Historical Document · 1953
US 2,632,817 Testing Apparatus for Telephone Systems
Telephone test apparatus patent.
Historical Document · 1953
Telephone test apparatus patent.
March 24, 1953 F. KESSLER ' 2,632,817 TESTING APPARATUS FOR TELEPHONE SYSTEMS Filed Feb. 8, 1951 10 Sheets-Sheet 1 FIG- 7 CORD CIR. 70o ' I2 4 722 T 7321 75/ \721 731 DIAL TEST SW 733“ Kflo SET K720 K730 P705 -°—_°. ,ms 714 703 [/723724 OPER. TESI BOARD 30 FIG .' l ‘ 8 0 TEST 7 7» 1880 :5] CENTRAL AUTOMATIC CIR. TEST ~ TEST DIST. OFFICE I0 LINE TESTING T???” Y DIST TRK.'—- DIST >0 800 SW. 900 H80 I * ' SELECTOR _ FINDER‘ 200 H83 "82 " TEST TEST TEST DIST TRK-DISI Sw->°_ 860 865 EXCHANGE 20 ‘ DIST' 1 869 SELECTOR FIG '2 f 878 a 9 -!O u 2 3 4 5 " FINDER ' 877 -> s INVENTOR. Frank Kessler BY , a. a \ ,3. r March 24, 1953 F. KESSLER 2,632,817 TESTING APPARATUS FOR’TELEPHONE SYSTEMS Filed Feb. 8, 1951 10 Sheets-Sheet 2 CONTROL SWITCH 2/0 02 TEST START 88 K202. K203 ruous. HUND. ‘ \ ‘STEP *II' STEP HI‘ 887 88! SELECT 37" SELEtCT 27 INVEN TOR. 9 .0 2? AUTOMATIC LINE TESTING CIR. 200 FIG. _2 Frank Kessler . BY ‘ M. MM AHXs. March 24, 1953 F. KESSLER 2,632,817 TESTING APPARATUS FOR TELEPHONE SYSTEMS Filed Feb. 8, 1951 207 10' Sheets-Sheet 5 mo'usmvo SWITCH 310N [ggitéssmm 315 393 33a \ INVENTOR. v 3 ' Frank Kessler BY March 24, 1953 F. KESSLER 2,632,817 TESTING APPARATUS FOR TELEPHONE SYSTEMS Filled Feb. 8, 1951 10 Sheets-Sheet 4 N HUNDRED SW 4I0\ TEST R450 4521 l PR'EPARE 453 430 4 - 420 D fgMggEG 45 CAMR 457 FINISH ' TEST CONN. SW. BUSY . Fla 4 A Frank Kessler BY ~ March 24, 1953 " F. KESSLER , - 2,632,817 TESTING APPARATUS F‘GR TELEPHONE SYSTEMS 87 INVEN TOR. 'TFIG. 5 _ Frank Kessler BY I ‘ \ March 24, .1953 F. KESSLER» 2,632,817 TESTING APPARATUS FOR TELEPHONE SYSTEMS Filed Feb. 8, 1951 ' 1o Sheets-Sheet 6 UNIT 200 394 . UNIT SWITCH 6I0 00000000 o I 000000 LAMPS U _ o(mo ’ | 69 l R6 0 . R625 I V | R645 l I 656 I 67!‘ R655 R66 I R650 7 | I 8 ' . ~ l l PRIME LOOP R670 coum COUNI 674,; ' COUNT.’ I RESISTA Ivc'E SELECTOR ssos ; 677 ‘ u -5 59 A BA ' » L60! 63;; I Y ' - ' L232"' ' 4 ' ' LOOP -n 647 X ' L503 INVENTOR. Frank Kessler _ .FIG. 6 March 24, 1953 _ 2,632,817 F. KESSLER TESTING APPARATUS FOR TELEPHONE SYSTEMS Filed Feb. 8 , 1951 lO-Sheets-Sheet 7 TEST DISTRIBUTOR TRUNK CIR. 800 OPERATOR . v TEST 87A BOARD 30 8,2 8m A\| L8” J80! “ ‘ ‘ II ~ 1X: 1980" . . I ' ' 814 | ' 872 Y1 ' ' . L/ - ' 822mm‘ - - J~A8I3 . 872d _ 'v ' _ 806 ‘$823 8/5”” "/8I6 L802 ' L352 |\ ' j SUPY. ' L 85/ . . - " ' ' I I ' I l ITEST . 1 R8! \ 874b ] l K803 ' L804 875 5 L 870 1 BUSY I MARG. 05 - B00. rid/3W0 I 825“ I 826%?‘ 4/ ' 8763 4 ,—+—5—' B M856 —SEIZE 8830 —'J,/857 j j 807 I’ TEST > TEST D151, “8010mm. - I _ ' ' l ,H 013T‘ l "a CENTRAL OFFICE I0 ILC--868 I [E 867 SEL. FIND. -J ‘ 878 877 4- . -’O.___. ‘ EXCHANGE 20 " 6) 2 INVENTOR. FIG- 8 ' || R840 844“? I-PM-_||. —-*I*' Am‘ TEST 015T TRK. K883, % 843 CONIEBSO L‘_'___ 0| J86! v——-— TD-R- L864 -' — L1 ‘2*854 “842' \ ,_ TEST 375\ CONN. ‘ 3 ___T\84III Trim ‘8.13 M 874 DIST RLSE. my R820 ,./824 8 3:3 . M ' BIC I sup)’. 873 v 88% Frank Kessler BY JM‘ 06AM March 24, ‘1953 2,632,81 7 F. KESSLER TESTING APPARATUS FOR’ TELEPHONE SYSTEMS Filed Feb. 8‘, 1951 r 10 Sheets-Sheet 10 TEST msT. sw. 900 I | l l I J 942 ‘ I 1 l l a l ' .. 3-1505: , - FIG. 9 INVENTOR. Frank Kessler Aftys. Patented Mar. 24, 1953 2,632,817 UNITED STATES PATENT OFFICE 2,632,817 TESTING‘ APPARATUS FOR; TELEPHONE SYSTEMS’ ‘ FrankKessler, Rochester, N. Y.,v,assignor toAutoe matic‘ Electric Laboratories, Inc., Chicago, Ill.,, acorporation ofiDel'aware Application February‘s, 1951-, Serial Ni).210}040' 44; Claims; (Cl. ?lls-17.5.2) 1 Thai present: invention-v relates to; telephone: systemsiand' more particularly to; combinedv man-t ual andiautomatic line» selecting and testing ap paratustherefor. ' ‘ In antautomatlcll telephone» system, there: is frequently'provi'ded in the-central oilice amanual‘ dial: operator test‘board that has access via‘v test switch: trai'nst'o the‘ subscriber‘lines in the cen tral- of?ce and‘ to the'subscriber lines in the ad‘ jacenti exchanges. A telephone system of this general character is? disclosed in the copending: application of‘F‘rank K‘essler; Serial No. 774,495; ?led? September 17, I947, nowv Patent No. 2;550,819, granted May: 1, 1951; and‘ in this sys tem the operator at" the test‘ board“ in testing; a subscriber line‘ in the-central office ?rst connects the position equipment- to' the test“ switch train, dials the required digits comprising the numeri cal portion of" the directory'number‘ of‘ the dew siredi subscribenlme to cause the test switch, train to select the desired subscriber line, and then manipulates‘ the various test keys in the position equipment in order to cause the‘ various line fault testsv to-be performed upon the selected subscriber line; 2 located; and. identi?ed, by" the} automatic. appa ratus. Another object of the invention is to provide automatic routine apparatus of improved; circuit 'v connection and arrangement'for' sequentially se lecting the subscriber lines in an oihce of an automatic- telephone» system and for’ performing a given series of' predetermined line fault tests upon each selected subscriber line. Another object of1 the invention is‘ to provide‘ in an automatic telephone‘ system‘ including a central“ office and at least one» exchange, an arc-1 rangement for selectively connecting automatic routine apparatus of‘ the character noted" ar i‘ranged in the central office to the test‘ switch train in the central oihce and‘ to the test switch train, in the exchange; whereby the operator at' the: test board in thecentral o?ice'may supervise the operation of‘the» apparatus to test the sub scriber linesin the o?ice' and the‘ subscriber lines in :the exchange. Another‘ object‘ of ‘ the invention is to provide? automatic routine apparatus of' the character noted that also incorporates an improved ar 25 rangement forv testing itself incident to the test While‘this testing arrangement is very ?exible permitting the detection of each individual? type ing thereby of each group of subscriber lines in the of?ce that is undergoing the routine testing of‘ line‘ fault; as well‘ as the measurement of the operation.‘ Another object of' the invention is to provide severity’ or intensity thereof, a‘ greater number of‘key operations‘ on the part of-"the operator at 30 automatic routine‘ apparatus of ' the character noted that‘ is, in response to the connection the test board‘ are required‘ and more time-iscon thereo? to. a particular o?ice, automatically sumed‘ in performing aroutine test'upon the subs‘ adapted. to. the particular grouping; arrangement scriber lines in the‘ o?i'ce than‘ are desirable; Accordingly i'tgis'a generalobj ect of the‘ present of, the subscriber lines in the particular o?ice; so‘ that the. apparatus is automatically controlled to invention to providev automatic line selecting; and testing apparatus that“ may be employed" in con skip any vacant; group of subscriber lines in the particular o?ioe and‘ so that operation of the ap junction with a manual dial operator test‘board paratus is, automatically arrested when it has‘ of‘ the general character noted in- the central‘ office~ of‘ an automatic‘ telephone system; so that been operated to test each, group of subscriber theoperator' at the test board may be relieved: of‘ 40 lines in the particular office. a great“ amount“ of work' involved in‘ making" rou A further object of the invention is to provide in automatic routine apparatus of‘the character tin-e line fault tests‘ upon the subscriber lines; which apparatus is operative automatically‘ to noted,_ anv improved arrangement of a single set of counting relays for the- purposes of, sending set; up test connections sequentially to the var ious subscriber lines and automatically to‘ per switch setting signals to the test switch train so form a given series of predetermined line fault tests‘ upon; each selected‘: subscriber. line, auto: mat-'i'cally toidientify the particular line rfaultlthat" as. to e?ect sequential setting up of. the test con nections to‘ the di?erent subscriber lines, of‘ in dicating the different subscriber linesas they are sequentially selected to be tested, of‘periorming, automatically tie-identify the- numerical portion. 50 the-sequential linefault testsupon aselectedsub scriber line, of identifying the particular fault of" the directory number of" the, particular. sub scriber» li'neupon which the line-faulthas? been that is‘found on aselected subscriber line, andof cycling the apparatus itself. found-=3 whereby the operator at the test. board A further object of the invention isto provide mayU devote-most of her time to; measuring; the in anjautomatic, routine apparatus. of the char severity or characterfofline faultssthathave-“been ' it’ has found‘ upon a selected subscriber line; and 2,632,817 3 4 acter noted that is capable of sequentially test the ninth thousand group of subscriber lines com ing a maximum of 10,000 subscriber lines in an prises the last thousand group that is equipped; and in the exchange 20, the eighth thousand group of subscriber lines comprises the last thou sand group that is equipped. In the central o?ice In each of the subscriber lines is provided with a line circuit individual of?ce, an improved arrangement for effecting skipping of each vacant thousand group of sub scriber lines, of each vacant hundred group of subscriber lines in each thousand group of sub scriber lines, and of each busy subscriber line that is selected to be tested. A still further object of the invention is to pro vide in automatic routine apparatus of the char thereto, the subscriber line I050 being provided with the individual line circuit H60; and each 10 hundred group of subscriber lines is provided with a distributor, the ?rst hundred group of acter noted, an improved arrangement for camp subscriber lines, including the subscriber line I I50, ing upon a busy switching element in the con being provided with the distributor H00. Fur nected test switch train and then for controlling ther in the central office [0, each hundred group the last-mentioned element of the test switch train when it becomes idle in order to effect the 15 of subscriber lines is provided with a group of ?nder-selector links, the ?rst hundred group of selection of a subscriber line to be tested. subscriber lines, including the subscriber line Further features of the invention pertain to l 1150, being provided with the group of ?nder-se the particular arrangement of the circuit ele lector links, including the link illustrated that ments of the telephone system and of the auto matic routine apparatus, whereby the above-out 20 consists of the ?nder H82 and the selector H83. Of course the various groups of ?nder-selector lined and additional operating features thereof links comprise a portion of the local switch train are attained. in the central office 10, that further includes Section 1.--The general arrangement of the groups of intermediate selectors, not shown, and telephone system 25 groups of connectors, not shown, having access The invention both as to its organization and method of operation, together with further ob jects and advantages thereof will best be under to the hundred groups of subscriber lines. Final ly in the central o?ice ID, the group of ?nder-se lector links, including the link illustrated, is operatively associated with the distributor H80. stood by reference to the following speci?cation 30 Similarly in the exchange 20, each of the sub taken in connection with the accompanying draw scriber lines is provided with a line circuit in ings in which Figure 1 is a schematic diagram dividual thereto, the subscriber line 801 being of the central ofiice and the exchange of a tele provided with the individual line ciruit 808; and phone system embodying the present invention each hundred group of subscriber lines is pro and illustrating the general arrangement of the 35 vided with a distributor, the ?rst hundred group apparatus incorporated therein; Figs. 2 to 11, in clusive, taken together, illustrate the details of certain of the apparatus incorporated in the tele of subscriber lines, including the subscriber line 801, being provided with the distributor 869. ‘Further in the exchange 20, each hundred group of subscriber lines is provided with a group of therein the feature of the invention as brie?y 40 ?nder-selector links, the ?rst hundred group of outlined above; and Fig. 12 is a block diagram subscriber lines, including the subscriber line 801, illustrating the mode of combining Figs. 2 to 11, being provided with the group of ?nder-selector links, including the link illustrated that consists inclusive, to form a uni?ed circuit diagram. More particularly, Figs. 2 to 6, inclusive, illus of the ?nder 811 and the selector 010. Of course trate the details of the automatic line testing cir the various groups of ?nder-selectors links com prise a portion of the local switch train in the cuit incorporated in the central o?‘ice of the tele phone system; Fig. '7 illustrates the details of one exchange 20, that further includes groups of in of the cord circuits disposed at the operator test termediate selectors, not shown, and groups of board in the central o?ice of the telephone sys connectors, not shown, having access to the hun dred groups of subscriber lines. Finally in the tem; Fig. 8 illustrates the details of one of the exchange 20, the group of ?nder-selector links, test distributor trunk circuits disposed in the ' including the link illustrated, is operatively as central o?ice and accessible to the operator test board therein; Figs. 9‘ and 10 illustrate the de sociated with the distributor 809. Further the central o?ice [0 comprises a test tails of one of the test distributor switches dis posed in the central o?ice and operatively con switch train that includes a plurality of test nected to the test distributor trunk circuit shown 55 distributor trunk circuits 800, etc., a plurality of in Fig. 8; Fig. 11 illustrates the details of one of individually associated test distributor switches the test connector switches disposed in the cen 900, etc., and a plurality of test connector switches tral of?ce and accessible to the test distributor H00, etc. Each of the test distributor switches switch shown in Figs. 9 and 10. 000, etc., has access to each of the test con Referring now more particularly to Fig. 1, the 60 nector switches l I00, etc.; and the test connector telephone system there illustrated serves an area switches H00, etc., have access to the individually comprising a central o?ice l0 and at least one ex associated hundred groups of subscriber lines. change 20. The central o?ice {0 serves a maxi Thus the test connector switch H00 has access mum number of 10,000 subscriber lines, includ— to the ?rst hundred group of subscriber lines, ing the subscriber line 5 £50 extending to the sub 65 including the subscriber line H50. Also in the scriber substation Ti; and for purposes of illus central oiiice l0, certain of the hundred groups tration, it may be assumed that the second and of subscriber lines within a given thousand tenth thousand groups of subscriber lines therein group of subscriber lines may be vacant; and are vacant. The exchange 20 serves a maximum number of 10,000 subscriber lines, including the 70 for purposes of illustration, it may be assumed that the third hundred group of subscriber lines subscriber line 0107 extending to the subscriber in the ?rst thousand group of‘ subscriber lines substation T2; and for purposes of illustration, it is vacant. In this case, special connections are may be assumed that the ?rst, second, ninth and made in the bank of the test distributor switches tenth thousand groups of subscriber lines therein are vacant. Accordingly in the central o-?ice l0, 75 900, etc., corresponding to the trunk that nor-I phone system, which apparatus has embodied aesasuzix 6? many would have». extended to: the. associated‘. to; the? associated‘. jaclzandi accessible to. tIIBtQJltDL‘ maticliheztesting circuit: 21001;: the-test: distributor; trunk: circuit. car. being: provided?‘ with. the; cable; 88%] in‘ multiple to; the‘: jack J as]. and. accessible; to. the. automaticline testing‘ circuit; 200. Finally" the operator test board E806. comprises: a. plur rality: of cord. circuits: 100,. etc.,. having. access; to- the» jacks: JSDI, JBB‘I', etc. test“. connector switch. More speci?cally: in; the case illustrated; abooster battery“ I BSI'I'IIof- 45i-volt's'i is" connected. to the negative terminal. of the: contact‘. set:- that would: normally: terminate thetrunkr I3; and a group strap isconnect'ed' to‘ thcE; C. terminal of the; contact: setthatzwouldI normally terminate the“ trunk I3‘; In‘ the are rangement. illustrated, it" may: be assumed‘- that‘. Section; 2.--The apparatus. incorporated‘. in. the trunk‘ I'l appearing: in the contactibanks of‘the. 10 r telephone system test‘. distributor switches 960', etc.,- extends: to they» test connector switch H00, and that‘linef II in In the. central‘ office‘ III, each ofl‘th'e‘ subscriber the contact bank of the test connector- switch substations TI, etc.,, is‘ provided with’ conven I166 comprises the subscriber line" H50; whereby" tional subscriber substation apparatus, includ the- numerical" portion of the- directory“ number ing. a. ringer,’ a dial,’ and a telephone instrument: of" the; subscriber line H50 extending- to the each of the line circuits may‘ be identical to the subscriber‘ substation TI? is I'II'I. Also» in the line circuit H60. that_ includes, as illustrated in‘, central office Ill; in each test connector-switch‘ Fig; 11, a line relay‘ RI I65 and‘- a B. C: 0. relay“ H160, etc., line 99 comprises a test line that-Ais RI I110. The‘ distributors H80, etc., are/preferably employed only for the purpose of controlling the‘ of a suitable conventional type, the. ?nders‘ I'I'82, automatic line testing‘ circuit 200; in a manner etc., are of. the. conventional Strowger type; and‘ more fully‘ described hereinafter. For example, the selectors. H83, etc., are of a conventional‘. in the ?rst hundred group“ of subscriber lines‘ in Strowger. type, the selector H83 including; as‘ il the ?rst thousand group of‘ subscriber'lines; line lustratedinFig. 11,, a line relay RII.85. Simi 99v appearing before the test connector switch 25' larly in the exchange: 210,.each. of‘ the subscriber‘ I106 comprises a‘ test line and consists of a re substations T2‘. is providedjwith. conventional sub sistor Hill of 10,000 ohms bridged between the scriber substation apparatus, of the character + and — contacts of the associated‘contact set, previously noted; each of. the line circuits. 868., as" well‘ as exchange battery potential applied etc., may be. identical. to the line. circuit, H60; through a resistor H92‘ to the C contact of :the‘ 30' the distributors 869-, etc., may be identical to. associated contact set. the distributor IIB?g. the. ?nders. 8.11. may‘ be Further the exchange 20 compri'sesa test switch identical to the: finder. H62; and the selectors train that includes a plurality of test‘ distributor 8.18;. etc.,.may be identicaltothe. selector H33. trunks‘ 860, etc., a plurality of individually asso Preferably‘ the testconnector switches II I 06,, etc., ciated test distributor" switches 865‘, etc, and a 35 in. the central o?ice I I! and. the test connector plurality of test connector switches 866, etc. switches 866;, etc., in. the‘ exchange 2|! are identi Each of the‘ test‘distributor"switches"865. etc., has cal; and the test connector switch I I09 comprises, access to each of‘ the" test connectorz'switches 866,’ as- illustrated in‘ Fig. 11-, a Strowger mechanism etc; and the test; connector switches“ 8.6.6; etc., I'IIil, including, a. wiper. carriage, carrying, three’ have access" to the individually" associated. hun dre'd groups" of subscriber; lines. Thus the test‘ connector switch 866 has access. tow the. ?rstyhun dred group of subscriber lines, including‘the sub‘ scriber line 861. Also. in the exchange 20,.cere tain of the hundred. groups of’ subscriber; lines; within a given. thousand group of subscriber wipers IIII- to- II-I.3, inclusive... as well. as an. as lines may be vacant; however in‘ the interest'of" brevity this arrangement isv not disclosed, but}. sociated contact banlc, including ten. vertically spaced-apart arcuately-arrangedi rows ofjten con.‘ tact; sets; each. Also the Strowger. mechanism. IIIID- comprises, a. vertical magnet MI II 4." for driv ing'the wiper carriage step by step irrthe vertical‘. direction, all rotary magnet. M.“ I 5. for driving.‘ the. wiper carriage step.- by step. in the‘ rotary direc tion, and. a releasevmagnet MI I lit for releasing'the wiper carriage and for causing it to bereturnedlt‘o o?ice I0, described‘ above. Also in‘ the exchange 50 its‘ normal. rotary anctuertical. positions. Also ‘as sociated with the wiper carriage of. the. Strowger. 26‘ in each test. connector switch. 866; etc.,. line mechanism. IIiIl are two. sets of switch springs 99 comprises. a test line. just as. is‘. the. case in S I .I 23- and SI I24. areoperated whenthe-wiper car each test connector switch H50, etc.,.in the cen if‘ provided, is the. same as that in the. central; tral" o?ice I0. Finally the central. of?ce I0 comprises. an. op erator. test boardt?. and‘ an automatic line. test. 111g. circuit 2%. Each. of the. test distributor trunk. circuits. 5511,. etc., terminates in. an. inch‘; riage is; moved away. from. its. normal vertical. position. Finally the test connector switch IIIJI! comprises a. busy key KII35. and a- relay group, including- a linerelay RI i2Il,. a hold relay EH38, and aseries relay RI I40. As previously explained, in the» test connector switch. I IKIlLthe subscriber test board; 3% in order to. permit full manual‘. 60 line M50: extending» to. the: subscriber substation Ti comprises line‘ !-.I therein, and line 9.9: therein. testing of. the subscriber lines. inthecentralof?‘ce. comprises, a. test line, including‘,' the: resistors II 9 I II); and? eachv of the. test distributor. trunk cir and. H92‘ connected- and arranged initiate-manner cuits 8.60, etc., terminates. in. anindividually as. vidually associated‘jack-I??l, etc., at the operator. sociated jack 186i, etc., at. the operator test. boardi 3.9 in order, to. permitfull. manual. testing; of; the. subscriber. lines in the exchange. Z6. At. previously» described. Preferably theetest distributor switches 95.0., etc., least one of. the test distributor. trunk circuits; in the central: of?ce I?- and the testv distributor switches 865; etc., in the exchange 20. are identi- 3M. etc.,. is. provided. with. a. cable. in. multiple cal; and the test distributor switch 900-» comprises.; to. the associated. jack and, accessibleto - the. auto‘ matic line.- testing circuit. 2M5. thetest distributor trunk. circuits. 8M}. being provided with1the. cable. 810- in multiple: to. the jaclLJ 801. and. accessible to the automatic linetest. circuit ‘290. Similarly- at. illilstratedrinshligs. 9 and 10,. a Strowgermech- . anism NIH}, including a wiper carriage car rying six wipers 1.9M. to “lit, inclusive, as. well. asan. associated contact.banlgihcluding ten-verti cally spacedeapart arcnately arranged rowsof ten. contact sets each. Also. theS-trowger mechanism; 860, etc., is provided with a cable in multiple 75 IIHO comprises a vertical magnet MIG I‘! for driv least‘. one of the. test distributor. trunk. circuits 2,632,817 7 ing the wiper carriage step by step in the vertical direction, a rotary magnet MIOIB for driving the wiper carriage step by step in the rotary direc 8 a rotary magnet M2I5 for driving the wipers noted step by step in the clockwise direction. The thousand switch 3| 0 is of the rotary type, in— cluding three wipers 3| I to 3I3, inclusive, provid tion, and a release magnet MI020 for releasing the wiper carriage and for causing it to be re : ed with individually associated contact banks, as turned to its normal rotary and vertical posi tions. Also associated with the wiper carriage wipers noted step by step in the clockwise direc well as a rotary magnet MSIII. for driving the of the Strowger mechanism l0l0 are two sets of tion. The hundred switch M0 is of the rotary type, including three wipers 4“ to M3, inclusive, ated when the wiper carriage is moved away from 10: provided with individually associated contact its normal vertical position, as well as a set of banks, as well as a rotary magnet Milli for driv switch springs SI023 that is operated when the ing the wipers noted step by step in the clock wiper carriage is moved two steps away from its wise direction. The ten switch 5I0 is of the re normal vertical position. Finally the test con tary type, including four wipers 511 to EN, in nector switch 500 comprises a relay group, includ 15 clusive, provided with individually associated con ing a B. C. O. relay Rtl?, a supervisory relay R920, tact banks, as well as a rotary magnet M5I5 for a control relay R936, two line relays R940 and driving the wipers noted step by step in the clock R950, a hold relay R960, a circuit breaker relay wise direction. The unit switch 6I0 is of the ro R910, a transfer relay R5030, a rotary step relay tary type, including four wipers 6H to BM, in RIMU, a digit relay RI050, a busy relay RI060, a clusive, provided with individually associated con test relay Rliilil, and a switch relay Rliit?. As tact banks, as well as a rotary magnet M815 for previously explained, in the test distributor switch driving the wipers noted step by step in the 900, the trunk extending to the test connector clockwise direction. Also, the thousand switch switch I I00 comprises trunk I I therein, and trunk SIB includes a set of switch springs S3I6 that is switch springs SI02I and Sl022 that are oper I3 therein is vacant and is provided with the ar rangement including the booster battery I090 ar ranged in the manner previously described. Preferably the test distributor trunk circuits 800, 860, etc., in the central o?ice H! are identi cal; and the test distributor trunk circuit 800 comprises, as illustrated in Fig. 8, a relay group, including a test connect relay R3 I 0, a supervisory relay R820, a- B. C. O. relay R830, a seize relay R340 and a control relay R850. As previously ex plained, the test distributor trunk circuit 808 ter minates in the jack J80I at the operator test board 30 and is accessible to the automatic line testing circuit 200 via the access cable 810. At the operator test board 30 and individually as sociated with the jack J80I, there are provided a supervisory lamp L802, a busy lamp LStifi and a test distributor release key K803. In a sim ilar manner, the test distributor trunk circuit 860 :_ operated when the wipers noted thereof are moved away from their home positions; the hun dred switch M0 includes a set of switch springs 8M6 that is operated when the wipers noted thereof are moved away from their home posi tions; the ten switch 5E0 includes a set of switch springs Still that is operated when the wipers noted thereof are moved away from their home positions; and the unit switch 610 includes a set of switch springs Still that is operated when the wipers noted thereof are moved away from their home positions. The thousand bank of lamps comprises ten in dividual lamps MI to M0, inclusive; the hun~ dred bank of lamps comprises ten individual lamps CI to C0, inclusive; the ten bank of lamps comprises ten individual lamps XI to X0, inclu sive; and the unit bank of lamps comprises ten individual lamps UI to U0, inclusive. Of course, terminates in the jack 86l at the operator test it will be understood that the four banks of lamps board 30 and is accessible to the automatic line ,1 mentioned are disposed at the operator test board testing circuit 200 via the access cable 880. At ‘ 30. Also at the operator test board 30, and com the operator test board 30 and individually as sociated with the jack J 85I, there are provided a supervisory lamp L862, a busy lamp L864, and a test distributor release key K863. , Also as previously noted,’ the operator test board 30 comprises a plurality of cord circuits ‘100, etc., that may be identical; and the cord circuit 100 comprises, as illustrated in Fig. '7, a plug P70 I, a connector release key K130, a B. C. 0. test key K750, a switch key K720, a dial key K1“), and a dial relay R160. Finally the operator test board prising a, part of the automatic line testing cir cuit 200, there are provided a routine ?nished lamp L4H, a test connector switch busy lamp L4I8, a battery fault lamp L60I, a ground fault ‘lamp L602, a loop fault lamp L603, a test start key K20l, an of?ce select key K203, an exchange select key K200, a thousand step key K202, a hundred step key K2 03 and a manually adjustable resistance selector S605. Further the automatic line testing circuit 200 comprises a relay group, including an office mark relay R220; an o?ice select relay R230, an ex set ‘102; the details of the test set ‘I02 have not change mark relay R24Il, and an exchange select been illustrated, as they may be entirely conven 60 relay R250. In the circuit 250, the o?‘ice select tional or of the general character disclosed in the key K205 is individual to the central of?ce I0 previously mentioned Kessler application. and the exchange select key K204 is individual The automatic line testing circuit 200 disposed to the exchange 20, the keys K205 and K204 be in the central o?ice I0, as illustrated in Figs. 2 ing arranged in interlocked relation. Operation to 6, inclusive, terminates the access cables 810 of the o?ice select key K230 connects the circuit and 880 respectively extending to the test dis 200 to the access cable 870 extending to the test tributor trunk circuits 800 and 860 and com distributor trunk circuit 800; while operation of prises a control switch 2H3, a thousand switch the exchange select relay R258 connects the 3I0, a hundred switch 4H0, a ten switch 5H], and circuit 200 to the access cable 880 extending to 30 comprises a head set lIiI, a dial ‘I65, and a test a unit switch 6H), as well as a thousand bank of lamps M, a hundred bank of lamps C, a ten bank of lamps X, and a. unit bank of lamps U. The control switch 2I0 is of the rotary type, including four wipers 2H to 2l4, inclusive, provided with individually associated contact banks, as well as the test distributor trunk circuit 860. Opera tion of the o?ice mark relay R220 marks, at the contacts 22! to 2220, inclusive, ,the respective marking conductors in an associated marking cable 200 corresponding to the thousand groups of subscriber lines that are vacant in the central "12,582,51? 9 the busy lamp L804; ‘and when the plugP105 is ‘office I10, ;a :strap to :ground being provided .on the contact 222 ;since.it has been assumed that inserted into the jack J 8001, the contacts 801' of “thez-second thousand group ‘of subscriber lines is wacant {in the central o?ice 10. ,Also the o?ice -»the,g_jack J80;l are closed completing a circuit, including the resistor 805, for energizing the flower winding of the seizerelay R040, causing the latter relay to operate. Also when the plug P105 is ‘:thus inserted into thejacl: J80 l ,-;a path,.includ to thehinth marking “ conductor in an associated .ing the rcontacts 133 of the connector 'release'key 'tmarking cable 20'! indicating that ‘the ninth K’iil?-andlthe contacts 16 i, is completed ior'apply thousandvgroup .ofsubscriber lines in ‘the central ‘o?i'ce vl01is the .last thousand group of subscriber 10 ing resistance, ground to the sleeve conductor 814, _-completing;acircuit ,for energizing invseries the ,lines (therein. Operation of the ‘exchange mark ‘winding of ‘the test connect relay R310 and the relay 3122240 marks, "at ‘the ‘contacts 241 to 240, upper windingiof the B. C. ,0. relay R830. When inclusive, the .:respective marking conductors in ‘the :associatedmarking cable 200 corresponding this series circuit is ‘thus completed, the test con .ne'ctrelay 'Riilil operates; however the B. C‘. O. to'the thousand :groups :of :subscriber lines that relay does not operate ‘as it is 'of the marginal iarevva'cantiin'the :exchange 20, astrap ‘to;ground type. cb'eingrprovided on'the ‘contacts 24.! and 2262 since Upon operating the seize relay R8e0 completes, zit has been :assumed that the J?rst and second at the -:contacts 8e0,>a'circuit for. illuminating the thousand group "of subscriber lines are :vacant ,busy lampL804 in order to indicate to the opera ~in the exchange ‘office 20. .Also the "exchange toryat the test board 30 thepresent busy condition -:markzrelay;R>240 completesat the contacts 24 l ’ ca of :the test distributor trunk circuit 800 ; and com connection 1to the conductor-213 that isrstrapped ,pletes, lat-the contacts 803, a path, including the :to ‘the ‘(eighth marking conductorin the asso mark ,relayR220 .completes,;at the contacts 22V, reconnection :to the conductor 21'? that is strapped. ciated vmarking cable 20'! indicating that the contacts, 001 ’ of the jack J80 l ,V ‘for short-circuit "eighth'thousandfgroup of subscriber lines in the ~ : ,ing the windingiof thecontrol-relayR850in order ,positively to prevent operation-of the latterrelay at this time. Upon operating the test connect exchange '20 is the last thousand group of sub 3scriber llines ‘therein. -relay ‘R8100 completes, at ‘the contacts 8!] a cir *T-heirelay group providedzin the automatic line ~cuit forenergizingthe lower windingof the super testing circuit 200 vfurther comprises ‘a :control "relay R260, a ‘transfer relay R32 0, iazprepare relay '30 »visory .relay R820; however, the latter relay-does not operate at ‘this time, as it is of the polarized R330, a lhdld relay R340, arstart ‘relay R350, a type. :Eurther the test-connect relay R810 com ‘switch vrelay R360, .a ‘level ‘?nish ‘relay R310, .a ;pietes lat theicontacts 8 i 5, apath for-bridging the ‘hundred ?nish relay R380, :a thousand .?nish *rela‘y R390, aroutine ?nish‘relay-R?m-a prepare upper ‘Winding {of the supervisory relay R820 ‘relay R430, -a camp "relay R4‘40,:a test'relay R450, 35 across the+0r and-0 leads and consequently for #a-‘supervisoryirelayR460, 'a vacant relay R3470, :a energizing in series the upper winding of the switch-relay Renae digitfstop re'layiR400, aline supervisory relay R820 .andithe windings of the line relays R940 and R950. The circuit men tioned ‘extends from groundby way of the Wind ' R560, "a ‘cycle ‘relay R510, and twelve individual 40 'ing of the line relay R040, the contacts .925, the ‘5H1 :lead, the contacts ‘M5, .the upper winding of ' count relays R500, R500, R620, R62 5, R630, R635, "test ‘relay R520, vgicontrol'relay R530, a ‘test lline “relay R540, 'a‘pulsetimer relay-R550, a pulse relay "RS-‘40, R645, R650, ‘R655, ‘R560 "and ‘R610. The individual count relays‘R62‘0,'R530 and‘R640rser-ve _ the supervisory relay R020, the (contacts 833 and "to'prime the line'test‘relay R520 and ‘have ‘been 'ri‘l‘e's'i‘gned “prime” "in "Fig. 56. Similarly ‘the ‘in 'diviiiual count ~relays R525, R535 rand R545 :set "thejcircu'itto "cause the ‘line ‘test *re'lay‘R520 to - ing-of the linerelayR050 to battery. When this . series circuit .is thus completed, the .line relays ‘perform "respective battery fault, ground vfault "and ~loop ‘fault ‘tests '“and have been respectively BM, the —10,-lead, theycontacts 921 and the wind R000 tand.‘R$50,operate; however, the supervisory .relay R820 still does ,not operate since the upper ‘winding thereof .is .not poled in the proper direc tion. ‘Upon operating the line relay R940 com ‘designated “battery,” “ground” and “loop” in ' _ ‘pletes, at the contacts ‘04!, a circuit for operat ing the ‘control ,relay R930. Upon operating the Fig. 6. .line relay R950 completes, at the contacts 95L A ‘better "understanding of “the "connection ‘and a circuit for operating the hold relay R960. Upon tzarrangement ‘or ‘the “apparatus v‘incorporated "in . operatingthe .controlrelay R930 completes,at the ’the ‘telephone :system ‘will be ‘facilitated from -a contacts £31,, a multiple holding circuit for re consideration of ‘the'ext'ens'ion‘o‘f the'various test A ~-taining'operated the ,hold relayRQGii. Also upon connections and ‘the performance of the various wqperating the seize :relay BNO completes, at the tests’in conjunction therewith ‘appearing ‘herein contacts R844, 2, ‘multiple circuit, including the after. “set of .‘SWitCh v-springs $1022, .for energizing the :Section..3:-—\Setti1tg.-up a ltestrconnectton from the 60 :upper winding of the supervisoryrelay R1030, in , operator test board 30 in the centmtof?ce 10 _ order to :cause the latter relay to operate. Upon .to alsubscriber line therein Y operating lathe hold .relay R850 completes, at the contacts >802, Pa -multiple circuit for illuminating ‘First assuming thata test connection is 'to'be the :busy lampmiiliand for energizing the-upper "set ‘up from ‘the ‘operator test ‘lboard'l30 in the 5‘ ‘central office it ‘to iaisu'bscr‘iber line ‘thereinrsuc'h, 165 winding-of the transfer relay R1030. At this time, the test‘distributor trunk circuit ‘iorexample, as'the "subscriber vline ‘l [50 extending 1800 :and :the individually :connected ‘test distrib 'to the ‘subscriber rsub‘stationiTl, the operator ‘at ‘zutor switch @900 have been seized; and the op the "test-board '30 ?rst ‘.‘selects1an:-id1e~;cord ‘circuit, I eratorratthe operator test board 30 operates the such, for example, as ‘the cord circuit 700 and inserts the plug ‘thereof ‘into 1a ‘jack terminating dial :keyzKi H] in the cord circuit 700. When the dial-key Klzliiiis thus operated, the head set MI ‘an idle test distributor trunk ‘circuit, such, {for “example, as‘ the "test Jdistr‘ibutor ‘trunk circuit 800 is disconnected, atathe contacts .112 ‘and 71 ll there mi from :theracross the tip and ring of the plug ifthat is included in ‘the vtest switch train :in ‘the central office 10. The ‘test distributor .800 ‘P105, .and“ the 'dial 3*? 6.5 is connected, :at ‘the con "marked :as idle'by the iextinguis'hedrconditionpf Emil}; :‘IH and flit?xthereof :across :the tip and 2,632,817 11 12 ring of the plug P105. The operator then pro ceeds to dial the numerical portion of the di rectory number of the subscriber line 1 150 in the restores in accordance with the ?rst digit 1 driv ing the wiper carriage of the Strowger mecha central office 10 that is to be tested, which nu merical portion of the directory number is 1111. from its normal vertical position, whereby the nism 1010 one step in the vertical direction away sets of switch springs S1022 and S1021 are op When the operator actuates the ?nger wheel of erated. The set of switch springs S1021 is 01) the dial 165 in accordance with the ?rst digit 1, erated to prepare a circuit, traced hereinafter, for operating the release magnet M1020; and the the set of off-normal switch springs 161 in the set of switch springs S1022 is operated to inter dial 155 is closed effecting operation of the dial rupt the circuit for energizing the upper wind relay R160. The set or“ o?-normal springs 161 ing of the transfer relay R1030 so that the latter is retained in its closed position until after the relay may restore following the ?rst digit 1. ?nger wheel of the dial 165 is returned back into At the'conclusion of the ?rst digit 1, the ?n its normal position, and during the return of the ger Wheel of the dial 165 is returned back into finger wheel back in