US1667830A - Telephone system - Google Patents

Description

May l, 1928.

May 1, 1928. 1,667,830

H. W. ULRICH TELEPHONE SYSTEM Filed Dec. 23. 1926 3 Sheets-Sheet 2 w s h@ n. m I Q n 6 & l N w, Rm .n lle h NUN V n www p 5l -@Q m @M 2M QW: gq

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i tJNfirEn A frE-S; P=AT*EN1- Honkcnfw. Unnlci, voiisns'i ORANGE@ NEW JERSEY. Assmnon Tonarm T'Enninfonn y LABBJA'TORIES, INCORPORATED, or NEW YoRKyn. Y., e: CORPORATION oFNEW Yo'n'ii TELEPHONE SYSTEM. i

` Application flied ncemier 2e, ieee. serial No. 156,576.

This invention relates to telepl i one, sys tenis ,and more particularly to straightfoi wardtrunking systems.

In accordance with .this invention there is provided means whereby seizure of a straightforwardtriink and the actuation of a keyindividual thereto'causes the;coiinec` equipment is recoiiiiecte'd toV the trunk andn a tion to said trunkfof" control equipment common to a plurality of trunks.

Another feature of the linvention resides" a key controlled Vmeans whereby said in trunks may be divided intogroups, each group normally assigned for use with a certain control equipment and whereby the common control equipments may be'trans-- fei'red or arranged in any y-desired nianiiei` so that any one or more control equipments may be usedifor association with any trunk in any of said groups orbe restricted for.

use with any particular group or `groups of any one of said trunks.

Other, 'more speciiicfeatures ofthe invention, as applied toa system in which a control equipment iiia'y coiiiprisea ringing key equipment" and a Boperators telephone set arrangedfor association with the incoming end of said trunks, may be out-lined as follows An arrangen'ient whereby only one trunk at time may be connected to the `common control equipment, tliatis7 the oper-l ationl of the individual key` of one 'seizedl trunk will be ineife'ctive while another trunk is connected to the operators telephone set and ringing key equipment.

An arrangement whereby a tone signal comprising one-or more impulses" of tone current is transinittedoyer a seized' trunk to an A operators position after the individual key is operated but prior tothe actual connection of'tlie B operators telephone set to saidA trunk. i

An arrangement whereby the desired ringing key may/be operated toset the ringing Yequipment of an associated trunkeither before or after the trunkis connected to the wanted subscribers line'.`

y vAn arrangement whereby An arrangement whereby the conin'ioiiv control equipment is prevented from being reconnected to a trunk7 until a trunk is dis` `the usualpilot light common to the trunks in a" group isf connected'froin the wanted su'bscribers line" andthe A operators' cord is' recnn'ected tb' the tiunk at the A operators position. y

A ii arrangement whereby the reringiiig'of a called subscriber is prevented uiitillthe yconf nection to the subscriber has been taken44 down and ieconiiected land the ring-ing key, thereof actuated. This 'iiyention has "igeniiiseraitd infile accompanying ydrawing in whichA Figl shows la straighttorwiard trunk eiiib'odyiiig certain features of thefiiiveiitioiiand in 'dia` gaininiaticforinga `calling subscribes line;y the ack of a wantedsubsciibeizswliiie and A operators cord circuit for= coriiiectingJ the callingsubscribers liiie" with the "oiitgof" ing end of' the straiglitforwai'ditrunkl 2 shows a circuit arrangement wherebyv a pli'irality of groups'of. trunl s'? of' the kiridjk shown-in Fig. l, may be variously arranged or'association with,` c'onnnon ringingy k'ey'V equipment's`- and B operatoi-s teleplioneV sets. In 3 has b eeir'sliowii'a Vc`on'iifiio`nringing key equipment and' aniassocia'ted` B operators telephone seit; which-'is nforinally associated for use withtlie groupy of trunks,v of whieli'tlie 'ti1iiik shown ii' i Figf 1 is one. Fig. 4 sh'owstlie manner Iiii'wliicli Figs. lto maybe assembledfor the read! ingof lthe circuits. l

It should. be rstoodftliaththe paiticui` lar system shown is merely illustrative of the invention and thattlie iiiife'ntion is plicable to systems of different'desigiis with outl departing from the' spirit tliereot`.'

Referringfnowto the drawings, it: is suinedi'tliat the calling subscriber of lineV 10h hasj been connected to the Astraightro'rvtia'r'cl-.` trunk STtlirougli an AH operators cord 10B andijacks'lOQand 104i'. The''following"` description will relate l*`irst, to the associa-l tion of ther common ringing key equipment and tlie B Loperators set shown in Fig.' Sto this .trunk on the operation of key 123, and to manipulationsofthe party line ring.; ing keys in the coninion ringinglnejyeqhuip-y inent to prepare the ringing equipment associated with the trunk ST iortlie transmission ofa ringing signal to Ia wanted Asubsciibers line 110,' wlieii-the operator inserts lier' pluglll intojack 112- oii this line, and howVVV thecominon equipii'ient is released from trunk ST after the manipulation of tlie'ringing' 1,ee7,eso

relay 3115. It is noted that this `circuit is traced through ythe lower, outer armature and front contact of relay 328. Itis evident by examining the circuitthat this relay is operated as soon as the operators telephone set 321 is connected through the jacks and plugs 330 to the repeating coils 331." That is, When thisconnection Iis made a circuit is completed for the operation of relay 332 through the operators transmitter and the operation of relay closes an obvious circuit for the operation of relay 328. Hence, these two relays remain operated as long as the operators telephone setis connected at this point. Relay 326m operating connects the. secon lary 'Winding of repeating coil 334 Vto the tip land ring leads now connected through the operation of relay 127 to the conductors of trunk ST. This ircuit may fbe traced from the tip and ring conductors of trunk ST fAthrough the upper outer and lower outer armatures and front contacts of 4relay 1270 tip -and ring Vconductors and 134,' 'upper and lower inner armatures and back contacts of `relay 327, upper outer and lower inner armatures and back contact of relay `336, uper outer and lower inner armatures ant fron-t contacts Vof relay 326 through the secondary Winding of repeating coil 334. The primary winding .of this repeatingcoii is connected through the operation of relay 326 as follows: ground, secondary Winding `of repeating coil 337, primary Wind-ing of repeating ceil 334, lower outer armature and front .contact of relay 326, make-beforesbreak contactsofrelay 338, lower armature and back Contact of relay 340, upper .inner varmature and back contact of relay `336 to ground at the inner upper armature and front contact A.of relay 326.` The secondary Winding of repeating coi'l`337 is associated aviththe ringing source 325 so rthat an impulse of tone current is now transmitted from this source through trunk ST toithe A operators telephone set connected :to cord 1103. vrllhe operation of relay 326 now closes an obvious ,circuit for the operation of the sloW-to-operate lrelay y 338. y'Ilhis relay operates after a short interval and opens the circuit for the secondary Winding yof repeating coil 337 and the primary Winding of repeating coil 334i, so that the simpulse of tone ciufrent applied through these windings to the `trunk AST is cut `off as soonas relay 338 operates. The operation `of relay '338 closes an obvious circuit for `the operation of the sloW-to-operate relay 3.42. `Relay `342 lin operating again closes a circuit for the Vcoupling between the ringing source 395 and the secondary Nvinding ofrepeating` coil .334 Joy yclosing a circuit that new extends through the lower armature :and front vcontact of relay v338, the lower armature and front .Contact of relay 342 through r.the `,lower armature and baclr relay 340 the circuit for :the secondary Winde ing of repeating coil 337 and primary Winding yof repeating coil 33d is again opened this time atthe lower armature and back Acon.- tacts of relay 340. Consequently, `the `second application of tone current to the trunl is disconnected `as soon as relay `34.0` operates. The operation `of relay 340 closes an obvious circuit for lthe operation of relay 336 and this rela-y in operating closes a locking circuit for itself to ground `at :the inner upper armature and front contact 0f relay i326. Relay 336m `operating opens the connection for the vsecondary Winding of repeating coil 334 to the tip, and ring conductors of the "trunl: and also .the `original circuit through the secondary winding 4oit repeating` coil 337, As long as relay 336 'is operated7 no further application lof tone current will be made during the connection of the circuits shown 'in Fi 3 to Lthe true-.l 1ST. On `the opera-tion of relay .336 .the operator"s telephone set 321 is connected through ithe repeating coils `331 to the tip and ring conductors of trunk ST at the upper router and inner lower armatures and front contacts of relay 3BG. Thus the tone signals are sent before the operators telephone is connected to the truuk` ST. y

The operation of relay i127 connects certain other kleads between `the* common ringing key `etpiipment andthetrunk ST, vsuch as leads 13G, 13.7 and 13S, for the ycon-trol of the ringing equipment associated with the trunk through manipulations `of* the yringi-Ilg keys 322.

As the B operatoi"s telephone is now connected te the trunk and the A operator has received a signal to thisetl'ect, this latter operator will `pass the information for the extension .of a connection `by the l5 operator and the B operator will operate the corresponding key in the common ringing key equipment. If the subscriber Wanted is on a party line the corresponding party line ringing key is operated. For example ifa party Mis Wanted key M is depressed :and the following operations will take place .to prepare the ringing equipment associated with trunk ST for the sending of the proper signal when the plug lll of trunk ST is associated With jack 112. of a party line 110.

As key M is depressed relay 344 is op-` erated through an obvious circuit. This relay in operating ilirepares a locking circuit for itself through its right hand rarmature and front Contact to ground at the left hand armature and` front Contact `of relay ,319., The operation of relay 34e `causes circuits to be completed for the operation of relays 1453 lilo and 14A. The circuit for relay 143 may be traced from battery, winding of relay lll-5l. middle lower armature and front contact ol relay 127, lead 13G, left hand armature and a front contact of relay 311- to ground at the left hand armature and front contact of relay 310, while the, circuit lor relay 111 may he traced :troni battery through the winding ot' relay 114, middle upper armature and 'lront contact ot relay 127, lead 13H, left hand armature and a 'liront contact olA relay :lilto ground at ther lelt hand armature and front contact of relay 31,1). These relays lfll and 11i provide locking circuits' lor theniselves through their right hand inner arinatures and front contacts to ground at. the innei left hand arinaturc:-: and lront contacts of relay 117 when this relay operates as will be described presently. Relays 1423 and 111 in operating connect ringing current :trom source lor the subsequent application to the tip conductor oi the trunk ST as follows: source 11:3, lett hand arlnature and front contact otl relay lill, winding of the alternating current rcsponeive relay or the socalled ringing trip relay 1151, outer left hand armature and `lront contactof relay 111 and the l'ront contact associated with the Lipper outer armature ot' reiay llo which is connected to the tip conductor ot trunk ST. The operation ot rcla y l-l-lapplies a ground at its inner lcl't hand arinature and tront contact to the liront contact associated with the lower armature of relay 140, which is connected to the ring conductor of trunk CT. Thus, the operation oi key M prepares the ringing equipment associated with trunk ST lor transmission ot' a signal for party M on a line when the trunk is connected therewith.

The operation ot' relay 2541: also closes a circuit for the operation ot' slo\\'toope1ate relay 345 as follows: battery, winding of relay 345. right hand armature and a front contact of relay l-lto ground at left hand, armature and front contact of relay 2115). Relay ll-5 in operating cloes a circuit to battery for the operation of relay 11T as follows: battery, right hand armature and frontl contact of relay 315, inner right hand armature and front contact ot relay 310, lead 1,37, inner lower armature and front contact oll relay 127, winding ot' relay 117. arnlature and back contact ol' relay lll, inner .lefthand armature and back contact ol' relay 112 to ground. Relay 117 in operating completes a locking circuit l'or itselt lroin battery at its inner right hand armature and liront contact to ground at the inner lel't hand armature and back contact of relay 112, and also completes the above mentioned locking circuits l'or relays 113 and l-l-l.

The operation of relay 117 by opening its inake-belore-break contacts to battery opens the energizing circuits for relays 108 and 127, which are now released to disconnect the leadsl 130 to 138, 131, 133 and lil-'l from the trunk ST.

Relay 108 in releasing opens the circuit for the flashing ot' guard lamp 121, and this lainp will now be lighted with a steady light over a circuit as follow-i: battery, lamp 121, outer inner armature and back contact of relay 108. right hand armature and back contact ott relay 112, iniddlc right hand armature and lront contact ot relay 117, inner lower armature and back contact ol' relay 115, winding ol relay to ground. Thus, the pilot lainp .120 is maintained lighted and the lanip 121 will be steadily lighted. The steady light ol' lainp 121 indicates to the li operator that the ringing equipment associated with the trunk has` been set by a ringing key.

1t the ringing key J is operated instead ot key Ill, relays 111 and 117 will operate. In this Aase ringing current troni source 147 is connected l'or association with the tip conductor ol trunk S'l and ground is Connected Yl'or association with the ring conductor.

Il ringing key R is depressed, relays 117 and 113 are operated. In this case current troni source 115 is connected 'or the ring conductor and ground for the tip conductor of trunk ST.

it ringing key W is operated relay 117 only is operated. In this case current from the ringing source 141-7 is connected for the ring conductor and ground for the tip conductor. When the trunk key l is operated relays 117, lei-et and 143 remain unoperated and thereby prevent the setting ol1 the ringing equipment in trunk ST. lhc circuits in this case only `function to release the coniinon control equipment from the trunk. That is, the operation of relay 317 closes a circuit for the operation of relay 317. This relay in operating opens the holding circuit for relays 316 and 127. It, should be noted that relay 1,08 would, under these circumstances, remain actuated and lamp lill would continue to ilash. The trunk key 'l would be operated when it is desired to eli1ninate the ringing and connect the trunk for supervision or other ]'iurposcs but not Vtor extension to a wanted subscriber as is well known in the art.

As stated the lainp 121 would ordinarily be lighted steadily to indicate that the trunk is ready for extension to a wanted suhscribers line. Hence, the operator will now insert plug 111 into jack 112 ol the desired line. llt-lay 115 will now operate through the sleeve circuit. The operation of relay 115 connects the tip conductor to the contacts of relay 146 and causes the guard lamp 121 to be extinguished on the opening ol* the circuit therefor at the lower inner armature and back contact ol this relay. The operation of relay 115 also closes a circuit for the llltl lll?) llo Loperate while ,relay `tact of relay 144, upper inner armature and backcontactot relay 146 and the winding oi' this relay, outer right hand armature and Vfront contact of relay `117, lower outer armature and iront contact of relay 115 to ground at the armature and rontcontact of relay 106, that is, provided relays 143 and 144 are in released condition which would be the ease if the WV `key had lbeen operated.

If `either or both of the relays 143 vand 144 were operatedas would be-the case when M, J or lt keys are operated, the circuit for theoperation of relay 146 will extend from the 'battery through pick-,up interrupter 149, outer left hand armature and front contact of relay 117, outer right hand armature and front contact ot' relay V143 or make-beforebreak contacts ot relay 144 to 4the upper inner armature and ,back contact of relay 146 and from-there to the ground at the armature and front contact of `relay 106 as hereinbe'liore traced. The fparticular'type o'li ringing system shown here is that known as foui'fparty semi-selective in which ringing current is connected to either the tip or ring conductor and the two stations on the selected conductor are called by a one or a two-ring code. The pickup' interrupter 149 is necessary to avoid mutilation of the two-ring code and, although its' use is not necessary 'in ringing parties J and lV, it is used in connection with party J merely as a matter of `convenience in arranging the circuit details. A system of Vthis nature is shown and described .in Patent 1,609,395

granted to R. S. Bailey, December` 7, 1926.

lrlelay 146 yprovides a locking circuit ior .it-

selthrough its makebeforeebreak contacts to battery at the upper inner armature and front `Contact oi' relay 1 15. Relay 146 in operating opens the short-circuits across the ring back condensers 150 and 151 "ter the tip and ring conductors of the trunk and connects ringing current to the tip and ring conductors of the. trunk at its upper outer armature and front contact and jlower armature and Jfront contact in accordance with the various settings of the relays 1,43, 144 and 117 as hereinbefore described. Thus the wan-ted subscriber will be called as soon as his line is connected to the trunk.

It Aplug 111 has been 1inserted into `jack 112 before the operation of Aa key of the common ringing key equipment relay 115 will 146 would remain released and the lamp 121 will continue to flash, due to the fact that relay 108 would then still be maintained operated through its left hand winding. Lamp 1,21 would theretore indicate to the operator that a ringing key should be actuated. When any of the ringing keys are'now actuatedthe circuits-of the trunk and 'the I common equipments, operate in the same -manner as hereinbefore described, that is, fthe operation jot relay `-117` `will cause the releaseo'frelays 127 and 4108 and thusfdisconnect the'common ringingkey equipment -and the -operators telephone set` from the trunk, as hereinbe'fore described. The release of relay 10S causes the lamp 12121 `to be extinguished 4and `the-operation of yre- Alay 117 ,causes'theoperationof relay "146 as hereinbetore described to apply ringing current to the-wanted subscribesline.

When now the Wanted subscriber answers the call by removing 4his Yreceiver tromthe hook, the trippingrela-y 141 opera-tes, which causes the release of relay 117. Relay 117 yiin releasing causes the release-ot relay =1461a-nd either or both of the -relays 143 and 144,i"f they are operated. Relay 1461'thereforedisconnects the ringing current from `the l'ine, releases the tripping -relay :141,1a-nd1short c`ircuits the condensers 151 `and v152 in thetalking connection, rwhich is thereby completed through lthe trunk. It should -be noted that the called subscriber cannot-be -againicalled unless the connection `istaken down and reestablished as Athe relays 143, i144 and 1147 have been released and consequently `a new setting of these relays must be effected.

On the release 'of relay -146 the supervisory relay 152 Vwill operate. The operation of this relay short-circuits the right hand high resistance winding of relay 105, thereby Eincreasing the current Atlow through the'trunk, which is suiiicient to cause the usual supervisory relay in theA; operators'cerd "103A to operate and extinguish the `supervisor-y lamp. This indicates lto the A operator that the connection has been extended to the wanted subscriber and that conversation may now begin,

'It' an attempt `-is made to reconnect `the common vringing key equipment 'before the trunk has been disconnected 4from thewv-ant-l ed subscribei"s line by yoperating -the trunk key 123, this attempt will Anot `be successful as relay 108 is released and consequently there will `be no circuit to battery atV relay 117 for relay 127.`

At the end of Athe conversation when the called subscribers receiver is replaced en the hook relay 152 `will release. The release of -tll tore-break contacts ot relay '10G to `ground. ARelay l-lZ in operating locks to ground at its inner lett hand armature and front Contact and hy operating its right hand armature closes an obvious circuit for the lighting of lamp 121. The lightingr of this lamp indi- 'ates to the B operator that conversation has ceased and that the connection may he taken down. She will then remove plug` 111 from jack 112, which causes the relay 115 to release. This relay in turn will release relay 142 and cause the lamp 121 to he extinguished. thus restoring the circuits to normal.

If the Ai operator should ahandon the call hetore the called subscriber answers the ringing would he discontinueiil and the disconnect lamp lighted as relay 112 would operate to release relay 11T which would in turn release relays 1413 and lll.

In reference to the arrangement for grouping the trunks and transferring the common control equipments from one group to another, a description will now he made of a circuit for this purpose which is shown in Fig. Q. It is evident, however, that other arrangements can he made than that illus trated and this arrangenient should he considered only as illustrative of the invention.

The common control equipment shown in F ig. 3 is normally ar 'anged for use with a group of trunks to which the trunk shown in Fig. 1 belongs and' also for a group of trunks terminating in the leads marked 200. Two other groups ot trunks may terminate in leads such as Q01 and Q02 respectively and leads marked may tern'iinate in a common control equiijunent identical with that shown in Fig. Il normally arranged 'tor use with said last mentioned two groups of trunks. Vertical groups ot relays marked 210. 211. 21:2 and Qlfi are controlled res'l'icctirely hy means o'l" keys Qli. 210. i217 and SIS to transfer control equipments such as shown in Fig. 3 for use with other groups ot trunks or for comhining a plurality of groups ot' trunks for association with ay certain control equipment or equipments in any manner desired.

For example. if it is desired to prevent the control equipment connected at 203 from heilig used in connection with the groups oic trunks terminating at Q01 and 202 and to transfer these trunks tor association with the common equipment shown in Fig. 3, key 215 is left in its normal position to leave the group ot relays 21() in their normal nonoperated position while key 216 is operated to release the group of relays 211. This connects the leads from the points 201 and Q02 through the armatures and back contacts of the relays in groups 210 and 211 that are required for the use of the common equipment shown in Fig. 3 in connection with these two groups of trunks. The operators telephone set of the common equipnient, type terminating at 20?) is also remored l'rom the use ot this etuiipment. ln this case, therefore, a call incoming Afrom any trunk in either ol the groups terminating at QUI or 202 will cause the common equipment shown in Fig. P to he connected to said trunk in the saine manner as this equipment; is connected to any ot the trunks in the group tern|inat1 ing at Q00 and to any ol the trunks in the group to which the trunk shown in Fig. l helongs.

For example, it a trunk of the group tei'- minating at Q01 initiates a call. the t'ollowing circuits are estalilished on the operation ot` the correspoiulingr hey: 'l`he tirst circuit to he closed may he traced as follows. l'roni hattery lsupplied through the winding of the relay of the, trunk that originates the call correslionding to relay 12T ot trunk S'l to lead Q correspondingr to lead litt) to ground at the lett hand ari'nature and hack contact oi' the relay, in the con'nnon control equipment; connected at Q0?. cmresponding to relay 'll. This causes the operation ot the relay in this trunk corresponding to relay 12T to operatic. The operation of this relay prepares a locking circuit for itsel` which may he traced through the upper arnniture and front Contact of this relay through lead 5281 correspondin;r to lead 131 through the relay corresponding to relay 316 to ground at the armature and'tront contact of the relay corresponding to relay 317 in the control equipment connected at; i303. The operation of this relay provides a ground for the op eration ol the relay correspomling to relay 315 as well as the relay 315. 'l`he circuit l'or the operation of' these two relays may he traced as follows: from haltcry through ther winding o't the relay corresponding to relay 315 of the common equipnlcnl connected :it 2053. to ground at the inner right hand armature and liront contact ol' the relay correspending to relay 'lt in this equipment. while the circuit for the operation ol` relay 315 may he traced Afrom hattcry through the winding oil. relay 315, lead Q51. lower outer armature and hack contact ol1 relai' .l.

`lower outer armature and hack contact ot' relay Q58. lead 255. to ground at the inner right hand armature and l'ront contact olf the relay eorrespoiuling to relay lt' in thc common equipment connected at 2h13. The operation ol` the relay correspondiner to rclay BIT causes the operation ol' the relay corresponding to relay Il!) in the common equipment connected at 5203. hut no l'urther operation of relays takes place in this common equipment as the operateur; teleplmne set is disconnected therefrom and consequently, the relays corresponding to relays 332 and 328 are not operated.

The operation of relay 315 in the equipnient shown in Fig. 3 due to the connection tlll lull

llt)

nemesio ofA the operators' telephone set 321, however,

operates to associate the ringing key equip-- ment andthe operators telephone set shown in Fig. 3 with theseized trunk in the' group connected' through leads 201 and it will function as' hereinbefore described in connection with this trunk in the same manner as it functions when it was connected to trunk ST.l

Itfwill be noted that the leads in this trunk corresponding to the leads 136, 137 and 138 Will be connected as follows tothe common equipment shown in Fig. 3. The leadcorresponding' to lead 136 is identiied aslead 236 and may be traced to the common equipi'nentin Fig. 3 over the lower inner armatures and back contacts ,of relays 258 and 2,53' to lea-d '136;` while the lead correspondin'to lead 137I is marked 237 and may be tracel through the upper outer armatures and hack` contacts of relays 258 and to the. leadf 137 and finally the lead Corresponding' to lead 138 marked 238 and may be traced through the upper inner armatures an'dffront contacts of relays 258 and 253 to lead` 138. The talking leads of a trunk connected at 201 corresponding to leads 133 and 134 from trunk ST are marked 233 and 234 respectively and* may be traced through the upper outer and lower outer armatures and back4 contact of relays 267 and 256 to leads 135 and 134k respectively. The busy test lead frornythe trunk connected at 201 may b'e tracedfrom lead 240 to the upper and lower inner armatures and back contacts of relays 267l and 256 tothe lower inner armatures and front contacts ot relay i328 to the loW'eu' busy test Winding 360 tol ground. The lead in the trunk ST corresponding to this busytest lead 240 is marked 1410. T he ea'd in the` trunk connectedat 201 corresponding to lead 124; in trunk ST that leads to the flashing equipment tor the lamp correspoi'iding to la'fnp 121 is marked 224.

The above description of the use of a common equipment such the' one shown in` Fig, 3 for trunks associated with leads 201 is illustrative" of the connections that can be made for using al common equipment for any ,number of groups of: trunks by means of the transfer equipment shown in Fig. 2. If it is decided, for example, to have the trunks connected at 202 served by the common equipment shown in Fig. 3 and exclude the trunks connected at 201, key

`215 may be operated to actuate the relays 267, 257 and 258. In this manner the operation of a key of a trunk of the group connected at 201 will not cause the operation of" the relay 315 of the common equipment shown' in Fig. 3 While the operation aV "key of a trunk of the group connected at 202-` will cause such an operation. It seems unnecessary to trace the circuits for" doing this, as 1t is evident that it 1s done in a simi-liar manner tothe operation of this relajjf' from a trunk connecting at leads 201; However, to illustrate the use of relay 257 in this connection, it should he noted" horsT the lead from the group of 'trunks terminating at 202, corresponding to lead1230, is out ett from 230 at the upper inner armature and back contact of relay 257 and connected to lead 259 which in turn is connected to lead 130. Similarly, the `operation of the rela-y' corresponding to relay. 362, and the-lightingH of' the lamp corresponding to lamp 363, in place of the yoperation of the relay corre-Y sponding to relay316 and the lighting oit, the lampcorresponding to lamp 318 in Fig'. 3 when a trunk of the groupy termii'iating at' 202 is initiating a call t'o indicate theE .tact to the operator that trunk in this group initiatinga callis established over they lead 260. The circuit in'this case may be` traced asfollows: from battery at the inner upper armature and front contact of the relay corn responding to relay 127, through the' leadi 261, Winding of the' relay' corresponding'to relay 362 lead 262,'upper' armature andE front Contact of relay 257 leads 260 and" 263, arm-4 ature and back Contact of' relay 3:17 to ground. i

It may also be illustrated howzlead 265 is employed.` This' lead is' normally not conr pleted when only the groupy of trunks ter-` minating at 202 is associated for'use with the common equipment shown' in Fig. 3, eX- cept When both groups of" trunks terminating at 201 and 202 are associated for' use with the common equipment shown Figt 3. In this lattercase, both the relay 317, and the relay corresponding toj this relay in the common equipn'ientl connected at 203 are connected through to the battery at the outer left hand armature andl front `contact oi relay 3&7 so that these relays operate on the actuation of the' trunk key T to release the relay 316 and the relay corresponding to relay 362 in the common equipment connected at 203'. The` circuit i'n this case is as follows: battery, right hand arma-ture and front Contact of relay 347, Winding of relay 317 to ground, and from the above men'- tioned battery throughleads `266 and 265, lower armatures and back contacts of relays 269 and 257 and lead 26dto ground, through the Winding ot the relay corresponding to relay 317 inthe common equipment connected at 203. y

To further illustrate the flexibility oty this lsystei'n :for transferring oity the trunks normally assigned to be controlled by one control equipment to be; controlled byanother equipment, it should be'inentionedthat it is notY necessary for an operator" to use the particular key equipment assigned to "be used With certain groups of trunks When such trunks have `been transferred thereto,A but that the keys o another control equipment, i

notalily the keys of the control equipment to which these trunks are normally assigned, may he employed to set the ringing equipment of a calling trunk in any of said groups of trunks. It is quite evident from the drawings that this may he donc, as the relays 31,5. 317 and 362 or Siti and all other correspondiiig relays in each equipment. tor the `groups or trunks tranterred are oper ated. Consequently the keys ol2 all these control equipments are normally availalile. The purpose of this arrangement to enable an operator to `sit at any position ot' the positions segregated and while she will connect her telephoneI lset with one ol thel control equipments she may use the keys ot the same or any other control equipment the trunks of which have heen transferred. It seems uimecessary to describe hov.' this is done in much detail as it is readily seen that, for example7 it the operator has her telephone set connected to the equipment shown in Fig. 3 and the groiqis oit trunks terminating' at 201 and Q03 have heen transferred to he controlled hy this equipmei'itl the keys of the control equipment terminating 'at 203 may be used to set the ringing equipment in any of the trunks calling; in any of the groups teri'ninatinp' at Q01. Q02. 200 or in the group to which trunk ST lie,- longs in the same manner as the keys 322 may be used Ltor this purpose.

What is claimed is:

l. In a telephone system, a. plurality of lines, a ringingr key equipment and an operators telephone set common to said lines, a key individual to each of said lines and means responsive to the initiation ot ar call over a` line and to the operation ot' the corresponding key for associatingr the ringingr key equipment and the operators telephone set with said line.

2. In a telephone system a plurality of calling lines. a ringinpr control equipment and an operators telephonel set, common to said lines` a. key individual to each line, means individual. to a line responsive to the seizure of said line for preparing it for the subsequent connection thereto of the common ringing' equipment; and the operatoi"s telephone set and means responsive to the actuation of said means ot a seized line and the actuation of the corresponding key for connecting the common ringing" equipmentl and the operator`s telephone set to said seized line.

ln a telephone system a plurality ot; calling lines, a ringingr control equil'nnent and an operators telephone set common to said lines, a key individual to each of said lines, means individual to a line automatically responsive when a call is incoming thereover to prepare said line tor the suhsequent connection of the ringing control equipment and the operators telephone set to said line on the operatimi of the corre.- spendingr key.

4. In ay telephone system a plurality of lines, a connnon control equilfnnent for said lines, a key individual to each of said lines, means responsive when a call is incoming over a line and the correspondinpr key is operated for connecting said control equipment to said line and means for preventing more than one ot .said lilies trom lieinpr connectcd to the connnon equipment at any one time.

In a telephone system a plurality of lines. a ringing1 key equipment and an oplratorls teleplione .set common to said lines, a key individual to each ot said lines.y means responsive to a call incomingover a line and to the operation ot thel corresponding key tor associatinpr thc ringinpr key etpiipment and the operatons telepllone sety with said line and means in said line responsive to the operation ol the rin;'in, f T key equipment 'tor preparina .said line for the transmission ot a signal thereover.

tl. In a telephone system calling lines, called lines. a ringingr key equipment and an operators telephone .set common to said callin a' lines, a key individual to each of said callingij lines, means responsive to a call incoming over a calling line and to the op- 0 eration oi the corresponding key for associatinethe ringing key equipment and the operators telephone set with said line, meansy for connectingr said calling;r line to a called line, and means Iin said calling line responsive to the actuation of the ringing key equipment for preparing; said line for the transmission of a. signal over the connectcd called line. the preparation of said means for the transmission of a signal beiner M5 effected regardless of the operation of the ringingr key equipment hel'ore or after said callin;r line is connected to a called line.

7. In ay telephone system calling lines, called lines, a ringing' key equipment and an operato1"s telephone set common to said lines, a key individual to each of said calling lines7 means responsive to a call incoming over a callingr line and to the operation ot the corresponding key l'or associatine` the ringingr key equipment and the operatoi"s telephone .set with said line. means for conneetii'ie' a. callingr lino with a called line, means in said callinga line. responsive to the actuation oit the ringing: key equipment for the transmission olli a signal to a called line when said called line is conmicted to said calling; line and means for automatically disconnecting the ringing key equipment. and the operators telephone set from said calling' line responsive to the actuation of ringing key equipment.

8. In a telephone system lines, a ringing key equipment and an operators telephone set common to said, lines, a key individual 13u txt) lttt.)

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to each of said lines, ringing means individual to each line, means responsive to the seizure of a line and the operation of the key .individual to said line for connecting the ringing key equi ent and the operators telephone set to sa l line and for setting the ringing means individual to said line in accordance with the setting of the common ringing key equipment and for thereafter removing the common ringing key equipment and the operators telephone set from said line.

9. In. a telephone system incoming lines, outgoing lines, means for connecting an incoming line with an outgoing line, ringing means individual to each of said incoming lines, a key individual to each incoming line, a ringing key equipment and an operators telephone set common to said incoming lines, means responsive when a call is incoming over a line and the corresponding key is actuated to connect the ringing key equipment and the operators telephone set to said incoming line, means to prepare the corresponding ringing means ot said incoming line lor signaling under control of said common ringing key equipment, means re'- sponsive to said last means for removing the operators telephone set. and the ringing key equipment Jfrom said incoming line Iand means for actuating said ringing means to transmit the prepared signal to an outgoing line effected on the connection of said incoming line with said outgoing line.

10. In a telephone system a plurality of groups of lines, a control equipment for each group of lines, a key individual to each of said lines, means responsive when a call is incoming over a line and the corresponding key is operated for connecting the corresponding control equipment to said line, and means for eliminating a variable num# ber of said control equipments from the rcspective groups of lines and substituting a variable number of the remaining control equipments therefor.

. 11. In a telephone system, link circuits, called lines for association With said link circuits, a ringing equipment individual to each link circuit, a ringing key equipment common to said link circuits for controlling said ringing equipments, means responsive to the appropriation of one of said link circuits for associating said common ringing key equipment with said appropriated one of said link circuits, means for disconnecting the common ringing key equipment from said link circuit in response to its operation, and means for preventing said common ringing key equipment from bein(T reconnected to said link circuit until alter said link circuit has been connected to a called line and disconnected therefrom.

12. A telephone systemcomprising lines, a control equipment common to said lines,

a key individual to each of said lines, and

means responsive to the seizure o'ione of said lines andthe actuationoi its individual key for temporarily and exclusively con necting saidcontrol equipment with said seized line, characterized by the provision of means for transmitting a signalcoinprising a plurality of impulses ot tone current over said seized line during the operations incident to the connection ot said control equipment to said seized line.

i3. In a telephone system, a plurality of lines, a ringing key equipment and an operators telephone set common to said lines, a key individual to each of said lines, and means responsive to the initiation of a call over a line and to the operation ot the corresponding key for exclusively associating the ringing key equipment and the operators telephone set with said line.

14.-. In a telephone system, a plurality of lines, a ringing key equipment, and an operators telephone set common to said lines, a key individual to each ot said lines, means responsive to the initiation of a call over a line and to the operation of the corresponding keyv for associating the ringing key equipment and the operators telephone set with said line, and means for rendering the corresponding individualkeys of other lines ineffectivev While said ringing key equipment and said operators telephone set are connected to said line.

15. In a telephone system, lines, individual signals, a common signal, means responsive to the seizure of one of said lines for operating the signal individual to said line and said common signal as a calling signal, and means for operating said individual signal only as a disconnect signal.

16. In a telephone system, a straightfor- `Ward trunk, a signal individual to said trunk, a signal common to said trunk, an operator-s control equipment, means responsive to the seizure of said trunk for connecting said operators control equipment to said trunk and for operating said signals as a calling signal, and means for operating said individual signal only as a disconnect signal.

17. In a telephone system, a straightforward trunk, a signal individual to said trunk, a signal common to said trunk, an operator-s control equipment, means responsive to the seizure of said trunk for operating said common signal and for operating said individual signal in one manner, means responsive to the manipulation of said operators control equipment for operating said individual signal in another manner, and means for operating said individual signal only as a disconnect signal.

18. In a telephone system, a straightforward trunk, a called line, a signal individual to said trunk, a signal common to said trunk, an operators control equipment,

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means responsive to the seizure of said trunk for operating said common signal and for operating said individual signal in one manner, means for connecting said operators control equipment to said trunk, means responsive to the manipulation of said operators Control equipment for operating said individual signal in another manner, means responsive to the extension of said trunk to said called line for disabling said signals, and means for operating said individual signal only as a disconnect signal.

19. In a. telephone system, a straightfor- Ward trunk, a called line, a signal individual to said trunk, a signal common to said trunk, an operators Control equpiment` means responsive to the seizure of said trunk for operating said common signal and for operating said individual :signal in one manner, a key individual to said trunk, means responsive lo the operation ol' said he;7 after said trunk has been seized and said signals are operatingir in the aforesaid manner for emineetingg said operatofs control equipment to said trunk, means responsive to the manipulation of said operalors control equipment for operating said individual signal in another manner. means responsive to the extension of said trunk to said Called line for disabling said signals, and means for operating said individual signal only as a disconnect signal.

In Witness whereof, I hereunto subscribe my name this 20th da)v of December, A. 1').

HORACE W. ULRICH.

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