Schematic

SD-66507-01: No. 755A Station Circuit (issue 10D)

The 755A's key-station, control-key and emergency-transfer circuits.

Author: Bell Telephone Laboratories / Western Electric
Type: Schematic
Credit: The Telecommunications Archive (telecomarchive.com), SD index

FIG. (MFR.DISG.) | FIG. 2 TSS5A FIG.3 FIG.8 (MFR, DISC.) KEY STATION WITH COMBINED HAND KEY STATION . Y STATION wit TELEPHONE SET WITH KEYS IN BASE WITH WALL SET STATION CIRCUIT KEY Bret oe SAR a BANG SET 206M, 206n ont! ses a Wir SEPARATE MEGS 46248 O8 462AC TELEPHONE SET 6538S SUB. SET_ _ 213 TYPE HAND TELEPHONE SET S84BS SUBSET TYPE_HAND TELEPHONE SET 68485 SUB. SET + 1 | a i | = alex sa 8 Hac. Rp BK R 3 we RE fsx] a ORD coRD 44 Of 5H TYPE SH TYPE woee K cca | fe EBS, s | GN | = pao \ R 1 8 TD CORD =! BL oe. K TO EXTENSION CONTACTS 7S BK CONTACTS ut > CONTACTS L TO EXTENSION ae CSTAS. WHEN RFQ | AMaKe LAST) | oe ERS ke SNE MAKE LAST eM EAT ENS MAKE LAST ,0.8 3} [ STAS WHEN REQ 1 SCE NCTE 108 wo SEE NOTE 101 BB, "5 : Ca OO SPE NOTE ior MET | | SEE NOTE 101 323.6R| TRANS Be Br, 4% |w MET wyatt x i 337 "a ¥ opr Pe 7 ro 'p 2 Ni L, 7 u ri T “| Ly | St) ett | Pe. R Lent omect oR i ar ALLOTTER Io i CALL ALLOTTER Wa) | rR LCALL ALLOTTER mo SR \ s| KEY FIGS OR = os Lj KEY ries ONE SS SKE FIGS ORE (epappg7 7 TO COROT Leck S g| Ker ric’s One O2! SN] 3 [8 S 4) ’ a H \ 1 4 Hop wi mw) —= iT 2 se way 5 1 au fet Hl 2 ! ! (Hy ‘om pee? 1 \ (TKI) WE TKI) eg | t € oO wiw | |4 2| To LINE, LINE if 2 2 alo LINE, LINE 2 2 (TKD) 2 2} 2 | TO LINE: LINE (rK2) eS + SWsAND CALL \(tK2) -¥ SW, AND. CALL aera £ { Wy AND CALL 8s ie (7 3| ALLOTTER cKT al 3 3] ACCOTTER cKT, 3 afallarrer ckt » (TK#) ve: 3 | atlortea che TK3) WE T ¢ < { ax lax. (6 ry (TK3) al 4 4 4 L 4 (73) a=? 4 4 4 (TKa) TKa! a7 BL faue Ts \ L (Kal L L L b L ae" L L L € wo ves ina Qrvs T Te uy A 3 Aas L C L _ - CONN, 14 [ilalala -—-} LL __ I ries Ielsla _. Fie.4 por | __3,12 A BLock F'IG-4 WN izi3l4, wets, a ~ lu2iis, ~ Fic.4 hletsla, TO FIG.10 ; TO FIG. 10 To FIG.10 TO FIG.10 WHEN REQ pide G7 ey WHEN REQ. WHEN REQ. WHEN REQ. (PU) @soi7e FIG.5 FIG. 6 FIGS 7 EMERGENCY TRANSFER KEY ERGENCY TRANSFER KEY FI FiG.4 ® « TO LINE,LINE ano TSENG Sar TERY SOBRE cit KEY ttt DISC) os TYPE CONTROL KEY CIRCUIT TO FIG.1.2,3 ro >————* sw.,ANO' CALL (em) (eM) HAND SET WITH KEYS IN BASE 8.90Ri OR TO ae ma @ ALLOTTER CKT. 6017s 6017 TYPE PER D-98792 _ PRECEDING FIG.4 : 15 | 4 . | = 2056, 205H,OR 2 ; (con) 6ol7R L ce (pu) j 4 TYE HAND TELEPHONE SET 68485 SUBSET - _ * F 1 68485 SUBSET t_ 6, ste Qssi ] L 1) TO CINE, EINE: Lt - - SW, AND 4 t ALLOTIeR CKt TO LINE, LINE | t L} SW, ANO CALL q 2. t 5) F ALLOTTER CKT aC RI] Jax A T CORD R \ r t R sn 19 6 8) ' t TO TRK.CKT | mr GN 6 [ TO LINE, LINE SW. 8 Foi aa} CALL ALLOTTER CKT ! S| (er i 1 is (KEY CONTROL STA) OR Cott t —i} TO SUB. LINE \ = BK U TO PRECEDING FIG.6 12. t 2-4 ME ‘CKT. IN WAGHETO BI CONTACTS. e - n TO LINE, LINE SW. & = R| 2-WAY RINGDOWN TRX. te. tho a i 08 SEE NOTE 1 7 L_ n TO GING: LINE SW T =} CKT IN MAGNETO CENT OFF BK MET | rt (FIRST OR INT KEY- TO FIs. —-—— ¥ ie . A £ ; tess 12,3, 48 aa j ths. a O LING, —t {| SEE Ut B,9 ORM: TO FIG. yeL2 LINE Sw. Tete 2 2 i We. | K R| CALL ALCOTIER 102 Tt TO LINE, LINE SW, & tb 89 OR IH -al cl SRO EM TANS 1] CALL ALLOTTER CKT B: S) KEY FIGS OR L at [ (FIRST KEYLESS STAD 299F SUB. SET 6s T 4 OR TO PRECEDIN FIG.10 ‘OR AS SPEC. ¢ tema 4 K “| RINGDOWN TIE TRK wy) ~~; Wave os? 1 | ct t | a ve w 2 : z is s - ‘2 OR KS-6572 | (2) 88 ‘Been, 3 3, ALLOTTER CRT. 17 | TO LINE, LINE sw. (RING) i @) t | Te i CALL, ACLOTTER. ‘ee | es _ a 18, [ONT OR LAST, @eoi7e ° ae Tee yew we L q oe € - alata 8, air uy vs a TO SUCCEEDING FIG.4 t8. _ | "op | pws. 1ss. | ! rn ————— = ore | SD-66507-01 | swe wuss [70] c.0. iss. eo $0 -66507-01 NO. 755A STATION CIRCUIT iss. [too] | 3 H3t CORO FIG.U Y STATION WITH COMBINED Hi TELEPHONE SET WITH KEN AND LAMPS WY BASE 466AC TELEPHONE SET _ «—SONTACTS _ MAKE LAST La) c TO EXTENSION SEE NOTE 10) P STAS. WHEN REO. TOL OR THRU EM, TRNS. KEY FIG. 5 OR 6 P joy LINE SW IND R CALE altortea CKT DIRECT S 4] 1 2 4 f L 10 LINE LINE Wi ALL ¥ TKS BL BR-G1 9 ALLOTTER CRT. — sac sts ' 44a BK ON Tha Psee = au NOTE ae 10) aL ‘ [ BR-w Al BL aaa. |{! a 3 = 7 ul al is e615) SRO Tt TRK.CKT. i Coaley LL t6 trk cKT ul TO TRK CKT 2 -2K) [6 mes Ll 59 TRK.CKT 3 . ~ LY to TRK.CKT. 4 pisa_tly cORD oO] lo jo lo} 444 CONN BLock of _|ndel a Ten -nasnr-o) 5D-66507 “To Fis. 10 He WHEN REQ PRINTED IN USA 4 D/CD.ISS. 10D Tows.1ss.| CIRCUIT NOTES: 101 THE FOLLOWING 1 BASED ON THE USE OF 104. GH IMPEDANCE RINGERS. IF LOW IMPEDANCE OPTIONS PROVIDE RINGERS ARE USED AT KEYLESS, SYATIONS, FOR KEY STATION WiTH COMBINED EACH RINGER SHALL BE TREATED AS T! HAND TELEPHONE SET WITH KEYS | FIG.1 EQUIVALENT OF TWO HIGH IMPEDANCE RINGERS IN_BASE WHEN A KEY OR KEYL ION 15 A EN ee oe COMEERENCE SERVICE. FOR KEY STATION WITH WALL SET | FiG2 THE NUMBER OF RINGERS ACROSS EACH FOR KEY STATION WITH HAND SET | Fig 5 ) STATION LINE SHAL Nor ESE fag ANO SEPARATE KEY: (8) w Ki K FOR KEY STATION oat 206 TYPE NOT To BE USED FOR CONFERENCE SERVICE FIG.8 MOE ee INC RS ORS: HANO SET WITH SEPARATE «i STATION LINE SHALL NOT EXCEED FOUR. FOR KEY STATION WITH 205 EE FIGS (C) THE NUMBER OF RINGERS, ACROSS A HAND SET WITH KEYS tN BASE AL OFFICE TRUNK AND ANY KEY HE EMERGENCY TRANSFER STATION LINE SHALL NOT EXCEED FOUR, EN Te EER ENN A TRON co TO AM 102. ADJUST 60:7R KEY SO THAT "A" CONTACTS if SHALL BREAK BEFORE "B" CONTACTS BREAK. DIAL CENTRAL, OFFICE OR TOA | Figs 2-WAY RINGDOWN TRUNK CIRCUIT! 103. WHICH IS LOCATED IN ' |RECORD OF FIGURES, WIRING, AND APPARATUS CHANGES| NETO CENTRAL OFFICE. WHEN THE EMERGENCY TRANSFER lcnangedaeconos|orrion|see| USE IN CIRCUIT PEATURE TS REQUIRED ON A THUNK ON 1S5.[DO NOT | WAS stolen CENTRAL OFFICE | fig g SPECIFY | FURN. LD. RU A 2-WAY RINGDOWN TRUNK azo Be baclan oa SH rl Gircut WHICH TS LOCATED AT 7- FIG. 6| 7 gaa WHEN a aon 15 REQUIRED TO = Fic.3| PICK UP THE LOCAL LINE fics ANOTHER STATION Of A CENTRAL | 8-D [FIGIORI FIG! Figit Fig OFFICE LINE NOT ASSOCIATED WITH) FIG.7 1 ZORY| Zz Y THE SWITCHING EQUIPMENT OF THE] oo (xoaw| x wx RB.X, AN AL KEY U 1op [vort| v T Vv REQUIRED. FOR KEY STATION WHERE CENTRAL OFFICE OR RB.X. SEAVICE TO KEY | FIG.4 STATIONS 1S CONTROLLED FOR KEY STATION WHERE RING” WN TIE TRUNK SERVICE IS FIG.10 Pa 7 PEROVIDED | ries, TAR RS AND LAMPS IN BASE " 105. THIS CONNECTING BLOCK SHALL BE THE ONE NEAREST BUTT OF CABLE. Ww + 7 a EJ i id | 0 {| FiG. 7K OWN CHARGE & 2 DISCHARGE CKT. MISC. PCHG. TS "a" (PU) KEY 3 WORKING LIMITS TS °A" ORB" TRSSoelateD wiry LINE ARRANGED T PICK UP ANOTHER LINE EQUIPMENT NOTE Ss 20). THE EQUIPMENT DESIGNATION OF THIS CIRCUIT Is “STA”. $D-66507-0I PRINTED IM US.a FIG, |) LAMPS MAX. RES. OF EACH "LI“LEAD IS oc MAX_RES OF "GRO" LEAD !S DIVIDED BY NUMBER OF LAMPS IN isa WHERE 3 OR MORE STATIONS ARE LOCATED NEAR i THE NUMBER OF STATIONS IN THE GROUP, [100 | DWG. ISS. 70 | c,d. 1ss.