Manual / Guide
756A PBX Circuit Description Binder (CD-65741-01 and others)
About 30 circuit descriptions for the 756A crossbar PBX: line link and marker, dial-pulse register, junctors, trunks (465 pp.).
Manual / Guide
About 30 circuit descriptions for the 756A crossbar PBX: line link and marker, dial-pulse register, junctors, trunks (465 pp.).
TABLt::~ OF CUt'J 11::.NT CD-DRAWING CIRCUIT NO, CD-65741-01 CD-65742-01 ).~ ) CD-65744~01 CD-65745-01 CD-65746-01 CD-65747-01 CD-65750-01 CD-65752-01 CD-65753-01 CD-65754-01 CD-65756-01 CD-65757-01 CD-65910-02 CD-65942-01 CD- 66796-01 CD-66902-01 CD-66908-01 CD-66909-01 CD-66910-01 CD-66911-01 CD-66920-01 CD-66921- 01 ISS TITLE 9-L/ LL 8 MKR 14--1 DP REG J-1 TRAF REG 5-1 DIAL CONF 3-JJ... CABLING DIAG LOUD SPKR 'i 'l-3 JCTR 134 2-WAY C.O. TRK 8-a.. ATT TRK 3-/ BUSY TONE TIE TRUNK ~ COLS POS ki CURRENT DRAIN I J-1 DSS 'f-1 ALM.TRANS 8 TRK ~-i DIAL CONF 1-3 DIAL CONF 2-/ DIAL TRANS CONT a., REM TRK ANS ;3 BUSY VERIF J._ -if CABLING DIAL 1 f\ANS TRK ~.-1 27 ' .'II.. 2b 29 -. ',.. I ~ 3C FIG- OPT WRG 31 32 33 {, 34. ·- t ) .. , ! ----------------· MFG LAYOUT ISSUE /,;J.... DATE COLLATED (WEEK ENDING) f'-J- ,23 H-919-209 PAGE CD-1 TCI Library www.telephonecollectors.info . --- - ...---, ..... ·-·· .... ----------- -·-~···- -. ~ .~ ISS TABLE OF CONTENT CD-DRAWING CIRCUIT NO. CD-81326-02 CD-81328-01 CD-81329-01 CD-81577-01 CD-81581 -01 CD-81600-01 j_-1 PWR BAT RSV < LOW TONE ~* AC-DC RING 33 31 !~3 CD-81920-01 1-1 ·---·· 32 ·--·- CD-81540 · 01 ·- 30 -31 ·-·- 20 "1 SUPPLY 7 29- FIG. OPT WRG LOAD CAP BAT-LESS ~l.. PWR---~-r RECTIFIER -·-- 0 TITLE ISS 27 28 ·--·-·---- -- - -96V DC APLQ --- - -- -- - CD-5E003-01 CD-5E021-01 1-1 IN. RESTRICTION .1-cl.. STA MESS REG CD-5E029-01 ~ MAKE BSY DISPL CD-5E037-01 1-1 VOLT RED DET i I I I ., ~ '' . - 0 U.· I MFG LAYOUT ISSLJE 0 DATE COLLATED (WEEK ENDING) _ _ __ H-919- 209 TCI Library www.telephonecollectors.infoPAGE CD-2 ti 1t /IE' CD-65741-01 ISSUE 9D APPENDIX 4B DWG ISSUE 50B CIRCUIT DESCRIPTION PBX SYSTEMS NO. 756A LINE, LINK, AND MARKER CIRCUIT .,.._ CHANGES B. Changes in Apparatus B.1 Superseded Superseded by: HA and HB diodes, 446F, XV option HA and HB diodes, 426H, UI option D. Description of Changes D.1 On Issue 26 option XV was added. This issue changes the code of diodes HA and HB from 446F, option XV, to 426H, option UI. D.2 The change is required to prevent failure of diodes HA and HB. During a camp-on sequence the marker functions to release and reoperate the trunk hold magnet to transfer from the dial tone link to the busy station link. This release generates a negative pulse which may destroy the HA and HB diodes (446F) if all-registers-busy relays ARBA and ARBB are operated. Option XV is rated Mfr Disc. and option UI is rated Standard to provide 426H diodes which can withstand the reverse voltage surges. BELL TELEPHONE LABORATORIES, INCORPORATED DEPT 3224-TEH-RVL Printed in U.S.A. TCI Library www.telephonecollectors.info Page 1 1 Page Ci)·~7~)-a/ JSSutT "l./'I ""'· .Jl!J o/11'11' w4l'N'1ssvr ~94 - ·.... P4XSYsn:~ #/>. ?5341f ~H4 ,.-'~,y"'A_; ,pdp "1',P£/t'F£, c,//Cu/:r C/1'1H4'E~ f}, Ch.QN~.S ;h 41:11--fl?/VG B~I ~ent~Y~<L ;eT/~ P/o ""5 J -¥-¥~ !"',, V W ~ h;H "2_·--~~i:(,,l!.~4(11 __¥- ?4,qh?t!!S . . p, /.av+.-:.~ 1jS4,, -~ V V ~ . ~r~-"'!a?lrd .Ascui ~ -~~ w ~4<J/ ~ 4'sl.4el ~ ;;,/-~d4-~~ ~~/~- ..,y_r v 4~·. ?8 .. -~ Nn-rA ~ //~r.e ~-~ ~ YW ~ __,...,_~ ~.·.fa~ A.4-· ~ ~ ~ -.;..,.._, ~~ Vll ~ ~ ~.;t,eJ • • ·g.~-t:/po~nv ~w~~ ~~ -r:;,,.,; 6 ~Yfa-.~ ---/ ~ v~ ~ . ~ . . ... . . . . $ELL leL.1:-/'&l··t~ L/~P/..# /?'//EV...A'l~~/..:Jt:TRA Te.0 ot:l'r 3;;utl- -WY5- K6/0 i . . ~. - .·.; ~~. .,. . ·" ·, . . ·' .. . ~. TCI Library www.telephonecollectors.info ...·- . ~--------~-.....:--.------~----------------- CD-65741-01 ISSUE 9D APPENDIX 2B DWG ISSUE 4SB CIRCUIT DESCRIPTION PBX SYSTEMS NO. 756A LINE, LINK, AND MARKER CIRCUIT CHANGES B. Changes in Apparatus B.l Superseded Superseded by ATB, INT relay, AK6, Fig. 4, UC option ATB, INT relay, AK37, Fig. 4, UC option B. 2 Added AO, Bl relay, AK6, Fig. 4, UC option AO; Bl diode, 446F, Fig. 4, UC option ATB thermistor, Sc, Fig. 4, UC option INS diode, 446F, Fig. 4, UC option D. Descri~tion of Changes On sheets B5B, B6, B7, B8A, BBB, and B35 changes are made on a no-record basis to option UC (A&M Only). Option UC is provided on a local basis only (A&M Only). Options UI, UJ, UK, UL, and UM are ca_ncelled due to the modification applied to option UC. D.1 BELL TELEPHONE LABORATORIES, INCORPORATED DEPT 3221-TEH-RGP Printed in U.S.A. TCI Library www.telephonecollectors.info Page 1 1 Page CD-65741-01 ISSUE 9D APPENDIX lD DWG ISSUE 470 CIRCUIT DESCRIPTION PBX SYSTEMS NO. 756A LINE, LIN~, AND MARKER CIRCUIT CHANGES D. Description of Changes o.l The lead index is changed to add reference to the automatic trunk level interconnecting unit. 0.2 On sheet B35, reference to the automatic trunk level inter~onnecting unit is added to leads T2, R2, and S2. 0.3 Circuit Note 102 is changed to reflect Issue 470. F. Changes in CD Section F.l In the TABLE OF CONTENTS add under part heading 17., the following: (Options zo, L. Automatic Trunk Level Interconnecting Unit ZS, WP, VC, and VE) F.2 In SECTION II - DETAILED DESCRIPTION under part heading 17. add the following heading and paragraphs: L. Automatic Trunk Level Interconnectin WP, vc, an VE Unit (O tions ZD, ZS, 17.83 When a line circuit is assigned to an automatic trunk level interconnecting unit, options zo, ZS, WP, VC, and VE are used, and leads T2, R2, and 52 are connected to the unit. A calling station or trunk is connected to the unit by the marker in the same manner as when a calling station or trunk dials the recorded telephone dictation trunk. 17.84 F. 3 In SECTION III - REFERENCE DATA, under 3. CONNECTING CIRCUifS, add: (ak) Automatic Trunk Level Interconnecting Unit - SD-1E255-0l. BELL TELEPHONE LABORATORIES, INCORPORATED DEPT 3221-WVS-RGP Printed in U.S.A. TCI Library www.telephonecollectors.info Page 1 1 Page CIRCUIT DESCRIPTION _,I CD-65741-01 ISSUE 9D DWG ISSUE 46D PBX SYS~-!S NO. 756A LINE, LINK, AND MARXER C:!.RC'·I"r PAGE TABLE OF CONTENTS ) SECTION I - GENERAL DESCRIPTION • • Register ReQuests Service • • . • 13 13 14 c. 1. PURPOSE OF CIRCUIT. 1 D. 2. GENERAL DF.sCRIP.rION OF OPERATION. 1 E. QPeration • • • • • • . • • • • • Hold k~et Check apd Marker and A. B. Subcircuits and Arr~ement • • • 1 F. RegisterRelease • • • • • • • • All Trunks Busy - aisx Tope Trnnk • Call-TenniJiating Connections. • • 4. 5 6 6 6 'f,SC5, llfflt TO. . STATfOi c:~mon • . . . • • • • '. · • • 15 A. E. General . AlaYm8 • - • • • • • -. • • • • • 1 E. SECTION Il - l)gTAILED DESCRIPl'IOlf 1 F. D. E. F. G. H. I. J. IC. L. 1. ~. T~n~ ~o~~c~i~~e~ ~~e. Called Station Line Busy. Paths Busy. • • Camp-On • • • • • Abandoned Calls . Marker Time-out . • • • • Checks. . . • . . • Pel"JiBnent Signals • • • • • Dial Back by Attendant - RP Test. 3 3 5 5 7 t 1 ™. . . . . . . . . . . . 1 Station Dial Tone Connections B. Code 8 Tie Trunk Dial Tone Connections {SC30). . . • . • 5 Central O:f'fice or Ringdown Tie Trunk Dial Tone Connection {SC2). 5 Attendant Trunk Dial Tone Connection. • . . 7 Busy Ver1:f'ication Trunk Diel Tone Connection • . . . 7 D. E. 2. A. General B. E. Register Requests Service . . Junctor Testing and Selection 'I'erminatiJJg Link Selection. . • Called Station Selection and F. Testing • . . . • Ccnnec ti cm o:r Called Sta t i on C. G. H. I. J. 7 7 7 8 8 . • . . • . . . . 8 to Junctor. . • . . • . Connection of Calling Station to June tor. . . Marker and Register Release Called Station Bus - Station in Huntin Grou Idle SCu . • Ca led Station and tations in 9 Tr1mk Idle (scr_ . . 11 9 10 H. STA~ION TC CENTRAL OFFICE OR RINGDOWN TIE ~g:ffK CA L TERMI!iATIONS General . . 13 . • . 15 Re s r -.:-;· -• --'"--.... .• . 17 ..... • Called tation Bu.sy - ·.Station in Hunting Group fdle. • • . • • • . • 17 Camp-On - Called Station and All Other Stations in Hunting GiOijD Busy - No Other Trunk Camped CG Called Station {scg). . . . . . . 18 Camp-On BUSY - Called Station apd All Other Stations in Hunt!Dg Group Busy - Another TrunkJUread.y Camped On Called Station (sc20) • 21 CaMp-On Busy - PBX on Remote Trunk Answer QPeration (XF Option) • . • 21 Car1cel Ca::.p-On - Called Station i sc·26). . . . . . K. .-_::-tile~ ..... Ca1 ltd Station is Inward Restricted (sc28) . . T 21 Station Busy - Message Registration Pulse on Sleeve. 21 .. . 23 5. • 23 A. E. c. F. 6. . 13 . . • • Reiister Reguests Service • • • • 16 Called Station TestJ.ng and Select Magnet Operation. • • 16 Hold Maplet <>eera~i~ • • • • 16 Hold Ma et Cliici. d ker = E. >c). . . 14 Busy Dial Con:ference Trunk ----~---••--....,-...__..:: i!-~ui t - Station or Attendant con r;r -·lle-~, or St9.tion Dial Trans:'er Tru..'1k Circuit in Use 11 Hunting Group Also tfsy - BUsy Tone A. D. S'I'ATION-ro-STATION CALL TERMIN- ATI1G CONNECTIONS {sc3) D. c. G. ESTABLISHING DIAL TOME CONNECTIONS •• A. C. ) B. Trunk Test~ . . • • • '. · ~ • Trunk Seleeton and Hold Mamet c. ) 1 ~~n~r~l ~eg•s:er . . Requests Service ::'ri..Lk !'es ting and Select Magnet o~eration . . . Hc·l :i '·lagnet Operation • . H:::L: Nagne~ Check and Marker and Register Release. • . • • • Ai l Trunks Busy (SC 15) • • • • 23 23 24 24 24 2l< ·'.::b:W;:'RAL OFFICE OR RIN@OWN TIE TRUNK l'C CENT.BAL OFFICE OR !ti~·; }DOWN TIE TRUNK -CALL :'E~~-~Ir:AT:C:IS. • • • • • • • , • • 25 Printed in U.S.A. TCI Library www.telephonecollectors.info TABLE OF CONTENTS Page 1 7. '--. C. 9. :..JC.:.C.! __ r: A.\J :i~:-.3 :·~\~F..:..i·~1~J~Ci CO:'~IJ.~:\J~ ,, ::..:;::i<out Contro:.. Te~s ?reference Control lO. A3ANuONED CALLS (SC17) 27 l l .. A;:.LO:;'TING MD SEQUENCE CONTROL 27 . ......_ .. i). :i.;gis:;er Allotter . . . Li~k Group Sequence Control ,SC24) . • . . . . . . . . . Link Se uence Control (SC2 ) Units Sequence Control SC25) 12. PATHS 30SY . . . . A. 3. Al:.. C. D. E. :3. Lir.e ( Optj_ons M, ZD, WP, ari_d VE) . . . . . . . . • . Tw0-~ay Tle Trunk (Options ZD, ZF, '.<IQ, VC, and VE) . . . • . • 36 36 Conference Circuit (See ~. ·-· -- ~~~1 .:::.r:C~Xt ~. ~~~orded Note 3·r 126 - .Sheet DlB) • 7elep~~0ne Dictation Trunk --- - ,::Jptio::3 2D, z:c•, WP, VC, and VE). Loudc;peaker ?aging Trunk (Options ZD, ZS, W?, VC, and VE) • • . • . 1-:.__ 3A Code Call Circuit ( O~ions ZD, ZG, ZE, WP, VC, and ). • • H. Auxiliar Position Circuit for Renote Trunk Answeri'Vf Options ZD, ZF, WP, VC, and ) • • • • ·• I. Dial Ccnference Trunk Circuit Station Controlled (Options ZD, Zl", XD, WP, VC, and VE) • • • J. Dial Conference Trun~ Circuit Attendant Controlled (Options ZD, XC, WP, VC, and VE) • • • • • • • K. I~terface Trunk. Circuit - (~tions ZLJ, ZG, ZE, N, WP, VC, and . ) • • Hegisters Busy Busy . . A~: Lin~s 28 28 29 2J . . 18. 2? All Junctors Busy (3Cl2) Busy Tone Trunk Busy (SC13) All Attendant Trunks Bus on Intercepted Call \SC19 LI~K ,.,.., CI SHIFT TIMING 30 31 31 A. Ce::eral . . :ink Shift Timing --~:?4) ..... ~~~K ~v~l; J. , • M1~ ~ o • o •••••• ~ARKER TIMING (SC16, sc36) . . 33 O?TIJ:; V'< • . . . 43 J:',~ A~;_m 43 20. - ·ALA::\MS --A. General B. ~nits Alarm 43 I,• Pelease Alarms lJ. A la:-'ms . • :w: n;,_ J:e~~ t Ala!"'m E. J~. :a. D. ,Jene~al F. . ~ Sec0r.d 7:-:.a: '. :;o Conr.ection ~r:,·1.1ble Release 21. .· VR . 34 ]eneral 31, OPTlOi~ A. . . ~- Secc~d ~rial 3'+A C. :;c C::.r:nec~. .l.:·.c~ '3,4A D. Trouble F.e ::..ease ?:1B 15. :-rnE-O:JT CHECK :sc1•3) 16. ~~AFFIC 40 C:JRD SWITCHBOARD (OPTION Y AND z-:, 0R OPTION XW 1 OR OPTION 32 • Timing 40 43 v_~_-_m_,~_n~g~~~~~~~ Lin~Shift SClO) 14. ~ni 39 42 42 42 32 -· ::~,"ft- 39 General • • • . ___W_a_y Station Hunting Group One-Way Station Hunting Group 3? -~· 38 42 r~d-.-=•r_w_o C. 37 STATION AND TRUNK HUNTING GROUPS . . • . . • . . E. ..., 37 F. ''. :a. a. St'lU on -m-- vc I 44 44 45 45 46 46 ?em; Tirne-Clut Alarm Ala"":: (~ontrol . 46 VESSAGE WAITING SERVICE (OPTION ZQ) ....• 46 2 2. liI :''.ECT STATION SELECTION 47 _.'\. ;,::e!"ldant Direct Station Selection an::i ZX) • 47 2 3. 2 ::;Gi,E-DI GIT DIALING ~ :i:Jti:'ns ZY ) 47 '-'.ake Busy Key and Lamp REGISTER CON7ROL 47 tL A. B. c. D. 17. A. General • • . • . . • . • . Peg Count Register Control Overflow Register Contrc~ . Trouble Register Con:rol 35 35 LINE GROUP 20-29 36 i_;:~::L'JERSAL General . . . Jictance Options YE, YF, Y0 1 and YP) . • • . . • , • . • • ?Ar CON'.i'ROL CIRCUIT :IF, Vi 1 . 20, 211 35 3" 36 A. B. C. General • • • . . Incoming Galls (SC30) Outgoing . • • . • • • TAB:..E OF CON'J:'Ei'<?S FA32 2 TCI Library www.telephonecollectors.info 47 (OPTIONS .. 1 • 47 47 48 l!9 ) CD-657q1-01 - ISSUE 9D - TABLE OF CONTENTS 25. MAKE BUSY AND BUSY DISPLAY CIRCUIT • • • • • . • • A. Function of L1n;{s with Make Busy and Busy Dis~lay Circuit • • • • . 50 Function ofunctors with Make BU!l. and Busy Displ83 Circuit • • • • • 50 Function of Busy Tone Trunk with Make Busy and Busy Disolay c!rcUit . . . . . . . . . . 51 Function of Universal Lines with Make Bus~ and Bus~ Dlspla~ Circuit (Option tt ~ • • • • • 51 B. c. D. 26. s. c. 50 MISCELLANEOUS • • • 52 SECTION III - REFERENCE DATA. 1 27. 1. WORKING LIMITS. 1 2. FUNCTIONAL DESIGNATIONS 1 3. FUNCTIONS • 3 4. CONNECTING CIRCUIT. 5 5. MANUFACTURING TEST REQUIREMENTS 5 6. TAKING EQUIPMENT OUT OF SERVICE 5 7. ALARM INFORMATION 6 51 4. B. Indication Action Required • 6 6 52 SECTION IV - :REASONS FOR REISSUE • • • TRAFFIC MEASUREMENT SYSTEM NO. lA REMOTE SCANNER CIRCUIT . • . . • • 51 51 1 'rABLE OF CON'l'EN'l'S Page 3 TCI Library www.telephonecollectors.info TCI Library www.telephonecollectors.info CD-65741-01 - ISSUE 9D - SECTION I SECTION I - GENERAL DESCRIPTION l. PURPOSE OF CIRCUIT 1.01 The circuit provides means for establishing dial tone connections for stations and trunks to dial pulse registers, and talking c.onnections between two stations or two trunks, between a station and a trunk, or between a station or trunk and a special service circuit, through a crossbar switch networK. 2. GENERAL DESCRIPTION OF OPERATION A. Subcircuits and Arrangement 2.06 The line circuits, busy tone trunk, Junctors, attendant trunks, ~entral office and ringdown tie trunks, and the dial pulse registers are terminated on the switch verticals. Each dial pulse register is assigned two verticals. One of these verticals is used as a temporary memory device to record the link number used in the dial tone connection. The crosspoints of the register memory verticals are not multipled to the crosspoints of other verticals and therefore, do not form part of the links. The junctors also have two vertical appearances each, one for the originating side, the other for the terminating side. 2.01 Line circuits are provided for a maximum of 60 stations, which are assigned numbers from 20 to 79. The line circuits for the 20 to 29 group are made convertible so that they may be used as terminations for tie trunks and miscellaneous special service trunks and circuits. Wt.en 'l trunk or special service circuit is coru.... ,_ .,ed to a universal line circuit, the assigned number changes from a 20 to 29 number to the corresponding 80 to 89 number. Only one link is used for establishing dial tone connections, stationto-trunk connections, and trunk-to-trunk · connections. Station-to-station connections are established through a junctor and thus use two links per connection. Trunk-tostation connections are established using only one link. An exception is the code 8 tie trunk to station connections, which are established through a junctor and employ two links. 2.02 2.08 Terminations are provided for ten central office trunks, which are assigned numbers from 90 to 99. A maximum of four ringdown tie trunks may be substituted for four central office trunks; when this is done the ringdown tie trunk assumes the number of the central office trunk it replaces. When all of the trunks in the 90 to 99 group are arranged in. a single trunk group, the PBX may be arranged for onedigit operation in this group, and these trunks can be reached by dialing the single digit 9. Terminations are provided for three attendant trunks, which may be reached by dialing the single digit O. If a call is completed to an attendant trunk under an intercept condition, a distinctive mark is given to the trunk so that, upon answering, the attendant may distinguish the call from a dial-zero call. 2.07 The central office and ringdown tie trunks are usually arranged so that they may be dial selected for outgoing calls. Incoming calls over these trunks. however, can be answered and completed only by the attendant, unless an auxiliary position circuit is provided as a special service circuit. If an attempt is made by the attendant to complete an incoming call over one of these trunks to a busy station (assuming all other stations in the same hunting group, it any, .are also busy.), the trunk will camp-on the busy station, provided no other trunk is already camped-on the same station. 2.03 2.04 Terminations are also provided for one busy tone trunk, two dial pulse registers, and both ends of six Junctors. 2.05 The crossbar switching network consists of eight 10 by 10, 6-point crossbar switches. The horizontals are arranged so that a total of sixteen 3-wire links are available. The 16 links are realized by using eight 6-wire horizontals (levels 2 through 9) and choosing either the left or right halt of the crosspoints by operating the crosspoints of either the 0 or 1 level in combination with t.hose of one of the 2 through 9 levels. 2.09 Incoming calls over central office trunks may be answered and completed by any PBX station if the PBX is provided with an auxiliary position circuit and the attendant places the PBX on remote trunk answer operation. In this case, any attempt by the answering station to complete the incoming call to a busy station will not cause the trunk to camp-on the busy station. 2.10 Although the central office and ringdown tie trunks are dial selected, only nonres.tricted station, nonrestricted code 8 tie trunks, and other central office and ringdown tie trunks will be connected to them directly. Restricted stations and code 8 tie trunks, upon dialing a 9 code, will be connected to an attendant trunk. For restricted stations, the attendant may then hold the c'.'ll at the attendant trunk fJn1j C(Jnn<>ct :.1 central office or ring, l11wn tlt· trtmk u . tile c ~ 11.Lng s t::i tiou on SECTION I Pagt 1 TCI Library www.telephonecollectors.info a dial-back (no-t~st) basis. In the course of establishing this connection, the attendant trunk, which is holding the calllng under cunt.rol ot' a units sequence circuit in the n•arker. When beth registers are busy, the rn·1rk<~r will stop serving any restricted code 8 tie trunks, the attendant may not use the dial-back feature. Instead, the restricted code 8 tie trunk must be asked by the attendant to go on hook to be called back later on a central office or ringdown tie trunk to code 8 tie trunk connection basis. regist.er reqllests service, thereby making it available again before proceeding to serve the next lower preference group. station, will be mode to release. For 2.11 Stations may be arranged into one-way or two-way hunting groups, or in combinations of both types, but with the restriction that all stations in a hunting group must be within the same tens group. Trunks of the same type may also be arranged into two-way hunting groups. 2.12 The following conditions will signal the marker to set up a dial tone connection to the station or trunk; the removal of a handset from a station switchhook; an incoming seizure signal from a code 8 tie trunk; the operation of a pickup key associated with an attendant trunk; the operation of a pick-up associated with a central office or ringdown tie trunk followed by the operation of the hold key in the attendant cordless position circuit or the remote answering of an incoming call over a central office trunk through the auxiliary position circuit followed by a switchhook flash from the answering station. The completion of dialing in a dial pulse register wil~ signal the marker to set up a connection between the dialing station, trunk or remote answered central office trunk, and the station or trunk correspending to the dialed number. 2.13 Since the marker will process only one call at a time, a gating and preference arrangement is provided to cope with simultaneous bids for its service. When the marker is idle, the gate is open. ~e call or a group of simultaneous calls for the marker will close the gate. The marker will proceed to process each register bid, one trunk bid in each of two trunk preference lroups (not including code 8 tie trunks , one station or trunk bid in the 20 to 9 (and 80 to 89) tens groups, and one bid in each of the higher numbered tens group in ascending order, until all groups have been accommodated. 2.14 Only those trunk and tens groups in which a bid was admitted while the gate was open will be served. Once a trunk or tens group has registered a bid, individual bids within those trunk and tens groups, which are originated before the group is served, will be recognized. The station or trunk actually served is SECTION I Page 2 trunk or tens group and watt until a The particular station or code 8 tie trunk served within a tens group is controlled by the position of a units sequence circuit within the marker, which determines preference in accordance with the uni ts d1gi t of the s tf.I t i on or code 8 tie trunk. The mechan:l.cal and electrical interlocks in the attendant. cordless position circuit prevent more than one code 9 or code 0 trunk, under control of the attendant, from originating more than one CRll at the same time. The units preference changes after each marker operation involving units selection. 2.15 2.16 The units sequence circuit in the marker also controls the order of preference in the selection of trunks, attendant trunks, Junctors, and stations in a hunting group under call-terminating conditions. Other sequence cOn.trol circuits control and change the order of preference for the selection of link groups and links within a link group. A register allotter circuit is also p:.·ovided to equalize to some extent the use of the two registers. 2.17 The marker contains a timing circuit that starts functioning at the beginning of each marker usage. If a blockage occurs and a connection is not completed within an interval of time, the processing of the call is restored to its initial stages and a second trial is made. If the connection is not completed on the second trial within another interval of time, the marker will attempt to provide a connection that will return busy tone to the calling end. If this cannot be accomplished within still another time interval, the markP.r will release on a trouble-release basis and restore to normal. 2.18 Arrangements are provided to prevent en auxiliary switchboard, which can be used in conJunction with the PBX on an optional basis, from interfering with the marker while it is processing a call. 2.19 Provisions are made for scoring groups of peg count, overflow, and "trouble registers under appropriate circumstances. 2.20 Alarm circuitry and alarm lamps are provided to record circuit irregularities. TCI Library www.telephonecollectors.info CD-65741-01 ISSUE 9D - SECTION I Dial Tone Connection (See Ifote 3o4) B. 2.21 When a PBX station Utts the receiver to make a call, the line relll,J operates. 'ae line ~la,y operated the tens _. units identity ot the calltnc statica to the marker. All calla desiring service coapete tar the marker.· 'l.'tMt tens select~cn circuit (FS2) of the marker accepts tbe tens intormatioo and allows onl,y one call at a time ~o be processed. pa•••• Linea, trunks, and registers are assigned a .loca~~<*i- .1,n the 1;en• .preter.encer·ohaln (1'83); ,Jnd .811iiUltaneous calla are aerMd · accortUng t~ that locattQll.· (When n0 more regi.ter& are available, the marker stops processing dial tone cQn.Dections witil it can serve a register, ~ i'reeing it tor another dial tone ccnn.e. tion. ) . ; '~" 2.22 . an originating staticxi line has been given preference, the tens cqnnect~r (FS4) tor the group of tens linia in which that station 1s located operates. 'l'he tens connector allows the units inforaation from the 11.fte rela,y to be extended to the units selection circuit (1'85). 2.23 Wh~ 2.24 All atatiana 1n the preferred tena group that 4ea1re·aerv1ce will,... unlt1 .1ntol'll&tlon to the units aelect1on c lrcu1 t. However, onlJ that line which has the blgheat units preference 1n that tens Cr'ou.p will be Hl"Yed at this ti.t .. '1'he line and trunk hunting circuit (1'86) detel'ldnea which line will be served. · 2. 25 The oper.a ti on ot the tena pretere1fU! .ai.1n also the re&i.ale:i' cont.rol clrcuit ('PSJ.O) to connect .n 141• dial r.S,ster. 1'be regiater control circuit c~,- a ~&later and ,...._. . cla1a•'Of·9'r.lei intoraation from the cla8sot-aenlce c1rcd1t (J'8ll,) to th~· ·.· ater. The register cOlitroJ, cS.rcuU also · · ta the link teat circuit (7812 or · . ) to find an idle link. 1"11•• •t&nal• 2.28 When the attendant is completing a call on an incoming trunk to a PBI ~ station or another trunk, when the attend~ ant is placing a call via ,an attendant trunk, or when the PBX 1s .on r-.ote truall answer operation and a PBI •tat1on ta completing a call on an 1DcOltln& tnanlt to a station, the trunk 1ta tena and unite identit, to the aarker. '1'be marker connects tbe trunk· to;,• •ul pulfe register.~ .:t;he •'- ta8hlcn .~ the same c1.rcU1 ta aa tor • •teU.cm· um. PBX P••••• •4 c. Call-Te!!1nat1.ni Comiecti<?Qt .. : . -·, . ,. aeaeral When the dial pulse register has received all the 41ale4.1Jd'orat1~, it signals the marker fer ,.rvS.c•. t'tle · tena ~lection circuit •cOani•.. tile .._,~ 1ater NtU••t tor een:ice end tM ·~ intoraa tlon on to the tens pref'erence . .. circuit. The regiaten have the highest preference in the ll&l'ke~ and will be served bet'ore an.y trunkli or stations tbat ~t originate calla at the .... tiae that a reglater requests ael"lice. 2.29 ltU••• 2.30 orct1nar11.F the ilarbr wUl contlnu to ••rv• l.imta or trublta that were waitln& wbep tbe ·1'9&1•t9J' .oall•O. However. 1t the •ft.er ·•ncaaten :• all<tfMl•t•r•-: . bus' condtt1Clll, lt rill aern a witting .,. reg1ater tirat, 1n order to ,.... tbat reaiater tor another.dial c•ll. 'CDll < I BtatifA Line to Station L1ne (Sie 39• M thf'OQjb $'11 · l .. 2.31 When the register .has Ileen 11vea pre~ terence; tl}e ten111 prefer~ Oba1n connects leads from the reg11ter tb~ to the sequence control circuit ('88). · !ntoraat1on passes over the drc~t that a Juncto. , will be required. 1'b9 aequ•• c<JBtro1 circuit requests the Un• uid trunk bwitinl clrcu1t to find an idi~ ~unctor. 2.33 The register c~c•or operated allows the tens and unS. t• ldentl t,p or. tbe called station to" ')l'ID8"i~d to'thfl aarter. The tens connect ;r ·correl)Clllding to the tens digit of the atat1Clll 11,operated, and the units rela,y ot the unite selection circuit corresponding to the IUlits di&it ot the called station is operated. The line SEC'l'IOlf I Page 3 TCI Library www.telephonecollectors.info ~-----~------ -- CD-65741-01 - ISSUE 9D - SECTION I connector circuit. Units information is also transmitted from the register to operate the units selection circuit. By means or the H terminal strapping in the units selection circuit 1 units relays corresponding to all the trunks in the desired group are operated. The units selection circuit then signals the line and trunk hunting circuit to select an idle trunk. and trunk hwiting circuit then tests the sleeYe of the called line to see if it is idle. 2.34 The link test circuit, finding an idle link, signals the select magnet control circuit to operate the select magnets corresponding to the selected link. The select ll18gl'\et control circuit then sisiials the line and trunk hunting circuit to operate the hold magnet associated with the called station (assuming it is idle} and to operate the terminati?)g hold magnet of the selected junctor. 2.35 The line and trunk hunting circuit When an idle tl'unkhas been round, the line and trunk hunting circuit oper_ates t.he hold magnet associated with that ~;--· trunk to check that· tije trunk is holding the connection. Then the line and trunk hunting 2.40 . functions to check tha'I; ~he .,,tµnct().t: , . "" ·• ~~~~ ~1"18.la tb~ l'O!olt• ~rol aJ.l'OQi.t· ~· ··'!'ff l'mTdtlflt' ml"'l!!'ll"l!lf ?!fie Qt4 "then s1gniis~ fo release the· urker. 'l'he route control . the sequence control circuit to advance . :...: f'rom the terminating to the originating par~-4-' of' the call. The sequence control circuit <-· ' advances and restores the tens connector, the units selection, the line and trurilt hunting, the link test, and the select magnet control circuits. 2.36 The sequence control circuit then signals the register control circuit to operate the select magnets corresponding to· the link to which the calling line and the dial pulse register are connected (see Note 307). The sequence control circuit also signals the line and trunk hunting circuit to operate the originating hold magnet of the selected Jwictor. 2.37 The line and trunk hunting circuit checks that the junctor is holding the originating station and signals the route control circuit to release the marker. The route control circuit signals the register control circuit to release the dial pulse register, an·1 the route control circuit restores the marker to normal. circuit signals _tpe register control circuit t() release. the register and then restores the marker to normal. Class-of'service information is passed from the register to the selected trunk through the register corim;ctor. · · Trunk to Station· Line ('See.Note 309) 2.41 When a register ~alls for the marker and desires to connect a calling trunk to a station line, the tens preference chain connects leads f'rom the register through to the sequence control circuit. Information passes over tne circuit that a junctor will not be required. 'l'he sequence control circuit then operates the register connector of the tens connector circuit and signals the register control circuit to operate the select magnets associated with the link to which the calling trunk and the register are connected. 2.42 The register connector allows the tens and units identity or the called station to be transmitted to the marker operating the corresponding tens connector and the corresponding units relay ot the units Station Line to Tr1.mk {See Note 308) selection circuit. The units Belection circuit then signals the line and trunk hunting 2.38. When a register calls for the marker circuit .to t.~st .t;.t_l~--~.le~ye 21.:.~lltt~~QIL.-.·- ..: ,.,_.:..:,._c-: __ .... ••-_,..~ ~· ;,;;r · &'·~~~~~~cfli:11.iJrt.!~~Cf.ngc:... ···"'!~-:'s'.tS'~~.ilf~,;aJJy.·~W~"f:d?'IJ:::c<"'.'.,.':" ~''."."''-~··· ··:""''· · • .• ~--Ttatfon . to '.a trllnk', ttie tens .prefe:rence·· · · ·· · ··· ·· "" · · ·· · · · · ·· ·~ · ._. chain con! .ec ts leads from the register 2.43 The line and trunk hunting circuit through to the sequence control circuit. then operates the hold ~agnet asInformation oasses over the circuit that a junctor will.not be requ~red. The sequence sociated with the called station (if i t is control circuit then opera t.es the register idle) and check.a that the trunk is holding connector of the tens connector circuit and the connection. The line and trunk hunting signals the regis·ver contrc·l circuit to circuit the~ signals the route control operate the selec~ magnets associated with circuit to release the marker. 'l.'he route the link to w~ich the CHlling station and control circuit signals the register conthe register P.re c<ennec Le'.l, trol circuit to release the reg1ater and then restores the marker to normal. The register connector allows the identity of ~he called trunk group to be transmitted ~o :he m~rker, operating the corresponding ·.runk. relays in the tens 2.39 Trunk to Trunk 2.44 When a register calls for a marker and desires to connect a calling trlmk SECTION I Page 4 TCI Library www.telephonecollectors.info \ CD-65741-01 - IS' m: 9D - SEC1'ION I to another trunk, the operation is geneJ"allf-"' F. Cam,p-On the same as when it connects a calling . station to a tl'unk. · ·· · ·· ·Sta ti.on Bus,y - No ·rrunk Ca..'liped-On D. Called Staticn Line Bllsz 2.45 When the line and trunk hunting cir-· cu1t tests a station line and finds it bua,y, the hunt connt:etor .relays of tnat circuit operate to test whetbe~ the line is 1n a hunting group and whether any lines in the hunting group are i~le. If an idle line is found, the marker proceeds.to complete the call to that line. 2.47 If the line busy ia ve~1t1ecr• ~e marJ[er either connects the c'allirig station to a busy tone trunk or returns a busy stsnal to the calling trunk, which returne both an audible and a visual signal to the attendant.· 2.53 When the rnarker atteilpts to complete a ca11 from a central office or rlngdown tie trurik to a station line and finds that the station and all other stations in the same hunting group are .busy, it sets the trunk to camp-on the station line so that i t will become connected to the station as soon as the station becomes idle. If the PBX is on remote trunk answer operation, the marker will function as described in Lin~ Hus.y - Trunk Alrea~ Camped-On and wlli not set the trunk o camp-on the station line. 2.54 When the l~e and-trWik hunting cir- tercept portion of an attendant trunk, cuit finds that the station line is busy, 1 t p_asses this information to the route control circuit. The route control circuit;.· recognizes the lin~ busy and the central office or ringdown tie trunk class 1nd1cation frOllll the regist.er as instructions to set.up a camp-on condition in the trunk. E. 2.55 2.48 It the. line busy la not verified, the marker completes the call to the inPaths Busy All Ltnlts Busy 2.49 It all links are busy when the marker , triea t.o .connect a station line or a trunk to a dial pulse register~ the link test circµit signals the units selections circuit to abandon the call. Thia marker action is repeated on successive calla until a link becomes idle. 2.50 If all link.a are busy when ~he marker tries to canplete a call trOlll a dial pulse register, the link test circuit will signal the ro11te control circuit to complete the call to a busy tone trunk. The link used tor this connection is the same one connecting the calling station or trunk to the register. All Trunks Busy 2.51 I t all trunk.s in a desired group are busy, the line and trunk hunting circuit signals the route control circuit to complete the call to the busy tone trunk. Busy Tone Trunk Busy 2.52 If the b11sy tone tl'\a'lk is busy, the marker, through the line and trunk hunting circu1 t and the register control circllit, signals the register to retum busy t.one to the calling subacriber and releases. The route control c1rcu.1t signals the link test circuit to find the link to which the desired station line is coonected and directs the line and trunk hunting circuit, after a suitable interval, to release the hold magnet of the central office trunk. 'l'he line and trunk hWlt1ng circuit tell• the central office or ringdown tie trunk that the line is busy. - ----~.:..;_~.,;.-;:.--.~ ~ 2.56 When the link test circuit finds the proper link, it signals the select magnet control circuit to operate the select magnets corresponding to that link. The select magnet control circuit then directs the line and trunk hunting circuit to reoperate the hold magnet associated with the central office trunk. The line and trunk hunting circu.it then cbecu that the hold magnet has operated and signals the route control circuit to release the marker. The route contral circuit signals the register control circuit to release the register and then restores the marker to normal. Line Busy - Trunk Alread.r Camped-On 2.57 It the marker t1.nda ano.ther trunk alread,v camped-on the called station line, it will signal the central office or ringdown tie trunk that a call is already waiting. 2.58 When tbe, link teat circuit starts to look tor the link to which the desired stat1Pri 11ne 11 connected, the SECTION I Page 5 TCI Library www.telephonecollectors.info ____ _J -- CD-65741-01 - ISSUE 9D - SECTION I . t l' trunic already camped-on that station line signals the link test circuit that it should not try to set up another call to that etation. The link teat circuit signals tbe central office or r1ngdown tie trunk to return a camp-on busy signal and di rec te the line and trunk hunting circuit to reoperate the trunk hold magnet. The line and trunk hunting circuit signals the route control circuit to release the marker. The route control circuit directs the register control circuit to release the register and then restores the marker to normal. aial - Station Dial Conference Trunk circuit - !Fation or Xttendirit controlled, or station Diai transfer TrUiii circuit 2.59 A provision is made to cancel the normal caap-on function if the marker encounters a busy station when atteapting to add a station to either of the dial conference trunk circuits or when attempting to transfer an incoming central office trunk call via the station dial transfer trunk circuit. Li.De Bur - Rw>te Trunk Anner Operation 2.6o When the PS la an reaote trunk Ulfter operation and the ·urker atteapta to CQllPlete a call fl'Oll a central office trunk to a station l.1ne and finds that the station and all other stations 1n the same hunting group are busy, it aeta the trunk to retuni a caap-on busy signal to the anenri.ng station as ui 1ntU.cat1on ot a bu&J' line. 2.61 'l'he link teat circuit recognizes · the line busy and the central office trunk class intU.cation from the register as instJ'Uctlons not to set the trunk to camp-on the busy line. The link test circuit signals the central office trunk to return.a camp-on busy signal and directs the line : nd trunk hunting circuit to reoperate the trunk hold magnet. The line and trunk bunting circuit signals the route control circuit to release the marker. 'lhe route control c1rcu1 t directs the register cc:mtrol circuit to release the repater and then restore• the marker to noraal. G. Abandoned Calls 2.62 If a atation line or a trunk starts to make a call and then disconnects before the marker can connect it to a dial pulse register, an abandoned call condition is presented to the marker. 'Ibe marker proceeds nol'll&lly up to units selection. Since the calling party has already disconnected, no units infonnation 1~ available. SECTION I The units selection circuit recotPli&e• ui abandoned call and signal• tbe route control circuit to release the ll!&J'ker. 2.63 If the abandonment 1• atter tbe units 1ntormat1on bu be.a U.tlfted, the urker· tlm1nl: c1rc..S.t 11Uat adYmae to no connectlm before tbe -.rur ruton• to normal via the aNnclcned call route. Marker Time-Out H. Secmd Trial .....-r 2. 64 As aom as tbe J.• Hi.H4, tbe advanc•t.:!;--out, ua4 n i.... circuit starts t tbe marker. U the route control circ..S. t baa not rel.eased tbe marker within a abort tllle, the·&d•anc•, time-out,and release clre..S.t functiona to advance the ll&l'Ur to HOaad tl'lal. 'lbe marker 1a reetored to lte call atart con41tion, and the sequence clrcuita ot tbe line and trunk hwitin& clrcait UM1 tbe select magnet control circuit ue-...anced. .!fo Connection 2. 65 It the 11&rker 1• •mebi. to COllpl.ete a connection an a MCcmd tl'ia1 Mf'on the advance, tt.-oat, UM1 NIMM clftult runcticna tor the aecond UM, tbe rcNte control circuit l