US1648031A - Party-line automatic telephone system - Google Patents

Description

Nov. 8, 1927. LMHOS 4 L. L. RUGGLES PARTY LINE AUTOMATIC TELEPHONE SYSTEM Filed Aug. ll, .925 2 Sheets-Sheet l Nov. 8,1 192 7.

K 1,648,031 L. L. RUGGLES PARTY LINE AUTOMATIC TELEPHONE SYSTEM Filled Augll 1 92 2 .zets-Sheet 2 1 u I Ji. n I fs I i C1HII\ I l Q ly k1' V i @L Il IH" @2| Sei l a I "1 N l i S *x L,... J L I KL u\ N (fc/ Q c K O g T-O, T-0

CCB'

-f-Inuan m: Lennard L. .Engg/155 lliatented Nov. tl, llr

U Nl'lE@ d g atraen avertir ortica.

WARE.

'IO AUTOMATCC ELECTREC INC., ,GF QHIAGQ, ILLNOIS, A COBORILTON Ol? DELA- fPAR-TY-LNE AUTMATC TELEPHONE SYSTEM.

Application filed August 14h 1325.

The present invention relates to partyline automatic telephone systems7 and the broad general object is thc provision of new and improved circuit .arrauo'enients whereby a call fora party-line station 'that has been disconnected in a codesignalling,v party-line system may be extended to an intercepting operator. f

" Arrangements have been provided in the past in connection With party-line automatic telephone systems in Whichthe subscribers are selectively signalled for routing' only those calls intended :torparty-line stations disconnected from the line to an intercept" ing operator. Y

Jfor doing this have utilised, Auji-uiorally. selective apparatus which practically duplicates the signalling` device at the disconnected station. .vhichrcsponds (only when a call is extended to the line and intended rtho disconnected station) to signal the ii epte ingr operator. Hoivevei; such arrangements cannot be applied to a code signalling system because in that system the only ditl'erence be tween the "al 'for one station and the siginal for another station is in the number or operations of `the rinecrs on the called line or possibly in some instances in the length et time during which the ringers operate continuously.

ln order to provide arrangements tor sig;- nallinze the intercepting. operator only on calls to disconnected stations in a codering'- ing party-line system, a. selectively operable device has been provided for association with a line vtrom. 'which one or more stations has been disconnected. This device is operated simultaneously with the operation ot the code selecting,` switch as the latter selects the particular codeL accordingi to which the called line is to be signalled. ln this y *uy the control of the extension of a connection to the intercepting operator is controlled by the same means that controls the operationoit' the device that picks out the code according` to which the called line is to be signalled, rather than being controlled selectively by the signalling' current after it has been applied to the called line.

lnothcr object of the invention may be stated broadly to be the provision of practical and economical arrangement or the intercepting equipment so that, when the service ot' the intercepting operator is required in connection with a given station on a particu- The arrangements provided Serial No. 50,191.

lar line, this service can be provided economically and Without the necessity of providingl a great number of select-ing` devices when only a few may be actually required at any one given time. The arrangement is such that the number of devices required isno greaterv than the number ot lines that may bc simultaneously in the need of interceptingr service. At the same time, the only changes that need to be made to switch aselecting` device from one line to another is the mere changing` of jumpers at a few points. c

vlleiegring now to the drawings. Fig. l, shows the party line connector C having access to 100 lines, one olz which is shown. The connector C may be reached through lirst, secondq and third selectors, or merely through tiret and second selectors, depending` of course upon the sir/ie of the system of which it forms a part.

rlhe auxiliary code selector CS is associated ith the connector C and it operates after the called line has been select-ed to select the particular code to be applied to the called line in accordance with the station desired.

From a mechanical standpoint the connector C is a vertical androtary switch in which the bank contacts are arranged in l0 horizontal rows or levels7 Wit-h ten sets of contactsin each level.

The code selector CS from a mechanica standpoint is va simple single-motion switch having the Wipers 70 and 71 Which are ad anced in a 'forward direction by the steppingl magnet i8 and which are released to their normal position by the release magnet 72, which is controlled by relay 8 o'l" the connector (l at armature 8l, which relay is in turn controlled by the off-normal contacts @il oi the code selector CS. Y

rllhe party line shown associated with the bank contacts -58 is provided With ten substations Ahlen-10, of which substations ili-l and Ami() are the only ones shown.` Five of the substation ringers are connected from one line conductor to ground and the other tive ringers are connected between the other line conductor and ground. Accordingly, the application ofringingourrcnt to one line conductor allects live ringers and the application of ringing current to the other line conductor allects the other live i'ingrers. The ringing current may be applied to either of the line conductors in any one of five ways, consisting of from one ring to live rings. i

Regarding the apparatus for producing the different codes, -it may be pointed out that the distributer D, Fig. 1, energizes the relays S1 85, successively, and that these relays apply ringing current from the generator S9 to the conductors 76-80 according to the five codes desired, conductor 76 representing one, ring and conductor 80 representing live rings. The particulary code desire-:gl and the particular line conductor over which it is to be applied is determined by the setting of the code selector CS.

Regarding the equipment shown in Fig. 2, it will be noted that the line conductors the private normal conductor corresponding to the line of the substations A-l-A-lO and also a fourth pulse conductor are extended to the left-hand contacts of the cross connect block CCB, one of these blocks being provided 'for each 10() line group. From the right-hand contacts of the cross connect block CCB there is a group of conductors 101 extending to the left-hand side of the intermediate distributing frame IDF. When the apparatus is installed a number of groups of conductors is run 'from the righthand side of the cross connect block CCB ro the left-hand side of the intermediate distributing frame IDF which is suiiicient-ly large to take care of the maximum number of lines that itis calculated will require intercepting service simultaneously in the particular hundred-line group under consideration. This number may vary somewhat in dierent instances but it may for example be assumed to be fifteen groups per 100 lines. This arrangement will take care of providing intercepting service for ifteen lines simultaneously in any hundred line group.

Considering now the intermediate distributing frame IDF, the above mentioned groups of conductors terminate at the lefthand side of this intermediate distributing frame and when the occasion demands any one of these sets of conductors is cross connected in the manner of the set shown to an auxiliary switch AS which then becomes for the time individual to a particular line.

Regarding the number of the switches such as AS required, the number of these switches depends, not on the number of lines simultaneously requiring intercepting service in one hundred-line group, but on the tot-al number of lines in the entire office that simultaneously require intercepting service, which, due to the Well known law of averages, should in all cases fall far short of the total number required simultaneously in any hundred-line group multiplied by the number of such hundred-line groups.

It will be noted that the auxiliary selector AS is similar to the code selector CS. The switch AS carries a single wiper 11() which selects any one of ten conductors according t0 its setting which extend from the associated bank to ten contacts on the associated cross-connect block CCB. This cross-connect block is provided with an eleventh contact which may be connected to any one of the iirst ten by means ot a jumper such as 111 to extend the connection through to the intercepting trunk IT only when the wiper 110 lands on the contact connected up by a jumper such as 111.

Since it- Would be uneconomical to provide a. separate intercepting trunk for cach of the auxiliary switches such as AS, arrangements have been provided whereby a single intercept-ing trunk such as IT may serve a great number of these auxiliary switches. That being the case, arrangements must be provided whereby two calls cannot be extended simultaneously to the same intercepting trunk. That result is accomplished by the relay group RG which is common to as many of the auxiliary selectors such as AS as arf.- associated Wit-h the intercepting trunk IT. It is contemplated that t-Wo or three intercepting trunks can take care of the intercepting calls arising in a ten thousand line office, in which case the auxiliary selectors such as AS are divided into a corresponding number of separate and distinct groups with a relay group such as RG associated with each group of auxiliary selectors.

The manner in which the equipment shown operates will nonv be explained. For this purpose it will be assumed first that the subscriber at substation A-lO is called through the connector C.

IVhen the connector C is seized through the trunk comprising conductors 14.#16, line relay 2 pulls up over conductor 14 and 16 and closes at armature 18 a circuit for release relay 3. Release relay 3 applies ground at armature 2O to the release trunk conductor 15 so as to maintain the preceding switches operated; applies ground to the local locking conductor G3 at armature 19; and at armature 21 opens a point in the circuit of release magnet 11 and prepares a circuit for vertical magnet 12.

Then the calling subscriber dials the next digit in the desired number, line relay 2 falls back a corresponding number ot times and, upon each deenergization, it closes at armature 18 and its resting contact a circuit for vertical magnet 12, the circuit at the time of the rst closure being as follows: from ground by Way of armature 18 and its resting contact, armature 21 and its Working Contact, lower contact of off-normal spring 91 and said spring, series relay 4, and thtl vertical magnet 12 to battery. By the operation of vertical magnet 12 the wipers 51- 54 are raised step by step until they stand opposite the desired level of bank contacts. Relay 4 is energized in series with vertical dbi 15ans-,osi

magnet 12 on the iirst impulse of: current delivered to the latter and` maintains its armature attracted by virtue oit its slow action. The olf-normal springs are shifted at or near. the end ot' the first vertical strolrc with the result that the last part ot the iirst impulse to the vertical magnet as well as all the following impulses traverse a ircuit path which includes the two lower otllnormal springs and armature 22 and its work.- ing contact.

At the end of the vertical movement, relay 4 falls back and at armature 22 opens a further point in its own circuit and that ot vertical magnet 12 and closes a point in the circuit of the rotary magnet 13.

Vhen the calling subscriber dials the nent digit' in the desired number, line relay 3 tallsbaclr a number of times as before and each time it falls baclr it closes a circuit for rotary magnet 13. The circuit ot' rotary magnet 13 is as follows: trom ground by way ot' armature 13 and its resting Contact, armature 21 and its working Contact, the two lower ott-normal springs, armature and its resting Contact, resting contact and armature 32, armature i3 and its resting Contact, and rotary magnet. 13 to battery. By the operation of rotary magnet 13 the wipers 51-5-1 are rotated into engagement with the bank contacts 5th-58.1 9 is energized in multiple with rotary magnet 13 and it remains energized throughout the rotary movement by Virtue ot' .its slow acting arrangement t armature 35 relay 9 disconnects the test wiper from the test winding ot' relay 10 and connects it instead through armature 42 and its resting contact to the busy relay 8, and at armature 3T shunts armature andits resting Contact so as to guard its own circuit and that ot rotary magnet 13 at armature in case busy relay 8 energizes during the rotary movement due to ycertain ot the test contacts encountered by test wiper 53 being grounded.

The operation at the end ot the rotary movement depem s upon whether the called line is busy orv idle. If it is busy, busy relay 8 is energized and it remains energized until the slow acting relay 9. tallsbaclr whereupon a. locking circuit is closed at the normally closed contacts controlled by armature 35 and is as follows: from groundby way ot the grounded release trunk conductor 15, armature 30 and its working contact normally closed contacts controlled by armature 35, and armature 42 and its refting contact to the busyk relay 8. At armature 34, busy relay 3 closes a circuit from the busy signalling conductor T5 through the resting contact and armature l5 and armature 3st and its working contact and the normally closed contacts controlled by armature 23 for applying the busy signalling tone to the lower talking conductor 16. The calling subscriber, on hearing this busy signalling tone, is supposed to replace his receiver whereupon the connector C is released in the usual manner.

Assuming that the called line is idle at the end of the rotary moigement or' the cons necto'r @,busy relay 8 is not energized and as soon as relay 9 tails bach the upper wind-- ing ot relay 10 is included in a circuit as tollows from ground by way ot the grounded release trunk conductor 15, armature 30 and its resting contact, upper winding of switching relay 10, resting contact and armature 35, wiper 53, bank contact 57, 'relay 60, and magnet G2 to battery. Relays 10 and (SO pull up over this circuit but magnet G2 is not operated on account ot the relativelyhigh resistance ot rela f 39. lclav does Vnot operate fully and does not therefore connect up the associated wipers owing to the usual mechanical interlocking device (not shown) between its armature proper and that of the associated line relay til,

- In the connector C, relay 10, upon energizing, locks its lower winding to the local conduct-or 63 at armature fil; opens a point in the circuit of relay 3 at armature 42; pre-V pares a circuit for piclenp relay 6 at arman ture fiel; opens at armature i5 a point in the busy tone circuit; prepares an impulsing circuit to be later discussed at armature 39; and aty armatures 38 and 46 connects up the wipers 51 and (el.` at the same time placing direct ground on test wiper 53 at armature 40. kThe calling subscriber now Vmanipulates his calling device in accordance with the digit 0 so as to bring the wipers 70 and 71 ot the code selector CS into engagement with the tenth set ol the associated bank contacts to apply the correct signalling current to the called line to signal the subscriber at substation lli- 10. The ten impulses ot' current produced by the ten deenergizations of line relay 2 at this time are transmitted over the previously traced circuit to armature ot' switching relay 10, but instead ot going through the resting Contact ot armature 113 to rotary magnet 13 these impulses are sent through the working Contact o't armature Li3 to stepping magnet 73 ot the counting switch CS. By the operation of stepping magnet 73 the wipers and 71 are driven into engagew ment with the tenth set ot associated bank contacts. The oflnormal contacts Tel are closed upon the first step ot the wipers o't the code seleftor CS and they close a point in the circuit ot relay 8. This circuit is not completed right away on account ot the tact that the slow acting relay 9 is energized by the impulses transmitted over the operating circuit7 and this relay, beingl slow acting, remains operatedI throughout the series of impulses.

`When relay 9 falls back it completes at armature 36 a circuit tor relay 8. Relay 3 new energizes but it does not close a locking circuit for itself at this time owing to the fact that armature 42 is operated. Furthermore, the busy tone circuit is not completed at armature 34 on account ot the fact that armature 45 is operated. it armature 33 relay S prepares a circuit -lor piek-up relay 6. rlhis circuit is completed as soon as the Wiper S7 ot the distributor' D places ground on the pick-up Aconductor 86, whereupon piek-up relay 6 energizes and loc is itself to the grounded conductor 63 at armature 2,4-, at the same time opening its initial circuit. At armatures 23 and 25 relay 6 extends the wipers 5l and 53 of the connector through armatures 2Q and 28 and their resting contacts to the wipers and 7l ot the counting switch CS. Ground through the upper winding ot the ring-cutoff relay 7 is eonnected through the tenth contact in the bank of wiper v70 to the said wiper 70 and thene to wiper l ot the connector C so as to provide a circuit for pulling up the ring-cut-oif relay 7. rlhe code conductor 8() is connected through the tenth contact in the bank ot wiper 7l and the said wiper and through armatures 25, 28 and 46 to the wiper 54 to supply ringing` current to the lower talking conductor which is the one to which the ringer oi' the substation ity-l0 is conneted.

As the arm 87 moves over the contacts ot the distributor' D the relays Sltl are consecutively energized with the result that ring- 'ing current from the generator 89 is supplied lire times to the conductor 8O on each complete revolution of the wiper S7. The result is that all the ringers connected between the lower talking conductor of the called line and ground are operated lire times. The ringers which are connected between the other talking onductor and ground are not operated because the ringing current is not applied to that talking conductor. The various subscribers who hear their ringers operating' realize that the call is not for them with the exception of the subscriber at substation A-lO who, upon recognizing his code, answers the call by removing his receiver.

lVhen the receiver is removed at substation A-lO, a circuitis completed tor ringeut-ot relay 7 as follows: trom ground by way ot ring-cut-otl relay 7, tenth ontact in the baul; ot' wiper 70 and the said wiper, armatures 23, 26, and 3S, wiper 5l, bank contact 55, the called line, bank contact 5S, wiper 54, armatures 4G, 28, and 25, wiper 71, the tenth associated bank Contact, and conductor S0 to battery either through the generator S9 or independent of the said generator, depending upon the position of the wiper 87 of the distributor D. Upon energizing, relay 7 locks its lower winding to the conductor 68 at armature 27, and at armatures 26 and 28 disconnects wipers 51 and 54 from the corresponding wipers oi the code selector CS and connects them instead to the windings ol the battery-feed impedance 5. Battery through the impedance 5 now flows out over the called line to ener i'lfe the transmitter and receiver at the substation A-l0. The calling and called subscribers may now converse with each omer in the usual manner. lVhen the con.'er.-1ation is completed they both replace their receivers.

When the receiver is replaced at substation AwlO currentmerely ceases to .flow over the associated line.

When the receiver is replaced at the calling substation, line relay 2 falls back and opens the circuit of release relay il which falls back shortly thereafter and removes ground from the release trunk conductor l5 at armature 20, at the same time removing ground Yfrom conductor Gil at armature 19 and closing the release magnet circuit at armature 2l. Responsive te the removal of the ground petential from local locking` conductor 63, relays 6, 7, and lO 'tall back, and responsive to the removal of ground from the release trunk coneuctor l5 the preceeding switches are released in the usual manner. Respoir're to the closure of the release magnet circuit at armature 2l, release magnet ll eneugizes` through armatures 18 and 2l andL ott-normal contacts 90 and restores the vipers l5-l to their normal position, whereupon the release magnet circuit is opened at armature 90. As a vfurthe; result of the deenergization ot relay 3 it closesl at armature 2O a circuit through armature 3l and its working` Contact for release magnet 72 of the cede selector CS. Release magnet 72 energizes and permits the wipers 70 and 7l to be restored to their normal position, whereupon the contacts 7st open and relay 8 deenergizes and opens at armature 3l the circuit et release magnet T2. The entire connection is now released and the apparatus is ready to be used to set up another connection.

Then the connector C is operated to call a station whose ringer is connected between the opposite side ot the line to ground, for example, the substation A-l, the wipers TO and 7l of the code selector CS are operaated (after the connector C has been set on the called line) into engagement with one of the first live sets of bank contacts. In this case they are operated into engagement with the first set ol bank contacts beause the substation A-l is the one desired. lViper 'Tl engages the first contact which associates the upper windingl of the ring-cutoff relay T with the lower line comluctor. lViper TO engages the lirst ringingI conductor 76 with the result that when pick-up relay 6 subsequently operates as it does in the previously described manner a series of single rings takes place, one ring for each rotation'of the wiper 87 Lof .the distributor D. vThe subscriber at substation A-l answers the call with results similar to' those described hereinbefore.

Assuming now that the telephone service is discontinued at the premises of the subscriber at substation A-10, the 4'attendant at the automatic exchange is informed of this fact and he connects the temporary jumpers shown on the cross-connecting block CCB with the result that the conductors 651-68 are connected with thecorresponding cable conductorsv 101 leading to the intermediate distributing riframe IDF. The fattendant then connects jumpers on the IDF to connect the conductors 101 to the corresponding conductors of an idle auxiliary seioctor, forcxample, the auxiliary selector AS. The above operationsassociatethe auxiliary selector AS with the party line, and in order to provide so that the intercepting operator will be ysignalled vonly when the subscriberfat substation A-10 is called, the jumper 111 is connected between the contact associated with the common conductor 114: and the tenth contact in thebank of wiper 1&10, Vthetenth contact correspond ing with thesetting ot' the code selector CS, Fig. :1, when a callfis intended orthe subscriber at substation A-10- In this case when a call comes in for thesubscriber at substation A-10 the stepping magnet 108 of the auxiliary selector AS is operated simultaneously with the operation ofstepping magnet 7 3 ot the code selector CS, the circuit of magnet 108 being as follows: from ground by way of the resting contact and armature 17 `of line relay 2, `armature 29 and its resting Contact, armature 39 and its working contactA or" switching relay 10, wiper 52, bank ycontact 56, conductor 66, corresponding conductor of thegroup 101, corresponding jumper on the intermediate kdistributing trame IDF, lower winding `ot relay `102, magnet 108, common conductor 113, `normally closed .contacts controlled by armature 118, and relay 117 to battery. The lower winding of relay 102, as .well as `the winding of relay 117 is a low resisting wind ing with the result that magnet 108 operates through these two windings. By the operation ot' magnet 108 the Wiper 110 is advanced step bystep into engagement with the'tenth associated bank contact. 'Relays 102 and 117 are energized in 'series with magnet 108 and, being slow acting, maintain their respective armatures attracted throughoutthe series ot impulses. Relay 117 operates to place bat tery on conductor 114: so as to short circuit the lower winding ofthe guard relay 116 `for a purpose torbe pointed out later. 'Relay 102 opens at armature 106 a `point in the vcircuit of release magnet 109 so as yto prevent a premature operation of this magnet.

When Wiper 1110 lands on the tenthassociated bank contact, a circuit is closed 4from the :grounded 3 private normal conductor 67 through the path shown including the cross connect block CCB and the yintermediate distributing trame IDF tozarmaturelOl and its working contact and thence .by way of the=upper winding of relay 102, wiper 110, thetenth associated vbank Contact, jumper 111, .common conductorv 11e vand armature 119 and its working Contact to battery. Accordingly, relay i102 remains energized over this circuit instead ot' `allingback responsive to thecessation of the seriesy ot in1- pulses. That being the case, as soon as relay 117 :falls back'responsive to the termination of the series of Limpulses it remotes the shunt from around the lower winding of the common guard relay 116 with the result that relay 116 energizes and at armature 11Ssubstitutes its fhigh resistance upper `winding for the low resistance winding of relay 117 orfaxpurpose to be explained later. As a further result of the energization ot relay 102, the'conductors 65 and V68 of the called line are extended at armatures 103 and 105 to the=conductors Vof the intercepting trunk IT. That beingthecase, whenthe ringing` current is applied to ythe called. line the ringers ofthe substations A-6-A-9 are operatedin the usual manner, the substation A`10 being disconnected inthis case. At the same time, the :ringing current passes over conductors and 68 and through armatures 104 and `1O5-to the intercepting trunk IT. The ring-up relay 120 (at the distant switchboardy SB) 'whose lower win ding is/bridgedsacross the conductors of the intercepting trunk AIT through the' associated condenser, '.energizes and -closes a locking circuit for yits upper winding at `armature 121 and at armature 122 closes a circuit for the lamp 123.

Vhen the intercepting operator notes the lighted condition ofthelamp 123 she throws the key YK soas to connect thelistening .taps offher headset to the trunk. The .upper contacts of the-key K open'the locking circuit of fthe upper winding of relay 120 whereupon relay 120 'falls back yand opens the circuit of thelamp 123 at armature 1.22. A circuit for the ring-.cut-.oft relay ot the connector C is afforded by the operators head set, 4whereupon `relay y7 energizes and cuts ol the ringing current in the hereinbefore described manner.

The operator now converses with the calling` subscriber and informs him that the ser- Vice'has beendiscontinued'at the called'substation, after which lthe operator may restore-her key K.

When the calling subscriber replaces his receiver, the connector `C and the remaining part .of the operatedlswitches are released in the manner vhereinbefore described. In

addition relay 102 falls back responsive to the removal of ground from the private normal conductor 67 ,f as does also theslow acting relay 116 which has been maintained operated in series with relay 102, and restores the relay circuits to theposition shown in the-drawing. At armature 106 a circuit is closed through contacts 107' t'or release magnet 109 which energizes and restores wiper 110 to its normal position,whereupon the circuit ot therelease magnet is opened at oil-normal contacts 107.

Considering the guarding arrangement provided, it will -be ynoted that with relay 116 energized, as it is as long as the. connection remains established between the calling line and the intercepting operator, the magnets of the auxiliary switches such as AS cannot beoperated over the common conductor 113 at this time owing to the high resistance of the upper winding'oi' relay 116. conductor 113 is connected to the upper' winding of relay 116 at armature 118 at this time instead of vbeing lett open so that in case the existing call is cleared out during the impulsing period of another call to a line equipped for intercepting service relay 116 will remain energized `t irough its upper winding until the impulsingrperiod is completed. rlhis is done because it is better to prevent a switch similar to AS from operating at all than to permit it to operate incorrectly as wouldbe the case in case the operating circuit through common conduc tor 113 were restorediny the middle of an impulse period. f Y

Regarding the utility of the arrangement for maintaining the lower winding Vof the guard relay 116 short circuited until the end ot the series of impulses that operates relay 117, the utility of this arrangement isvtwo fold. It is useful where there are two or more subscribers disconnected trointhe line in which case two or more of the contacts in the bank or the wiper 110 are connected by lmeans of jumper such as 111 to the common conductor 114;. In this case the short eircuiting arrangement prevents .the premature energization of relay 11G when the first bank contact is encountered that is connected to conductor 114when the subscriber called is one corresponding to one ot the following contacts in the bank of the switch. It will be readily seen that it relay 116 were permitted to energize when the first Contact is reached it would prevent a 'further advance of the switch AS.

Regarding the other utility for the short cireuiting arrangement, it may be pointed out that it will inevitably ,happen that occasionally a secondpswitch similar to S Will start to operate before the iirst switch has finished its operation. In this case it the first switch were permitted to complete its operation and disconnect condnetorll from its battery Asupplythrough the low wound relay 117 the operation ot the second auxiliary selector would be stopped oft-times before its completion. It is considered to be better practice to permit the operation ot the second auxiliary selector to be completed than it is to terminate the operation bei'ore its completion. Ut course as soon as the second switch has completed its ope ation relay 117 falls back and relay 116 responds by pulling up in the hereinbetore described manner.

It will be seen oit course that it is possible that two calls may be extended to the intercepting trunk I'l simultaneously but it is thought that this occurrence is .so rare that it may be overlooked.

That is claimed is:

1. In a telephone system, a connector switch having wipers, a party line accessible to said wipers, a first party-selecting switch individual to said connector, a second partyseleeting switch individual to said line, a line relay tor said connector, a magnet controlled by said line relay to bring the wipers into engagement with said party line, means in said lirst pa1tyselecting switch responsive to a subsequent opeiation of said line relay for selecting the desired party on the called line. and means in said second partyline selecting switch also responsive to said subsequent operation of said line relay for selecting the desired station on the called line.

2. ln a( telephone system, a party line, a switch individual to such line having positions corresponding respectively to the parties on said line, means for extending a connection to .said line, a. plurality of signalling means corresponding respectively tc the parties on said line, means controlled subsequent to the selection of the called line for selecting the signalling means corre sponding to the desired party, and means responsive to the same control il'or operating the switch on the called line to the position corresponding to the called party.

3. ln a telephone system. a party line` a switch individual to such line having a plurality of positions corresponding respectively to the parties on the associated line, means tor extending a connection to said line, and meansl controlled over said connection lor operating said switch to a position corresponding to the desired party.

e. In a telephone system, connector switches mounted in groups, groups or part): lines accessible to said connector groups, respectively, a plurality of party-selecting switches mounted in a single group, an intermediate distributing trame, connectionsfrom each of said party-selecting switches to said distributing trame, and separate cables extendingfroin said :trame to each of said groups of connectors.

5. ln a telephone system, a plurality of f lines and the switches, and a jumper individnal to ca h party selecting switch connecting' a c act Correspending` to the party to whom intcrcepting' kservice is to be given Yith a common conductor.

G. in a party-line telephone system in which certain party lines are provided with individual party-selceting` switches to compiete the connection to an intercepting trunk conneetin'j relay individual to each selecting switch tor connecting the d l ie to the interccpting trunk line,

and a cncuit for said relay'closed or not by the Wiper ot the switch depending` upon the 1 position in which the wiper is set.

` in a party-line telephone system in which party lines are provided with indinal party selecting switches set by imp to complete connections to an interceptingtrunk line, release magnet for each individuai si itch, a slow acting relay energized the setting,` ot the switch to close points in the connection to the interceptinp, trunk and to maintain the circuit of said release Vnignet open, and another circuit for said relay completed through a wiper et said switch to maintain said relay energized after said impulses have ceased..

8. ln a. party-line telephone system in which certain party lines are provided with individual party selecting1 switches to complete connections to an intercepting` trunk line, an operating magnet for each ot said switches, a current supply circuit common to all oit said operating magnets, and means responsive to the sett-ing' of one of said swi ches i'or opening 'said current supply circuit.

9. in a party-line telephone system in which certain party Vlines are provided with individual party selecting switches to complete connections to an intercepting trunk line, an operating magnet for each ot said switches, a current supply circuit common to all oi said operatingmagnets, means responsive to the setting,` otl one of said switches for opening said current supply circuit, and means cont-rolled over said common circuit ior preventing the operation of the last named means during" the setting of one of said switches. i

10. in a party-line telephone system in which certain party lines are provided with individual party selecting switches to complete connections to an lntercepting` trunk line, an operating;- magnet for each of said switches, a current supply circuit common to all of said operating magnets, means responsive to the setting of one ot said switches for opening said current supply circuit,

means effective upon the restoration of the i, named switch for again completing; said current supply circuit, and means effective in case an attempt is being` made to operate another one oit said switches at the time said release takes place to prevent the reclosure ot' said circuit until such attempt is terminated. i

11. ln a part-y line telephone system, `a

party line, a connector having access toI said line via a single setwot contacts, means associated with said connector for signalling any desired station according` to a distinctive code, an intercepting trunk, and means effe/G- t-ive in case the desired station is out of service for extending the call to said trunk.

12. in a party line telephone system, a party line, means for extending a connection to said line and for signalling a desired station thereon, and means including a switch individual to said line for extending the call to an operator in case any desired station is out ot service.

13. In a party line telephone system, a

aart `line. a connector havino access to said C line via single setot contacts, means associated with said connector for signalling` any desired station according to a distinctive code, an intercepting trunk, and directively operated means effective in case the desired station is out oi service ttor extending; the call to said trunk. l

14. ln a party line telephone system, a party line, a connector having access to said line via a single set of contacts, means for transmitting one of a number ot distinctive codes over the line, means associated with the connector for selecting the code tofbe used in accordance with the station wanted, an interceptinp,` trunk, and means-operated simultaneously with said last named means tor extending the call to said trunk in case the desired station is to be given intercepted service.

15. In a telephone system, a party line, means for extending a connection to said line, an operators switchboard, means opeative for precletermining` which party on the line is to be called, and means operative into one out' a plurality of positions simultaneously with said last named means for extending' the cali to the operators switchboard under predetermined conditions.

16. In a telephone system, a party line, an operators switchboard, means for exif-andina` calls to the line, and step-by-step means in' dividual to the line for extending` calls for certain of the parties on the line to the operators switchboard.

17. In a telephone system, including a lll() iBU scriber on the line, a branch extendingfrom said line to a switchingdevice, and means for conditioning said switching device so that it responds alike to extend the call to an operators position when any of certain signals are used.

1S. l'n a telephone system, plurality o party lines, subscriber controlled means for selecting a. desired line, subscriber controlled means etective to call a desiredy party on said line, a subscriber controlled device having' a plurality of operative positions, one for each party on the line, for extending the call to an operators position, and means for rendering the device eective when certain parties are called.

19. In an automatic telephone system, a plurality ot' party lines, automatically operated means for selecting` a desired line, a switching device individual to each of said means, a switching device individual to each of said lines, means for directively operating both of said switching devices to any one ot' a plurality of positions, one of said switelr ing devices being etlective to apply signalling current of different characteristics to said line, and the other being edective from certain positions to extend a path for signallinfi` current to an operators switchboard over a branch of the line.

20. In a telephone system, a plurality ot switching devices, means for individually7 directively operating any of said devices 'to anyone of a plurality of positions, an electro-responsive mechanism, means. 'for conditioningA each device so that it Will control the mechanism from any desired position of each device. means in said mechanism effect-ive when operated for preventing the initiation into operation of any of the devices.

2l. In a telephone system, wherein intercepted ser Yice is provided for certain party lines, an operators switchboard, selecting devices connected to those lines requiring that service for connecting the lines to the switchboard, and means responsive to the setting up of one of said devices ior openingr the current supply through all of the other devices.

29.. In a party line telephone system, in which certain party lines ai'e provided with party selecting,- switches to complete connections to an intercepting operators switchboard, means for operating each of said switches, a current supply circuit common to all of said means, means responsive to the setting` oi one o1 said switches 'for openingr said current supply circuit, and means controlled over said common circuit for preventing the operation ot' the last named means during` the operation of one of said switches.

in a telephone system, a plu -ality ot party lines, means for code calling any desired party, a cross connecting frame, a branch extendingl from each line to the trame, an operators switchboard, a plurality ot' switchingI devices connected to the trame, each of which may under predetermined conditions extend a connection from the frame to the switchboard, and jumpers connecting certain lines with certain of the devices.

In Witness whereof, I hereunto subscribe my name this 11th day of August, A. D.,

LEONARD L. 4RUGGLES.

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