US1665489A - Telephone system - Google Patents

Description

April 10, 1928.

J. WICKS TELEPHONE SYSTEM Original Filed Aug. 25, 1922 5 sheets-sheet4 1 55m Hicks J. WICKS TELEPHONE SIYSTEM Original Filed Aug. 25, 1922 5 Sheetsvsheet 2 mill-[v -Inuen 1jr- Jnhnlnfmk's April 10, 1928. 1,665,489

J. wIcKs TELEPHONE SYSTEM original Filed Aug. 2:5,l 1922 5 sheets-sheet 5 Apnl lo, 192s.

TELEPHONE SYSTEM Qrixinal- Filed A@ 2541922 5 sheetsrsheet 5 1,665,489 J. wlcKs y n Patented Apr. 10, 1928.

iiniTED STATES PATENT OFFICE.

JOHN WICKS, OF OAK PARK, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 AUT- MATIC ELECTRIC INC., QF CHICAGO, ILLINOIS, ACORPORATION 0F DELAWARE.

Application filed The present invention systems in general, but

TELEPHONE' SYSTEM.

relates to telephone is concerned more particularly with methods of establishing toll or long distance connections;

principal object, briefly duction of a new and and the stated, is the proimproved universal cord circuit for use in interconnecting manual and automatic toll li nes with each other or with toll service trunks.

Another object is the and improved toll connector in which rovision of a new P the seizing of the called line after the number is dialled is under the control of the operator,

and in which the operator is given a distinc tive indication when the to be seized. These objects, together withV called line is ready such others as are not specifically mentioned above, will be explained fully hereinafter,

' tion to a subscribers line; Fig. 1 represents; the improved cord circuit, together with cer reference being had to the accompanying drawings, comprising Figs. 1-5, inclusive.

Referring now to the drawings, they can be understood best when Figs. 1, 3, 4, and 5 are laid out in order with the corresponding lines at the ends thereof in alignment, and

1' with Fig. 2 under Fig.

spending interconnecting lines in alignment.v

When laid out thus, Fig

1 with the corres. 3, 4, and 5 represent a train of toll service lswitches in a multi-office telephone system by means of which a toll operator may extend a connectain other apparatus at position;

toll line Y.

The apparatus shown together with the' trunk selector oflice, while the selector the toll ,oper'ators and Fig. 2 represents a repeater and a selector associated with an automatic on Figs. 1 and 2, circuit TG2 and the F, Fig. 3, is assumed to be in the toll G, Fig. 3, together with the switching mechanism Y shown iii Figs. 4 and 5, is assumed to be any onev of the other offices in the system.

The automatic switches comprising the selectors E, F, G, and H, and the connector M are of the welLknown vertical and rotary type. Accordingly, the

arranged in horizontal rows or levels.

individual line switch C bank contacts aren The associated with the line of substation A, Fig. 5, is ofthe w'ellknown rotary type, in which the wipers have no normal position and direction only. l

The SyStem, having move in a forward been described in plugs in, battery is placed on the toll lineY through the midpoint of the two windings of the repeating coil bridged across the distant end thereof. Then this occurs, line relay 261 of the repeater R energizes over the following circuit: From ground by way of relay 261, resting contact of armature 228 and said armature, armature 268 and its resting contact, upper and lower left-hand windings of the associated repeating coil in inult-iple, and the upper and llower conductors of the trunk line Y to battery in the distant toll office. ALine relay 261, upon energizing, closes' a bridge across the conductors leading to the selector E at armature 237, and at armature 239 closes a circuit for release relay 262. Release relay 262, upon energizing, disconnects the release trunk oonductor26 from relay 255 and connects it to ground at armature 242, aiidat armature 241 prepares avcircuit for relay260. The placing of ground on release trunk conductor 26 v renders the toll line Y busy tothe automatic switches havingaccess'to it by Way of conductors 25, 26, and 27. v e

- The operator in th distant toll office now operates her ringingkey, thereby projecting ringing current out over the toll line Y. This ringing current is repeated through the windings of the yrepeating coil associated with the repeaterR and operates the bridged ring-,up relay 3 in the trunk-circuit TC', Fig. 1.` Relay 3, upon energizing, closes a locking vcircuit for its lower winding at armature 7, at the same time closing a circuitfor the line lamp L. A branch of this circuit extends by way of theresting Contact of armature 5 and said armature to the visual busy signal 8 and its multiples in front of the other operators.

The operator, uponV noting the lighted condition of the lamp L', inserts `the plug of an idle cord circuit, the plug P of the cord'circuit O for example, into the jack J. When the sleeve of the plug comes into engagement with the sleeve contact of the jack,

relay30 of the cord circuit O and relays 2.57 i

i tact of armature 242 of release relay 262 at way of relay of the cord circuit O, lower left-hand pair of contacts of the `key K', sleeve of the plug P, corresponding contact of the jack J', sleeve conductor 29, relay 257, and relay 258 to battery. Relay 258, upon energizing, places ground on the resting conarmature 227, and at armature 224; opens the circuit 01:' relese relay 262, whereupon release relay262 deenergizes and at armature 2112 shifts lrelease trunk conductor 26 to ground by way of armature 2-27 andits working contact.- As a further result of its energization, relay 258 disconnects line relay 261 at armature228, whereupon line relay f261 deenergizes and opens the bridge across i ture 237.

the trunk leading to tlieiselector E at arma- A still further result of the energization of relay 258 is that it prepares a circuit` for relay 259 at armature 226, `and at aimature 224 places ground on conductor 28tliereby closing a circuit for cut-od relay 2 of the trunk circuit TC. Relay 2, upon energizing, opens the circuit of the visual busy signal 8, the circuit of the lower Winding ofrelay 3, and the circuit of the lamp L at armature 6, and at armature 5 dis-` connects the visual busy signal 8 and its multiples at the other positions from the lamp L and the lower winding of relay 3 andV grounds them again?. Relay 3 now deenergizes and the lamp L becomes extinguished.

Relay 257 in the repeater R, upon ener- 5 gizing, in series with relay 258, closes at armature 222e circuit for the lower winding of relay 259 by way of armature 230 and its restingcontact. Relay 259, being margin-` ally adjusted, energizesenough` to operate its lightly adjustedarmature 229 but notV enough to operate the `more stiflly adjusted armatures 225 and 230. Armature 229, upon coming into engagement with its associated contact, places 'ground on the upper winding of relay 259 by way of armature 227 and its working contact. No current fiows Vthrough this upper `winding at this time, however, ortlie reason that it is grounded at both terminals; i

In the cord circuit O, relay 30, upon ener`` gizing in response to the plug P being 1nserted into the jack J', closes a circuit for relay 31 at armature 37 by way ofthe resistaiicel.` Relay 31 does not energize "at this time, however, owing to the fact that it is short circuited by ground by way of the working contact of armature and said armature, armature 1-1V and its resting contact, (and the resting contact of armature V39 and said armature. 0, y

The operator, after plugging in, throws her key K2 into` listening position, thereby operating the left-hand springs thereof soy as to connect up the listening taps of lier headset.` "She, now couverses with the distant operator and nds out the desired num? ber. Assuming that the distant operator desires the connection to be extended to the line of substation A, the operator inserts the plug P of the cord circuit, O into the jack J2, the associated trunlrbeing idle as def noted by the unoperated condition of the visual busy signal 16.r When the sleeve con.`

tact of the plug P coinesinto engagement `with the corresponding contact of the jack 2, a circuitis closed over sleeve conductor 53 through relay 36 and resistancell. of the cord circuit O in series with relay54 and the lower winding of relay 55 ofthe trunk circuit TC. Relays 36 and 55, however,

being marginally adjusted,do notenergize` at this time. Relay 54, upon energizing, disconnects relay 56 from in bridge ofthe line conductorsland 52 of the jack J2 at armature 58, and at armature 57, places ground onV conductor 50, thereby closing a circuit for the visual busy signal 46 and its multiples in front of the other operators.

The operator now restores her listening key K2 and throws her calling device key curs, line relay 650i. the selector F energizes over conductors 51 and 52, the` corresponding conductors of the cord circuit O, and the operators calling device taps 13 and 1li which are connected up to the upper andA lower strandsof the cord circuit `by the Isprings ofthe key K. The operators calldevicetaps 13 and 14 are connected together through the `control contacts 15 of the calling device CD, right-hand winding` of the operators induction coil, and armature 2O and its resting contact. i i

Line relay of the selector F, upon energizing, closes a circuit for release relay 66 at armature 70.` Release relay G6, upon ener Vgizing, places a rmultiple ground uponvcoiiductor 50 at armature 71, and at armature 72 opens a point in the .circuit of release magnet iand prepares a circuit for vertical magnet 85.

The operator now turns the `calling device Y CD in accordance with the first digit of the desired number, `thereby interrupting the ,circuit of line relay :65 `of the selector F a corresponding number of times at contacts `15. Upon .each deenegization of line relay 65 thereby produced, a circuit is closed vfor vertical magnet as follows: From ground by way of the resti-ng contact of armature iii 78 and said armature, armature 7 0 and its resting contact, armature 7 2 and its working contact, relay 67, and vertical magnet 85 to battery. By the operation of vertical magnet 85, the shaft and wipers of the selector F are raised step by step until the latter stand opposite the desired level of bank contacts. Slow acting relay 67 is energized in series with vertical magnet 85 and retains its armature attracted throughout the vertical movement. Uponthe closure of oil normal contacts 84, which occurs at the end of the first vertical step, a circuit is closed for stepping relay 68. This circuit includes armature 71 and its working contact and interruptor contacts 83. Relay 68, upon energizing, closes a locking Circuit for aself at armature 741 and at armature 7 5 pre pares a circuit for rotary magnet 81. At the end ot the vertical movement, relay 67 deenorgizes and completes the circuit of rotary magnet 81. Upon energizing, magnet 81 advances th-e wipers 86-88, inclusive, into engagement with the rst set of bank contacts in the level opposite which they are raised., and at interrupter contacts 83 opens the circuit of stepping relay 68. Relay 68, upon deenergizing, opens a point in its previously established locking circuit at armature 74, and at armature 75 opens the circuit of rotary magnet 81. Rotary magnet 81, upon deenergizing, closes its interruptor contacts 83 again.

Il the trunk terminating in the first set of bank contacts is idle, switching relay 69 energizes immediatelyattcr the closure of interruptor contacts 88 upon, the deenergization of rotary magnet 81. However, if the lirst trunk is busy, switching relay 69 is short circuited by the ground potential which is present on the test contact thereotl and stepping relay 68 energizes again, whereupon rotary magnet 81 energizes also and steps the wipers into engagement with the next set of bank contacts. This alternate operation of stepping relay 68 and ro tary magnet 81 continues until an idle trunk is reached, which trunk it will be assumed is the one extending to the selector Gr, whereupon switching relay 69, being no longer short circuited, energizes in series withstepping relay 68 upon the decnergization of rotary magnet 81, after the latter has stepped wipers 86-88, inclusive, into engagement with bank contacts 89-91, inclusive. Stepping relay 68, however, is not energized at this time on account oit the high resistance of switching relay 69. Relay 69, upon energizing, opens the test circuit and places ground on test wiper 87 at armature 77, so as to make the seized trunk busy immediately to the other switches having access to it; disconnects ground 'from armature 76 of line relay 65 at armature 78, thereby opening the circuit et release relay 66; and at armatures. 76 and 79 disconnects the line conductors from the windings of line relay 65, and extends them'by way. of the line conductors of the seized trunk to linerelay 68 of the selector Gr in the distant ollice. Line and release relays 63 and 64: of the selector G now energize and prepare the switch for operation in Vtheusual manner.

In response to the calling of the second ydigit in the desired number, the` selectorG operates in the same manner as the selector F tovraise itsv wipers to the desired level and select an idle trunk, which trunk it will be assumed is the one comprising conductors 97-99, inclusive,-and extending to the transmission selector H, Fig. 1.

When the trunk extending to the selector H is seized, line relay 110 energizes over the calling loop, the circuit being as follows: From ground by way of the normally closed contacts controlled by armature'120 of relay 106, lower left-hand winding of the associatedA repeating coil, the calling loop, upper left-hand winding of the associated repeating coil, normally closed contacts controlled by armature 117, normally closed contacts controlled by armature 123, resting contact of armature 150 and said armature, and the upper, winding of'line relay 110 to battery. Line relay 110, upon energizing, connects up wiper 156 at armature 185, and at armature 136 closes a circuit for release relay 111. Release relayY 111, upon energizing, opens a point in the circuit of release magnet 1541 and prepares a circuit for vertical magnet 152 at armature 142, and at armature 141 places ground on the release trunk conductor 98, thereby establishing the usual holding circuit for the switching relay of the selector Gr before release relay 64 has had time to deonergize.

The operator now operates her calling device in accordance with the third digit in the desired number, thereby producing la corresponding number or' interruptions Vin the circuit of line relay 110 of the selector H. Each time line relay 11() deenergizes in response to one of these interruptions, it

closes a circuit for verticall magnet 152 'as follows: From ground by way of armature 186 and its resting contact, armature 1f12and itsworking Contact, armature 138 andA its resting contact, relay 112, and vertical magnet 152 to battery. tical magnet 152, the wipers of the selector H are raised to the desired level of bank contacts. y Slow acting relay '112 is energized in series with vertical magnet 152 and retains its armature attracted throughout lthe vertical movement. l Upon the closure oit oil normal contacts 1116, a circuit is closed for stepping relay 113 by way of armature 143 and its Vworking contact. Relay 113, upon energizing, closes a locking circuit for itself at armature 1414, and at armature 145 pre- By the operation of ver-v lll!) at this time ,on account of the high resistance 115. At the end of the vert-ical movement, relay 112 deenergizes and complet-es the circuit of rotary magnet 153. Magnet 153, upon energizing, advances the wipers 156,-

159, inclusive, into engagement with the irst set of bank contacts in the level opposite which Vthey are raised, and at interrupter contacts 151 opens the circuit .0f stepping rela-y 113. Stepping relay 113, upon deen- C ergizing, opensthe circuit of rotary magnet 153 at armature 145., Rotary `magnet 153, upon deenergizing, lcloses its interrupter contacts 151 again. I the trunk terminating in the first set of bank contacts is idle, switchingl relay 109 energizes immediately in series with stepping relay 113, but if the trunk is busy, switchiing relay 109 is short circuited by the ground potential which is present on the test contact thereof and stepping relay `113, is `energized again, whereupon rotary magnet 153 energizes also, and steps-the switch wipers into engagement with the next set of bank contacts. This alternate operation of stepping relay 1-13 and rotary magnet 153 `continues until an idle trunk is reached, which trunk it will be assumed is the one `comprising conductors 160-163, inclusive. Stepping relay 113, however, does not energize over this circuit on account of the high resistance of switching relay 109. Switching relay 109, upon energizing, opens a point in the circuit of vertical magnet 152 at armature 133; opens the test circuit and prepares the holding circuit at armature 132, thereby grounding release trunk conductor 162 of the connector` M and making the seized trunk busy; places ground on wiper 157 at armature 131, thereby preparing a locking circuit for relays 168 and 169 of the connector M; and at armatures and 13'4 connects up the line wipers 156 and 159. Since line conductors and 163 of the connector M extend to the upper and lower windings` of line relay by Way `of the normally closed contacts controlled by armatures 285 andV 206 of relay 174, and `armatures 207 and 209 and their resting contacts,

line relay 165 energizes over a local bridge across line wipers 156 and 159 in theselector H. This bridge includes the working contact of armature 134 of switching relay 109 and said armature, loWer-right-hand winding of the associated repeating coil, upper winding of relay 105, resting contact of armature 1118 and .said armature, upper r right-.hand repeating coil winding, armature 130 `and its workingcontact, and the working contact of armature 135 and said armature. Relay 10.5, the upper winding of which included in this bridge, does .not Lenergize at. this time for the reason that the ,current net and prepares a `circuit `for vertical magnet 186 at armature 178,4 and at armature 179 closes a circuit for ring-,cut-oll' ,relay 168. Relay168, upon energizing, locks itseltto the grounded `c011Gl11ctor ,i161 at armature 184 by way of the normally closed contacts controlled by armature 193, md at armatures 183 and 186 disconnects `armatures 285 and 206 from its own upper vwinding and the common ringing lead land connects them to conductors 163 and 160, respectively.

In response to the calling `of the next digit in the desired number, the circuitof line relay 110 of the selector is opened the desired number Vof times. Each `time the said relay 110'deenerg1zes, 1t opens the .circuit `of line relay 165 of the connector M at armature 135. `Each time the line relay `165 deenergizes, it sends an` impulse o'fcurrent to vertical magnet 186 the rstyimpulse of current being sent over the following circuit z` From ground by Way of armature 191 and its resting Contact, armature 208 `and its resting contactarmature 176 and its resting contact, armature 178 and its working contact, contact of olf normal spring 181 and said spring, relay l167, and vertical magnet 186 tobattery. By the operation of vertical magnet 186, the shaft and wipers of the connector M are raised step by stepuntil the latter stand opposite the desired level ot-bank contacts. Slow acting relay 167 is energized in series with vertical magnet 186 and retains its armature attracted throughout the vertical movement, thereby'maintaining its own circuit and that of vertical magnet 186 intact after the ott normal springs shift as they do upon the first vertical step. At the end of the vertical movement, slow acting relay 167 dcenergizes and transfers the operating circuit from the vertical to the rotary magnet.

When the operator manipulates her call- 1 ing device for thenext and final digit in the desired number, line relay 165 is deenergized the desired number of times and, upon each deenergization, closes a circuit tor rotary magnet 187'as follows: From ground by way of a circuit previously traced to the working contact of armature 178 and thence by'way of the normally open contacts controlled by off normal spring 181, armature 182 and its resting contact, relay 173, and rotary inagnet 187 to battery.l By the operation of ro tary magnet 187, the wipers 211-218, in-

clusive, are advanced into engagement with the desired set of `bank contacts, which, in this case, is the set ot' bank contacts in which the line of substation A terminates. Slow acting relay 178 is energized in series with rotary magnet 187 and retains its: armature attracted throughout the rotary movement. Upon energizing, relay 173 disconnects test wiper 212 from the lower windingof relay 169 and connects it to busy relay 17 2 at armature 282, and at armature 284 disconnects the lead which comes from the busy signalliiw machine B. v Y Y ssuming that the called line is busy the test contact lthereofl is grounded, consequently, busy relay 172 isV energized through test wiper 212 when the wipers of the switch arrive upon the contacts of the called line. Busy relay 172, upon energizing, opens' a point in the circuit of relay 174 at armature 196; prepares a locking circuit for itself through the lower winding of relay 169 at armatures 197 and 199; and at armature 200 prepares the busy signalling circuit. Relay 173, upon deenergizing at the end ot' the rotary movement, opens the initial circuit of and completes a locking circuit'for busy relay 172 in series with the lower winding of relay 169 at armature 282; and at armature 284 connects up a lead Jfrom the busy signalling machine B to the lower heavy talking conductor through theworlr- Iing contact of armature 200 and said armature. This sends an audible busy tone back to the calling operator to inform her that the desired line is, for the time being, inaccessible. Relay 169 energizes in series with busy relay 172 over the following circuit: From ground by way of test wiper 212, working contact of armature 197 and said armature, lower winding of relay 169, armature 199 and its working` contact, normally closed contacts controlled by armature 282, and busy relay 172 to battery. Upon ener gizing, relay 169 locks itsel'tl to control conductor 161 at armature 190; removes ground from armature 17 6 of line relay 165 at armature 191, thereby opening the circuit of re lea-se relay 166; closes a circuit for relay 171 at armature 188; prepares a circuit for connecting a lead from the interrupter I to the lower talking conductor at armature'192; places a shunt around armatures 197 and 199 of busy relay 172 and their working contacts at armatures 189 and 199'; and-at armature 187 opens a point in the circuit of relay 17 5 and prepares a circuit for switch- Aing relay '174. Relay 171, upon energizing,

opens the initial circuit of relay 171 at arma-4 ture 177; opens the initial energizing circuit of 'ring-cut-ofl' relay 168 at armature 179, and at armature 178 yopens a point in the magnet operating circuit and prepares a circuit for release magnet 185.'

The operator, upon hearing the busy tone,

which is sent back by the connector M as previously explained, knows that the desired line Iis busy. n In case she desires to wait for the line to become idle, the operator merely restores her callingA device key K to normal position, whereupon impedance 34 and relay 35, in series with armature 44 and its resting contact, are bridged across the strands of the cord circuit, and the operatorsfcalling device taps 13 and 14 are disconnected. At the same time, direct ground ,is removed from the sleeve conductor of the plug P at the lower right-hand contacts of the key K. This latter operation, however, vdoes not produce any particular result at vthis time. When the bridge including the polarized relay 35 is placed across the talking conductors of the cord circuit, current begins to flow through this bridgeand polarized relay is energized, but in such a direction as to move armature 43 still further away from its associated contact.

Assuming now that the line of substation A becomes idle, busy relay 17 2 deenergizes vwhen the ground potential is removed from the test contact of the called line, and opens a point in its previously established locking circuit at armature 197 and another at arma-V ture 199. These points, however, are bridged by armatures 189 and 199 of relay 169 and their working contacts. As a further result 'or' the decnergization ont relay 172, it disconnects the lower talking conductor from the busy lead and connects it to armature 204 of relay 174 lby way of armature 192 `and its working Contact and at armature 196, completes a circuit for relay 174, which circuit includes release trunk conductor 162 and armature 187 and its working` contact. Relay 17 4, upon energizing, locks itself to conductor 162 at armature 202; closesa point in the circuit of wiper connecting relay 175 at armature 201; shunts resistance 286 around armature 284 and its resting contact and condenser 287 at armature 205; and at armatures 285 and 206 reverses conductors 160 and 163 as regards their connection withv the windings of line relay 165, the line relay current passing through armatures 188 and 186 of ring- LaA eat-olf relay :maaien working aimais after the reversal. When this reversal occurs, the

marginally adjusted` polarized relay` 105 in the transfmis'sio` `Selector H energizes on faecoun't et the faet that the Anirre'in flowing through itsupper Winding assists the current flowing` through its lower Winding at this time. Upon energizing relay105 placesa shunt around resistance` 11.5 at armature 116 so as to maintain the relay energized independent of its upper Windin disconnects its upper Winding from in bri ge of the condenser associated with the right-hand repeating coil windings and connects up` bat'- tery feed relay 106 atarrnatures 118 and 119. lVlienthis `occurs,line iiellay 165 of the connector M` deenergizes because it isso p oled at this time, as, regards relay matta no current vflows through either relay 165 or relay` 10G; Upon deeergizing, une relay 165 opens 1a still further point iny the circuit of release relay 166jand`clo'ses avpoint the circuitcf release', magnet 185 at armature 176. As astill further result `of the ,venergizationof` relay 105 in the transmission selector H, it reverses p the direction of current flow intrunl 'conductors 97and 99 atarinatures 117 and 120, at the same timeinclud'ing the lower"yvindingjof line Irelay 110 andreisi'stances 137 and 13:6l the circuit extend ing baclrto the operator. As a further` result of the energization of relay`105, it-

bridges relay 107 in series with condenser 164i across thecondens'er associated With the left-,hand repeating coil Winding at the' normally. open contacts c'ontrolledby armature 117. i

In the cord circuit Fig. 1, relay respends to the reversal of current` brought about by relay 105 of the transmission selector I-Iby bringingrarmature ISinto engagement with its associated Contact, Wherenpon the supervisory lamp L3 becomes lighted. 1 i

Returning notv to the connector M, as a still `further result of the energization oiE re'- lay 17 4, a lead from the interrupter I is connected tol theI lower talking conductorv at armature 2011. Consequently, each time the common interrupter lead is grounded, relay Y 165 of the connector M is energized through its upper` Winding, and relay 106 of the transmission selector IjI energized through its loiv'ei1 Windinginmultiple with the upper Winding of line relay 165. The ,operation of line relay 165 of the connector M is merely incidental and does not produce any particular result at thistime. Relay 106, in the selecetor IL upon energizing, disconnects line relay 110 from conductors 97 and, 99 at armature122 andtlie'norm'ally closed con- 4tants,controlled by armature 123, and at armature 123' and its Working*contact closes a local'circuit for line relay 110 by Way of resistance 139, thereby maintaining relay 110 energized. In the cordy circuit 0, supervi-V When ground is removed from the lead of the interrupter I, Fig. 5, line relay 165 of the connectorM and battery feed relay 106 of the selector H deenergize. Relay 106, uponideenergizing, connects up line relay 110 to conductors 97 and 99 again, at the same time opening the local circuit of line relay' 110. lVhenthis occurs, supervisory relay 3'5,.in the cord circuit 0, attracts its armature 113 again, whereupon thelamp L3 again becomes lighted. Tliisjoperation is' repeated leach time the' lead associated' with interrupter I is groundedp thereby causing the supervin sory la'inp L3, associated with the cord circuit O, to flash intermittently so as to give theoperator a distinctive signal that the line, upon Which the connector' M is camped, has becorneidle. i f

The operator may `now seize the line of substation A and make it biisy in a manni to be explained subsequently. Assuming hoWeve1",`that` the operato-r does not seize the line of substation A immediately, for example, because she ist at the` moment otheriifise occupied or because the distant operator lias informed her that the calling subscriber will not be at the telephone for several ininjutes, andassuming also that therline of sub-` station A again becomes busy in the meantime, busy relay 172 again energizes from ground by Way of test` Wiper212, armature 189 and itsworking Contact, lovver Winding of relay 169, armature 199" andl its Working contact, and thel normally closed con` tacts controlled by armature 282. Upon energizing, busy relay 172` diseoniiects the lower talking conductor from 4the interrupter I at armature 200 and connects it to ground, by way of resistance 286, the' vorki ingcontact `of armature 205 and4 said `armature, and the right-hand Winding of the transformer of the busy machine B. In

"case relay106 of the selector H is' energized at this time, it remains energized through the busy lead and supervisory lamp Lf et' the operators clrcuitO remains extinguished but ii the Vrelay" 106 happens tobe deenergized at this time,`itimmediately energizes, whereupon the lamp L3 becomes extinguished. The operator, upon, noting that the` lamp L3 has stopped flashing and is extinguished,

knows that the line of substationA.` has become busy again. Incase she desires to verify this indication, she mayy do so by throvlfing her listening` key, Whereupon` the busy tone supplied by the busy machine B to the` lower talking conductor will be heard.

vWhen the line `oiI substation A becomes idle again, busy relay 172 deenergiz'es, Whereupon it ldisconnects the lower talking con'- ductor'163 from the busy machine B and connects it to the interrupter I again.

Vhen this occurs, the supervisory lamp L3 in the cord circuit O starts toflash again.

Assuming now that the operator desires to seize the line of substation A and make it busy she throws her key K2 into ringing posit-ion, thereby applying ringing current to conductors 97 and 99. This ringing current energizes the alternating current relay 10'! in the transmission selector 1-1, Fig. t. Relay 107, upon energizing, disconnects ground from wiper 157 and consequently from conductor 161 at armature 124C, thereby opening the locking circuit of relay 169 in the connector M. Relay 169, upon deenergizing, disconnects the interruptor I from conductor 163 at armature 192, and closes a circuit for release magnet 185 at armature 191, the said circuit including arm'ature 208v and its resting contact, armature 176 and its rest ing contact, armature 178 and its resting contact, and off normal contacts 180. As a further result of the deenergization of relay 169, it closes a circuit for relay 175 at armature 187, the said circuit including armature 201 and its Working contact. Consequently, release magnet 185 and relay 17 5 start to energize simultaneously. Relay 17 5, however,

upon energizing, opens the circuit of release magnet 185 at armature 208 before release magnet 185, which magnet has a comparatively heavy armature, is able to operate its armature. As a. further result of the energi zation of relay 175, it places ground on test wiper 212 at armature 208, thereby making the called line busy to the other switches having access to it. W'hen this occurs, cut olf relay 210 of the line switch C energizes in series with the -associated stepping magnet and clears the called line of its attachments. Relay 210, however, owing to the usual mechanical interlocking device (not shown) between its armature and that of the associated line relay, operates only about half way at this time. Consequently, lthe wipers of the line switch are not connected up. The stepping magnet of the line switch C, through which relay 210 is energized, is notoperated at this time on account of the high resistance of relay 210. As a still further result of the energization of relay 175, the talking conductors are disconnected from the windings of line relay 165, and are connected up to the line wipers 211 and 213 at armatures 207 and 209.

llihen the operator restores her ringing key, relay 107 in the transmission selector H deenergizes and replaces ground on conductor 161. This ground potential extends by way of armature 190 of relay 169, Fig. 5, and its resting contact, and armature 1941 and its working contact to the junction of resistance 170 and relay 171, thereby short circiiiting re-. lay 171 and allowing it to deenergize. Upon deenergizing, relay 171 opens its locking circuit at armature 195; disconnects conductor 161 at armature 194; and at armature 193 shifts the locking circuit of ring cut olf relay 168y back to conductor 161. The opcrater has now caused the line of substation A to be seized. not yet applied to the called line.

Assuming now that the operator learns that the calling subscriber' is ready to converse, she operates lier `ringing key again, whereupon relay 107 in the selector H is again energized, therebyl opening the locking circuit of ring-cut-off relayl 168 in the connector vM. Ring-cut-olf relay 168, upon deenergizing, disconnects the'wipers 211 and 213 from conductors 160 and 168 and connects them to its own upper winding and to the common ringinglead at armatures 188 and 186, respectively, and at` armature 1811 opens a further point in its previously established locking circuit. Ringing current is now applied to the called line intermittently by the ringing machine RM. The small condenser 286 allows enough ringing current to flow back over the upper' talking conductor to give the operator a ringing signal. lhen the operator restores her ringing key, relay 107 in the transmission selector H deenergizes 'and replaces ground on conductor 161.

lVhen thecalled subscriber responds to the ringing of his bell by removing his receiver, ring-cut-ofll relay 168 in the connector M energizes through its upper winding, whereupon it closes a locking circuit for itself at armature 1841, and at armatures 188 and 186 disconnects its own upper winding and the common ringing lead from the line wipers and connects the latter to the talking conductors 160, and 168. Battery feed relay 106 in the transmission selector H now ener gizes over the called line, whereupon it disconnects the line relay 110 from conductors 97 and 99, at the same time closing a localcircuit for line relay 110 through resistance 139. lNhen this occurs, supervisory relay 35, in the cord circuit O, deenergizes and extinguishes the lamp L3, thereby giving the operator answering supervision. Assuming that the line of the calling subscriber is con'- nected up by the distant operator to the distant end of the tollline Y, Fig. 2, the calling and called subscribers mayk now converse with each other in the Vusual manner, the talking` circuits that are shown, being outlined by the heavy conductors and talking battery being supplied to the called subscribers from the transmission selecte-r H.

Upon the termination ofthe conversation, the two subscribers replace their receivers. When 'the receiver is replacedat substation A, the circuit ofbattery feed relay 106 in the selector H is opened. Relay 106, upon deenergizing, connects line relay 110 to con- However, ringing current is ductors 97 and 99 again'at armatures 122 and 123, at the same time opening the local ing current coming in over 'thetoll line Y' i operates the alternating current relay 32 in the cord circuit O. Relay 82, upon energizing, removes ground from the unction or' relay 31 and resistance 37 and closes a circuit for relay 33 at arn'iature 41. Relay 38, upon energizing, opens the lower talking conductor of the cord circuit at armature 42, so as to prevent the ringing current from passing through to relay 107 in the transmission selector I-I. In case relay 107 energizes momentarily, it falls back again before ring-cutoff relay 168, in the connector M, has had time to deenergize. Relay 81, upon energizing in response to the removal of the short circuit from around its winding at armature 41, disconnects itself from the resting contact of armature 41 at armature 39, and at armature closes a circuit for the lamp L2, whereupon the lamp L2 becomes lightechthereby giving the operator a second disconnect'signal. y

The operator, upon notingthe lighted condition of the lamps `L2 and L3, may irst throw her listening key K2, so as to lind out whether or not the distant operator has anything to say to her, and, assuming that she gets no response, she then pulls down the connection. vWhenthe plug P is removed from the jack J', relay 30 deen'ergizes and opens the circuit of relay 31 at armature Relay 31, upon deenergizing, opens the circuit of the lamp L2, whereupon thesaid lamp L2 becomes extinguished. In the repeater R, relay 258,7upon deenergizing, connects up line relay 261 again at armature Q28; con-r nects relay 255 back to release trunk conductor 26 at armature Q27 opens the circuit of relay 259 at armature 226, whereupon relay 259 deenergizes; and at armature 224 removes ground from conductor 28, where upon cuteotl' relay 2 deenergizes; Upon de-I energizing, cut-off relay 2 connects the upper winding of relay 3 in bridge of the line conductors of the jack J at armature 4, and at armature 5 opens the circuit of the visual signal 8 and its multiples.

When the plug P of the cord circuit O` isremoved from the jack J 2, relay 35 Vdeenergizes and `the lamp L3 becomes extinguished. Relay 54 in the trunk circuit TG2, upon deenergizing, removes ground at one point from release trunk conductor 50 of the selector F at armature 57, and at armature 58 connects relay 56 in bridge of the talking conductors. Relay 56, upon energizing in series with line relay 110 in the selector H, opens the locking circuit of relay 55. Relay 55, upon deenergizing, opens another further point in itslocking circuit at armature'60; disconnects the lower talking conductor at armature 61, thereby opening the circuit of relay 56 and line relay 110 ot the selector H at armature 61; and at armature 59 removes ground from release trunk conductor 50 of the selector F. 'In responseto the removal of the ground potential from release trunk conductor 50, the visual busy signal 46 `and` its multiples in. front of the other operators become deenergized, and switching relay 69 inthe selector F `deenergizes and closes a circuit for release `magnet at armature 78; Thiscircuit includes armatures 70 and 72 and oit normal contacts 82. Release magnet 80, upon energizing, restores the shaft and Wipers of the selector F to normal, the circuit of release magnet 80 being opened at off normal contacts 82 by the switch shaft when thelatter reaches normal position.

In the transmission selector H,\Fig. v4,fline relay 110, upon deenergizing in response to` the opening otthis circuit at armature 61 of relay 55 in the trunk circuitTC2, Fig. 3,

opens the circuit of release relay 111 at arI mature 136. Releaserelay 111, upon deenergizing, removes ground from` release trunk conductor 98 at armature 141, thereby removing ground from release trunk conductor 162i of the connector Mralso.v Vhenthis occurs relay 109 deenergizes. As a further result of the deenergization or' release relay 111, it closesa circuit for release magnet 154V by way of armatures 136 and'142 and their respective resting contacts, and off` normal contacts 148. Release magnet 154, upon energizing, restores the shaft and wipers of the selector H to normal, in the usual manner. W'hen the oit normal springsfare opened by the switch shaft, the circuit of release magnet 154 is opened at oit' normal contactsV 148; a pointiin the circuit of stepping relay 113 is opened at oil' normal` contacts V146; andthe circuit of relay 105 isopened at olf normal contacts 147, whereupon relay 105 deenergizes. Relay 114, it may be stated, is maintained energized in 'multiple with releasev magnet 154 during the release of the switch. This relay maintains the locking circuit of stepping relay 113 open at armature 149, and at armature 150 maintains the upper winding of line relay V110 disconnected `so as to prevent an accidental energization of relay 110 due to the kick ofthe condensers associated with the repeating coil.

In the connector `M, relays 174 and 175 deenergize in response to the removal of ground from releasetrunk conductor 162 by release relay 111 of the selector H, and ringcutsert' relay 168 deenergizes in response to the removal of ground from the control conductor 161 by switching relay 109 of the selector H. Relay 175, upon deenergizing, disconnects the line wipers of the switch at armatures 207 and 209 and at armature 20S removes ground from test wiper 212 and closes a circuit tor release magnet 165 as l'ollows: From ground by way of armature 191 and its resting contact, armature 206 and its resting contact, armature 176 and its resting contact, armature 17S and its resting contact, olll normal contacts 160, and release magnet 185 to battery. By the operation of release magnet 185, the shalt aud wipers o1" the connector M are restored to normal position in the usual manner.

ln the preceding example, it was assumed that the line of substation A wasbusy when called, and thatvthe operator waited -for-the line to become idle. The operations accompanying the seizing of the line of substation A when the line is idle when called will now be outlined brieily. It will be remembered that series relay 173 is maintained energized during the rotary movement of the switch. Assuming that vthe line of substation A is idle, as above noted, busy relay 172 is not energized when the wipers ot the connector M come to rest upon the contacts of the called line, and series relay 173, upon deenergizing, completes a circuit for the lower' Winding of relay 169 as follows: From ground, by way of working contact of armature 177 and said armature, armature 183 and its resting contact, resting contact of armature 197 and said armature, lower winding of relay 169, armature 199 and its resting contact, resting contact of armature 282 and said armature, test wiper 212, and thence to battery by way of the cut-off relay and rotary magnet of the line switch o1 the called line. Relays 210 and 169 energize in series over this circuit. Relay 169, upon energizing, closes a locking circuit for itsel'l at armature 190 and at armature 188 opens its initial circuit and that of relay 210 and closes the usual circuitfor relay 171. When this occurs, relay 210 deenergizes, but relay 169 is maintained energized over its locking circuit. As a further resultof the energization of relay 169, it opens the circuit of release relay 166 at armature 191; connects busy relay 172 with test wiper 212 at armatures 199 and 189 so as toenable the busy relay to energize in case the called line becomes busy before itis seized; and at armature 187 closes the usual circuit for relay 174C. Relay 1711, upon energizing,

reverses the current flow in conductors 160 and 163 at armatures 285 and 206, thereby causing relay 105 in the selector H to become energized as hereinbefore described, and at armature 204C connects up the lead controlled by the interrupter 1. The operator new gets the flash supervision to indicate that the called line is idle and that she has not yet cut through to seize the line. seize the line or wait.

lt will be noted that relay 169 is energized at this time over a circuit which eX- tends tromy ground in the connector M to battery in the line switch C, and it will be remembered that relay 169 was energized in the previously described case over a circuit which extended from ground on the test contact of the called line to battery through busy relay 172. However, the current is made to iow in the same direction through the lower winding of relay 169 in both cases by the reversing operation of armatures 197 and 199 of busy relay 172, which armatures are attracted in one case and are normal in the other case.

It will be assumed now that the operator onthe distant end of the automatic toll line Y, Fig. 2, desires to extend a connection to one ot the other toll lines which is accessible tothe selector E, Fig. 2. rlhat being the case, the operator seizes the distant end of the toll line Y in the usual manner, whereH upon linerelay 261 of the repeater R .is energized by battery coming over the two conductors of the toll line in parallel. Upon energizing, line relay 261 closes a circuit for release relay 262 and the latter relay, upon energizing, places ground upon release trunk conductor 26 at armature 242, and at armature 2411 prepares a circuit for relay 260. As a further result of the energization o1 line relay 261, it closes at armature 237 a bridge across the conductors ext-ending to the selector E, whereupon line and release relays 27 O and 271 energize, thereby prepa ing the switch for operation in the usual manner.

In response to the calling of the digit assigned to the desired group o1 trunks, line relay 261 is deenergized a corresponding number of times and, upon each deenergization, opens the circuit of line relay 270 of the selector iE at armature 237. As a result, the wipers ofthe selector E are raised, oppo site the desired level of bank contacts by the operation of the associated vertical magnet which is controlled by line relay 270.V At the end'of the Vertical movement, the wipers of the selector E are rotated into engagement with an idle trunlnwhereupon the con nection is extended through in the usual manner. f

In the repeater R, relay 260 is energized upon the firstk deenergization of line relay 261 and closes a locking circuit for itself at armature 235; completes a bridge around the condenser associated with the right-hand winding of the repeating coil at armature 234; and at armatures 232 and 236 connects up the conductors of the selector vE to the right-hand windings of the repeating coil, at the same time disconnecting the direct She may now bridge at the normally closed contacts contion to the desired other toll line, may now` signal the operator on the distant end thereof by ringing,'or she may dial `still another digit in case she desires to extend the connection automatically through the `toll office in which the distant endof the seized toll line terminates. In any event, when the connection is finally completed andthe conversation` terminated, the operator on the 'distant end of the toll line Y pulls down the connect-ion, whereupon line relay 261 of the repeater R deenergizes, opens the bridgeV across the conductors of the selector E atarmature 237 and at armature 239 opens the circuit of release relay 262.` Relay 262, upon deenergizing, opens thecircuit ot' relay 260 at armature 24:1 and at armature 242 removes ground from release trunk conductor 26, thereby rendering the toll line Y accessible Y to the automatic switches having access to it, opening the locking circuit of relay 260, and allowing the selector E to release. Relay 260, upon deenergizing, removes ground from conductor 28, `whereupon cut-olf relay 2 `deenergizes and opens the circuit of the` visual signal 8 and its multiples. y

It will be assumed now that the operator on the distant end of the `toll line Y signals the local toll operator by projectingringing current out over the toll line Y. That being the case, the line lamp L, F l, becomes lighted in the hereinbet'ore described manner. The operator, upon noting thelighted condition o'f the lamp L', respondsby insertingk the plug ot an idle cord circuit, `the 'plug P of the cord circuit O, for example, into the jack J', whereupon theline lamp L becomes extinguished in the usual manner.l The operator nows throws herlistening key 'K2 and converses with the calling operator, and assuming that she learns that the connection is to` be extended to theoperator on the `distant end ofthe toll line X, she inserts the plug P of the cord circuit O into a jack associated with an idle tollV line in the proper group, the jack Jjfor example. When this occurs, the marginally adjusted sleeve relay 36 energizes in series with resistance 4-7 and the sleeve relay `of the jack J. Relay 36, upon energizing, disconnects the bridge including supervisory relay 35 from across the talking strands ofthe plug P and places a shunt around armature 42 and its resting contact at armature 44:. The cut-oli1 relay in `the trunk circuit TC, upon energizing, closes a circuit for the associated visual busy signal and its multiples, and removes the upper winding of the associated ringup relay from in bridge of the toll line X.

The operator now rings out on thetoll line,

X by operating her key K2, thereby signalling the distant operator, after which she restores her key K2 to normal and allows the originating operator to proceed with the call.

.After the connection is completed and the conversation terminated, the originating operator rings out on the toll line Y, thereby operating the ring-up relay 32 inV the cord circuit O., whereupon relay 31 becomes energized and lightsthe lamp L2. Relay33 energizes at this time but does not produce any effect owing to the tact that its contacts are shorted by armature 44 of sleeve relay 36. Accordingly, the ringing current `passes through the cord circuit O `and out, over the toll line X to signal the'operatoratthe distant end thereof. Y A

The switching operator, upon noting the lighted condition of the disconnect lamp L2,

by a selector such as E, associated with a similar repeater, ground isplaced on release trunk conductor 26 byway of test contact 245 by the seizing selector, upon the seizure of the trunk. This ground potential extends by way of armature 242 and its resting contact, armature 227 and its resting Contact, to relayr255. Relay 255, upon energizing, diconnects line relay 261` at armature 268; places ground on conductor 28 at armature 264;v andfat armatures 265 and' 266 connects the upper and lower windings of line relay 256 in bridge of the condenser associated with the right-hand repeating coil winding. Line `relay 256, upon energizing over the following loop, places battery on toll line Y at armature 220 by way or' resistance and through the two left-hand windings of the repeating coil in parallel, thereby energizing the line relay of the repeater on Vthe distant end of the toll line. It will 'be noted that no arrangement is made for holding up the seizing switch from the repeater R. The seizing selector, however, is held'up by the repeater with which it is associated vin the saine manner that the selector E is held up by the repeaterR when a connection is extended through the latter by way of the former. As .a result of the ground potential being placed on conductor 28, cutoff relay 2 in the trunk circuit TC isfenergized and closes a circuit for the visual signal 3 and tion to the toll line Y may now signal the distant operator by ringing, or she may dial a digit and extend the connection through the distant office, the impulses being repeated at armature 220 oit the line relay 256.

lVhen the calling operator pulls down the connection, line relay 256 deenergizesV and opens the circuit of the distant line relay at armature 220, and when ground is removed from release trunk conductor 26, relay 255 deenergizes and removes ground from conductor 28, whereupon the cut-ott relay 2 deenergizes and opens the circuit of the visual signa-l Sand its multiples.

It will be assumed now that the operator on the distant end of the manual toll line X desires to signal the operator on the near end ot' the said toll line X. That being the case, the distant operator plugs in on the toll line X and rings in the usual manner, whereupon the line lamp L becomes lighted. lVhen this occurs, the operator plugs in with an answering plug of an idle cord circuit, the plug Pof the cord circuit O, for example, whereupon the two sleeve relays energize in series with each other and the lamp L becomes extinguished. The operator now throws the key K2 to listening position and converses with the calling operator. In case the calling operator desires the connection to be extended to a local subscriber, such as the subscriber at substation A, the local toll operator inserts the plug Pginto the jack of an idle trunk circuit, such as the jack J2, and extends the connection to the desired subscriber Ain the hereinbefore described manner. In this case, however, it will be assumed that the distant operator desires the connection to be extended to the exchange reached by way of the group of trunks of which the tolll line Y is one. That being the case, the operator inserts the plug P of the cord circuit O into the jack J, the associated trunk being idle asdenoted by the unoperated condition of the signal 8. When this occurs, sleeve relay 36 ot the cord circuit O and relays 257 and 258 of the repeater R energize in series. Relay 258, upon energizing, places ground on conductor 28 at armature 224, whereupon the visual signal 8 and its multiples become operated by the energization of cut-olf relay 2. As a further result of the energization of relay 258, it disconnects line relay 261 at armature 228; prepares a circuit for relay 259 at armature 226; and at armature 227 places ground on release trunk conductor 26, thereby rendering the repeater R busy to the automatic switches having access to it. Relay 257, upon energizing, prepares a circuit for the upper winding of line relay 256 at armature 221, and at armature 222 closes a circuit `for the lower winding of the marginally adjusted relay 259. Relay 259 energizes just far enough to operate arma-ture 229. The operator now throws her ringing key K2, thereby signalling the operator on the distant end of the toll line Y. f

. The distant operator now responds and converses with the operator on the distant end of the toll line X, and completes the connection according to the direction of the latter operator and when the conversation is terminated, the operator on the distant end of the toll line X pulls down the connection and projects ringing current over the toll line. This ringing current operates ring-up relay 32 of the cord circuit O, whereupon relay 3i energizes and lights the supervisory lamp L2. rI his ringing current also passes out over the toll line Y and operates the disconnect signal at the distant end thereof, The local operator now takes down her cord circuit O.

Assuming new that the operator on the distant end of the toll line X signals the lor-al operator, and that the latter responds by inserting the plug P into the jack J, and that the local operator learns that the distant operator desires the local operator to extend the connection to the` exchange on the distant end et the toll line Y, and thence to a third exchange reached by way of the distant exchange, the local operator removes the plug P from the jack J and inserts the plug P into the jack instead. The operator now inserts the plug P into a jack such as the jack J', the associated toll line being idle as denoted by the unoperated condition oit the visual signal 8, whereupon relays 30, 257 and 258 energize in series and produce the hereinbefore described results. The operator now throws her calling device key K in such a direction as to operate the left-hand springs thereof. The lower lett-hand pair of springs of the key K', upon being operated, remove the shunt from around resistance 38, whereupon the marginally adjusted relay 257 in the repeater R, deenergizes and removes the shunt 'from around the upper winding of relay 259 at armature 222. Relay 259 now energizes and disconnects its windings from the .working contact oi armature 222 at armature 230, and at arn'iature 225 connects the upper windii'ig ot line relay 256 to conductor 27 by way oil the normally closed contacts controlled by armature 221, the resting contact oi armature 265 and said armature, and the upper rightdiand winding ot' the repeating coil. Since conductor 25 is grounded by way of armature 226 and its working contact, armature 222 and its resting contact, the resting contact of armature 266 and said armature, and the lower right-hand winding of the repeating coil, relay 256 energizes over conductors 25 and 27, through the talking strands of the cord circuit O, and through thev operators calling device key K. The line relay 256, upon energizing, places batlll) tary on `the `toll line Y `at armature 220,

NL operator, the interruptions being repeated at armature 220 of line relay restores her key K to normal.

As regards the establishing of connections which originate in the local toll ollice, it is thought that the detailed. operation accompanying the establishing of such connection will be readily comprchended in vien7 ofthe foregoing detailed description of the operation accompanying the establishing of the various other connections. Briefly, however, the operation is as follows: The toll recording operator receives calls from subscribers desiring toll connections and passes 256, and then them over tothe correct `toll operator, Which operator may first extend the connection to the distant subscriber andthen, after the distant operator responds, signal the calling subscriber again, and tell him that the connection is completed.

i In establishing' such connections, the use of connectors such as the connector K, Fig. 5, permits the toll operator to handle the tra-flic much more economically than herei tofore, for the reason that the toll operator can set up the local connection completely over the toll service trunking system While she is Waiting for the distant: subscriber to respond and at the same time not tie up the line of the originating subscriber from receiving and making local calls of short duration. This arrangement permits the toll operator to dial the local numbei ,during a time when she has a few moments to spare, and at a. time when she can do so Without neglecting any of her other duties.

Referring now particularly to the selector E, Fig. 2, it may be said that, although the bracket which is placed around the bank contacts of the selector E is labeled To toll lines, several levels of selector E may be multipled with the corresponding levels of the local first selectors, and that one level, the tenth for example, may extend to a group of toll svvitchiing selectors. which selectors rather than the selector E have access to the toll lines. This arrangement, if used, permits the operator on the distant end of the toll line Y to complete connections automatically to the local subscribers ifdesired, instead of extending the connections through the local operator as desired hereinbeforc.

I/Vhat is claimed is:

l. In a telephone system, a trunk terminating in a jack, a line relay for said trunk, a` cord circuit, a plug associated therewith inea-45e sponsive to the actuation of said key and the resulting current change for closing said contacts.

2. In a telephone system, a trunk termi-V nating in a jack, a line relay for said trunk, a. cord circuit, a plug associated. therewith and adapted to be inserted into said jack, a circuit for said relay including a conductor of said trunk and a conductor of said cord circuit in series, a pair of normally open contacts in said trunk conductor, a manually operable key associated with said cord circuit, and normally inoperative means for closing said contacts, said. means being rendered effective by an increase in the current flow over thesleeve conductor of said plug responsive to the actuation of said key.

3. In a telephone system, a trunk terminating in a jack, a line relay forsaid trunk, a cord circuit, a plug associated'therewith and adapted to be inserted into said jack, a circuit for said relay including a conductor of said trunk, contacts of said jack, contactsY of said plug, andra conductor of said cordV circuit in series, a pairvof normally open contacts in said trunk conductor, a manually opeable key associated with said cord circuit for changing the current tlow over the sleeve conductor of said plug, means responsive to the actuation of said key and the resulting cui-tent Vchange for closing said contacts, and means controlled by the `first named means for maintainiing said `lirst named means effective independent of direct control over said sleeve conductor.

4. In a telephone system, a trunk terminating in a jack, a line relay for said trunk, a cord circuit having a plug adapted Vto be inserted in said jack to connect the con-` ductors thereof With the conductors of said cord circuit, a circuit for said line relay in-,

cluding a conductor of said trunk and a conductor of said cord circuit in series, `an open point in said trunk conductor, manually operablekey associated with said cord circuit, means responsive tothe actuation of said -key for energizing said relay by closing said open point, and means responsive to the restoration of said key for maintaining said relay energized independent of said cord circuit conductor by closing a local circuit therefor. Y

5. In a telephone system, a plug ending cord circuit, two jacks, a manual trunk terminating in one jack and an automatic trunk terminating in the other jack, a marginal sleeve relay associated with said cord circuit, a direct current holding bridge, and contacts controlled by said relay through the medium of which said bridge is placed across the talking strands of said cord circuit when said plug is inserted into said other ack and disconnected vfrom across said talking strands when said plug is inserted into said one jack.

6. In a telephone system, a cord circuit terminating in a plug, two jacks, a manual trunk terminating in one jack and an autoe matic trunk terminating in the other, a conductor of said cord circuit extending to said plug, a pair of normally closed contacts in said conductor, means for applying ringing current to said plug by way of said conductor and said contacts, means controlled by said ringing current forropcning said contacts to cut orf said current from said plug, and means controlled over the sleeve conductor of said cord or rendering the opening of said contacts effective in case said plug is inserted into said one jack, the last named means being inoperative in case said plug is inserted into said other jack.

7. In a telephone system, a connector switch having wipers, remote controlled means for bringing said wipers into engagement with the terminals of a desired line, means in said connector for seizing the desired line only in case it is idle and for mal ing it busy, and means in said connector for applying ringing current to the desired line, said means for seizing said line and said means for applying ringing current being separately controlled from a distant point.

8. In a telephone system, a connector switch having wipers, remote controlled means for bringing said wipers into engagement with the terminals of a desired line, means in said connector for seizing the desired line only in case it is idle and formal;- ing it busy, means in said connector for applying ringing current to the desired line, said means for seizing said line and said means for applying ringing current being separately controlled from a distant point, and a supervisory signal at a distant point controlled by said connector to .indicate distinctively as regards the busy or idle conditions of a desired line and whether or not said connector has seized said line.

9. In ia telephone system, two lines, a cord circuit connecting said lines, and means in said cord circuit responsive to ringing current received over one of said lines 'for preventing ringing current from reaching the other of said lines via said cord circuit.

10. In a telephone system, two lines, a cord circuit connecting said lines, means in said cord circuit responsive to ringingv curb rent received over one of said lines for preventing ringing current rom reaching the other of said lines via said cord circuit', and

a relay having contacts for opening a conductor of said cord circuit constituting said means'.

l1. In a telephone system, two lines, a relay connected to one of said lines and responsive to ringing current, a cord circuit connecting said lines, and means in said cord circuit responsive to ringing current received over the other of said lines for preventing such ringing current from operating said relay.

12. In a telephone system, two lines, a cord circuit connecting said lines, a signal individual to said cord circuit, a second signal individual to one oit said lines, means for projecting ringing current over the other of said lines to operate the' said cord circuit signal, and means responsive to such ringing current for preventing theoperation of said line signal.

,13. In an automatic telephone system, an automatic connector switch controlled by an operator for selecting a subscriber-s line, a controlling device at the operators switchboard, a wiper connecting relay in -said switch responsive to the actuation of said device, and a ringing relay in said connector responsive only to a second actuation of said device.

. 14. In an automatic telephone system, an automatic connector switch controlled by an operator for selecting a subscribers line, a wiper connecting relay and a ringing relay in said connector, and means whereby the operator can control said relays separately.

15. In an automatic telephone system, an automatic connector switch controlled by an operator for selecting a subscribers line, open contacts at said connector in the conductors leading to the wipers thereof, a relay controlled by the operator at will for rclosing said contacts, and a second relay controlled at the will of the operator thereafter for signalling the called subscriber.

16. In an automatic telephone system, an automaticconnector switch controlled by an operator for selecting a subscribers line, a wiper connecting relay in said switch, means whereby the operator can energize said relay at will any time after the switch is operated and before it is released, a ring cut-oil relay in said switch energized automatically, and operator controlled means operative any time after said wiper connecting relay has energizedfor deenergizing said ring cut-oil relay to signal the called subscriber.

17. In a telephone system, an automatic connector switch controlled by an operator for selecting a subscribers line, said line remaining in idle condition, and means for automatically signalling the operator in case a connection is established with said line by way of another switch.

18. In a telephone system, an automatic connector switch controlled byl an operator for selecting a subscribers line,`said line remaining in idle condition, means in said switch controlled by the operator at will for making the selected line busy, and means for automatically signalling the operator in case said line is connected with at another point before the said busying means is operated.

19. In a telephone system, an automatic connector switch controlled by an operator for selecting a subscriberls line, said line remaining in idle condition, meansin said switch controlled bytheoperator at will for making the selected line busy, and means 'for automatically signalling the operator in case the subscriber on said line busies his line by making a call before the busying means in said switch is actuated. y

20. In a telephone system, an automatic connector switch controlled by an oaerator for selecting a subscribers line, said lineremaining in idle condition, means controlled by the operator at will to make said line busy, other means for connecting with said line and for making it busy, and means for giving the operator a diiierent signal in each case. y

21. In a telephone system, an automatic connector switch controlled by an operator for selecting a subscribers line, said line remaining in idle condition, av signal at the operatoi"s switchboard, means for operating said signal in a distinctive way to indicate that the line is idle, means controlled by the operator at will for making said line busy, and means 'for then operating said signal in a different way.

22. In a telephone system, anv automatic connector switch controlled by an operator for selecting a subscribers line, 4sind line remaining in idle condition, means for signalling the operator to advise her that the line is idle, means controlled by the operator thereafter to make the line busy, other means for making the line busy, and means for giving the operator a different busy signal in each case.

23. In a telephone system, an automatic connector switch controlled by an operator for selecting a subscribers line, said line remaining in idle condition, means for sig* nalling the operator to advise lier that the line is idle, means controlled by the operator thereafter to make the line busy, and `means for then signalling the operator to indicate the changed condition or the line.

24. In an automatic telephone system, an automatic connector` switch cont-rolled by an operator for selecting a subsc1ibe1"s`linc, a wiper connecting relay in said switch,`means whereby the operator can energize said relay at will, and means for signalling the operator in dilierent waysbefore and after said relay is energized.

25. In an automatic telephone system, an automatic connector switch controlled byan operator for selecting a subscribers line, a test relay inr said switch, means for signalling the operator to notify her whether `said relay is energized or deenergized, a wiper connecting relay controlled by the operator if said test relay fails to energize, and means for signalling the operator when said con necting relay energizes.

26. In a telephone system, a connector switch and means for operating the same to selecta subscriber-s line, a relay energized 'automatically when the operation of the switch is completed, a Vlocking circuitfor said relay, means for subsequently unlocking said relay provided the selected line is idle,

28. In 'a telephone system, a connector switch and means for operating it to connect witha called subscribeis line, a cut off relay for thesaid line, a relay in said connector initially energized inseries with said cutoff relay, a locking'circuit for said connector-relay, and means for opening the initial energizingv circuitto deenergize the said cut-off relay Vwhile maintaining the switch in selective position.`

29. In a telephone system,a connector switch and means `t'or operating it to connect Vwith a called subscribers line, aV cut-olil relay for the said line,` a relay in said connector initially energized in series with said cutolf relay, a locking circuitfor saidl connector relay,'means for opening the initial energizing circuit todeenergize the said cutoff relay while maintaining thc switch `in selective position, andmeans controlled by the callingparty iior'closing4 another energizing circuit for said cut-oir relay.

30. In al telephone system, a connector switch and means or-operatingit toconnect with a called subscribers line, a cut-off relay for the said line,a Wiper connecting relay in said connector, abusy test `relay in saidV connector, a relay controlling the circuit of said wiper connecting-"relay, a circuit-for energizing said last mentioned relay in ser-ies with saidA eutlolf relay if the line'is idle, and another circuit for energizing said llast mentioned relay in series with-said test relay if the line'isbusy.` C y 3l;` In aftelephone system, a link circuit, lines, means including said"` link circuit for `setting up connections between pairsosaid llo lines, and means in said link circuit responsive to ringing current received over one connected line for preventing such ringing current from reaching the other connected line, the last named means being effective or not depending upon the identity of the lastnamed line.

32. In aI telephone system, a link circuit, lines of two dili'erent classes, means for connecting the outgoing end of said link circuit with lines of both classes, means for applying ringing current to the incoming end of said link circuit, and means in said link circuit for permitting said ringing current to pass through or not according to the class ot the line to which the connection is made.

33. In a telephone system, a link circuit, means for setting up a telephone connection including said ylink circuit, discriminating means in said link circuit, blocking means in said link circuit, means for applying ringing current to one end of said link circuit, and means responsive to the ringing current for operating said blocking means to blockthc passage oi the ringing current through said link circuit or not depending upon the actiony oi said discriminating means.

34. In a telephone system, a conductor, means lor setting up a telephone connection, means 'lor applying ringing current to one end of said conductor, and means for permitting said ringing current to pass or for blocking said ringing current 'depending upon the class of the connection set up.

35. In a telephone system, an operators switchboard, an automatic switch, a spring jack at said switchboard, a trunk line extending t'roin said spring jack to vsaid automatic switch, a normally open point in said trunk line, an operatoi"s cord circuit having a plug adapted to cooperate with said spring jack, a calling device at said switchboard for controlling said automatic switch to extend a connection to a desired line, means for connecting said calling device to said cord circuit aiter the same has been connected to said trunk line through said plug and jack, and means responsive to the connection of said calling device to said cord circuit i'or closing the normally open point in said trunk circuit.

3G. In a telephone system, an automatic switch, an operators switchboard, a trunk line extending from said switchboard to said switch, means in said switchboard for extending a connection to said trunk line, the last named means including a plug ending cord circuit, a calling device, means for connecting said calling device to a talking strand of said cord circuit, means responsive to the last named means for closing a control circuit for said automatic switch including a conductor of said trunk line, a strand of said cord circuit, and said calling device in series, said automatic switch being responsive to the operation oi said calling device to further extend said. trunk line, and means responsive to the disconnection of said calling device from the cord circuit to close a local holding circuit for said automatic switch independent of said cord circuit.

37. In a telephone system, an automatic switch, an operators switchboard, a trunk line extending from said switchboard to said switch, means in said switchboard for extending a connection to said trunk line, the last named means including a plug ending cord circuit, a calling device, means for connecting said calling device to a talking strand of said cord circuit, means responsive to the last named means for closing a control circuit for said automatic switch including a conductor of said trunk line, a strand of said cord circuit and said calling device in series, said automatic switch being responsive to the operation of said calling device to further extend said trunk line, means responsive to the disconnection of said calling device from the cord circuit to close a local holding circuit 'for said automatic switch independent of said cord circuit, and means responsive to the breaking down of the said connection at the switchboard tor opening said holding circuit.

38. In a telephone system, a connector switch having a release magnet and a release relay for controlling the circuit oi" said magnet, means :for operating the switch to extend a connection to a desired line, contacts forming a part of the circuit of said release magnet and also a part of the circuit of said release relay, and means for opening said contacts responsive to the said operation of said switch.

In witness whereof, I hereunto subscribe my name this 22d day oiE August, A. D.,

JOHN WICKS.

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