AUTOMATICXELECTBIG COM- MEASUREDsSEBVICE TELEPHONE SYSTEM.

Specification of Letters Patent. Pal-tented Ju1yf31, 1917.

Application filed March 30, 1909, Serial No. 486524;? *RenewedyNovemberAS, 1916.1 ,;Seria1No. 132,206i-= To all whom it may cont/crux Be 1t known thatl, Joan EmcKsoN, .a

citizen of the United States :ofAmerica, and-i resident of Chicago, Cook-county; Illinois have invented a certain new: and useful 1m cation.

My invention relates to; telephone-em change systems in general, but inorea-par-w tlCllltlll to systems in whichthe-callsi-are extended in whole or in part by automatic shown with slight modifications toiadaptjt switches, and especially lo systems lnwhich measured service devices-arc employed at the substations, whereby calling subscrlbers-may:

not converse with called subscribersuntil".

after the successful call is either paidfor or registered at the calling substation-+that21s to say, not until after tollis assessed in somen suitable manner.

lily

measured service system in which the meansat the substation for transmitting aname g :of a well-known type, butmod1fied to'adapt: 30-

pulse or impulses "to the centralstation' are normally short-circuited, whereby the calling subscribers must first remove such shortcircuit before impulses of currenttor operatzing purposes can be transmitted to the. central station, and in whiclrthe-act of removing the said short-circuit, as by operating a push-button or other. S\\'1l,(.'ll,'-f01"Ctlllllng purposes serves also to establish another SllOItCIITHIt around the calling subscribers talking transmitter, thus making it necessary for the subscriber to perform some other act suitable for removing theirs-hortcircuit from around the talking transmitter, as by pushing a button or depositing-a coin,

after he hears the called subscriber answer, and before he can conversewith thelatter.

To these and other useful ends my invention consists in matters hereinafter set forth and claimed.

In the accompanying drawingsiFigure-l shows diagrammatically a subscribers station A equipped with a call registering device F, in a system embodying the principles The line conductors at substation A terminate atthe central office of my inventionin the line switch C; the master switch-Dis provided for operating the plungershafta'of the group of line switches ofwhich C is a member; and at E there 'lS-SllOWIl a first selector switch.

In Fig. 2 there is shown a connector at the substation invention contemplates, therefore, a

switch H foroperating in connection with theline and selector switches of Fig, 1; the

central office ringerv generator is shown at I and a busy-signaling machine atJ;,Jthe

subscribers station A is also equippeclwith i a call register F switch Fig. is a side elevation of the call reg- .ister, and Fig. t is a frontelevation-of the same...

In Fig. 5 the call-.registering device is to operate in connectionwitha coin device,

Fig.1; 1s a front view of FigF SL ,Figs. 1 and 2 taken togethen rep-resent diagrammatically 4 the central :ofiice switch:

.ing apparatus involved Vinl establishing a connection betweentwo subscribers" stations;

A central otiicebattery is shown atB itFig.

2), having itspositive. terminal preferably:

grounded at G.

The central office switching apparatus is it to operate-as a two-wiresystem+thatiis,.

a system in which theoperatingimpulses are transmitted over the; two usualline con-v The subscribers stations, it will be seen, are also somewhat-smodiliedductors in series.

for the same purpose, to operate in a twowire system. and with the central office.

I switches of the twoaviresystem. Snbstacondenser 8, ringer S), andimpulse wheel 10 which has the usual impulse teeth 11. The impulse wheel 10 is secured to the shaft '12, to which shaft there is also secured the dial (not shown). When thedial is turned and thereafter released the impulse teeth 11 engage the cam 18 upon the end of the spring 14, and therebycarry the latteront of engagement with thespring 15. Upon the switch-hook 3 there is a ca m 16 which, when the hook rises, carries the spring 17 out of engagement with the spring 18 and into contact with thesprings 19 and 20.; Also secured to the shatt'lz is the normal arm 21 which eontrolsthe springs22 and 23.-

The line switch (7 and the. master switch I) are of the general type described in English Patent No. 26,301 of 190G, id e-stem lL'Zcct r'iciu-n of January f 25, 1908, Chicago,

0,. and the lineconductors, A terminate in the? 111161 Illinois, and the American Telephone Jam'- vmZ of Chicago, Illinois, dated June 6, 1903. The circuit connections, however, are Inodified to adaptthe switches to operate in connection with the two-wire system.

The first selector switch E is of the general type shown in United States Letters Patent No. 815,321, issued March 13, 1906, to "Keith, Erickson and Erickson. As shown in Fig. 1, the bridge-cut-oii' relay and the normal conductors have been omitted and the circuits otherwise changed to operate conjointly with the line switch C. The connector switch H shown in Fig. is of the general type of connector switch shown in United States Letters Patent No. issued March 13, 1906, to Keith, Erickson and Erickson. Like the line switch C and the first selector switch E it is also arranged to operate in a system in which the central office apparatus is controlled by impulses delivered over two sides of the calling line in series.

The call registering device F (Fig. 3) comprises a meter 21 mounted upon a bracket The push-button 26 controls a group of springs, and the button 27 controls the operation of the meter 24 and also the button 26, as will be explained. The polariZed relay 28 controls an armature 29. The armature 29 is maintained in normal position by a spring 30, and upon opposite ends of the armature 29 are the fingers 31 and 3l"-. The finger 31 at the right'ot the armature is adapted to be engaged by the lower part 32 of the member 33, and the finger 31 on the left of the armature 29 is adapted to be engaged by the end 3 1 of the member 35. The locking dog 36 is also provided for locking the member in normal position, as shown. \Vhen the button 26 is pressed the member 33 is moved about the pivot screw 37 and the bottom part or end 32 is carried into engagement with the finger 31*of the armature 29. lVhen this occurs the member 33 engages the top part 38 of the locking dog 36. The locking dog is then moved about the pivot screw 39 until the notched end 40 is raised to the position indicated by dotted lines and out of engagement with the member 35. hen the button 26 is thus pressed the arm 11 moves to the right, permitting the springs 42 and 43, and 44 and $5 to disengage, and the springs 46 and -17 are'carried into contact with th spring 45. The finger 31 on the armature 29 engages the tooth sections of the end 32 nearestv the heel and maintains the button 26 in its operated position. The button 27, when pressed, moves the member about the pivot screw 48, thereby carrying the end 34: into engagement with the finger 31 on the left end of th armature 29. As the end 34 presses against the finger 31 the armature 29 is moved from its normal position, thus moving the finger 31 out of engagement with the end 32 of the member 33, and the button 26 is restored to normal position due to the tension spring 49. Also, when the button 27 is released the member moves about the pivot screw 48 and the link 50 operates the meter 21 one step. The push-button 27, when released. always restores to normal position, owing to the tension in the spring 51. After the button 27 and the member 35 are fully restored the end 40 of the locking dog 36 again falls to normal position, thereby locking the member 35. The spring 52 is provided for restoring the locking dog 36 and also for moving the locking dog 53 about the pivot screw 54.

The object of the pawl member is to prevent a fraudulent operatii'in of the meter mechanism-that is, after a call has been made and the meter mechanism operated the pawl 53 is arranged to lock the member 33, which is controlled by the button 26, in normal position until the member 35, which is controlled by the button 27, is fully restored. After the button 26 has been pressed and a connection established, then befor the calling subscriber may be heard by the called subscriber the button 27 must be pressed in order that the member 33 and springs controlled by the arm 11 may return to normal position. Suppose, however, that when the button 27 is pressed it, isretained in its depressed position; the subscriber intending to press the button 26 and mak another call in the meantime retaining the button 27 depressed, so that it will not be necessary to operate the meter and thus register the second call. This is prevented, for when the button 27 is pressed the finger 24 on the member passes beneath the end 40, since the mechanism is now in its operated position indicated by the dotted lines. The pawl member53 is also raised to the position indicated by dotted lines. Now, when the end 34 engages the finger 31 and operates the armature 29, so that the end 32 is released from the finger 31, the member 33 restores to normal position against the stop 25, where the finger 26 of the member falls behind a tooth of the pawl member 53 and is thereby retained locked in its normal position until the member 35 fully restores to normal and the finger 24 passes from behind the end 40 and permits the-latter to restore, whereby the pawl is also restored and the member 33 unlocked. When the mechanism thus restores to normal it will be seen that the button 27 and member are locked in normal position by the end 40 falling in front of the finger'24.

The pay station or measured service device shown in Fig. 5 is merely a modified form of the meter mechanism shown in Fig. 3that is, instead of having two push-buttons 26 and 27 as in Fig. 3, one push-button 55 is locked in its operated position bythe M1113")?vv which is pivoted at 59. The buttonton'restoring the mechanism is omitted, and .Inats stead the coin-controlling mechanism is pros vided for restoring the push-button 55 H); normal position. \Vhen a coin Vie-dropped in the slot it rollsdown the chute'and-eomes in contact with thearm58. The-Weight-of i i all idle plungers that are in hickedengagethe coin is sutlicient'to"movethearrm:and'the arm 57 is moved "about the pivot point -59 thereby unlocking the member-56 and per mitt-ing the button "55 to return to north position. The armature 57* 'of-"the 'elec-tr magnet carries arm 57 from the arm 56. Thus it wilt'be seen that the coin chute and'the'armw58 merely take the place of thejpush button-2T1 as #220. To call'the number-"220 the subscriber at substation'A renioves-the-reeeiver from the switch-hook and operates U theca-l in; device for each digit in the wellkHOW manner. 'hen the receiver is I'BIIIOVGJtlEZEEO- the switch-hook, however, and the: spring is carried out otengagementnuththe spring 18 and thrustinto contact" with-the sprinfis,

19 and 20, an energizing circuit is esta lished through the tripmagnet tilhf theline switch C. Thetrip magnet thereupon-ene-i gizes and operates the phmgertov seize an idle trunk terminal leadingt'o the selector switch E. Theselector'switch E then operates in response to the first digit'to setect'an idle trunk line leading'to theconneoto switch H (Fig.2). The connector switchtH is in turn operated by the impulses-tenths last two digits to establish connection with the terminals of the desiredline. When the receiver is removed from the switch hook and the sprin gs17 19 andQO-engage, the-energizing circuit through the: trip 1 magnet 61 extends from ground G toithesprings'fiti and 67. line conductor" (itibthroughthie in pulse springs15 and 14, transmitter 7, p-ri- -f niary' winding 5,- springs20.'19*and 171 com ductor 65, springs 42 andi43--ot the meter-F to-the line eon(h-'1ctor'64,'through'the springs" 62 and 63, trip magnet61,springs.69rand an arm 57 whichisadap ted, to engage the arm 57 to disengagethe said;

at substation AP-(Fig; the, number of whichlatter is arbitrarilychosen any :13 and to "ground The-trip magnet s'thereupon energizes and Z- attracts its armature, permitting the plunger arm to thrust the pl u nger'i ntt an idleebanlctemnin a]. When the-plunger enters-the bank terminal the relay 72* energizes-andoperatesto close the springs 73 and 74 into contact; whereby an energizing circuit 1St3SiLtthi1Sl10tl through the motor magnet 75 ot .the master switch D.

"1 he motor magnet- "then operates "to-advance mentgwith the plunger sha-litmpposite the ext idle bank terminal-similar :to ithe-0ne nstengagedr The circuit through the motor magnet" relay 72 extends from ground 3G? Qthmughthe' motorvmagnetirelay :72,-common 1 segment 76- 'of the 1m asterswitch bank, Wiper 77,.rindividualsegment 78, -rconductor "79, bank" springs "80 I and 81, through the-winding of the release magnet 82 :and to the :battery lead .71, 'etc. Then-slay 7 2 ZtlIGICUPOIIGIIGY- ines and laces'thesprings-Rand 74 in contact, whereby :a circuitais closed through the. .motormagnet 7 5 'extending from .ground (t -"through the magnet 75, interrupter s rings 83 I and 84. springs '74 :and 73and to g. .t'e battery lead I71 5 etc. Th otor: magnet upon energizing; .iattracts its armature 1 and 1 the 'pawl 86: engages a tooth of the ratchet .wheel 87'- and l-moves the latter one step When thisoccurs-the spring "89 engages the spring; 88 (hearing. in *mind that the spring 189, prioruto t-his-o ieratiom'rests in"; a, notch of the toothed wheel "),;and when the ratchetwvheel S7 is given one step thespring 89-slides to the top Oftthe next 0th and engagesthespringfS-S. T he enagement of thesetwo springs provides a new energizing circuit for the =motor mag t "1'5, said circuit extendingthrough "ithe springs 88' and "89 to the battery-lead l 71 .in-

stead of through the-springs '73 "andfe.

--'urtherm ore. the Ame-ton mag-neg when enerw ized se )arates' the interru tor-s iri'n' 's 83 11d 84, therebybreakingrits own cireuitfinia manner similar to wh It'll a L buzzer operates.

The motor magnet '75 continues to -operate in this manner.aslongiasthesprings 88-and 9 remain in :engzrgement. lVhen thewnerrt succeeding notelr on :the wheel 90 atli'an ces tarfenough the springffifi disengages from the spring 88, thereby "opening the' 'energizr Zing circuit :for the inotor-magnet. By'the time this last notch disengages the springs 88 and 89, the master switch wiper '77 has passed from the first: contact 78"to the second contact 91. Suppose. however, that when the wiper 77 engages the individual segment 91 thereis a guartlihg potential 1 present. In that event an energizing circuit is closed through the motor": magnet relay 72-, said oi rc-uit extending .from the contact through: tl1eW1}-)8I"7 7 ,1 commonsegment 76 'of themaster sivitchbanlg through the windat r 1,235,301

ing of the relay 72 to ground, as previously traced. The motor magnet relay again energizes and closes the circuit for the motor magnet 75. The motor magnet operates as before, and the wiper 77 is carried to the next contact and the next notch of the wheel 90 separates the springs 88 and 89. This operation continues as long as the wiper 77 continues to find contact segments with protect ing potentials. Of course, it will be understood that when the motor magnet 75 thus operates the plunger shaft end of the plungers that are in locking engagenient with the said shaft are moved to av new position opposite an idle bank terminal similar to the one engaged by the line switch C. At the instant that the plunger enters the bank the following springs are pressed into contact: 92 and 93, 94: and 95, 96 and 97, and 81 and S0. The engagement of the springs 92 and 93 and 96 and 97 extends the calling subscriber's line conductors 6-1 and 06 to the trunk conductors 98 and 99, which latter terminate in the first selector switch E. The engagement of the bank springs 94 and 95 provides an energizing circuit for the bridge cut-oil relay 100 extending from ground G through the bank springs 94 and 95, bridgecut-oil relay 100 to the battery lead 71, thence through battery '13 to ground G. The bridge-cut-oii relay thereupon operates to separate the springs 02 and 67 from the springs 63 and 68, respectively. By this operation the trip magnet 61 is disconnected from the subscribers line conductors (i4 and 60. The engagei'nent of the springs 94 and 95 also provides a guarding potential over the private normal conductor 101 to the connector bank contact corresponding to the line of substation A, thereby protecting the calling line against seizure by some calling subscriber. Furthermore, when the subscribefs line conductors 6 and 60 are thus extended to the trunk conductors 98 and 99, an energizing circuit is established through the line relay 102 of the selector switch E. The circuit through this relay extends from ground G through the winding 108, side switch wiper 104:, conductor 99, bank springs 97 and 96, line conductor 60, through the substation impulse springs 15 and 14, transmitter 7, primary winding 5, springs 20, 19 and 17, conductor 65, springs 43 and 42 to the line conductor 6%, bank springs 92 and 93, trunk conductor 98, side switch wiper 105. through the winding 100 to the battery lead 71, thence through battery 13 to ground G. The relay 102 thereupon energizes and operates to carry the spring 107 from engagement with the spring 108 and into engagement with the spring 109, thereby providing an energizing, circuit for the slow-acting release relay 110, which in turn operates to carry the spring 111 out of contact with the spring 112 and,

into engagement with the spring 113.

The foregoing operation of the central office mechanism occurs when the calling subscriber removes the receiver from the switch-hook and bridges the primary circuit across the line conductor-s64: and 66. The normal position of the meter mechanism and circuit is shown at F in Fig. ,2. .It will be seen that the impulse springs are short-circuited by the springs of the meter mechanism, and before any impulses can be sent to the line conductors 04 and 65 the shortcircuit produced by the meter springs must be removed. The calling subscriber, therefore, presses the button 20 and operates the s} )rings 12, 43, 44, 45, +0 and 4:7 to the position shown at F in Fig. 1; the springs 42 and 43 are separated thereby breaking the short circuit around relay 2S and resistance 114. The energizing circuit for the line relay 102, however, is maintained through the resistance 114 and the polarized relay 28 in multiple. The circuit through the resistance 11 1 extends from the conductor 64 through the winding 11%, conductor 115, through the springs 19 and 20, and through the primary winding 5, transmitter 7 and impulse springs 14 and 15 to the line conductor 66. The disengagement of the springs 4st and 15 removes the short-circuit or shunt from the impulse springs 14: and 15, and when the dial returns to normal position for the first digit 2 the impulse springs 1t and 15 are separated twice, thereby breaking the energizing circuit through the line relay 102 twice. The line relay 102, upon deiinergiziug, permits the spring 107 to engage the spring 108, thereby breaking the circuit through the release relay 110. As previ eusly stated, the relay 110 is slow-acting that is, slow to deiinergize, and when its energizing circuit is momentarily broken during the transmission of impulses the said relay does not deenergize, but remains in an operated position with the springs 111 and 113 in contact. Thus when the spring 107 engages the spring 108 two impulses are trans mitted to the vertical magnet 116 extending from ground G through the springs 107 and 108, springs 111 and 113, private magnet relay 117, vertical magnet 110, side switch wiper 117 to the battery lead 71. thence through battery 13 to ground G. Two impulses being delivered, the vertical magnet 116 is thereby energized twice, and the shaft wipers are given two vertical steps in the well-known manner. It is thus seen that the pri 'ate magnet relay 117 is included in the energizing circuit of the vertical magnet 1.10. This relay energizes on the first impulse, and being a slow-acting relay it maintains its armature attracted until all of the impulses are of the digit transmitted. When the relay 117 energizes, the springs 118 and 119 are closed in contact and an energizing circuit is established through the private magnet 120 extending fromz ground G through the'springs 118 and 119, private magnet 120 to thebattery'dead 71, thence through battery B to ground G. The pri vate magnet relay 117 deenergizesafter-the last vertical impulse, since' this energizing circuit is no longer maintained after the springs 107 and 108 disengage; hence the said relay deenergizes, permitting thesprings 118 and 119 to disengage,whereby theenergizing circuit for'the private-magnet 1201s in turn broken. The private'magn'et now deenergizes and permits the side'switch to pass fromtirst to second position, thus'p'eriuitting the side switch wipers 117*:and 121 to engage the contact points 122 and'123", respectively. The closure otcontact-between the side switch wiper-117 and'the contactpoint 122 sets'up'an energizing circuit for the rotary magnet 123. lThis'energizing circuit extends from ground G through the interrupter--' springs 121, rotary "magnet 123, contact point 122, side switch wiper 117 to the battery lead 7 1. thence through-battery P to ground G. The said rotarymagnet then operates to rotatethe-shaft wipers 125, 126 and 127 of the selector switch E into engagement with the first-contact -of' the second level of the selector"banks, from which contactit isassumed the trunk line conductors 128, 129 and 130 lead-to the connector switch H (Fig; "I'f'the first trunk line is busy, however, and the wipers have to pass over busy contacts, then-as soon as the private wiper 127 engages the'first'priyate bank contact the private magnet 120 again energizes, locking'ithe side switch in second position. The energizing circuit for the said private-magnet extends from the grounded terminal G of the battery B through an occupying switch'(not shown), through the private wiper 127, thence tl'irough the conductor 131, side switch wiper 121, contact point 123*, through the private magnet 120 to the battery lead 71, thence through battery B to-ground G. The private magnet 120, upon thus becoming energized, locks the side swit'ch'wipcr117 in engagement with the contact point 122, whereby the rotary magnet 123 will beenergized step by step, and the Wipers 'are'ca'rried beyond the last busytrn'nk line. At the instant that the private wiper leaves the last busy contact point the energizing circuit through the private magn'et120 is'destroyed, and as a resultthe selector side switch passes to' third position. Ifthere are no busy trunklinesthe privatema'gnet 120 releases the side switch to'third position as soon as the wipersare carried into engagement withthefirst trunk line. 'As soon as the side switch passes tothird position, as

stated. the trunk line conductors98 and '99 are extended to theuconductors 1'28'a'nd 129 which, in this Ct1SQ,lt isassumed lead -to the into contact witli 'the spring 145. 'The enconnector switchH (Fig.2). 3 The extending ofthe' line occurs,'0f*course, as soon as the side switclrwipers 104 'and"105 engage the contact points132 and 133, respectively.

- \Vhen'the trunk,line-i's thus' extended to the connector switch :H' "an energizing circuit is established through-"the line relay 13st in the same manner in -which the'energizing circuit was established throu'ghthe'line relay 102 ofthe SGlGCtOP'SWitCh E. *Therelay 134, upon energizing, operates to shift the spring 135-out of engagement with the spring 136 andinto'contactwith' the spring 137. \Vhen the springs f and -137 engage, an energizing circuitis' established "through the slow-acting'relay- 138. "Thiscircuit extends from ground G through the springs I 135 and 137, back-bridge relay springs 139 and 110, conductor 141 'through'therelay 138*to the battery lead 71, thence through battery Bto ground G. "The relay 138, upon energizing, operates to "close the springs 141 and 142 in 'co'n'tact and also to shift the spring 1'43 'tr'onnthe spring'144 gagementof 'the sprin'gs l ll and 142Aprovides a guarding-=potentialto the p'riva'te bank contact corresponding ito the "trunk conductors "128' and 129. 'T-his potentia'jlextends from ground t'ir to "the "side switch uiper 146, springs 'l' tl and 142,"'conductor 130 to the private bank 'cont'act 'engaged by the'private wiper 127. Furthermore, a new energizing circuit is provided 'for the release relay 1'10 ofthe selectorswitch This circuit extends froin'fgr'oi'ind G "at the connector switclrHto the p'rivhtewiper 127, as explained, through the "conductor 131, side switch 'wiper 121,-contact point 117, conductor 148 to the' release'relay; 110, thence to the battery lead 71, and through battery B to ground'G." This-primaryoperation of the relays 13 1 and 138 ot the "connector switch H occurs at the instant that the side switch wipers'101' and 105'- of the selector switch E pass to"third'positionand extend the subscribers line conductorshG and 64: to the trunk conductors 120 and 128.

The operation-of the'dial for thel'ast two digits atl'ects'theconnector s'\v'itcl1,1and when I the dial is *operated for the second digit 2 the impulsespring '14 is twi'ce carried out of engagement 'with the impulse'spri'ng 15, thereby momentarily (leiine'rgizin'g' the line relay 134 of the connectorswitch twice. The spring 135thereby engages the spring 136 twice, thus sending-two impulses to'the' verticalniagnet 149' from"g'round G through the springs 135 and 136, springs 1-13 and 145, private magnet relay 150, "vertical mag-- net 1 19, side switch wiper 151 to the battery in an operated position until all of the vertical impulses are sent. The relay 138 is slow-acting and it also remains in its operated position. The vertical magnet 149, upon being energizechoperates one step at a time to carry the shaft wipers 152, 153 and 151 two steps to a point opposite the second level. The private magnet relay 150, upon energizin operates to carry the spring 155 out of engagement with the spring 156 and into contact with the spring 157. When the springs 155 and 157 engage, an energizing circuit is established through the private magnet 158 from ground G to the springs 155 and 157 private magnet 158 to the battery lead 71. thence through ba'ttery B to ground G. The relay 150, being a slow-acting relay, remains in an operated position while the vertical impulses are being sent; but after all of the impulses are delivered, and the line relay 131 returns to its operative position, the circuit through the relay 150 becomes broken, thus permitting the spring 155 to return to normal position. When the springs 155 and 157 disengage, the circuit through the private magnet 158 becomes broken, thereby allowing the said magnet to deenergize, whereby the side switch passes from first to second position.

The calling subscriber now operates the calling device for the last digit 0, thereby transmitting ten impulses and operating the line relay 131 ten times. Each time that the line relay springs 135 and 136 engage, an energizing circuit is established through the rotary magnet 159 from ground G through the springs 135 and 136, springs 113 and 115, private magnet relay 150, springs 160 and 161, through the winding of the rotary magnet 159. side switch wiper 151 to the battery lead 71, thence through battery ll to ground G. Again the private magnet relay 150 energizes, as in the previous case, remaining so until all of the impulses are transmitted, thereby retaining the private magnet also energized. The rotary magnet 159 operates to rotate the shaft wipers into engagement with the terminals of the desired line If this line is busy at the time. the connector will be locked in second position, and the calling subscriber is given the busy-signal, thus making it impossible to extend the calling line into connection with the called line. As soon as the line relay 134 ceases to operate for the last digit, and if the called line is idle, the private magnet relay 150 det nergizes, as heretofore explained, permitting, in this instance, the side switch to trip to third position. lVhen the side switch wiper 162 cugages the contact point 163 a guarding potential is completed at the private \viper 15% for protecting the seized line from interference while the connection is established.

This guarding potential extends from ground G through the side switch wiper 162, springs 161 and 165 to the shaft wiper 154, which latter engages the private bank contact corresponding tothe called line. Not only does this guarding potential preventother connectors from calling in on the same line over multiples of the normal conductors 166, 167 and 168, but it also pro-- vides an energizing circuit for the bridgecut-oli relay 169. This circuit extends from ground G to the private wiper 154, as explained, thenthrough the bridge-cut-ofi' relay 169 to the battery lead 71, thence through battery B to ground G. The bridge-cutoff relay, upon energizing, shifts the springs 170 and 171 out of contact with the springs 172 and 173, respectively, whereby the switch C is prevented from operating, when the called subscriber removes his receiver from the switch-hook. lVhen the side switch wiper 1&6 passes to third position, ground G is disconnected from the private trunk conductor 130, but a new guarding potential is, however, provided from ground G as follows: From ground G through the springs 135 and 137, through the springs 139 and 140, conductor 141 side switch wiper 146, springs 141 and 142 to the conductor 130. When the side switch wiper 151 engages its third-position contact point an energizing circuit is established through the ringer relay 174. said circuit extending from ground G through the ii'iterrupter 175, springs 176 and 177. ringer relay 174-, conductor 178, side switch wiper 151 to the battery lead. 7.1, thence through battery B to ground G. The relay 17% therefore energizes intermitteutly and presses thesprings 181 and 180 into contact with the springs 179 and 182 respectively, whereby the terminals of the ringer generator I are bridged across the line conductors 183 and 184 of the called substation. When the called subscriber answers an energizing circuit is established through the back-bridge relay 185 extending from ground G through the winding 186, through the springs 187 and 189, side switch wiper 188, shaft wiper 153, normal conductor 167, line conductor 184, impulse springs 189, transmitter 190, primary Winding 191. springs 192 (which are in engagement after the called subscriber answers). conductor 193, meter springs 19% and 195 to the line conductor 183. normal conductor 166, shaft wiper 152. side switch wiper 196. ringer relay springs 181 and 197. winding 198 of the relay 1545 to the battery lead 71. thence through battery ll to ground G. The relay 1H5 thereupon energizes and operates to separate the springs 176 and 177. thus breaking the energizing circuit for the ringer relay 174. The s 'irings 139 and 140 are also separated, but their operation merely introduces the low resistance coil 199 in a guarding potential circuit: The twosubstations A and A are now connected over a circuit shown by the heavy-linevconductors in Figs. 1 and 2. The calling subscriber may hear the called subscriber answer, but before the calling subscriber may behea rd by the called subscriberthe push-button 27 of the meter F must be pressed-,thereby restoring the meter to normal position and removing the short-circuit otthe-transmitter 7 when the springs 45, -16 and l7'disenga e.

\Vhen the push-button 27 ispressed tie member 35 is moved about-the pivot: screw 48 and the end 2-H raises the-end 31 of! the armature 2%) a trifle. \Vheirthis orcursthe finger 31 is carried out: of engagementwith the end 32 ot' the member 33'. The pushbutton 26 andthe arm 41, beingv released, restore to normal position. \Vhenthe arm 11 restores tonormal, the springs 421and'43,

and .ifit and 45 are pressed into contaet,.and

the springs-46 and 47 are separated. The engagement of the springs 42 and*'13completes the subscribers talking; circuit' and the disengagement of; the springs-45,.46and l7 removes the short-circuit of the transmitter 7. The subscriber at station A may now talk to the subscriber atsubstation A1. When the button 27 is released, as. explained, the link 50is given a forward motion, and this in turnoperates to move the-meter 24. one step, whereby the callis registered.

The release of the central office switching apparatusoccurs whenthe calling. subscriber restores the receiver: 2. to-thc switchhook I), thereby opening. the-energizing. circuit for the linerelay 134, when the springs 17. 19 and 20 disengage. The relays 13. 1 and 138 thereupon restore tonormal position, closing an energizing circuit for the release magnet 200 of the connector switch H. This circuit extends fronrground (1:

through the springs 135 and 136, springs- 143 and 144'. normal spring 201 and contact point 202- through the release magnet 200 to the battery lead-71', thence through battery B to ground (in. The release magnet energizes and operates-to restore-the con-- nector switch shaft and side switch to normal position. When I the springs-141 and 142 of the relay 138' disengage, the energizing circuit for the release relay 1100f." the selector switch E is broken. The release relay 110 also deenergizes and. permits the springs 111 and 1.12 toengage, thereby in turn closing. an energizing; circuitrthrough the release magnet 203, said circuit extending, from ground (l through theasprings 107 and 108-, springs-111anda112, release magnet 203. contact: point 204. normal spring 205 to the battery lead. 71, thence th rough battery B to I ground G. The/magnet 203 thereupon energizes-and: closes the springs 206 and2O71incontact, whiclrprovides anenergizing circuiti for; the: release.

magnet 82. of the lineswitcli hen. the switch shaft of? the connector; switch H restores to normal position the: normal arm 208 carriesthe spring; 201. out of. engagement with. the contact point 202, whereby the circuit for thex- 1'elease.magnet 200*becomes broken. Thexsw-itchshaftot the selector switch E, upon restoring; also operates to carry the spring205' out. of engage ment with; the contact point 2.Ol,.vin,.turnv a subscriber may: operatehissubstation and meter to establish:connection-zwith another line. Suppose, however, thatthecall isnot successful-that is, assume thatv the. called.

subscriber does at not: answer,-,or thatztlie desired lineis busy. In; thataeventthe 1 calling subscriber does-not: press. the button. 2-7 to: registerthe call, but merely returnsthe re ceiver. to the switch-hook and leaves themeter mechanism in ope-rated position- Now,

if some other subscribercalls the substation A whilethe metcr-lifis in its operated position, the connection will extend over. the line conductors-0tthe calling"subscriber to the normal-conductors211and 21201. the line switchG. Ringingrurrent is therefore sent from the cmuluctor.212atothe line conductor (it; throughthecondenscrfi', ringerD,

springs 18' andv 17 comluctor (35,- winding of the polarized .relay 28 of the meter.mechanism- F to the lineseonductor 6%, normal conductor211, back to the/ringer generator.

The )olarized relay. bein -included. in the circuit with'theringer 9, operativcly energizes and attracts itsarmature 29 -to engage the core of thewrelayi, andasince the. relay is polarized the armature is attracted one way only, and the'finger- 31 is carried: out: of engagement. with the end 32* of the member The member: beingrelieved. responds to thetensionofthe springl) and 'restores.v

the push-button 2(' :and:tlie.arm 41 to normal position. v The springs 42,43, 44,45, 46'

and4t7 alsorestore to normal position, as shown at F in Fig.2: Thus it will'be seen that the operationiofz thepolarized relay 28 restores the meter mechanism to-normal position the same as when. the button 27 is pressed. In thiscase howcver. themcter is not operated},one step and the previous call. which was not; successful, is notre corded.

It will be evident from the foregoing that each subscribers line may be equipped with the same apparatus. For example, the subscribcrs line shown in Fig. 1 is equipped with a telephone A, the call register if and the line switch C, and the subscribefls line shown in Fig. 2 is likewise equipped with the telephone A the call register F and the line switch C being respectively the same as thesimilar devices in Fig. 1.

In connection with the registering device in Fig. 3, it will be seen that the locking member which is controlled by the pushbutton 26, is provided at its terminal with two teeth. The use of one of these teeth, the one next the heel, has already been described. The objectof the tooth next the toe is to prevent a fraudulent operation of the device, as follows: By the use of this extra tooth it is impossible for anyone to press the button 26 sufiiciently to operate the springs 42 to 47, inclusive. without locking the member 33, because if the member 33 is not caught in the tooth next the heel it is bound to be caught by the next tooth, the one next the toe, and in either case it becomes necessary to operate the button 27 before talking connection can be had.

The operation of the meter being fully described for the meter shown in Fig. 3, the operation of the modified form of the meter shown in Fig. 5 is obvious. The subscriber. in operating the meter in Fig. 5, must first press the button 55 for the same reason that he had to press the button 26 in F ig. 3. Then, after the called subscriber answers, he deposits a coin, as indicated, which, in falling, throws the lever 58 to the right, thereby performing the same function that the button 27 does in regard to the unlocking operation of the button previously pressed. Of course, it the subscriber gets the busy signal he hangs up his receiver without depositing a coin. The mechanism in the apparatus of Fig. 5 remains operated as in the case of the apparatus of Fig. 3. Therefore, in making a subsequent call it is not necessary to press the button because this button is already operated. If the subscriber should be called the polarized magnet acts exactly as did the polarized magnet of the previous apparatus.

From the foregoing it will be seen that before the calling subscriber can send current to the central station for calling purposes he must first remove the short-circuit from around the impulse-transmitting means, as by operating a push-button. This, it will be seen, enables him to transmit the calling current to the central station, and at the same time establishes a short-circuit around the transmitter. This does not prevent him from using his receiver, and when he hears the called subscriber answer he must then remove the short-circuit from around the transmitter. This he may do by any suitvital parts of the substation are successively rendered ino 'ierative, and successively restored to operative condition. \Vhcn one element is rendered operative the element the subscriber will use next is rendered inoperative. Hence, and until all of the conditions or restrictions placed on the service are complied with, the calling subscriber cannot converse with the called subscriber.

What I claim as my invention is 1. In a telephone system, a subscribers substation switch for transmitting current to the central station for calling purposes, a short-circuit normally closed around the said switch, a transmitter, a normally open short-circuit around the transmitter, means for simultaneously opening the first shortcircuit and closing the second'before the said switch can be used for calling, and means for opening the second short-circuit when the calling subscriber hears the called subscriber answer. 1

2. In a telephone system, a subscribers impulse-transinitting switch at the central station responsive to said device, a short-circuit around said device, and a measured service device provided with means requiring actuation thereof to open the said short-circuit to render the said device operative for controlling the said automatic switch.

3. In a telephone system, a subscribers substation impulse-transmitting device, an automatic switch at the central station responsive to said device, a short-circuit normally closed around said device, a transmitter, a normally open short-circuit around said transmitter, and a measured service device providing with means for opening the first short-circuit and closing the second, and with means for then opening the sec ond short-circuit.

i. In a telephone system, an automatic switch, a line, means for controlling said switch over the two sides of the line in series to extend a call in the direction of the called subscriber, a normally closed short-circuit rendering said controlling means normally inoperative, a transmitter for the line, a normally open short-circuit around the transmitter, and a measured service device provided with means for open ing the first short-circuit and closing the second, and having means for then opening the second short-circuit to enable the subscriber to use the transmitter.

5. In a telephone system, a subscribers substation apparatus, means for rendering the same inoperative for holding conversation with another subscriber, and means comprising a polarized magnet where-by device, an automatic.

private magnet 120 extending fromz ground G through the'springs 118 and 119, private magnet 120 to thebattery'dead 71, thence through battery B to ground G. The pri vate magnet relay 117 deenergizesafter-the last vertical impulse, since' this energizing circuit is no longer maintained after the springs 107 and 108 disengage; hence the said relay deenergizes, permitting thesprings 118 and 119 to disengage,whereby theenergizing circuit for'the private-magnet 1201s in turn broken. The private'magn'et now deenergizes and permits the side'switch to pass fromtirst to second position, thus'p'eriuitting the side switch wipers 117*:and 121 to engage the contact points 122 and'123", respectively. The closure otcontact-between the side switch wiper-117 and'the contactpoint 122 sets'up'an energizing circuit for the rotary magnet 123. lThis'energizing circuit extends from ground G through the interrupter--' springs 121, rotary "magnet 123, contact point 122, side switch wiper 117 to the battery lead 7 1. thence through-battery P to ground G. The said rotarymagnet then operates to rotatethe-shaft wipers 125, 126 and 127 of the selector switch E into engagement with the first-contact -of' the second level of the selector"banks, from which contactit isassumed the trunk line conductors 128, 129 and 130 lead-to the connector switch H (Fig; "I'f'the first trunk line is busy, however, and the wipers have to pass over busy contacts, then-as soon as the private wiper 127 engages the'first'priyate bank contact the private magnet 120 again energizes, locking'ithe side switch in second position. The energizing circuit for the said private-magnet extends from the grounded terminal G of the battery B through an occupying switch'(not shown), through the private wiper 127, thence tl'irough the conductor 131, side switch wiper 121, contact point 123*, through the private magnet 120 to the battery lead 71, thence through battery B to-ground G. The private magnet 120, upon thus becoming energized, locks the side swit'ch'wipcr117 in engagement with the contact point 122, whereby the rotary magnet 123 will beenergized step by step, and the Wipers 'are'ca'rried beyond the last busytrn'nk line. At the instant that the private wiper leaves the last busy contact point the energizing circuit through the private magn'et120 is'destroyed, and as a resultthe selector side switch passes to' third position. Ifthere are no busy trunklinesthe privatema'gnet 120 releases the side switch to'third position as soon as the wipersare carried into engagement withthefirst trunk line. 'As soon as the side switch passes tothird position, as

stated. the trunk line conductors98 and '99 are extended to theuconductors 1'28'a'nd 129 which, in this Ct1SQ,lt isassumed lead -to the into contact witli 'the spring 145. 'The enconnector switchH (Fig.2). 3 The extending ofthe' line occurs,'0f*course, as soon as the side switclrwipers 104 'and"105 engage the contact points132 and 133, respectively.

- \Vhen'the trunk,line-i's thus' extended to the connector switch :H' "an energizing circuit is established through-"the line relay 13st in the same manner in -which the'energizing circuit was established throu'ghthe'line relay 102 ofthe SGlGCtOP'SWitCh E. *Therelay 134, upon energizing, operates to shift the spring 135-out of engagement with the spring 136 andinto'contactwith' the spring 137. \Vhen the springs f and -137 engage, an energizing circuitis' established "through the slow-acting'relay- 138. "Thiscircuit extends from ground G through the springs I 135 and 137, back-bridge relay springs 139 and 110, conductor 141 'through'therelay 138*to the battery lead 71, thence through battery Bto ground G. "The relay 138, upon energizing, operates to "close the springs 141 and 142 in 'co'n'tact and also to shift the spring 1'43 'tr'onnthe spring'144 gagementof 'the sprin'gs l ll and 142Aprovides a guarding-=potentialto the p'riva'te bank contact corresponding ito the "trunk conductors "128' and 129. 'T-his potentia'jlextends from ground t'ir to "the "side switch uiper 146, springs 'l' tl and 142,"'conductor 130 to the private bank 'cont'act 'engaged by the'private wiper 127. Furthermore, a new energizing circuit is provided 'for the release relay 1'10 ofthe selectorswitch This circuit extends froin'fgr'oi'ind G "at the connector switclrHto the p'rivhtewiper 127, as explained, through the "conductor 131, side switch 'wiper 121,-contact point 117, conductor 148 to the' release'relay; 110, thence to the battery lead 71, and through battery B to ground'G." This-primaryoperation of the relays 13 1 and 138 ot the "connector switch H occurs at the instant that the side switch wipers'101' and 105'- of the selector switch E pass to"third'positionand extend the subscribers line conductorshG and 64: to the trunk conductors 120 and 128.

The operation-of the'dial for thel'ast two digits atl'ects'theconnector s'\v'itcl1,1and when I the dial is *operated for the second digit 2 the impulsespring '14 is twi'ce carried out of engagement 'with the impulse'spri'ng 15, thereby momentarily (leiine'rgizin'g' the line relay 134 of the connectorswitch twice. The spring 135thereby engages the spring 136 twice, thus sending-two impulses to'the' verticalniagnet 149' from"g'round G through the springs 135 and 136, springs 1-13 and 145, private magnet relay 150, "vertical mag-- net 1 19, side switch wiper 151 to the battery for the line, a normally open short-circuit around the transmitter, and a measured service device provided with means for opening the first short-circuit and closing the Second, and having means for then opening the second Short-circuit to enable the subscriber to use the transmitter.

15. In a measured service telephone trunking system, means for establishing a trunking connection between a calling and a called subscribers line, a subscribers receiver partially short-circuited to prevent the subscriber from talking through the same, for enabling the calling subscriber to hear the called subscriber answer, or to receive the busy signal, and means under the control of the calling subscriber and operative to open the line circuit for releasing trunking connection to the called subscriber.

16. In a telephone trunking system, means for establishing a trunking connection between a calling and a called subscribers line, a subscribers substation apparatus, means for rendering the same inoperative for bolding conversation with another subscriber, means whereby ringing current transmitted to said substation apparatus will render the same operative for conversation, and means under the control of they calling subscriber and operative to open the line circuit for releasing trunking connection to the called subscriber.

17. In a substation telephone set, the combination with a normally inoperative impulse sender and a normally operative talking equipment, of a call register, subscriber menses means for thereafter operating said register and additional means controlled in the same operation for rendering said speech transmitting equipment operative for talking.

19. In a substation telephone set, the combination with a normally inoperative impulse sender and normally operative talking equipment, of a call register, a switch controlled by the subscriber for rendering said sender operative and said talking equipment inoperative, means for locking said switch in set position, and subscriber controlled means for simultaneously operating said register and unlocking said switch.

Signed by me at Chicago, Cook county, Illinois, this 24 day of March, 1909.

JOHN ERICKSON. Witnesses:

BERNARD D. WHLIS, EDWARD D. Films.

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