US2467457A - Distributor switching apparatus - Google Patents

Distributor switching apparatus Download PDF

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Publication number
US2467457A
US2467457A US597461A US59746145A US2467457A US 2467457 A US2467457 A US 2467457A US 597461 A US597461 A US 597461A US 59746145 A US59746145 A US 59746145A US 2467457 A US2467457 A US 2467457A
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Prior art keywords
relay
contacts
circuit
lead
class
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US597461A
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Harvey W Balzer
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Automatic Electric Laboratories Inc
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Automatic Electric Laboratories Inc
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/42—Systems providing special services or facilities to subscribers
    • H04M3/50—Centralised arrangements for answering calls; Centralised arrangements for recording messages for absent or busy subscribers ; Centralised arrangements for recording messages
    • H04M3/51—Centralised call answering arrangements requiring operator intervention, e.g. call or contact centers for telemarketing
    • H04M3/523—Centralised call answering arrangements requiring operator intervention, e.g. call or contact centers for telemarketing with call distribution or queueing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M15/00—Arrangements for metering, time-control or time indication ; Metering, charging or billing arrangements for voice wireline or wireless communications, e.g. VoIP
    • H04M15/08—Metering calls to called party, i.e. B-party charged for the communication

Definitions

  • FIGS. 1 A first figure.
  • the present invention relates in general to telephone systems and more particularly to improved switching apparatus, for distributing calls tova plurality of operator positions in a cordless proposed that adistributorbe :used which would marka,batch of callingones of the lines to idle ones of the links, and which wouldprevent marking of lines over which callsgare subsequentlyreceive d until-all callinglines in themarkedbatch had been s eized by the idle links.
  • n has also been proposedthat a distributor beused which would mark severalgroupsoi-calling ones of the lines to idle ones of the linksvcausin h m to seize said calling lines roup by agroup and which would prevent -further markingof calling lines in a group, aiter all initialand subsequently received calls overlines in saidone group had been answered, until callingjines in all "other groups a be n eiz d- W en u th li es a e d ide in s l c a s an'dicerta o i a e llea ed to an w r-aparticu r la s c us ve y th t et od has the d sadv nta e o ot a tins any calls to saidce ainpositio a er-th calls of said particularifilass .havebeen-
  • a still further'gobjectof the invention is to provide a call. distributing. arrangement as stated in thej 'precedirig.objects wherein other positions are'allooated to receive only one of. the classes-0f calls, allocatedto saidcertainI positions, in which said fineans individual to each position will permit a new batch of .cansxw be ansW'eredLby said other positions when the previous batch of callsof the class allocated ith'erto has, been exhausted, regardless of whether or not batches of calls in the other .classes' h'ave'been exhausted by said certain positions.
  • hno'ther'objec'tlof the' invention is to provide means causing simultaneous calls. in. difierent classes to be given afdesired order of preference at'af position which 'is difierent than the order in jwhich corresponding marking .circuits are scanned by the links in searching for a calling line, p ,t
  • .St'i1l anothernobjctf is to provide means for removing; a marking corresponding ,to a group of lines in casefalink attempts vto find a calling line in saidgroup but fails .to doso, thereby preventing aifalse. marking .of any line in the group fromlolockingother groups of lines.
  • Another object is 1170 provide means for markingnew batches of .callingflinesin all classes in case, afllink attemptst'o lfindla calling lineinthe last choice group of the last choice class but fails Qt'odo so, .thereby preventing a false group marking fro'mlblocking all calls.
  • a further object is to provide animproved link and control circuit therefor'wherein certain con ductors are marked by the control circuit to identify asub-group ofcalling lines toa link when said link is searching. for a calling line in said sub-group,-,and "wherein said certain conductors are marked'by the link when a line has call by an associated link identifies the class of call being answered.
  • Fig. 1 is a schematic trunking diagram showing the general arrangement of a telephone system embodying the present invention
  • Figs. 2, 3 and 4 show conventional trunk circults adapted for use with a call distributor incorporating the invention
  • Fig. 5 is a schematic diagram of an improved link circuit
  • Figs. 6 and 7 taken together comprise a schematic diagram of an operator's position equipment and novel link control circuits associated therewith;
  • FIGs. 8 and 9 taken together comprise a schematic diagram of a novel call distributor constructed in accordance with the invention.
  • Fig. 10 shows a supervisor's equipment
  • Fig. 11 shows conventional distributors for routing calls to idle operators positions
  • Fig. 12 illustrates the mode of combining Figs. 2 to 11, inclusive, in order to form a unified system.
  • a system embodying the invention comprises a plurality of lines or trunks of several different classes, a plurality of operators positions each having a number of links having access to the lines or trunks, and a common call distributor for causing idle links to seize calling ones of the lines.
  • a pair of conductors extend from the trunk circuits to the common call distributor and each trunk is provided with a relay Whose operating circuit includes a normally open point individual to the trunk, one of said conductors, and a normally closed point in the call distributor common to a number of such relays.
  • the normally open point in the operating circuit of the relay associated therewith is closed, thereby operating the relay to mark the trunk and to extend a start signal to the call distributor over the remaining conductor of said pair.
  • the call distributor opens said common point in response to the start signal to thereby prevent the operation of other such relays in response to the reception of calls over other trunks, and directs an idle link to find the marked trunk.
  • the start signal is removed, thereby causing the call distributor to reclose said common point to permit operation of the relays associated with trunks over which calls have subsequently been received.
  • a pair of conductors is provided for each class of trunks, a normally closed point in the call distributor common to all of the trunk marking relays in each class being provided and being connected in series therewith over one conductor of the correspondingpair.
  • the call distributor opens the common point in the operating circuits of the corresponding class of trunk marking relays, thus preventing subsequent marking of other trunks in that class independently of the remaining classes. Thus independent batches of calling lines are marked in each class.
  • new batches of calls may be answered at other positions allocated to answer any one choice class exclusively.
  • trunks A, B and C there are three classes of trunks A, B and C, and that thereare four positions, one of which answers calls in any of the three classes and the other three of which each answer a particular class exclusively.
  • the trunks will be marked in separate and independent batches at varying intervals of time depending upon the calling rate and answering time prevailing for each class. There is thus no true correspondence between batches of marked trunks in different classes.
  • Each of the positions answering a particular class will act independently of the other two. However, the one position that is answering calls in all three classes is automatically caused to assist any one of the other three positions which is overloaded, or to assist all three other positions equally, by the distributing arrangement individual to said one position.
  • Relay I00 opcrates, connects lamps AN, BN, and CN to leads AL, BL, and CL, respectively, at contacts 102, m3, and 704 in series with contacts on the class of service keys 130, I40 and I50 corresponding to each lamp.
  • the letters A, B, and C represent the three classes of service into which the various types of calls are subdivided.
  • Relay 610 operates; removes ground from guard leads AGDI, BGDI, and CGDI at contacts 61!, 612, and 613, respectively; and closes ground from contacts 684, 685, and (-386, through contacts EM, 615, and 618 and contacts of the corresponding class of service keys to position distributor start leads ADS, BDS, and CD8, respectively.
  • the distributor start and guard leads for each of the three classes of service extend over a cable to the position distributors (Fig. 11).
  • Each distributor has a common distributor start lead, such as CDS, extending therefrom to all operators positions, and a pair of individual guard and start leads, such as CGDI and CSTI, extending to a particular position corresponding ,to the suffix number.
  • CDS distributor start lead
  • CGDI and CSTI guard and start leads
  • Relay H20 operates, closes a holding circuit through its upper winding in series with relay Hill and contacts II3I at contacts II22; connects lead CGDI to the lower winding of relay I I30 in series with contacts I I5I at contacts H23; and extends lead CSTI to lead CST at contacts H25.
  • Relay IIII] operates and opens the operating circuit to relay IIZI'I at contacts IIII. Since it has been assumed that the position equipment shown in Figs. 6 and '7 represents the first position and is now prepared to receive calls, there will be no ground on the guard lead CGDI and consequently the lower windingof relay I I36 will not be energized at this time.
  • Each of the other distributors operates in a similar manner to extend leads ASTI and BSTI coming from position I (Fig. '7) to the leads AST and BST, respectively, extending from the call distributor (Fig. 9) to the corresponding position distributors.
  • a toll selector terminating in a toll selector, a suburban selector, and a toll information trunk circuit.
  • the toll selector is employed by toll operators at a distant ofiice to extend toll calls to local subscribers over a toll switch train which is not shown, or via the repeater and toll selector intercepting trunk circuit shown to an information operator through the cordless switchboard.
  • the suburban selector is employed by subscribers of nearby oflices to complete connections to local subscribers over the local switch train, or via the suburban information trunk to an information operator through the switchboard.
  • a similar local information trunk is accessible from the local selector to permit local subscribers to call an information operator through the switchboard.
  • the toll information trunk is employed by toll operators at a manual toll switchboard to call an information operator through the switchboard. Since the switch trains follow conventional practice they have been omitted in the detailed circuit diagrams The trunk circuits have been shown in detail although they differ from conventional practice only in the adaption thereof to suit the novel call distributor.
  • the toll selector intercepting trunk circuit shown in Fig, 2 is seized over conductors 28I and 282 when ringing current is transmitted thereover from a preceding repeater under the control of a toll operator.
  • the ringing current flows through condenser 283 and relay 200 in series causing this relay to operate and complete a circuit to relay 23D.
  • Relay 23c operates, closes its locking circuit at contacts 232, connects relay 220 to conductor AH at contacts 233, and rounds lead 284 to light a call waiting lamp not shown.
  • calls received over the trunk circuits of Figs. 2, 3, and 4 are hereinafter referred to as class A, B, and C calls, respectively.
  • all conductors and relays associated are hereinafter referred to as class A, B, and C calls, respectively.
  • the AH lead to which relay 220 has been connected is associated with the class A trunk circuits. If there are no unanswered class A calls this lead will be grounded at contacts AG3 in Fig, 8, but if a batch of class A trunks have previously been marked there will be no ground on lead AH until all of the marked trunks have been seized by idle links.
  • the class A trunks may be divided into a number of groups, each corresponding to a particular level of bank contacts oi the links. In the present instance it is assumed that the class A trunks appear on two different levels of the links and therefor two AS leads are provided. to relay AI and is multipled to all of the class A trunks in one group, while lead AS nowadays
  • relay AI operates in series with contacts AGI, closes its holding circuit at contacts Al I, grounds lead VAI at contacts AI3, and closes a circuit to relay AD of Fig. 9 at contacts Al i
  • Relay AD operates, grounds lead AL at contacts ADI to light the corresponding class of service lamps, such as All (Fig. '7) at all occupied operators positions allocated to receive class A calls and in the supervisors circuit (Fig. 10), opens the circuit to normally operated relay AG and grounds lead AST at contacts A133, and grounds lead APG at contacts ADE.
  • Relay AG releases after a brief delay and opens the operating circuits to relays AI and A2 at contacts AGI and AGE, respectively; and removes ground from the AH lead to prevent marking of class A trunks over which calls may subsequently be received.
  • Relay .AI remains operated due to the shunting of contacts AGI by contacts AI I.
  • relay AD completes a previously traced circuit to relay AP (Fig. 6), and to corresponding relays of other coupled positions allocated to receive class A calls.
  • Relay AP operates, opens the circuit to relay 58%) at contacts API, shunts contacts 68I at contacts APB, closes a multiple ground to the ADS lead at contacts AP I, and closes a circuit to relay AR from ground at contacts AD3 (Fig, 9), over lead AST, through contacts such as I I25 of the A position distributor (Fig. 11) over lead ASTI, through contacts 63! (Fig. 6), contacts A1 5 and Hill, through relay AR and contacts ARB, CR5, BRIO,.and ARd to negative battery.
  • Relay AR operates, closes its locking circuit through its preliminary make contacts AR'I, opens points in its operating circuit at contacts ARG and ARE, closes a circuit to relay Slit at contacts ARI, transfers lead All. from the identity lamp AEL to ground at contacts AR3, and connects leads VAI and VA2 to leads LI and L2, respectively, at contacts AR& and ARA, thereby marking level I to the link since the VAI lead was grounded by relay AI in the call distributor (Fig. 3).
  • the LI to L9 leads extend over a cable to a set of vertical marking contacts of the link (Fig. 5)'
  • Lead ASI is connected I and are multipled to: all. links associated with the.
  • Relay 683 restores after a brief delay, opens the operating circuit to relay AP at contacts 68I, grounds the BGDI and CGDI leads at contacts 684 through contacts BP3 and CP3, respectively, and removes ground from the BDS and CD8 leads at contacts 685 and 68%, respectively. If other positions are occupied the B133 and CD8 leads will be grounded thereby and the ground placed on the BGDI and CGDI leads will cause the corresponding position distributors to advance to the next idle position. The ground on CGDI energizes the lower winding of relay H38 (Fig. 11) through contacts H23 and II5I.
  • Relay H30 operates, closes a locking circuit to its upper winding at contacts I I32 through contacts IHI and relay I I II) to ground over the CDS lead, opens the locking circuit to relay H23 at contacts SI, and extends the CST lead to lead CST2 at contacts H35.
  • Relay IIZEI restores, opens the operating circuit to relay H39 at contacts H23, connects the CGDZ lead to the lower winding of relay I M6 at contacts I I 24 through contacts H34, and disconnects lead CST from lead CSTI at contacts I I25. If the second position is busy the CGD2 lead will be grounded and the chain will continue to advance until an idle position is reached. If all positions are busy there will be no ground on the CDS lead and all relays will then restore to normal.
  • the B position distributor operates in the same manner to extend theBST lead to an idle position,
  • Relay 66 operates in response to the operation of relay AR and closes a circuit from ground through contacts 66 I, through the low resistance upper winding of relay 650, through contacts GI I, over lead ST to the link (Fig. 5) thence tln-ough contacts 561,. SRI I, and 533 to the high resistance lower winding of relay 540.
  • Relay 65 does not operate over the above traced circuit due to the high resistance of the lower winding of relay 549.
  • Relay 54 operates and closes a circuit from ground through contacts 5, 521, 54-3, 51!, and 583 to the vertical magnet VTM.
  • VTM operates to advance the link wipers WI to W5 to the first level, and closes a circuit to relay 510 at contacts VTMI.v
  • the advancement of wiper W5 to the first level marking contact completes a circuit from ground on lead Ll over wiper W5, through the upper winding of relay 580, and through contacts 584 and 531 to relay 510 in multiple with the circuit completed thereto by contacts VTMI.
  • Relay 570 operates and opens the circuit to VTM at contacts 5H. When VTM restores it removes a short circuit from the upper winding of relay 58!] thereby energizing this winding in series with relay 510. causing relay 580 to operate its preliminary make contacts 585 which complete a circuit to its lower winding.
  • Relay 580 then operates completely, connects the low resistance upper winding of relay 54!! in parallel with its lower winding at contacts 58I, grounds lead LB! at contacts 582 tolight the first link busy lamp LBIL (Fig. 6), opens a second point in the operating circuit to VTM and prepares a circuit to the rotary magnet ROM at contacts 583, and opens the circuit to relay 510 through the upper winding of relay 580 at contacts 584.
  • Relay 578 rostores. andv closes the circuit to ROM at contacts 5'. ROM operates to rotate the wipers WI to W4 to the first set of bank contacts in the first level and to disengage wiper W5 from the set of vertical marking contacts, and closes a circuit to relay 510 at contacts ROMI.
  • Relay 510 operates and opens the circuit to ROM at contacts 51!. ROM restores and opens the circuit to relay 516 at contacts ROMI. Relay 516 restores and recloses the circuit to ROM. ROM reoperates, advances wipers W! to W4 to the second set of contacts in the first level, and recloses the circuit to relay 516. This cycle of operations continues until Wiper W3 engages the contact connected to lead 285 which has been marked by the connection of negative battery thereto through relay 266 (Fig.
  • Relay 2l'6 operates, opens the circuit to relay 266 and connects resistance ground through windings of impedance coil 246 to conductors 28! and 282 to operate a ring trip relay in the preceding repeater at contacts 2! and 2!2, and removes ground from start lead AS at contacts 2l4.
  • relay 526 operates in response to the operation of relay 5!6; transfers wiper W3 from ground through relay 5l6 to ground through relay 566 at contacts 523, extends leads 286 and 281 through wipers W! and W2 to leads R! and R2 through contacts 563 and 564, condensers 563 and 564, and contacts 59! and 592, at contacts 52!
  • Relay 566 operates in series with relay 266 (Fig. 2). Relay 5!6 restores.
  • Relay 656 operates, transfers the end terminals of the secondary winding of the operators induction coil IND from leads R! and R2 to ground through condenser 622, and through contacts AR2 and condenser 623 to a source of tone current not shown at contacts 652 and 65!, respectively, and closes a circuit to its lower winding through resistance 624 in multiple with relay 646 at contacts 653.
  • Relay 646 operates after a brief delay, closes a multiple circuit to itself and the lower winding of relay 656 from ground through contacts 66!
  • Relay 636 operates after a brief delay and shortcircuits the upper and lower windings of relay 656 at contacts 633 and 634, respectively.
  • Relay 656 restores and reconnects the secondary winding of IND to leads RI and R2 at contacts 65! and 652.
  • Relays 636 and 646 remain locked to ground from contacts 66!.
  • a continuous tone is transmitted from the tone source to the secondary winding of IND.
  • the center portion of this winding is connected to the receiver of the operators headset 116 causing a single long audible tone to be given to the operator to inform her '16 of the acceptance of a class A call by an idle link associated with her position.
  • relays BR or CR would have been operated in place of relay AR as will presently be described.
  • the tone current would have been transmitted through condenser 623, contacts 64! and contacts after relay 656 operated until relay 646 operated to interrupt the tone current path at contacts 64!.
  • the subsequent operation of relay 636 would then close a second tone path through contacts 64! at contacts 632.
  • the subsequent release of relay 656, after a brief delay caused by the slugging effect of its short-circuited windings, would then interrupt the tone path a second time at contacts 65!.
  • Relay 6l6 operates from the ground placed on lead RS by relay 526 (Fig. 5), connects direct ground to lead ST at contacts 6! and opens the circuit to relay 616 at contacts 6l2.
  • Relay 616 restores, grounds the AGD! lead at contacts 61! to cause the A position distributor to advance to the next idle position in the manner previously described, removes ground from the ADS lead at contacts 614 to restore the A position distributor to normal in case there are no other idle positions, and opens the circuit to relay AR at contacts 611.
  • Relay AR restores and transfers lead AE from ground to lamp AEL which lights due to the ground placed on lead AE over wiper W3 of the link (Fig. 5) thereby indicating to the operator that a class A trunk has been seized.
  • Relay AR in restoring also opens the circuit to relay 666 which restores and opens multiple holding circuits to relays 636 and 646 at contacts 66! thus permitting these relays to restore.
  • relay 226 restores and opens the locking circuit to relay 236 at contacts 22!.
  • Relay 236 restores, connects relay 216 across leads 286 and 261 at contacts 23!, and opens the circuit to the call waiting lamp not shown at contacts 234. All of the common equipment has now been freed and a talking circuit is established between the distant toll operator and the information operator over conductors 28! and 282 through condensers 283 and 288, over leads 286 and 261, through wipers W! and W2, contacts 52! and 522, 59! and 562, condensers 563 and 564, contacts 563 and 564, over leads R!
  • relay 210 (Fig. 2) which operates and closes a circuit to relay'250 at contacts 212.
  • Relay 250 operates, closes its locking circuit to ground through contacts 262 at contacts 253, and transfers leads 28! and 282 from resistance ground to a loop circuit through contacts 2' at contacts 25! and 252.
  • the low resistance loop circuit operates a back-bridge relay in the preceding toll selector which reverses battery to the distant ofiice.
  • relay 590 restores and releases relay 210 which restores and opens the loop circuit to leads 28l and 282 at contacts 2', and opens the operating circuit to relay 250 at contacts 212.
  • Relay 252 remains locked to contacts 262. Opening the loop again causes battery to be reversed to the distant ofiice in the preceding toll selector.
  • Relay 53B operates, opens the circuit to relay 540 at contacts 533, and opens the locking circuit for relay 580 and closes a locking circuit to itself through contacts of the vertical oil-normal springs VON at contacts 536.
  • Relay 54D restores.
  • Relay 580 restores and at contacts 582, opens the locking circuit to relay 520, opens the circuit to link busy lamp LBIL over lead LBI, and closes a circuit to the release magnet RLM through contacts 534 and contacts of VON.
  • Relay 520 restores and opens the circuits to wipers WI, W2 and W3 at contacts 521, 522, and 523, thus opening the circuit to relay 500 in series with relay 2% (Fig. 2) over lead 285.
  • Relay 500 restores.
  • the release magnet RLM operates to release the link switching mechanism which restores'and opens the vertical off-normal springs VON, thereby opening the locking circuit to relay 530 which restores, opens the circuit to RLM atcontacts 534 and opens the circuit to relay 6H] (Fig. 6) over lead RS and through contacts 568 at contacts 535.
  • the release magnet RLM restores.
  • Relay 6H1 restores and recloses the circuit to relay 610 at contacts 6
  • Relay 610 reoperates to prepare the position to receive another call. All of the equipment in Figs. 5, 6, and 7 is now restored to the condition existing at the time the position was first prepared to receive a call by the operation of the link key LKI.
  • Relay 260 (Fig. 2) releases in response to the opening of lead 285 at contacts 523 (Fig. 5) and opens the circuits to relays 2H) and 250 which 12 restore. All relays in the trunk circuit have now been restored.
  • Fig. 1 both a local and a suburban information trunk circuit have been shown, the first being accessible to local subscribers from a local selector, and the second being accessible to sub urban subscribers from a suburban selector.
  • Only one type of trunk circuit is required for either use, the only difference being in the interconnection of the trunks with the cordless switchboard. Calls over either of these trunks are classified as class B calls, but it is desirable that the operator be informed whether the call is coming from a local or a suburban subscriber.
  • the trunk circuit of Fig. 3 is seized by the closure of a loop circuit thereto over leads 356 and 35l from the preceding selector.
  • the release trunk 352 is normally connected to resistance battery in case the preceding selector is the battery searching type.
  • Closure of the loop energizes relay 3H3 which operates and closes a circuit to relay 338 at contacts 3
  • Relay 330 operates, connects a source of ring back tone not shown through condenser 353, contacts 331 and 30! to lead 356, connects relay 345 through contacts 332, 323, 345, and 392 to lead BH, closes a circuit to a call waiting lamp not shown through contacts 333 and 303, and over lead 354, and connects ground to lead 352 to mark the trunk busy at contacts 331.
  • class A trunks were divided into two groups occupying the first and second levels on the banks of the links. It will now be further assumed that there 40 are insufficient class A trunks to fill the second level, the unoccupied contacts being connected to class B trunks, and that the next five levels, i. e. levels 3 through 1, are filled with class B trunks.
  • the class B trunks are further divided into two groups, local and suburban, but this latter grouping need bear no relation to the level grouping thereof. Due to this grouping by levels, six BS leads extend from the call. distributor (Fig. 8) to the class B trunk, the particular BS lead which is associated with a trunk being dependent on the level of the link on which that trunk appears.
  • the BH lead is not so subdivided but instead is common to all class B trunks. Therefore, if or when there are no marked class B trunks waiting to be answered, the BH lead will be grounded energizing relay 34B.
  • Relay 340 operates, connects the lower winding of relay 320 to lead 355 to mark the trunk to the link (Fig. 5) at contacts 343, grounds the BS lead (I to 6) corresponding to the level of the link on which the trunk appears at contacts 3M, and closes its locking circuit independent of the BH lead at contacts 345. Assuming that the call being considered is over a trunk connected to the second level of the links, lead will havebeen grounded to energiz the upper winding of relay Bl through contacts BGI. Relay Bl'operates, closes its holding circuit at contacts Bl l, grounds leadVBl at contacts BB,
  • Relay BG restores after a short delay and opens points in the operating circuits to relays B! to B6 at contacts BG! to BG6, respectively, and removes ground from lead BH at contacts BG! to prevent marking of class B trunks over which calls are subsequently received.
  • the BST lead grounded by contacts BD3 (Fig. 9) extends through the 13 position distributor (Fig. 11) to the corresponding start lead of an idle operators position, which will be assumed to be the position illustrated, in which case lead BST is extended to lead EST! and results in the operation of relay BR (Fig.
  • Relay BR extends leads VB! through VB6 (corresponding to relays B! to B6, respectively) to leads L2 through L'l (corresponding to the levels on which the trunks associated with relays B! to B6 appear), at contacts BR9 through BR4, thus marking lead L2 from ground at contacts BI3 over lead VBI, transfers leads BE! and BEZ from the corresponding identity lamps BEIL and BE2L to ground at contacts BRZ and BR3, and closes a circuit to relay 660 at contacts BRI.
  • the link is now operated to the second level and rotated to the marked trunk in the same manner as previously described.
  • relay 320 When this occurs relay 320 is energized in series with relay 5!0 through contacts 343, over lead 355, through wiper W3, contacts 523, relays 5!0, contacts 532, thence through wiper W4 to ground at contacts BB2 or BR3. Subsequent operations of the link relays are the same as previously described. When the W4 wiper is grounded by the operation of relay 520, and when relay BR restores, lamp BEIL or BEZL is energized over lead BE! or BEZ to identify the type of class B call which has been seized by the link.
  • Relay 320 operates over the above traced circuit, closes a multiple circuit to relay 330 and removes ground from the BS lead at contacts 322, opens the circuit to relay 340 at contacts 323, closes its locking circuit at contacts 32!, and closes a circuit to relay 300 at contacts 324, Relay 300 operates, closes its locking circuit to contacts 333 and opens the circuit to the call waiting lamp not shown over lead 354 at contacts 303, and disconnects the source of ring back tone from lead 350 at contacts 30!.
  • Relay 340 restores after a brief delay and extends a talking circuit from leads 350 and 35! through contacts 34! and 342, over leads 356 and 351, through wipers W! and W2 and over the previously traced circuits to the operators induction coil IND (Fig. 7).
  • dial key 604 may be restored to release relay 600 which opens the operating circuit to relay 550 at contacts 60!, reconnects leads RI and F! at contacts 602, and reconnects leads R2 and F2 through impulsing contacts 19! at contacts 603, thus connecting the calling partys talking circuit across the called line in multiple with the secondary of IND.
  • Relay 560 restores, substitutes direct ground for ground over lead DH for the locking circuit of relay 550 at contacts 562; disconnects the local line leads 505 and 506 from the position relays and connects them directly to the talking conductors of the link at contacts 563 thrpugh 566, opens the circuit to relay 540 at contacts 561, and opens the circuit to relay 6! 0 at contacts 568.
  • a holding loop is now closed to the local line through impedance coil 501.
  • Relay 6!!! restores and opens the circuit to relay 540 over lead ST at contacts 6!
  • Relay 540 restores and removes ground from wiper W4 at contacts 54! to extinguish the trunk group identity lamp BEIL or BEZL.
  • Relay 620 restores. The operator may now operate another link key like LK! to prepare for the reception of another call in the same manner as described previously.
  • the link circuit is arranged so that it is readily adaptable to either release the connection under the control of the calling subscriber or to permit recall of the operator by the calling subscriber.
  • strap X (Fig. 5) is used while in the latter case this strap is omitted.
  • Fig. 3 (Fig. 3) is released thereby removing a short circuit from the high resistance upper winding of relay 320 at contacts 3
  • Relay 320 is now held with its two windings in series over lead 355 and wiper W3 to ground through relay 500. The increased resistance of this circuit permits relay 500 to restore.
  • relay 500 restores it short-circuits itself at contacts 50! to provide locked in supervision, and closes ground throughcontacts H, 52?, and 502 to lead SYI thereby lighting the supervisory lamp SYIL. If strap X is omitted no further operation takes place. If desired, the connection between contacts SM and 541 may be omitted to permit flashing of lamp SYIL by the calling party.
  • Relay 530 operates and brings about the release of the link as previously described with the additional function of opening the locking circuit to relay 550 at contacts 53I.
  • Relay 5'50 restores and opens the local line circuit at contacts 552 and 553 to release the local switch train.
  • the circuit to relay 320 is opened at contacts 523 causing relay 320 to restore and open the circuit to relay 330 at contacts 322.
  • Relay 330 restores,
  • relay 530 as just described, but in this case when relay 5053 restores a circuit is closed to relay 53:! in multiple with lamp SYIL. The'operation of relay 5% releases the link and trunk as just described. Lamp SYIL will be energized in multiple with relay 530 until the locking circuit thereto is opened by contacts on VON upon restoration of the link switching mechanism to normal.
  • the dial key 5634 is first restored causing relay 5:70 torestore and open the operating circuit to relay 550 at contacts 60L after which key 605 is operated momentarily causing relay 530 to operate and open the locking circuit to relay 553 at contacts 631.
  • Relay 550 restores and opens the local line circuit at contacts 552 and 553 to release the local "switch train.
  • Relay SRI operates, closes its locking circuit to negative battery through its preliminary make contacts SRIZ' and to ground on lead SR at contacts SRIQ, extends leads FI and F2 through contacts SRI I and SRI5 to leads SI and S2, grounds lead SE at contacts SRI 6 to operate relay I080 (Fig. 10) and to light the supervisor busy lamps, such as 'SBL (Fig.
  • relays SR2 and SR3 represent relays corresponding to :SRI but which are associated with links 2 and 3, respectively.
  • Relay limo operates and extends ground over lead SS and through contacts IO0I and Hill to buzzer 5833, which operates as long as key 720 is held operated, to signal the supervisor, closes a circuit to a signal lamp I034 through contacts EOI2 at contacts I002, and closes ground from contacts I02I through contacts I003, over lead SP, through contacts SRI'I, and over lead SPI to the supervisor pilot lamp SPL (Fig. 7).
  • the supervisor answers the call by inserting the plug 103i of her headset I030 into jack I032, a circuit is completed to relay I023 through the transmitter of the headset I030.
  • Relay I020 operates and closesa circuit to relay I0 I 0 and opens the circuit to lamp SPL over lead SP at contacts m2 I.
  • i Relay IiIIlJ operates and opens the circuits to buzzer I033 and lamp I034 at contacts I0 and IOI2, respectively.
  • the information operator or the calling party may now converse with the supervisor. If desired, the information operator may retire from the connection by restoring the link key LKI, relay SRI remaininglocked to ground on lead SR. In this case the supervisors talking conductors SI and S2 will be connected directly to the link talking conductors at contacts .563 and .564 through contacts SR and SRI5 when relayv 580 restores.
  • the toll information trunk circuit showniii' Fig. serves a manual toll board located near the cordless switchboard.
  • relay i iii operates, grounds lead CS at contacts 452 through contactsdslconnects relayfltil to lead 455fat contacts M1 to mark the'trunk to'the link, and closes its'locking circuit independent of lead CH at contac'ts'Mt'.
  • the class" C trunks are divided into groups corresponding to the levels of the links on which they appear just as the othertrunks were. Thus there are three leads CSI, CS2, and CS3 corresponding to levels 8, 9, andtl of the links. Assuming that the callbeing considered'isover a trunk which'appearson'the eighth level of the links, lead CS! will be grounded causing relay Cl to operate and ground leadfVCI.
  • relay CR (Fig, 6) operates it extends the ground over lead VCI to lead L8 to mark the eighth level to the link.
  • the in formationoperator may extend negative battery and groundoveii leads 456 and 451 by operating her flash key rat-as previously described for a cl'as's'Acall.
  • relay 520 When' -this is done relay 520 is operated'and recohnects resistance battery to leads -i5ila'nd45 l contactsAZ'I' and i'22 to'si'gnalthe calliiig' operator. 'When the "calling operator removes the plug from the jack connected to this trunk", relay the restores and removes a short circuit from the high resistance lower winding" of rela str atcoritaets mil. Thischang'e intesistance over lead causes relay 5% to restorea'ndlightdamp SYIL and also release the link if strap X is used.
  • The'position group"- ing relays AP, BP, and CP will be operated in all positions and will release're'lay sense as to'preventreoper'atio'n' of any of the rel'ays'AP, BP,or CP, after they arereleased, until all three'have been released;
  • the threestar't leadsAST,-BST,- and CST will be extended through theircorre spending position distributors to" the correspond ing start leads of one of the'po'sitions;sa'yposition one)
  • the one which wil1"remain operated isdetermined'by the'strapping between terminals Tl to T7; With the strapping indicated changing the strapping any desired alter preference
  • the order oi-preference desired is BR; AR; CR ⁇
  • the class of service in which a marked batch of calls will first be exhausted will be that class in which 20 the number of calls included in the batch thereof divided by the number of positions giving preference thereto is the least. Assuming that the batch of class B calls is the first to be exhausted, when the last marked class B trunk is seized the last of the relays BI to B6 will be released causing relay BD to restore and reoperate relay BG.
  • relay BG As soon as relay BG reoperates all of the trunks over which calls have been received during the time that relay BG was restored will be marked to the links and will reoperate the corresponding relays BI to B6. Relay BD is then reoperated and relay BG released to prevent further marking of class B trunks. During the interval when relay ED is restored the class B position grouping relays, such as HP, will all be released. The circuits to these relays will be open at contacts such as 682 thereby preventing reoperation thereof when relay BD reoperates. Therefore the class B level marking relays, such as BR, are prevented from operating so that only the marked class A and calls may be answered at all positions.
  • relays such as BP and 680 restored there Will be no ground on the B position distributor start lead BDS thus causing this distributor to be inactive.
  • a new batch thereof will be marked in a similar manner and all positions will then answer calls in the remaining batch.
  • relays such as 680 will be operated in all positions causing relays such as AP, BP, and GP to be reoperated (assuming that there are calls waiting to be answered in all three classes) and the same cycle of operations will be repeated.
  • Blocking a position to particular classes of service When it is desired that a particular position shall answer one or two, but not all, of the different classes of calls, the class of service keys corresponding to those classes which are to be excluded from the position are operated. For example, if position I is to answer class A calls exclusively keys I40 and 150 are operated, thereby opening points in the circuits to lamps BN and CN, to the corresponding position distributor start leads BDS and CD8, to the position grouping relays BP and CP from leads BPG and CPG,
  • a position allocated to receive all classes of calls but strapped so as to give preference to a particular class of call will not necessarily receive calls in that particular class exclusively, although that position will receive more calls in that particular class than it would if the preference strapping 5 5 were omitted.
  • the preference strapping will then be effective to cause a preferred class to be answered to the exclusion of other classes, as long as calls in the ,preferred class are waiting, at positions strapped so as to give preference thereto because all three position distributors will start from normal and will reach the position thus strapped at the same time whenever that position becomes free.
  • relay 530 in the link causes it. to restore as previously described. Ifthere are.
  • a second type of false marking which might normally block all calls is an open circuit inone of the vertical marking leads, such as might be caused by a failure of contacts AI3 to ground lead VAI when relay Al is operated. In this case no link would stop on the first level, and consequently the marked trunk appearing thereon could not be seized.
  • Relay AI would-then continue to hold relay AD operated which would in turn hold all of the position grouping relays such as AP operated thereby, preventing relays such as 680 from reoperating after all marked trunks, other than those appearing on the first level, had been seized and relays such as B]? and.
  • relay 530 the operation of relay 530 as previously described.
  • relay 900 The momentary ground placed on lead ECS by this link causes relay 900 to operate, open points in the.circuits to all position grouping relays such as AP over leads APG, BPG, and CPG at contacts 90!, 902, and 993, close a locking circuitto its lower winding at contacts 904 .through contacts 835 to contacts AG3, and close a circuit to relay AG at contacts 905.
  • Relay AG reoperates and opens the locking circuit to. relay 960.; Relay 9910,; restoresand vrecloses the pointsin the operating circuits vto the .positiongrouping relays. During; he-timet at avflflfl 1 i. perated the relays.
  • the calls waiting onthe first level are still inaccessible butblocking of other calls has been prevented.
  • one operator will beaware of the failuresince she will receive anacceptance tone but will receive no call over the link which rotates to the eleventh step.
  • the operator may then operate the emergency start key which closes a circuit to relay 69E! and grounds lead EMS which ex-.
  • Relays Slfl and 828 are differential relays arranged to operate when the circuits thereto are opened, rather than when closed, as fully described in Patent No. 2,152,524.
  • the two windings. of relay. 829 are now energized in series opposition causing the relay to remain inactive for the moment.
  • Relay 69E! operates and closes circuits to relays AR, BR, and CR at contacts 69L 692, and 693,
  • Relay 82! operates, closes its locking circuit from battery on jack point 3Dl, through its; two windings in series aiding relation, and through contacts 82E and 802 to ground, and
  • Relay 800 operates and opens.
  • relayv 696 bypass the position distributors in the:
  • Relay s30 restores, opens pointsin the circuits to relays preferably jack mounted to permit ready removal I from the switchboard for repair or replacement. Only those jack points involved in the arrangements for preventing transfer in the event that the alternate distributor is out of service are shown. All of the negative battery and ground connections within the first call distributor DI are obtained from jack points IDI and SDI, excepting that negative battery for relay 820 is obtained from jack point SDI through fuse FDZ of the second distributor. Similarly, all of the battery and ground connections within the second call distributor D2 are obtained from jack points ID2 and 6D2, excepting that negative battery for relay BIO is obtained from jack point 3D2 through fuse FDI of the first distributor.
  • relay 820 cannot be operated to transfer control to the second distributor.
  • the connection between jack points ID2 and 2D2 will be opened which also prevents operation of relay 820.
  • the jacks are constructed so that the fifth and sixth jack points will make contact when a switch is removed so as to maintain ground on the fifth jack point to hold relay 830 in switch DI, or 806 in switch D2.
  • relay 830 will restore and close the circuit to relay 1800 at contacts 83'! causing the second distributor D2 to take over the functions of distributor DI.
  • the operators cannot return control to the first distributor as long as fuse FDI is open since relay 8I0 cannot be energized. If the first distributor DI is removed from its mounting while it is in service jack point SDI contacts jack point 5DI thereby operating relay 800 to place the alternate distributor D2 in service.
  • Relay 8IIl is disabled by the removal of the connection between jack points EDI and ID! in this case.
  • a telephone system a plurality of groups of lines, a marking relay associated with each of said lines operated in response to calls received thereover, a plurality of links having access to said lines, a first means individual to each of said groups of lines operated in response to the operation of marking relays associated with calling ones of said lines in the corresponding group to cause idle ones of said links to seize marked ones of said calling lines, and a second means individual to each of said groups operated in response to the operation of said first means to prevent further operation of said marking relays in response to calls subsequently received over lines included in said corresponding group until all marked lines included therein have been seized by idle links.
  • a telephone system a plurality of groups of lines, a marking relay associated with each of said lines operated in response to calls received thereover, a plurality of links having access to said lines, and means individual to each of said groups of lines operated in response to the operation of marking relays associated with calling ones of said lines in the corresponding group to cause idle ones of said links to seize marked ones of said calling lines and to prevent further operation of said marking relays in response to calls subsequently received overlines included in said corresponding group until all marked lines iii-' cluded therein have been seized by idle links.
  • a plurality of lines divided into two or more classes, a plurality of operators positions each allocated to answer calls over lines in one or more of said classes, a plurality of links associated with each of said positions having access to said lines, a marking relay associated with each of said lines operated in response to calls received thereover to mark the associated line to said links, a first means corresponding to each of said classes operatedin response to the operation of marking relays associated with lines in the corresponding class to cause idle links in said operators positions, al-
  • a plurality of lines divided into two or more classes, a plurality of operators positions each allocated to answer calls over lines in one or more of said classes, a plurality of links associated with each of said positions having access to said lines, a marking relay associated with each of said lines operated in response to calls received thereover to mark the associated line to said links, and means corresponding to each of said classes operated in response to the operation of marking relays associated with lines in the corresponding class to cause idle links in operators positions allocated to answer said corresponding class to seize the marked lines included therein and to prevent further operation of marking relays associated with lines 40 included in said corresponding class until all marked lines included therein are seized by idle links.

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US597461A 1945-06-04 1945-06-04 Distributor switching apparatus Expired - Lifetime US2467457A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2619549A (en) * 1948-12-29 1952-11-25 Bell Telephone Labor Inc Toll supervisory operator's telephone circuit
US2686843A (en) * 1951-04-26 1954-08-17 Bell Telephone Labor Inc Call distributing service desk
US2697134A (en) * 1950-08-25 1954-12-14 Automatic Elect Lab Toll switching system
US2757240A (en) * 1954-12-21 1956-07-31 Gen Dynamics Corp Gating circuit for lines incoming to an operator's position
US2883471A (en) * 1954-10-19 1959-04-21 Bell Telephone Labor Inc Call allotter
US2945917A (en) * 1957-03-26 1960-07-19 Siemens Edison Swan Ltd Arrangements for controlling the access of a number of equipments to a common apparatus

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1863292A (en) * 1930-12-31 1932-06-14 Bell Telephone Labor Inc Telephone system
US1866593A (en) * 1931-03-18 1932-07-12 Bell Telephone Labor Inc Call distributing system
US2237906A (en) * 1939-09-15 1941-04-08 Bell Telephone Labor Inc Telephone system
US2249516A (en) * 1939-12-29 1941-07-15 Associated Electric Lab Inc Telephone system
US2267987A (en) * 1938-12-19 1941-12-30 Associated Electric Lab Inc Signaling system
US2361314A (en) * 1943-04-01 1944-10-24 Automatic Elect Lab Telephone system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1863292A (en) * 1930-12-31 1932-06-14 Bell Telephone Labor Inc Telephone system
US1866593A (en) * 1931-03-18 1932-07-12 Bell Telephone Labor Inc Call distributing system
US2267987A (en) * 1938-12-19 1941-12-30 Associated Electric Lab Inc Signaling system
US2237906A (en) * 1939-09-15 1941-04-08 Bell Telephone Labor Inc Telephone system
US2249516A (en) * 1939-12-29 1941-07-15 Associated Electric Lab Inc Telephone system
US2361314A (en) * 1943-04-01 1944-10-24 Automatic Elect Lab Telephone system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2619549A (en) * 1948-12-29 1952-11-25 Bell Telephone Labor Inc Toll supervisory operator's telephone circuit
US2697134A (en) * 1950-08-25 1954-12-14 Automatic Elect Lab Toll switching system
US2686843A (en) * 1951-04-26 1954-08-17 Bell Telephone Labor Inc Call distributing service desk
US2883471A (en) * 1954-10-19 1959-04-21 Bell Telephone Labor Inc Call allotter
US2757240A (en) * 1954-12-21 1956-07-31 Gen Dynamics Corp Gating circuit for lines incoming to an operator's position
US2945917A (en) * 1957-03-26 1960-07-19 Siemens Edison Swan Ltd Arrangements for controlling the access of a number of equipments to a common apparatus

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