US2289896A - Telephone system - Google Patents

Telephone system Download PDF

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Publication number
US2289896A
US2289896A US329088A US32908840A US2289896A US 2289896 A US2289896 A US 2289896A US 329088 A US329088 A US 329088A US 32908840 A US32908840 A US 32908840A US 2289896 A US2289896 A US 2289896A
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United States
Prior art keywords
finder
switch
group
lines
switches
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US329088A
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English (en)
Inventor
Bakker Pier
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Associated Electric Laboratories Inc
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Associated Electric Laboratories Inc
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Priority to NL63264D priority Critical patent/NL63264C/xx
Application filed by Associated Electric Laboratories Inc filed Critical Associated Electric Laboratories Inc
Priority to US329088A priority patent/US2289896A/en
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Publication of US2289896A publication Critical patent/US2289896A/en
Priority to FR938296D priority patent/FR938296A/fr
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements

Definitions

  • Another object of the invention is to provide in an automatic telephone system, improved distributor apparatus for selectively controlling the operation of the nder switches in two associated groups of finder switchesto find calling lines in twoassociated groups of lines.
  • the telephone system comprises first and second groups oflines, first and second groups of finder switches, each of the finder switches in each of the groups of finder switches having access to each of the lines in each of the groups of 40 lines and being operative to find a calling line accessible thereto, first blocking means normally of nder switches from finding lines in the first group of lines.
  • the system comprises a rst distributor operative to assign idle ones of the 540 finder switches in the first group of finder switches in a predetermined order and to initiate operation of an assigned one of the last-mentioned finder switches, means for arresting optioned finder switch when a line is found thereby. means governed when all ofthe nder switches in the iirst group ⁇ of finder switches are rendered busyi'or rendering ineffective the second block.
  • this system comprises means governed in response to the presence of a calling line in the first group of lines for operating the first distributor in the event there is an idle finder switch in the first group of finder switches and for operating the second distributor in the event all of the finder switches in the first group of finder switches are busy and governed in response to the presence of a calling line in the second group of lines for operating the second distributor in the event there is an idle finder switch in the second group of nderswitches and for operating the first distributor in the event all of the finder switches in the second group of finder switchesare busy.
  • each of the distributors i's operative through a cycle to initiate operation of a. preselected finder switch in the associated group of finder switches and then to arrest operation of and to render busy the last-mentioned finder switch when a line is found thereby and finally to select another idle one of the finder switches in the associated group of finder switches.
  • the first blocking means comprises a blocking circuit adapted to be completed to prevent the finder switches in the first group of finder switches from finding lines in the second group of lines; and the second blocking means comprises a blocking circuitadapted to be completed to prevent the finder switches in the second group of finder switches from finding -lines in the first group of lines.
  • the first distribu tor comprises means governed when a finder switch in the-first group of finder switches is operating for preparing a point in the first blocking circuit and additional means governed while a finder switch in the first group of finder switches is operating or when there is an idle finder eration of and for rendering busy the last-menswitch in the first group of finder switches for when points are prepared therein in both the first distributor and the second distributor.
  • the telephone system there illustrated comprises an exchange terminating a plurality of subscriber lines, including the subscriber lines
  • the exchange comprises a number of finder-connector links, including the links 60 and l0, for setting up connections between the various subscriber lines. More specically, the exchange has an ultimate capacity of 200. lines, these lines being arranged in first and second groups of 100 lines each. Each 0f the links comprises a 200 point finder switch having access to each line in the system and a 200 point connector switch having access to each line in the system.
  • the links are arranged in first and second groups, each group of links being provided with va distributor individual thereto for assigning idle ones of the links in the group to the use of calling ones of the lines.
  • the number of links included in each group is determined by the amount o f traiiic which the exchange is requiredto handle and usually satisfactory serv- 'ice may be rendered when each of the two groups of links includes ten links.
  • the distributors 300 and SI2 are so connected and arranged that acall initiated on a line in the first group of lines is assigned for use an idle link in the second group of links in the event all of the links in the first group of links are busy; and a call initiated on a line in the second group of lines is assigned for use an idle link in the first group of links in the event all of the links in the second group of links are busy.
  • a subscriber substation is associated with each of the subscriber lines, the subscriber substations A and B being respectively associated with the subscriber lines
  • Each of the subscriber substations is provided with a telephone instrument, a dial mechanism and a ringer. Also,
  • 'a line circuit is individually associated with each ciated with the subscriber lines
  • these line circuits are identical, each including a line relay and a cutoii relay, these relays in the line circuit
  • each of the links is connected and arranged in a manner similar t0 that of the link B0 which comprises the finder switch
  • 30 as best shown in Fig. l, comprises a switching mechanism
  • 40 comprises upper and lower wiper sets respectively including the wipers
  • this Strowger mechanism includes a vertical magnet M
  • Associated with this Strowger mechanism are two sets of switch springs SI15 and S
  • rotary switch3II including six-banks ofilxed contacts andsix wip ⁇ ers individually associated therewith. the corresponding contacts in each bank terminating the control conductors extending to the respectiveV links in thel first group of.v links, "and the wipers terminating the control conductor extending to the distributori*
  • in ⁇ cludes arotary magnet M303 for driving the wipers associated with the contactbanks in a rotary direction.
  • the distributor "300 also comprises a start relayRl, a busy transferrelay R3, a step relay R310, a transfer relay R300, a timing relay R315, first and second test relays R320 and R325, respectively, and a, numberv ofl control relays R350, R300, R300 and R330. Also asso'- obvious path for lpplying ground potential to the s control conductor CI, thereby to cause ground potential to besppliedlby-.wa'y otthe circuit lnetwork IOI-to the start conductorCIIl extendingl into the distributorifassuming that the subscriberline III is included in the iirst groupoi.' subscriber lines.
  • the distributor 300 is of the preselective type in that an idle link in the first group of links is selected to be assigned to the use of a calling line in the first group of lines prior to the initiation of a call onl the line therein and another idle link in the iirst groupoi links is automatically ⁇ selected to be assigned to the useoi the next calling line inthe nrst group of lines as soon as the selected link operates to iind a calling line in the nrst group of lines. Also,
  • the distributor 300 is so connected and arranged that, when all of the links in the iirst group of links are busy, the start circuit of the distributor 300 is transferred to the distributor 3l! associated with the second group of lines, whereby the distributor 3
  • 20 When energized overthe above- Vtraced circuit the line relay R
  • the line relay Rin completes, at RAIZI, a path tor applying battery potential to the control conductor CIM of the subv scriber line III, thereby to mark the rotary position of the contact sets in the contact banks of the Strowger mechanismsincluded in the finder switches terminating the subscriber line IOI.
  • This path for applying battery potential to the control conductor .CIII of the subscriber line IOI extends from battery at the winding of the cutoff relay RI Il, by way of the winding of Rl I0 and RAIZI, to CIM. ⁇
  • This application of ground potential to the start conductor Clit extending into the distributor 300 completes a circuit for ⁇ energizing the winding of the start? relay R343, this circuit extending irom ground by way ofRAI25, the control conductor CI", a resistor included in the circuit network ISI, the start conductor CJIB, RAMI, RC3 and the winding of R345 to battery.
  • the start relay R305 When energized over the above-traced circuit, the start relay R305 operates to initiate operation of the distributor 300, thereby to cause the preselected idle one oi the links in the first group of links to be assigned to the use of the calling subscriber line. More particularly, upon -operating, the start relay R345 completes, ⁇ at
  • RANG a circuit for energizing the winding of the control relay R350 in series with the rotary I' magnet M300 of the rotary switch 30
  • control relay R350 Upon operating, the control relay R350 completes, ⁇ at RA353, van alternative holding circuit for energizing the winding of the busy transfer relay R340, this circuit extending from ground by way of RA344, RA350 and the winding of R340 to battery.
  • the winding ofthe busy transfer relay R300 is normally energized by way of a number oi multiple circuits completed ⁇ in idle ones'oi the finder switches of the irst group of links, one of these multiple circuits being completed at this time in the ilnder switch I30 oi the link 50 and extending from ground by way of RAI, RCI45, the switch springs
  • thecontrol relay R350 completes, atRAI'. a point in a-circuit traced ⁇ hereinafter for energizing the winding ofthe 4timingmelay.
  • R313, prepares, at RA331, a point in a circuit traced hereinafter for energizing the nnder switch
  • the control relay R350 completes, at RA35I, a circuit traced hereinafter for .energizing the windingof the start relay R
  • the link 60 in the rst group of links has been previously selected by the distributor 300 for the use of a calling line. Accordingly, the wipers 302 to 301, inclusive, of the rotary. switch 30
  • 30 extends from ground by way of RA35I, the wiper 303 and associated contact of the rotary switch 30
  • 40 When energized over the above-traced circuit, the start relay R
  • the connector switch 2I5 is conditioned to be operative in response to a digit dialed thereinto, in a manner more fully explained subsequently.
  • the circuit for energizing the vertical magnet MI10 extends from' ground by way'of RA352, RA31
  • 10 operates.
  • the vertical magnet MI10 drives the carriage of the Strowger mechanism
  • the circuit for energizing the winding of the step relay R310 extends from ground by way ⁇ of MAI10, the interrupter conductor C3
  • the step relay R310 When energized over the above-traced circuit, the step relay R310 operates, to interrupt, at RA31I, a Jpoint, in the previously ⁇ traced ⁇ circuit forV energizing the vertical magnet MI10, theres. by to cause the vertical magnet MI10 to restore.
  • the vertical magnet MI10 interrupts, at MAI10, ⁇ the previously traced, circuit for energizingA the ⁇ winding of the step relay lR310,thereby to cause the latterrelay to restore.
  • the step' relay R310 recompletes, at RA31I, the previously traced cir- V
  • MAI10 the -previouslytraced circuit for )energizing the winding of the step relay R310 in the distributor 300.
  • 30 continue to interact in the above-described manner, thereby to cause the carriage ⁇ of the Strowger mechanism
  • 30 is driven two steps in the vertical direction, whereupon the con-trol wiper
  • a circuit is then completed for energizing the lower winding ofthe transfer relay R360 in series with the winding of the step relay R310, this circuit extending from the grounded contact
  • the above--traced circuit for energizing the lower winding of the transfer relay R360 in series with the winding of the step relay R310 is completed immediately the carriage of the Strowger mechanism
  • the transferrelay R360 Shortly after the transfer relay R360 is energized over the above-traced circuit it operates, this relay being of the slow-to-operate type. Upon operating, the transferrelay R360 completes, at RA369, a holding circuit'traced hereinafter for energizing the upper winding thereof, interrupts, at RA366 and RC361, the previously traced circuit for energizing the lower winding thereof in series with the winding of the step relay R310, and prepares, at RA366 and RC368, a circuitl traced hereinafter for energizing the Winding of the first test relay R320.
  • the transfer relay R300 interrupts, at RA365, a point in the previously traced original circuit for energizing the winding of the control relay R350 in series with the rotary magnet M308, an alternative circuit for energizing the winding of the control relay R350 in series with the rotary magnet M308 being completed at this time. Also, the transfer relay interrupts, at RA36
  • the control relay R350 completes, at RAI", a circuit for energizing the winding of the timing relay R315, thiscircuit extending from ground by way ofv RA353, RA333, RC3, and the winding of R315 to. battery.
  • the timing relay R315 When energized over the above-traced circuit, the timing relay R315 operates to'complete, at RA313 and ⁇ RC318, RC319, a circuit for energizing the winding of thevcontrol relayA R330, this circuit extending from ground by way of RA353, RA318, RC318, RC313, and the winding of R380 to battery.
  • control relay R380 Shortly after the control relay R380 is energized by way of the above-traced circuit, this relay operates, this relay Being of the slow-to-operate type. Upon operating, ⁇ the control relay R380 completes, at RA333, a holding circuit for energizing the winding thereof, this circuit extending from ground by way of RA350, RA313, RC318, RA306, and the winding of R380 to battery.
  • control relay R380 interrupts, at RA382 and RC383, a point in a circuit traced hereinafter for energizing the upper winding of the control relay R330, and prepares, at RA382 and RC3", a holding circuit traced hereinafter for energizing the upper winding of the transfer relay R360. Also, the control relay R380 completes, at RA38I, the previously mentioned alternative circuit for energizing the .winding of the control relay R350 in series with the vious circuit for energizing the upper winding of the control relay R330, thereby to cause the latter relay to'operate.
  • the control relay R330 Upon operating, the control relay R330 completes, at RA336, a holding circuitfor energizing the lower winding thereof, this circuit extending from ground by way of RA35I, RA336, and the lower winding of R330 to battery. Also, the control relay R330 interrupts, at RA330 and RC33I, a point in the'previously traced original circuit for energizing the Winding of the control relay R350 in series with the rotary magnet M308, and completes, at RA330 and RC332, an obvious multiple alternative circuit for energizing the winding of the control relay R350 in series with the rotary magnet M308.
  • control relay R330 interrupts, at RA333 and RC334L'a point in the previously traced circuit for energizing the winding of the timing relay R315; prepares, at RA333 and RC335, a point in the previously mentioned holding circuit for energizing the upper winding of the transfer relay R330; prepares, at RA331, a point in a circuit traced hereinafter for energizing the winding of the rst test relay R320;v
  • the previously mentioned holding circuit for energizing the upper winding of the transfer relay R330 extends from ground by way of RANG, RA333, RC335, RAI", RC384, RA338, and the upper winding of R360 to battery; while the previously mentioned circuit for energizing the ro-v tary magnet M
  • When energized over the above-traced circuit, the rotary magnet M
  • the circuit for energizing the winding of the step relay R310 extends from ground by way of MAI1I, the interrupter conductor C3", and the winding of R310 to battery.
  • the step relay R310 When energized over the abovetraced circuit, the step relay R310 operates to interrupt, at RA31I, the previously traced circuit for energizing the rotary magnet MI1I, thereby to cause therotary magnet to restore.
  • interrupts, at MA
  • 30 continue to interact in the manner described above until the carriage of the Strowger mechanism
  • the latterv relay restores, thereby to cause the weighted armature RA31B thereof to vibrate between the associated contacts RC311 Y and RC318, in order to complete intermittently the previously tra-ced holding circuit for energizing the winding of the control relay R380.
  • 00 When the cutoff relay Rl l0 in the line circuit
  • the circuit for energizing the winding of the way of RA352, RA31I, RA38I, RC3, RA32I, RC323, the wiper 308 and associated contact of the rotary switch 30
  • the Yswitching relay RI When energized over the above-traced circuit, the Yswitching relay RI" operates to interrupt, at RAI85, a further point in the previously traced circuit for energizing the rotary magnet M
  • 34 of the trunk line I3I are respectively connected, at RAI8I, RA
  • the cutoil.' relay RI I0 When energized over the abovetraced circuit, the cutoil.' relay RI I0 operates to complete, at RAI I3, a holding circuit for energizing the winding thereof, this circuit extending from the grounded control conductor CI04 of the subscriber line IOI by way of CI04, RAI I3, and the winding ⁇ of RI I0 to battery. Also, upon operating, the cutoff relay RI
  • 30 interrupts, at RAI and RCI88, a point in a circuit traced hereinafter for energizing the release magnet lMI12, and prepares, at RAI56 and RC
  • the rotary magnet M308 When energized over the above-traced circuit, the rotary magnet M308 operates, thereby to condition the wipers of the rotary switch 30
  • the control relay R350 interrupts, at RA353 and RC355, the previously traced circuit for energizing the rotary magnet M308, thereby to cause the rotary magnet M308 to restore.
  • the rotary magnet M308 drives the Wipers 302 to 301, inclusive, of the rotary switch 30
  • the subsequent operation of the distributor 300 depend upon the idle or busy condition of the nder switch of the next link, in a manner more fully described subsequently.
  • the previously traced circuit for energizingvthe winding of the start relay R345 in the distributor 300 is interrupted, thereby to cause the start relay R345 to restore.
  • the start relay R345 interrupts, at RA346, the previously traced original circuit for energizing the Winding of the control relay R350 in-series With the rotary magnet M308.
  • the control relay R350 restores, as previously noted. it interrupts, at RA363, a further point in the circuit for energizing the winding thereof in series with the rotary magnet M308.
  • is connected by way of the to-interrupting contact MA308 and the rotary magnet M308 to battery, this connection extending. from the wiper 385 by way of RA353, RC354, RA345, MA308, and the rotary magnet M308 to battery.
  • the rotary magnet M308 operates to condition the wipers. of the rotary switch 30
  • the rotary magnet M308 When the previously traced circuit for energizing the rotary magnet M308 is interrupted, the rotary magnet restores, thereby to drive the wipers of the -rotary switch 30
  • the rotary magnet M308 startconductorC3I3 extending to the distributor 300 is connected, together with the start conductor C3I5, to the conductor C321 extending to the distributor 3
  • 2 is operative to assign idle links in the second group of links to the use of callingV plete, at RAI43, an alternative path for applying ground potential to the guard conductor C322, this path extending from ground by way of continues to operate in the above-described manner in order to cause the wipers of the relay switch 30
  • the busy transfer relay R340 interrupts, at RA344, a further point in the alternative holding circuit for energizing the winding thereof, interrupts, at RA345, a point in the previously traced circuit for energizing the rotary magnet M308, thereby -to prevent operation of the rotary magnet M308, andinterrupts, at RA34I and RC343, the connection between the start conductor C3
  • the bulsy transf fer relay R340 connects, at RA34
  • the control relay R350 in the distributor 300 interrupts, at RA352, the previously traced original' circuit for energizing the switching relay RI60 in the iinder switch
  • the transfer relay R360 interrupts, at RA333, a l further point in the holding circuit for energizing the upper winding thereof, interrupts, at RA36$ and RC358, a point in the previously traced circuit 4for energizing the Winding of the first test relay R320, and prepares, at RA366 and RC361,
  • the transfer relay R360 prepares, at RA365, a point in the previously traced original circuit for energizing the winding of thecontrol relay R350 in series with the rotary magnet M308,.interrupts, at RA36
  • RA38I and RC382 a point in a circuit for energizing the vertical magnet in the lnder switch of a selected link when the distributor 300 operates to select an idle link in the first group of links for the use of a calling line.
  • control relay R380 Upon restoring, the control relay R380 interrupts,'at RA386, a further point in the holdingl circuit for energizing the winding thereof, interrupts, at RA385, a point in the holding circuit for energizing the upper winding of the control relay R330, thereby to cause the latter relay to restore, and interrupts, at RA382 and RC384, a further point in the holding circuit for energizing the upper winding of the transfer relay R360.
  • control relay' R380 prepares, at RA382 and RC383, a point in a circuit traced hereinafter for energizing the upper winding of the control relay R390, and interrupts, at RA38I, a point in the previously traced alternative circuit for energizing the windingof the control relay R350 in series with the rotary magnet M308.
  • control relay R330 interrupts, at RA336, a further point in the previously traced holding circuit for energizing the lower winding thereof, interrupts, at RA331, a further point in the previously traced circuit for energizing the winding of the first test relay R320, Y
  • the control relay R330 interrupts, at RA333 and RC335, a further point in the holding circuit for energizing the upper winding of the transfer relay R360, prepares, at RA333 and RC334, a point in the previously traced circuit for energizing the winding of the timing relay R315, interrupts, at RA330 and RC332 a.
  • the first test relay R320 interrupts, at RA32
  • the distributor 300 is completely released for further use and the subscriber substation A is operatively connected by way of the previously traced circuit to the connector switch 2
  • ground potential is applied therein to the guard conductor ⁇ C322, thereby to complete the previously traced path for shortcircuiting the winding of the control relay R350 in order to cause the control relay R350 to restore and initiate the release of the distributor 300.
  • the start relay R345 in the distributor 300 remains in its operated position, and, when the transfer relay R360 and the control relay R330 restore, the previously traced original circuit for energizing the control relay R350 is recompleted, assuming that the rotary magnet M308 has already oper" ated to cause the rotary switch 30
  • the control relay R350 then operates, thereby to cause the finder switch of the previously selected link to operate and seize the calling subscriber line in the rst group of lines, as explained above.
  • the distributor 300 is operative to cause the finder switch of a selected link in the first group of links, such as the nder switch
  • 2 operates, thereby to cause the conductors C321 and C328 therein to be connected togetherin a manner similar to that previously explained, incident to the restoration of the busy transfer relay R340 in the distributor 300 when all of the links in the rst group of links are busy.
  • 5 is extended by way of the conductor C321 and the distributor 3
  • 30 of the link 60 is operative in a manner substantially identical to that previously explained to find a calling line in either the first group of lines or the second group of lines and accessible to the lower wiper set of the Strowger mechanism
  • 30 is rotated in the rotary direction to the position of the contact set terminating the calling subscriber line, battery potential is encountered by the wiper
  • test relay R025 operates to interrupt. at M320 and RC3", a point in the previously tracedcircuit for energizing the rotary magnet MIII ⁇ in the nder switch
  • the path for applying ground potential to the guard conductor C322 extends from ground by ⁇ way of the swltchsprings
  • Thisapplication of ground potential lto the guard conductor C322 causes the distributor 300 to be released and the rotary switch therein to ⁇ operate and select an idle link in the iirstgroporlinks, aspreviously explained.
  • the switching relay R150 interrupts, at RAl55, a pointin the previously traced circuit forv energizing the winding of the switching relay RIBO, and completes, at RAI 54, a holding circuit for energizing the winding thereof this circuit extending fromA the grounded control conductor CI I3 of the trunk line
  • the switching relay RI50 connects the trunk line extending to the lower wiper set of the Strowger mechanism to the trunk line
  • 40 may engage contacts in the contact sets in the associated contact bank terminating the controlconductors or subscriber lines having either ground or booster battery potential appearing thereupon; ground potentlal appearing upon the control conductors of the subscriber lines whenthe subscriber lines are busy. and booster battery potential appearing upon the subscriber lines when the subscriber lines are being metered.
  • 43 of the upper wiper set of the Strowger mechanism I 40 engages a contact having booster battery potential appearing thereupon, a circuit is completed substantially identical to the above-traced path, tending to energize the winding of the first test relay R320.
  • the copper oxide rectil iler 341 is so connected and arranged that current is prevented from traversing this circuit in a direction extending from the wiper
  • the first test relay R320 does not operate when the wiper
  • a path is completed for short-circuiting the winding of the second test relay R325 when the wiper '
  • 40 complete the previouslytraced circuits for respectively energizing the windings of the first and second test relays R320 and R325, respectively, thereby to cause both of these test relays to operate.
  • the iirst test relay R320 Upon operating, the iirst test relay R320 completes, at RA32
  • the copper oxide recticr 348 prevents the winding of the second test relay R325 from being effectively energized in the last-mentioned case.
  • the arrangements of the copper oxide rect.rs 341 and 348 in the circuits for respectively energizing the windings of thefirst and second test relays R320 and R325, respectively, prevent false operation of the iinder switch
  • 30 fails tol operate properly to seize the calling subscriber line
  • 30 fails to. seize the calling subscriber line
  • the vibratory armature RA313 of the timing relay R315 in the distributor 300 ⁇ assumes an intermediate position with respect to the associated contacts RC3" and RC313, thereby to interrupt the previously traced holding circuit for energizing the winding of the control relay R330 in order to cause the control relay R300 to restore.
  • the control relay R300 interrupts, at RA302 and RC334, the previously traced holding circuit for energizing the upper winding of the transfer relay R300, and completes, at RA382 and RC333, a point in the previously mentioned circuit for ⁇ energizing the upper winding of the control relay R330.
  • the circuit for energizing the upper winding of the control relay R330 extends from ground by way of RA356, RA333, RC335, RA302, RC333, and the upper winding of R390 to battery.
  • the control relay R390 When energized over the above-traced circuit, the control relay R390 operates to complete, at RA332.
  • a holdingcircuit for energizing the lower winding thereof, this circuit extending from the grounded conductor C330 by way of the switch springs 338 and 331 of the busy switch S334,
  • the alternative path for short-circuiting the winding of the control relay R350 extends from the upper terminal of the winding of R350 by way of RA33I, RA353, RC354, and the Winding of R350 to the upper terminal thereof. Also, upon restoring, the control relay R350 interrupts, at RA353, a 'point in the previously traced alternative circuit for energizing the winding of the busy transfer relay R340.
  • the control relay R300 interrupts, at RA303, the previously traced orig v inal circuit for energizing the windingofthe busy transfer frelay R340, kand interrupts, at RA334, the normal connection between the conductor C320 extending-into the distributor 3
  • the busytransfer relay R340 Upon restoring, the busytransfer relay R340 completes..A at RA34
  • the control relay R300 completes, ⁇ at RA392, a circuit for illuminating the supervisory lamp. 1.300, this circuit extending from the grounded conductor C330 by way of the switch springs 330 and 331 of thebusy switch S334, RA332, and the lamp L300 to battery. Illumination of the supervisory lamp L30! indicates to the exchange attendant that the distributor 300 is locked out of service.y The release" of the remainder of the operated relays in the distributor 300, incident to the restoration of the control relayR350 and the busy transfer relay R340, is the same as that previously described. At this time, the distributor 300 is locked out of service, as previously noted.
  • the distributor 300 remains locked out of service until the busy switch S334 is operated away from its normal position and returned thereto, which switch will no t be thus operated until the defective finder switch of one of the links in the iirst group of links is found and again placed in working order.
  • the busy switch S334 is operated away from its normal position, the switch springs 331 and 333 are actuated into disengagement, thereby to interrupt the previously traced holding circuit for energizing the lower winding of the control relay R330 in order to cause the control relay R300 to restore.
  • control relay R390 reconnects, at RA394, the conductor C320 extending into the distributor 3
  • 30 of the link 60 embodies an arrangement for causing the distributor 300 to select another idle link in the first group of links for the use of the calling subscriber line
  • 30 is actuated into engagement when the carriage of the Strowger mechanism
  • 30 of the link 80 may be rendered busy by operating the busy-switch SI83.
  • 33 When the busy switch S
  • the distributor 300 has operated to select the link 60 in the iirst group of links prior to operation of the busy switch S
  • this application of ground potential to the 'guard conductor C322 completes the previously traced circuit for energizing the rotary magnet M308 of the rotary switch 30
  • to select an idle link in the rst group of links is the same as that previously explained.
  • 2 is operative in an identical manner to assign idle ones of the links in the 75 second groups of links to the use of calling lines.
  • the links in the ilrst group of links are normally assigned to the usepof calling'lines in the first group of lines, but are as- 5 Signedtotheuseoi'callinglinesinboththefirst group of lines and the second group of lines when all ofthe links in the second group of lines are busy; while the links in the second group of links are normally assigned to the use of the calling lines in the second ⁇ group of lines, but are assigned to the use of calling lines in both the iirst group of lines and the second group of lines when :il of the links in the ilrst group of links are Further itis noted that the lines in the' ⁇ first group of lines are terminated in the first five levels of the Strowger mechanisms of the iinder switches in the ilrst group of links;4 while the lines in the second group of lines are terminated in thesecond tive levels of the Strowger mechanisins of the iinder switches in the first group v of links.
  • the lines in the first group of lines are terminated in the second' five levels of the Strowger mechanisms of the finder switches in the second group'of links; while the linesin the second group of lines are terminated in the iirst iive levels of the Strowger mechanisms of the finder switches in the second group oi' links.
  • the levels 2, 3, 4 and 0 in the Strowger mechanisms of the iinder switches in the ilrst group 4of links correspond respectively to the levels I0, 3, 8, 'l and-0 in vtheStrowger mechanisms of the finder switches in the second group of links, the
  • 0 in the Strowger mechanisms of the finder switches in the rst group of links correspond respectively to the levels 5, 4, 3, 2 and v
  • the iifth ⁇ and sixth levels in the Strowger mechanisms of the iinder switches in the iirst group of links respectively correspond to the sixth and fifth levels in the Strowger mechanisms of the finder switches in the second group of links.
  • a iirst path or blocking circuit is provided for applying ground potential to the contacts in the iii'th level of the Strowger mechanisms of the finder switches in the iirst group of links, which path extends, wh'en completed, from ground by way ofRA381, C20I, RA340' and C204 to the level mentioned; while a second path or blocking circuit is provided for applying ground potential to the contacts in the fifth level of the Strowger mechanisms of the inder switches in the second ⁇ group of links, which path extends, when completed, from ground by way of RA381, C202, RA340 and C203 to the level mentioned.
  • the control relay R380 and the busy transfer relay R340 in the distributor 300 respectively correspond to the control relay R380 and the busy transfer relay R340' in the distributor 3
  • - R340 in the distributor 300 occupies its operated the.
  • busy transfer relay am' in the distributor SI2 occupies its operated positionwhile there is an idle'link in the second group of links or while the distributor is operating while the control relay R300 inthe distributor I2 occupies its.
  • the first path for applying ground potential vto the contactsin the fifth level of the Strowgermechanisms of the finder switches in the first group of links is completed wh'en the control relay R000 in the distributor 300 and the busy transfer relay R340' in the distributor SI2 occupy their operated positions, which' condition prevails while the distributor 000 lsoperating, and when-there is an idle link in the second group of links or while the distributor )I2 is operating; while the second path for applying ground potential to the contacts in the fifth level of the Strowger mechanisms of the finder switches in the second group of links is completed when the control relay R380', in the distributor 3I2 and th'e busy transfer relay R340 in the distributor 300 ⁇ occupy their operated positions, which condition prevails while the distributor 3I2 is operating, and when there is an idle link in the first group of links or while the distributor 300 is operating.
  • the Strowger mechanisms of the finder switches of the links in the first group of links are positively prevented from operating beyond the fifth level thereof due to the presence of ground potential upon the cony tacts in the fifth level thereof, thereby rendering the lines in the second group of lines non-selectable by the Strowger mechanisms of the finder switches in the first group of links at this time.
  • the application of ground potential to the contacts in the fifth level of the Strowger mechanisms of the finder switches in the first group of links is effective to causev operation of the transfer relay R360 in the distributor 300 and the consequent arresting of the operation of the vertical magnet in the Strowger mechanism of the finder switch of the link assigned for use at this time, in the event the Strowger mech.. anism of the finder switch of the link assigned for use at this timev is operated to the fifth level thereof.
  • the rotary magnet in the Strowger mechanism of the finder switch of the link assigned for use at this time is then operated, thereby to cause the Strowger mechanism of the finder switch of the link mentioned to seize a calling line in the fifth level thereof or the finder switch of the last-mentioned link to be released in the manner previously explained.
  • the second path for applying ground potential to the contacts in the fifth level of the Strowger mechanisms of the finder switches in the second group of links thereby to render the Strowger mechanisms of the finder switches in the second group of links operative to seize a calling line in either the second group of lines or the first group of lines; similarly, when all of the links in the second group of links are rendered busy and the distributor 3I2 is released, the busy transfer relay R340' in the distributor 3I2 restores, thereby to transfer the second start conductor C3I5 to the distributor 300 and to interrupt, at RA340', the first pathi for applying ground potential to the contacts in the fifth level of the Strowger mechanisms of the finder switches in the first group of links, thereby to render the Strowger mechanisms of the finder switches in the first group of links operative to seize a calling line in either the first group of lines or the second group of lines.
  • the control relay R380 therein restores, thereby to interrupt, at RA38 ⁇ I, the first path for applying ground potential to the contacts in the fifth level of the Strowger mechanisms of the finder switches in the first group of links; similarly, when the distributor 3I2 is not operatingl the control relay R380 therein restores, thereby to interrupt, at RA38'I, the second path for applying ground potential to the contacts in the fifth level of the Strowger mechanisms of the nder switches in the second group of links.
  • connection and arrangement thereof positively prevent simultaneous seizure of a calling line in one of the groups of lines by the Strowger mechanisms of finder switches of two links in the respective groups of links incident to the abandonment of a call on a line in the other of the groups of lines.
  • 2 are initiated, whereupon operation of the Strowger mechanisms of finder switches of two links in the respective groups of links are initiated.
  • the Strowger mechanism of the finder switch in the second group of links is arrested when it is operated to the fifth level thereof due to the completed second path for applying ground potential to the contacts in the fifth level of the Strowger mechanisms o1' the finder switches in the second group of links; accordingly, there is no interference by the Strowger mechanism of the finder switch of the link inthe second group of links with the operation ofthe 'Strowger mechanism of the finder switch of the link in the first group of links.
  • the Strowger mechanism of the nder switch in the iirst group of links is arrested when it is operated ⁇ to the iifth level thereof due to the completed rst path for applying ground potential to the contacts in the fifth level of the Strowger mechanisms of the finder switches in the first group of links; accordingly, there is no interference by the Strowger mechanism of the finder switch of the link in the first groupV of links with the operation oi 'the Strowger mechanism of the finder switch of the link in the second group 4of links.
  • 2 are so connected and arranged that a line in the first group of lines is not selectable by the ilnder switch of a link in the vsecond group of links while the distributor 300 is operating; while a linein the second group of lines is not selectable by the finder switch of a link in the first group of links while the distributor 3I2 is operating.
  • the connector switch 2I5 is rendered operative in response to digits transmitted thereto from the subscriber substation A.
  • the subscriber at the substation A then dials the digits ofthe directory number of the called subscriber substation B at the dial mechanism at the substation A, thereby to transmit a number of series of impulses by way of the subscriber loop circuit to the connector switch 2I5, in order to causethe connector switch 2
  • the called subscriber line 230 is busy, ground potential appears upon the control conductor C234 thereof, thereby to causethe connector switch ⁇ 2
  • the connector switch 2I5 then operates to cause direct ⁇ ground potential to be applied to the control conductor C234 of the telephone line 230, thereby to mark the telephone line 230 busy to the connector switches having access thereto.
  • 5 After seizing the called subscriber line 230, the connector switch 2
  • the subscriber at the substation B answers the call by removing the telephone receiver of the telephone instrument thereat from its ⁇ associated switchhook, a loop circuit is completed by way of the line conductors of the subscriber line ⁇ 230 to the connector switch 2
  • the release of the established connection between the subscriber substations A and B is under the control of the subscribers thereat and. when both oi the subscribers replace the receivers o! the telephone instruments upon their associated switchhooks at .the substations A and B, the connector switch 2li rst releasesf
  • 5 is released, ground potential is removed from the control conductor C
  • ground potential is removed from ⁇ the control conductor xs CI I8 of the trunk line I I5
  • 30 is interrupted, therebyw to cause the latter relay'to ⁇ restore.
  • the switching relay RI Uponrestoring, the switching relay RI" prepares, at RAIBS, a point in the previously traced circuit for energizing the rotary magnet MI1I, interrupts, at RAIGS, a point in the previously traced path for applying ground potential to the guard conductor C322, interrupts, at RAI, a further point in the holding circuit for ,energizing the winding thereof, prepares, at RAI80, a point in the previously tracedcircuit for ⁇ energizing the winding of the switching relay RISO, and interrupts, at RAIBI, RAISZand RAIN, the connection between the trunk line II5 ⁇ and the trunk line I3I.
  • the switching relay RI60 interrupts, at RAISE and RC
  • the last-mentioned circuit extends from ground by way of RAI44, RCI45, the switch springs
  • the release magnet MI12 When energized over the above-traced circuit, the release magnet MI12 operates, thereby to release the carriage of the Strowger mechanism
  • the setsof switch springs SI15 and SI19 are actuated.
  • 8I of the set of switch springs SI19' are actuated into disengagement, thereby to interrupt a further point in the previously traced path for applying ground potential to the guard conductor C322;
  • 82 are actuated into engagement, thereby to connect the guard conductor C322 to the control conductor CI I8 of the trunk line
  • 18 of the set of switch springs SI15 are actuated into disengagement, thereby to interrupt the previous- 1y ⁇ traced circuit ⁇ for energizing ⁇ the release magnet MI'I2; and the switch springs
  • 18 of the set of switch springs SI15 are actuated into engagement, thereby to complete the previously traced path for applying ground potential in the finder switch
  • the previously mentioned connection between the guard conductor C322 and the control conductor CI I8 of the trunk line 14 V III extends from the guard conductor C322, by way oi .the switch springs lll and ill of the busy switch Si, RAI, and the switch springs Ill and i8! of the set o! switch springs Bill to the control conductor CHI of the trunk line I Il.
  • the connection of thev guard conductor C822 tothe control conductor CI Is of the trunk line lill insures 4that the link Il will not be se lected by' the distributor III for the use of Va calling one ot the lines unless both the finder switch I" and the connector switch 2l! thereof are completely released. At this time, the finder switch III is completely released. Accordingly, the link Il is completely released and is available to be selected by the distributor l for the use of a calling one of the lines.
  • first and second groups of lines, rst and second finder switches each of said finder switches having access to each of the lines in each of said groups of lines and being operative to find a calling line accessible thereto, first blocking means operative to prevent said first finder switch from finding a/ line in said second group of lines, l second blockin'g means operative to 'prevent said second finder 'switch from finding a line in said first group of lines, first start means operative to initiate operation of said first finder switch, 'means for arresting operation of said first finder switch when a line is found thereby, second start means operative to initiate operation of said second finder switch, means for arresting operation of said second finder switch when a line is found thereby, means governed while both said first finder switch and said second finder switch are operating for operating both said first blocking means and said second blocking means, and means governed in response to the presence of a i calling line in said first group of lines for operating said first start means in the event said first blocking means and said second blocking
  • first and second groups of lines, firstand second groups of finder l switches each of the finder switches in each of said groups of finder switches having access to each of the lines in each of said groups of lines and being operative to find a calling line accessible thereto
  • first blocking means normally effective positively to prevent the finder switches, in said first group of finder switches from finding lines in said second group of lines
  • second blocking means normally effective positively to prevent the finder switches in said second group of finder switches from finding lines in said first group lof lines
  • a first distributor operative to assign idle ones of the finder switches in said first group of finder switches in a predetermined order and to initiate operation of an assigned one of said last-mentioned finder switches, means for arresting operation of and for rendering busy said last-mentioned finder switch when a line is found thereby, means governed when all of the finder switches in said first group of finder switches are rendered busy for rendering ineffective said second blocking means
  • a second distributor operative to assign idle ones of the finder switches in said
  • said groups of finder switches having access to each of the lines in each of said groups of lines and being operative to find a calling line accessible thereto, flrst blocking means operative to prevent the finder switches in said first group of finder switches fromrecilng lines in said second groupof lines, second blocking means operative to prevent the finder switches in said second group of finder switches from finding lines in said first group of lines, a first distributor operative to assign idle ones of the finder switches in said first group of finder switches in a predetermined order and to initiate operation of an assigned one of said last-mentioned finder switches, means for arresting operation of and for rendering busy said last-mentioned finder switch when a line is found thereby, a second distributor operative to assign idle ones of the finder switches inl said second group of finder switches in a predetermined order and to initiate operation of an assigned one of said last-mentioned finder switches, means for arrestingl ioperation of and for rendering busy said last-mentioned finder switch when a line
  • first and second groups of lines, first and second groups of finder switches each of the finder switches in each of said groups of finder switches having access to each of the lines in each of said groups of lines and being operative to find a calling line accessible thereto
  • first blocking means normally effective positively to prevent the finder switches in said first group of finder switches from finding lines in said second group of lines
  • second blocking means normally effective positively to prevent the finder switches in said second group of finder switches from finding lines in said first group of lines
  • a first distributor operative through a cycle to initiate operation of a preselected finder switch in said first group of -finder switches and then to arrest operation of and to render busy said last-mentioned finder switch when a line is found thereby and finally to select another idle onevof the finder switches in said first group of finder switches, means governed when all of the finder switches in said first group of finder switches are rendered busy for rendering ineffective said second blocking means
  • a second distributor operative through a cycle to initiate operation of a pres
  • ⁇ means governed when a'flnder switch in said first group of finder switches and a finder switch in said second group of finder switches are operating for operating bothsaid first blocking i means and said Y second blocking means, and means governed in response-to the presence of a calling line in said first group of lines for operating said first distributor in the event there is an idle finder switchy in said first group of finder switches and for 'operating said second distributor in the event all of the finder switches in said first group of finder switches are busy and governed in response to the presence of a calling line in said second group of lines for operating said second distributor in the event there is an idle finder switch in said second group of finder switches and for operating said first distributor ln'the event all of the finder switches in said second group of finder switches are busy.
  • finder switches is operating and when there is an of a lpreselectedfinder switch in said first group of finder switches and then to arrest operation of and to render busy said last-'mentioned finder switch when a line is found thereby and finally to select another idle one -of the finderswitches in said first group of finder switches, means governed while a finder switch in said first group of finder switches is operating and when there is an idle finder switch in said second group of finder switches for operating said first blocking means, a second distributor operative through a cycle to initiate operationof la preselected nder switch ⁇ in said second group of finder switches -and then to arrest operation of and to render busy said last-mentioned finder switch when a .line is found thereby and finally to select another idle one ofthe finder switches in said second group of finder switches, means governed While a finder switch in said second group of finder switches is operating and when there is an idle finder switch in said first group of.
  • finder switches for operating said second blocking means, additional means governed while a lnder idle iinder'switch in said second group of finder switches for ⁇ operating said first blocking means, a second distributor operativethrough a cycle to initiate operation of a preselected finder switch in said second group of finder switches and then f' to arrest operation of and to render busy said last-mentioned finder switch when a line is found finder switch in said first group of finder switches and for operating said second distributor in the event al1 of the finder switches in said first group of finder switches are busy and lgoverned in response to the presence of a calling line in ⁇ said second groupof lines for operating said second distributor in the event there is an idle findswitch in said first group of finder switches and a finder switch in ⁇ said second group of finder switches areoperating for operating both said first blocking means and said second blocking means, and means governed in response to the presence of la calling line in said first group of lines for operating said first distributor in the event there is an idle finder
  • a first distributor operative toassign idle ones of the finder switches in said first group of finder switches in a predetermined order and to initiate operation of an assigned on'e of said last-mentioned finder switches, means for arresting operation of and for rendering busy said last-mentioned finder switch when a line is found thereby, a second distributor operative to assign idle ones of the finder switches in said second group of finder switches in a predetermined order and to initiate operation of an assigned one of said last-mentioned finder switches,

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Monitoring And Testing Of Exchanges (AREA)
US329088A 1940-04-11 1940-04-11 Telephone system Expired - Lifetime US2289896A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
NL63264D NL63264C (enrdf_load_stackoverflow) 1940-04-11
US329088A US2289896A (en) 1940-04-11 1940-04-11 Telephone system
FR938296D FR938296A (fr) 1940-04-11 1946-08-07 Dispositif téléphonique

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US329088A US2289896A (en) 1940-04-11 1940-04-11 Telephone system

Publications (1)

Publication Number Publication Date
US2289896A true US2289896A (en) 1942-07-14

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ID=23283790

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US329088A Expired - Lifetime US2289896A (en) 1940-04-11 1940-04-11 Telephone system

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Country Link
US (1) US2289896A (enrdf_load_stackoverflow)
FR (1) FR938296A (enrdf_load_stackoverflow)
NL (1) NL63264C (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2542283A (en) * 1947-03-05 1951-02-20 Automatic Elect Lab Telephone system
US2635147A (en) * 1948-10-25 1953-04-14 Automatic Elect Lab Telephone selector switch utilizing odd-even relay
US2656416A (en) * 1948-04-13 1953-10-20 Stromberg Carlson Co Line finder dual-allotter system
US2761902A (en) * 1949-06-27 1956-09-04 Int Standard Electric Corp Automatic telephone exchange
US2881259A (en) * 1951-01-11 1959-04-07 Gen Telephone Lab Inc Toll ticketing telephone systems
US2904634A (en) * 1954-04-14 1959-09-15 North Electric Co Automatic telephone system
US3037084A (en) * 1959-05-11 1962-05-29 Itt Linefinder and control circuits
US3159716A (en) * 1962-09-27 1964-12-01 Bell Telephone Labor Inc Link circuit
US3180942A (en) * 1961-09-05 1965-04-27 Bell Telephone Labor Inc Multicustomer private branch exchange

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2542283A (en) * 1947-03-05 1951-02-20 Automatic Elect Lab Telephone system
US2656416A (en) * 1948-04-13 1953-10-20 Stromberg Carlson Co Line finder dual-allotter system
US2635147A (en) * 1948-10-25 1953-04-14 Automatic Elect Lab Telephone selector switch utilizing odd-even relay
US2761902A (en) * 1949-06-27 1956-09-04 Int Standard Electric Corp Automatic telephone exchange
US2881259A (en) * 1951-01-11 1959-04-07 Gen Telephone Lab Inc Toll ticketing telephone systems
US2904634A (en) * 1954-04-14 1959-09-15 North Electric Co Automatic telephone system
US3037084A (en) * 1959-05-11 1962-05-29 Itt Linefinder and control circuits
US3180942A (en) * 1961-09-05 1965-04-27 Bell Telephone Labor Inc Multicustomer private branch exchange
US3159716A (en) * 1962-09-27 1964-12-01 Bell Telephone Labor Inc Link circuit

Also Published As

Publication number Publication date
FR938296A (fr) 1948-09-09
NL63264C (enrdf_load_stackoverflow)

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