US2187478A - Automatic telephone system - Google Patents

Description

Jan. 16, 1940- E. WOCHINGER' AUTOMATIC TELEPHONE SYSTEM Filad July 22, 1957 4 Sheets-Sheet 1 INVENTOR. 6Z8}; WOCHINGER ATTORNEY.

Jan. 16, 1940- E. WOCHINGER AUTOMATIC TELEPHONE SYSTEM Filed July 22, 1937 4 Sheets-Sheet 2 ATTORNEY.

EDUARD WOCHINGER Jan. 16, 1940. E. WOCHINGER AUTOMATIC TELEPHONE SYSTEM Filed July 22, 1957 4 Sheets-Sheet 3 i d 15w M E. J 1.. N6 tmu n M will 30 m s t3 H 21 is R B i M. +52 T: 3 25 g? 18 3 m m w w s t5 m NiW WQ m INVENTOR. EDUARD WOCHl-NGER ATTORNEY.

Jan. 16, 1940. E. WOCHINGER AUTOMATIC TELEPHONE SYSTEM 4 Sheets-Sheet 4 Filed July 22, 1937 il. 9+8; 318 m 9.

IE yin INVENTOR. EDUARD WOCHINGER BY iw ATTORNEY.

Patented Jan. 16, 1940 UNITED STATES- 2,187,478 AUTOMATIC TELEPHONE sYsTEM Eduard Wochinger, Berlin, Germany, assignor to Siemens & Halske Aktiengesellschaft of Wernerwerk, Siemensstadt, near Berlin, Germany I Application July 22, 1937, Serial No. 154,967

In Germany July 30, 1936 23 Claims.

The invention relates to automatic telephone systems having a plurality of exchanges and in particular to such systems as have a plurality of subsidiary exchanges disposed in series with a main exchange in which calling subscribers of one exchange reach a position in another exchangeserving to set up calls and in which calls to a subscriber of. the calling exchange or the calling exchange group are established over connecting lines seized on theinitiation of the call. It aims at utilizing the connecting line which was seized on the initiation of the call for completing the desired connection without using complicated testing circuits;

This is realized in that a connecting device in an exchange whichjisto be set in a desired direc tion is set in preparation on the connecting line seized by'the calling subscriber of a preceding exchange in dependence upon the automatic settingof a connecting device of the first-mentioned exchange and, independence upon the direction selected by the position controlling the setting up of the call, either effects switching operations enablingthe call to be established over the connecting line seized on the initiation of the call or searches for an outgoing line (connecting line or subscriber's line) in another direction.

One embodiment of the invention is represented in Figs. 1-3, Figs. 4-6 show variations in particular details.

Fig. 1 shows a diagrammatic layout in which the serially arranged subsidiary exchanges Ul, U2 and U0 have access to a main exchange HA in. which an operator is provided for establishing calls desired by the individual subscribers. Naturally further subsidiary exchanges can be associated with the individual subsidiary exchanges shown as is indicated for example in the case of the subsidiary exchange U2 (to U3) The equipmerit of the subsidiary exchange U2 is shown in detail in Fig. 2 and that of the exchange UK! in Fig. 3. The equipment of the subsidiary exchange Ul is not shown in detail. It corresponds largely to the arrangement of the exchange U2 with the difierence that no connecting lines are associated with the call finders AS and AS! (Fig. 1) so that the necessary switching devices ior junction trafiic are omitted.

Actually only two connecting lines are shown between the subsidiary exchanges but of course a large number ofconnecting lines could be provided. These connecting lines branch off either directly from between the connecting links comprising call finders and final selectors of a subsidiary exchange or, as is shown in Fig. l, for the necting lines for special reasons which will be I discussed later. The setting of the individual final selectors is effected by special setting switches which when influenced by impulses characterize the contacts on which the final selectors are to be set. In the embodiment the setting switches are associated individually with the final selectors but naturally common setting switches can be used for a plurality of final selectors.

The invention is not limited to the fact that the connecting links comprise only call finders and final selectors, other selecting stages could just as well be incorporated.

The general establishment of calls from subscriber Tnl of the subsidiary exchange Ul will first be described with reference to Fig. l.

Subscriber Tnl initiates a call in any desired manner and thereby causes a free call finder, for example, ASI, to be set on his line. 'If there is no call finder free the call remains registered in known manner in that the calling relay locks up. The subscriber Tnl is connected to the subsidiary exchange U2 over the connecting line al/bl, after the call finder AS! has been set. The call initiating impulse is transmitted to this subsidiary exchange and in the event of there being a 'free'call finder available this is thereby started up so as to take' up a setting on the connecting line al/bl. In the present case the call finder ASZ becomes set on the connecting line ai/bl, and thereby on the subscribers line Tnl. After the termination of the setting movement of the call finder AS2 the calling subscriber reaches the subsidiary exchange Ul) over the connecting lines al/bl and ail/b9. The call initiating impulse is received in this exchange and serves to start a free call finder (for example A84) hunting for the calling line. When this setting has also been completed a switch AW (secondary switch) is set in operation and this connects the calling subscriber to the main exchange HA over the connecting line a/b. Meanwhile, after the setting of the call finder A52 in the subsidiary exchange U2, the final selector LW2 has been operated and in accordance with the setting of the call finder AS2 has automatically become set on the connecting line ai/b l. Similarly the final selector LW4 in the subsidiary exchange U has'become set on the line aft/bi}, seized by the call finder A84. The final selector LWI in the subsidiary exchange U! has not been operated since the call did not proceed over a connecting line but proceeded from a subscribers line. The final selectors LW2 and LW4 also would not have become set if a subscriber had called from their associated exchanges.

After the establishment of theabove connecting path a call signal is operated in the main exchange HA. Thereupon the operator in the exchange I-IA plugs the corresponding jack. By this means a seizing impulse is transmitted successively from subsidiary exchange to subsidiary exchange. If now the calling subscriber Tnl has not replaced'hisreceiver the operator immediately receives a corresponding signal, otherwise she must recall the subscriber to his station in by the setting switch (Fig. 3; EW i) associated with the final selector LW4 is influenced. Since the setting already taken up by the final selector LW4. corresponds to this dialled digit the operator reaches the connecting line ail/DD over the final selector LW l. In a corresponding way the setting switch (Fig. 2: EWZ) associated with the final selector LW2 is influenced by a further impulse train. Since in this case the setting which the final selector LW2 has assumed does not correspond to the digit called the final selector LW2 steps on and sets itself on the contact closed by the setting switch, i. e., on the contact associated with the desired subscriber T124. The desired subscriber is now rung in the known way. When he replies the operator withdraws the plug from the line and the connecting lines which are not used for the conversation, i. e., lines all/b0 11/!) are released.

If the subscriber Tnl desires a call to subscriber T112 of his own subsidiary exchange III, the calling of the operator and the preparatory setting of the final selector LWQ in the exchange U9 and the final selector LW2 in the exchange U2 take place in the same way as that just described. The setting of the setting switch (Fig. 3: EW4) in the exchange U9 by the impulse trains transmitted by the operator also takes place in the same way so that the operator reaches the connecting line ail/bi] over the final selector LWfl. The setting switch (Fig. 2: EW?) associated with the final selector LW2 in the exchange U2 is now influenced by the following impulse train. Since, however, this impulse train characterizes the connecting line cl /bl on which the final selector LW2 is already standing the switch is not advanced further. Accordingly the operator reaches the connecting line al /bi seized by the calling subscriber, over this final selector.

- The next impulse train then causes the setting removed by the operator all the remaining devices in the exchanges U2 and U0 are released.

From this generaldescription it can be seen that by means of the preparatory setting of the final selector on the line seized when the call was initiated the establishment of the desired call by revertive selection in the calling, subsidiary exchange group can take place directly over the corresponding connecting lines seized in the first place by the call. 1

Further details will be explained in the following detailed description of. Figs. 2 and 3.

When the calling subscriber TM sets up a call in any manner (by removing the'receiver, by operating a magneto, by depressing a key, etc.) the call finder ASI is started up in known Way as has already been described with reference to Fig. l. The call finder sets itself on the'calling subscribers line so that the calling subscriber is now connected to the subsidiary exchange U2 over the connecting line al/bi; Since battery potential has been applied to the lead al (in any desired manner which does not concern the invention) after the call finder As! has been set, relay A2 is energized over this lead and contacts .IdZ, 202, winding I of relay A2 and earth. Relay A2 locks up over: earth, battery, winding II of relay A2, contact lMaZ, 402, d2 and earth. The

opening of contact removes a short-circuit from the high resistance winding I of relay D2 so that the line (ti/bl is guarded against being seized by a final selector. By the closing of contact Hla2 relay H2 is energized over: earth,

battery, winding I of relay H2, contacts l2p2,

M3112 and earth. The following circuit is completed over contact Hh2: earth, battery, rotary magnet DASZ, contacts l31'2, I 4da s2, J 171.2, l2p2, m2, and earth. The call finder 'ASZ takes a step forward. When the rotary magnetDASZ of the call finder ASZ operates contacts HldasZ is opened so that relay R2 is energized over: earth, battery, resistance Wi5, relay R2, contacts h 2, l2p2, lllafl and earth. The opening of contact I3r2 deenergizes the magnet DAS2. If the calling line ai /bl has not been reached the rotary magnet DAS2 and relay R2 mutually influence one another so as to advance the call finder ASZ stepwise. Since however, the connecting line al /bi seized by the calling subscriber is reached on the first step taken by the call finder, the following circuit is completed:' earth, battery, relay C2, contact I5a2, wiper cs3 of the call finder AS2, windings I and II of relay P2, contacts MM, 3603 and earth. In this circuit relays C2 and P2 energize. At contact I602 a locking circuit is completed for relay C2 independent of contact 15002. The locking circuit for winding II of relay A2 is broken by the opening of contact do! so that this relay releases. The previous guarding at contact M2 is now replaced by contact 602. Meanwhile relay H2 has become ideenergized through the opening of contact l2p2 on the energizing of relay P2 and thus the circuit for the further influencing of the rotary magnet DASZ and relay R2 is broken at contacts llla2,.l2p2 and HM. Through the disconnection of the high resistance winding II of relay P2 the seized connecting line is guarded against seizure by another call finder. The closing of contact 40112 completes the following circuit: earth, battery, contacts 318103 and 40122 lead 0.0 (Fig. 3) contacts M114 and 15c4, winding I of relay A4 and earth. In this cir cuit relay A4 energizes and locks up over its winding II after closing contact l 45a4: earth, battery,

winding II of relay'A4, contacts 145114, 1104 and cult of the magnet is broken. again at contact 'ergized by the closing of contact 19112. .by opening contact 3l'sp3 disconnects battery from the" energizing circuit of relay A4 just described.

"(14 and earth. The connecting line is guarded against seizure by a final selector through the opening of contact 8 M4. Meanwhile relay 8p3'in the subsidiary exchange U2 (Fig. 2) has. been en- This relay Moreover, in the meantime, since the call finder A82 has become set on a' connecting line so that its wiper cs4 rests on specially wired contacts, the following circuit is established by the closing ofcontact 58122: earth, battery, relay Q2, wiper cs4 of the call finder A82 (in position I), wiper 53712, 52113 and earth. The, final selector LWZ steps forward one step. Since, when its magnet DLW2 was energized, winding II of relay H2 was energized over contact 65dlw2 the energizing cir- 53b2 Relay H2 and thernagnet 'DLWZ then influence each other in turn until by way of its wiper 11.05 the final selector 'LWI has reached the contact seized by wiper asiof the call finder A82. In the present case, since the call finder A82 stands on the first contact, the stepping of the final selector LWZ terminates after the first step for after one step the following circuit is com pleted: earth, battery, winding II of relay H2,

wiper 1105 of the final selector LW2, wiper cs5 of the call finder A82, contact 33:12 and earth. Relay H2 remains energized in this circuit so that any further operation of the rotary magnet DLW2 is prevented by contact 53h2 being held pleted on account of the closlng of contact 8'lh4:

earth, battery, rotary magnet DASt of the call finder A84, contacts 88M, 89das4, 87724, 86304, 85:14 and earth. The magnet DA84 is energized in this circuit and advances the call finder A84 one step. The short-circuit over relay R 2 is re moved by the opening of contact flldas l so that relay R4 energizes and at] contact 8814 breaks the energizing circuit of the magnet. If the call finder A84 has not yet reached the calling line,

relay R4 and the magnet DA84 would influence each other so as to step the call finder. Since, however, the calling line all/bi) occurs at the first contact of the call finder A84 the following circult is set up after the first step taken by the switch: earth, battery, relay C4, contact'saa i,

wiper cs3 of the call finder A84, windings I and 31 of relay P4, contacts "35M, l86c5 and earth. Relays C4 and P4 energize in this circuit. Relay C4 locks up at contact 8404 in a circuit inde pendent of contact 83114. Through the opening of contact 1704 the locking circuit for relay A l isbroken. The guarding of the connecting line against seizure by a final selector is now effected by the opening of contact I904. The energizing circuit for relay H 4 is broken at contact 855104.

Any further influencing of the rotary magnet DAS-l and relay R4 is thus prevented. Battery potential is connected to lead a by the closing of contact H2104. The switch AW is accordingly started up to switch through the connecting path from the exchange U2.

to the main exchange HA and to indicate a call. If there is no such switch available the battery potential operates directly on the main exchange and switches on a call signal which is maintained. Since relay 8125 is energized through the closing of contact Mp4 this battery potential is disconnected again at M98115. Meanwhile, since the call finder A84 is resting on a connecting line and accordingly the contacts on which wiper cs4 is standing are specially wired, the following circuit is completed by the closing of contact 52pm earth, battery, relay Q l, wiper cs4 of call finder A84 in position wiper ew3'of the setting switch EW4 in position ii, contact 92124 and earth. Relay Q4 energizes in this circuit and by closing contact l33q4 energizes the rotary magnet DLWfil: earth,

. battery, rotary magnet DLWt of the final selector LW l, contacts l33q4, 32714, ltlpt and' earth.

The final selector LWA. "takes a step forward. When the-rotary magnet DLW4 energizes relay H4 is operated over contact l29dZw4 so that the rotary magnet DLWfl is disconnected again by the openingof contact l32h4. The magnet DLVV i and relay H4 operate on each other until Wiper 1105 of the final selector LW S reaches the con tact seized by the wiper asll of the callfinder A86. In the present case this occurs after only one step. The following circuit is established: earth, battery, winding II of relayHil, wiper 11.05 of the final selector LW4, wiper cs5 of the call finder A84, contact H3q4 and earth. Relay Ht is held energized in this circuit. whereby further infiuencing of the rotary magnet DL'W i is prevented by the opening of contact 532%.

At this moment the call finder A8! (Fig. 1) in the exchange Ul is standing on the line of the calling subscriber Tnl, the call finder A82 in exchange U2 (Fig. 2) is resting on the connecting line al/bl incoming from'the exchange Ul and the call finder A84! in the exchange UQ (Fig. 2) is resting on the connecting line ail/bi incoming The exchange Uil is connected with the main exchange over the con-- necting line a/b. Furthermore, in the exchange U2 the final selector LW2 (Fig. 2) has been set in preparation on the connecting line cal/bl since the associated call finder A82 has become set on a connecting line, namely al/bl. If a call had proceeded over another connecting line in this exchange U2 the call finder A82 would have become set on this and then the final selector LWZ would similarly have been set in preparation on this connecting line. Iffhowever, the call finder A82 had been brought to rest on a subscriber's line no preparatory setting of the final selector LW2 would have occurred This distinction in the mode of operation is produced in. that the call finder contacts to which connectingiines are connected are connected together in the contact bank traversed by wiper as i and cause the final selector LWZ to be connected up by the operation of relay Q2, the stepping of the final selector being new controlled over wiper est in dependence upon the setting of the call finder In the present case the final selector LW l operates in a corresponding manner. It is also set in preparation namely upon the connecting line aO/bil. As Fig. 2 shows, the connecting lines between the exchanges Ufl and U2 are repeated in the contact bank of the final selector LWZ. The final selector LWZ is thus prevented from executing a complete rotation in order to reach line to'the exchange Ul according to the setting of the settingswitch EW2 when the exchange U5 is characterized as the desired trafiic direction in the event of the final selector having been set in preparation on one of these connecting lines as a result of a call from the subsidiary exchange U3. This is only possible so long as the particular type of final selector admits of such repetition of the lines, otherwise the final selector must pass to the desired line across its normal position. In this case, disconnection on the eleventh step after completing the first rotary movement is prevented in that relay T2 is energized in this position so as to connect to contact III a disconnecting potential over its contact 66252 which brings the switch to rest when contact I!) is reached after the second rotation.

A call signal is operated in the main exchange HA by the transitory connection of battery potential as already described so that the operator is notified of the call. When now the operator inserts the plug in the jack associated with the connecting line a/b, battery is connected to the a-lead of this connecting line (in any manner with which we are not concerned), so that relay J4 is energized in the subsidiary exchange 'UIl over-this lead and contacts H2204 and IIIlspB. Through the closing of contact l2liy'4 the following circuit is set up: earth, battery, relay C5, contact l207'4 and earth. Relay C energizes in this circuit and locks up by closing contact 12105. The following circuit is established by the closing of contact I027'4 or 9905: earth, battery, relay X4, contact H3274 (in parallel with this: earth, battery, choke coil DTI, contacts 611A, 9905) contacts 9lk4, 94M, 93124, wiperasl of the call finder AS4 (in position I), lead at (Fig. 2), contacts 40122, 383113, relay J2 and earth. In this circuit relay J2 energizes. Relay G3, which looks up by closing contact 4803, energizes over contact 4672. Through the closing of contact 3472 or 26c3 battery potential is connected to the lead al of the connecting line leading to the exchange UI over: earth, battery, relay X2, contact 3472, (and in parallel: earth, battery, choke-coil D13, contacts 21142, and 2603), contacts 24102, 22112 20122, wiper asl of the call finder ASL (in position I) and lead al of the connecting line of the subsidiary exchange UI In the exchange UI whose equipment corresponds fundamentally to that shown in Fig. 2 a relay corresponding to relay J2 is influenced by this battery potential and promotes similar switching operations. If the subscriber TnI has not replaced his receiver a relay corresponding to relay Y2 (Fig. 2) is energized over the loop of the calling subscriber. Over a contact in the exchange UI corresponding to contact ilt/2 battery potential is applied to lead bI which energizes relay Y2 over wiper as2 of the call finder A82 (in position I), contacts 2Ip2, 23u2, 28702, relay Y2 and earth. The closing of contact 4Iy2 completes the following circuit: earth, battery, choke-coil Dr4, contact 4Iy2, lead bl), (Fig. 3) wiper cs2 of the call finder AStI (in position I) contacts 95174, 951M, IIJIk4, relay Y4 and earth. Relay Y4 energizes in this circuit and connects battery to lead 1) leading to the main exchange HA over: earth, battery, choke-coil D72, and contact I25y4. This operates a signal in the exchange I-IA which notifies the operator that the calling subscriber has waited without replacing his receiver. If the subscriber had replaced his receiver, this signal would not have been set up. The operator would then have recalled the subscriber.

In the present case the operator now makes her enquiry. If the calling subscriber Tnl of the exchange UI wishes to setup a call to subscriber Tn4 of the exchange U2 the operator sends back the first impulse train, comprising one impulse, over the connecting line a/b, i. e., she breaks thev energizing circuit of relay J4 (Fig. 3). When relay J4 deenergizes the following circuit is estab lished: earth, battery, relay V4, contacts M605, M9 4 and earth. gizes. Furthermore, the rotary magnet DEW I- receives an impulse over: earth, battery, rotary magnet DEW4, contacts I3Ic5, I389'4, and I39p5 and earth. The setting switch EW I takes a step forward. Through the closing of contact I I6dew4 when magnet DEW4 energizes relay K4 is energized and by opening contact IOIlc4 releases relay Y4. Relay K4 consequently locks up over: earth, battery, relay K4, contacts I I5k4, 411 4, wiper e205 of the setting switch EW4 and earth. Since relay J4 remains energised after the impulse train comprising one impulse, relay V4 deenergizes on account of the opening of contact I I572. Since relay Q4 hasheld up over contact 90114 during the time that relay V4 has been energized independently of wiper 61.03 the following circuit is established after relay V4 energizes and before relay Q4 has allowed its armature to relapse: earth, battery, winding II and I of relay D4, wiper Iw3 of the final selector LW I, windings I and II of relay P5, contacts I2lo4 and Ii28q4, wiper Z104 of the final selector LW4I- (in position I), wiper curl of the setting switch EW I (in position I) contact M305, earth. Relay P5 which has been primed over its winding III between the contact I28q l energizes and causes relay U4 to energize over contact I 42125 before relay Q4 deenergizes, relay U ilocking up over: earth, battery, relay U4, contacts I40u4, M2115, M305 and earth. Any stepping of the final selector LW4 is prevented by the opening of contact I3 I115 since the preliminary setting of the final selector corresponds to the setting of the setting switch EW 4. Relay H4 is deenergized by the opening of contact II3q4. Through the opening of contacts I22p5 and I23p5 the leads a and b of the connecting line incoming to the main exchange HA are switched through to the leads ail/b0. At contact I26p5 the connecting line which has been reached and which corresponds to the connecting line aD/bil seized on the initiation of the call is guarded. The final selector LW I is disconnected from the call finder AS4 at contacts 94% and 9W4. Relay Y4 is now energized again over: (Fig. 2) earth, battery, chokecoil DR I, contact 4Iy2, lead 122, (Fig. 3) wiper 1202 of the final selector LW4 (in position I), contact I23p5, relay Y4 and earth.

The operator transmits five impulses to form the second impulse train since it is subscriber Tn4 of the exchange U2 who is wanted. Accordingly the energizing circuit of relay J4 is broken 5 times. Consequently, the following circuit is broken 5 times at contact H3272, earth, battery, relay X4, contacts III2i4 and I22p5, wiper hu l of the final selector LW4 (in position I), lead all (Fig. 2), contacts 40192 and 38sp3, relay J2 and earth. When relay J2 deenergizes for the first time relay V2 is energized over: earth, battery, relay V2, contacts M103 and 4192 and earth. Furthermore, the rotary magnet DEWZ is operated over: earth, battery, rotary magnet DEW2, of the setting switch EWZ, contacts 6303, 5852, and 52133 and earth. The setting switch EWZ is accordingly displaced 5 steps. When the rotary magnet DEW2 of the switch EWZ energized for the first time relay K2 was energized over: earth, battery, relay K2, contacts 49dew2,

In this circuit relay V4 ener-' arth, battery, relay K2, contacts 45102, per 6105 andea'rth. At the end of the irnpulsetrain (relay J2 remains energized) relay V2 releases on account of the opening of con- .tactf lljz. After some time relayQZ also deenergizes on account of the opening of contact 51122. No circuitcan be established for relay P3 since the, preliminary setting of the final selector LW2 does not correspond to the setting of the setting switch EWZ. Instead the following circuit is set up; earth, battery, rotary magnet DLWZ, wiper .lwfionthe contact segment, contacts 153 722 and 52113 and "earth. In this circuit I the magnet DLW2is operated under the control of relay H2 until wiper Zwd reaches the contact characterized by; wiperewl of the setting switch EWZ (this rests onfthe th contact). The relay P3 is then influenced over the testing lead of the subscriber Ta l-wiper lwt of the final selector LWZ, winding r ,selector ,LWZ, Wiper ewlifof the setting switch 25 EW? (in position 5) ,"contact H03 and earth.

' further. advance ofthe final selector LW2 which Relay, P3 by opening contact 52123 prevents any now restson. the desired subscribers line (Tu l).

, Thfejjsubscriber TM is called in any desired man- .ner either by special switching measures taken by the operator inthe 'm ain exchange HA or by the automatic transmission of ringing current in the exchange U2. When, the wanted subscriber replies relay Y2 "energizes, over the loop established. The operator receives a signal. by

I in the exchange U2 and the final selector LWZ.

Afterreceiving the called partys reply signal the operator withdraws the plug from the jack in the main exchange HA Relay J4,( Fig. ,3). in the .subsidiary.;exchange Ul! consequently deenergiaes. Relay C5 is dee'nergized through. the

closing of contacts i Iljt and l IBM because relay Xd releases. on the opening of contact HBZM. The

opening of contact l0'lc5 deenergizes relay P4 and, the openingv of. contact Sip?! deenergizes relay S225. Relay C4- is also deenergized. Relay l P5 deenergizes through the opening of its locking circuit passing over winding III. and contact M 315 ".at'contact 14305. 7 The magnet DLW I of -tlf e final selector LWA is switched on over contact; i3'ip5 so that the finalselector LW4 restores normal, under the controlof relay H4. 7 When he qnorrnalposition is reached the rotary. magnet l .DEW I switched on over .wiper Zwfi so that this a o restoresfto normal under the control, n lvleanwhilethe circuit for relay J2 in I, .xchenrze U2 has been broken through the ore king of contact H3254 when relay J4 deener- .sothat relay J2 releases. Since. howeven.

sh'ort-circuitcd and remains energized so that the .call finder A82 and the final selector LWZ remain set. The connection nowfexists between subscriber Tic! in the exchange Ui and subscriber T114 in the exchange U2. sei blyconsisting of thecall finder A82 and the ispievented by the following circuit; earth, bat- Any seizure of the as- I tery, choke-coil DR Lcontact M1112, lead b0, (Fig. 3) relay Sp4, contactsllicul', "c4, 18114 and earth. The high resistance winding I of relay D4 is switched onat contact 82.9114 so that the line is guarded.

Establishment of a call to subscriber T122 of the same 0 subsidiary exchange If subscriber Tnl'desires to; call subscriber 'I'nZ of his own subsidiary exchange Ul, the operator, alter having'been reached by the subscriber in the same way as described above, transmits the first impulse train comprising one impulse as before so that the operator gains access to the connecting line cit/b0 over the final selector LW4 in the manner set out above. In order to set the setting switch EW2 in the exchange U2 the operator now transmits a second impulse train also consisting of oneimpulse. Relay J 2 (Fig. 2) is thereby decnergized once; In addition to the energizing of relay V2 over: l'l'jfi and Mice the a rotary magnet DEW2 is energized onceover' contacts 52103, 5312 and 6303 so-that the setting switch EWZ is set on the first contact. Since now wiper suit of the setting switch EWZ, rests on the same contact as does wiper Zw lof the final selector LW2, the following circuit is setup after relay V2is deenergized at the end of .theimpulsetrain since relay Q2 remains up over contact 61122 and is held. in this condition on account of its slowto -rclease feature: earth, battery, windings II and I of relay D2, wiper 1203' of the final selector LWZ (in position I), windings I and II of relay P3 (rare-energized over winding III contacts 5902 and 6M2, wiper Z104 of thefinal selector LWZ (in position i), Wiperewl of the setting switch EWE (in position i) contact lie? and earth.

"In this circuit relays D2 and B3 energize closing contact mp3. Relay U2 is energized before contact E3412 opens, over: earth, battery, relay U2,

contacts 'lBqZ, mp3 and i103 and earth. Relay U2 locks up at contact 'l2u2 in a circuit independent of contact l2q2. On the energizing of magnet DEWE relayl'fl was energized'ovei. contact 49dew2; it locked up after relay Y2 had been deenergized by the opening of contact 28b2, in a is held energized over: earth, battery; relay X2, contacts M72 and 42123, wiper Zwi of the final selector LW2 (in position i). lead al to the subsidiary exchange US, since contacts 42123 and 53193 are now. closed. i

The next impulsetrain transmitted by the operator is received by relay J 3 in the subsidiary exchange U53 and by relay J 2 in the exchange U2 and is from there transmitted to the corresponding relay in the exchange US. In this exchange the final selector LWI is set in the known way, in the present case on the line of the wanted subscriber T712. In the event of this subscriber being free, ringing current is transmited in the known way so that when the subscriber T722 replies the corresponding X and Y relays operate and indicate the reply to the operator.

The operator thereupon withdraws the plug in the exchange HA. The call finder A84 and final selector LW4 in the exchange U0 are'thereby released in the manner described in the case of finaljselector LWZ over the connecting line. ail/lad the preceding call. Since now the relay J2 in the subsidiary exchangeUZ is already deener- The relay J in the sub- I is deenergized. Similarly relay P3 (locking circuit over contact l48p3 andwinding III) is disconnected by the opening of contact H03 so that the following circuit arises: earth, battery, rotary magnet DLWZ of the first selector LW2, wiper M6 on the contact segment, contacts 5371.2 and 52113 and earth. 7 Relay H2 is switchedin for the purpose of advancing the final selector LW2 in the manner already described so that through the reciprocal control between this relay and the rotary magnet the final selector LW2 is restored to normal. When wiper Zw6 returns to normal the following circuit is set up: earth, battery, magnet DEW2, contact 5103, wiper e104 on the contact segment, wiper lwB in the rest position, contacts 53h2 .and 52 03 and earth. This magnet also is operated under the control of relay H2 until the setting switch -EW2 is restored to normal.

In the call finder AS2 relay P2 is released through the opening of contact 3Ic3 so that now the line between the call finder AS2 and the final selector LW2 is broken at contacts 20172 and 2 lp2 and 42193 and 43123. The connecting devices in the subsidiary exchange U2 are now restored to normal. Since as already mentioned a relay cor responding to relay Y2 (Fig. 2) is energized when subscriber T112. in the exchange Ul replies, i. e., since a contact corresponding to contact 4| 1 2 is closed, relay S102 in the exchange U2 is energised as was described in connection with relay S194 in the preceding call. The line al/bl is thus guarded against any seizure (opening of contact 9s'p2). I

The call between subscribers Tnl and T112 now proceeds entirely within the exchange Ul. the other connecting paths are released.

Fig. 4 shows a modification of the starting circuit for the final selector LW4 which of course can also be applied to the final selector LW2. In place of winding II of relay H4 a special relay H5 is provided. Moreover, a contact l50h4 is provided in parallel with contact 92194 and the start- All .ing position of the call finder AS4 is wired to the When a call If the final selector LW4 is required to start up only on the reply of the operator the circuit is modified as shown in Fig. 5. In this case a contact of relay J4 is disposed in the energizing circuit of relay Q4, the former relay being energized as usual on the reply of the operator and accordingly only operating relay Q4 over its contact P5074 at this moment, the final selector-LW4 only then being started up. Naturally this modification can also be applied to the final selector LW2. Fig. 6 shows a modification whereby the final selector LW4 only commences to operate When the operator sends back impulses. As may be seen from this figure, in which only those'circuit details are shown which differ from the arrangement shown in Fig. 3, relay V4 is energized by contact I I914 on the first impulse over the closed contact M605- Since now relay Q4 is energized over contacts 92114, l 5 |c5, and 90114 the final selector is advanced under the control of relay H4 on account of the closing of contact l33q4 (Fig. 3) in the manner described above until it reaches the line seized by the call finder AS4 and is brought to rest on this line as has already been described in connection with Fig. 3. Relay V4 remains up during the stepping of the final selector LW4 over contacts 15471.4, l53q4 and I52c4 since it is slow-to-release. I

In a similar way the setting of the final selector LW2 and any other final selectors present may be altered so that in the subsidiary exchange in which impulses are received from the operator the final selector in this exchange is only given a preparatory setting when these impulses are received in the event of the associated call finder standing on a connecting line (relay Q).

What is claimed is:

1. In a switching system serving a plurality of lines, a finder switch, a connector switch, means responsive to a call over any of said lines for causing said finder to seize the calling line. and

extend it to said connector'and also for causing said connector to set its wipers upon said calling line, means for characterizing in said connector any of said lines to which it is desired that said connector shall extend a connection, said connector effective responsive to said characterization if the line with which said wipers are. associated is so characterized to complete a connection to that line regardless of its condition or,

alternatively, if the line with which said wipers are associated is not-so characterized to move said i wipers to said characterized line and complete a connection thereto if said characterized line is idle.

2. In a switching system serving a plurality of lines, a line finder switch, a connector switch,

said finder effective responsive to a call over any of said lines to seize the calling line and to extend it to said connector, a control line, said connector effective responsive to seizure of said control line to set its wipers upon said calling line, means controllable over said control line for characterizing in said connector any of said lines to which it is desired that said connector. shall extend a connection, said connector effective responsive to said characterization if the line with which said L wipers are associated is so characterized to complete a connection to that line regardless of its condition or, alternatively, if the line with which said wipers are associated is not so characterized to move said wipers to said characterized line and complete a connection thereto if said characterized line is idle.

3. In a switching system serving a plurality of lines, a line finder switch, a connector switch,

said finder effective responsive to a call over any of said lines to seize the calling line and extend it to said connector, a characterizing switch, a control line, said characterizing switch effective responsive to impulses received over said control line to mark in said connector any of said plurality of lines to which it is desired that said connector shall extend a connection, said connector effective responsive to the initiation of said impulsing over said control line to set its wipers upon said calling line and efiective respon- -7 1 with 'which said wipers are associated is so n, um)

, means for seizing said connecting means over Y cordanc markedline is idle.

line is idle.

markedto complete a connection to that line regardless of its condition or, alternatively, if

theline with which said wipers are associated is notjs'oniarked to move said wipers to said marked line and extend a connection thereto if said izatio'n'j's the line to which said preliminary connectioii has been extended for causing said connection to be completed to said'desired line regardless of its condition, last said means effective if the line which is desired according to last said characterization is some line other than the linetowhich said preliminary connection is extended for causing said preliminary connection ,to be abandoned and a connection to be corn- I pleted to said desired line only if said desired In a switching control system, a plurality of "lines extendingto each of a plurality of stations,

connecting means having access to said lines,

armor said lines andfor characterizing the seizingiine in said connecting means, said connectns effective to extend an incomplete preliminary connection to said seizing line inac- With said characterization, means for charac izing, in said connecting means, any one of said stations to which it is desired said connecting" in-sans shall complete a connection,

effective only if the desired station according to last said characterization is the stato which said seizing line extendsior causcondi on, said last means effective if sire; station according to last said charzation is some station other than the stan tdwhich seizing line extends for causing connecting means to abandon said preliminary connection and to complete a connec tioh to an idle one of said pluralitynf lines e1:- ten, ngtosaid desired station if'one is available. BKIn a switching con rol system, a'plurality of lin seximding to each of a plurality of p11 stations, a line extending to each of aplu of secondary stations, connecting means iaving access to said Zines, means for seizing said connecting means over any of said lines, last said characterizing, in said connec ing means, any of stations to which it is desired said connec"-- eifectiveonlyif the seizing iine is from a primary station tocharacterize said seizing line: n said connecting means, said connecting Inca s effective to extend an incomplete preconnection to said seizing line in ac cewith said characterization if said seizlne is from a primary station, means for in g means shall compiete a connection, means-efiective only if the desired station ishoth'the station to 1WhiC1lSBdd seizing line extends and is also ive to the completion of said marking if the line a primary station for causing said connecting "means to complete said preliminary connection presetting the wipers of saidswitch upon the line by which said switch was seized, means for characterizing the lines ofany of said groups in said switch, means for moving said wipers from their preset position in search for an idle characterized line and, if one is found, for completing connection over saidwipers to said line, last said means efiective only if the line upon which said wipers are preset is characterized to complete a connection over said wipers in their presetposition to saidlineregardless of its condition.

8. in switching controlsystem, a plurality of lines, an automatic switch having access to said lines, for seizing said switch over any of lines, means effective at times for automat icaily 'presetting the wipers of said switch upon the line by which said switch was seized, means for characterizing any of said lines in said switch, means responsive to said characterization for moving said wipers to the characte-ized line, means for determining the condition of the characterized line and for completing a connection thereto over said wipers if said characterized line is idle, last said means effective only if said wipers arepreset and ii the line upon which said wipers are preset is characterized to complete a connection thereto over said wipers in their preset position regar less of the condition of the line.

i 9. In a telephone system, an automatic switch, a plurality of groups of lines accessible to the position for characterizing all of the lines of any,

or said groups in said switch, means in said switch for completing a connection from said position to said'calling line over said wipers if said calling line is one of the characterized lines,

or, alternatively, if said calling line is not one;

of the characterized lines, for causing the wipers to bemoved in search for idle characterized line and, if one is found, for causing a joint connection from the calling line and said position to be extended over said wipers to said idle char- 1 'acterized line. i

10. In a telephone system, an automatic switch, a plurality of lines accessible to the wipers of said switch, means responsive to a call over any one of said lines for extending the callcordance with said marking ifsaid calling line is' so marked,a control position, means for associating said position with said switch, means controllable at said position for characterizing any of said lines in said switch, means in said switch, efiective if said wipers are associated with said calling line and said calling line is so character ized, for completing a'connection over said wipers from said position to said calling line responsive to said characterization or, alternatively, if said wipers are not associated with said calling line or said calling line is not so characterized, for moving said wipers to said characterized line and trol line for characterizing the lines of any of said groups in the bank of said switch, means effective upon completion of said characterization for moving said wipers from their preset position to search for an idle one of saidcharacterized lines and, if one is found, to cause a joint connection from said one line and said control line to be extended over said wipers to said idle characterized line, last said means effective only if said one line is characterized by said characterization to interrupt the'original connection from said one line to said control line and to complete a connection from said control line to said one line over said wipers in their preset position.

12. In a switch for completing a connection to any of a plurality of lines, a control line, means 7 responsive to seizure of said switch by any one .said wipers to a final setting upon the characterized line and for completing a joint connection thereto from said one line and said control line if said characterized line is idle, last said means effective only if the characterizedline is said one line and said wipers are preset upon said one line to interrupt the original connection from said one line to said control line and to complete a connection from said control line to said one line over said wipers in their preset position.

13. In a switching center, an automatic switch for completing a connection to any lines of a plurality of groups of lines, a characterizing switch associated with said automatic switch, a control position, means for seizing said automatic switchover any of said lines, means responsive to said seizure for extending the seizing line to said control position, means for automaticallysetting the wipers of said automatic switch upon said seizing line, means controllable at said position for operating said characterizing switch to mark the lines of any of said groups in the bank of said automatic switch, means effective if the line with which said wipers are associated is one of the marked lines for causing a connection to be completed over said wipers from said control line to said line with which said wipers are associated, or alternatively, if the line with which said wipers are associated is not one of the marked lines, for causing said vipers to be moved in search for an idle marked line and, if one is found, for causing a joint connectionto be extended thereto from said seizing line andsaid control position.

14. In combination, a plurality of lines, an automatic switch having access to said lines, means for making any of said lines busy, means for seizing said switch over any of said plurality of lines, switching means in said switch, means effective at times for causing the wipers of said switch to be associated with said seizing line and for preparing a primary operating circuit for said switching means, means for placing a potential in the bank of said switch upon anyof said plurality of lines to which it is desired that said switch shall extend a connection, said potential effective if placed upon said seizing line and if said wipers are associated with said seizing line to operate said switching means in said primary circuit to complete a connection over said wipers to said seizing line, said third means effective if said switching means is not operated in said primary circuit responsive to the placing of said potential upon the desired line to cause a secondary operating circuit for said switching means to be effective and to cause said wipers to be moved in search for said desired line, said potential effective when said wipers are associated with said desired line to operate said switching means'in said secondary circuit only if said desired line is idle to thereby complete said connection, over said wipers to said desired line.

15. In a combination as claimed in claim 14, wherein busy lines are marked in the bank;of said switch, and wherein said switching means tests, in said secondary circuit only, the condition of lines encountered by said wipers in said search for said desired line to prevent the completion of said connection to a desired line which is busy.

16. In a link circuit serving a plurality of lines, a finder switch, a connector switch, a control line, means responsive to seizure of any of said plurality of lines for causing said finder to extend a connection from the seized line to said control line and to mark said seized line in the bank of said connector, switching means in said connector, means for causing the wipers of said connector to be associated with said seized line in accordance with said marking and for preparing a primary operating circuit for said switching means, means controllable over said control line for placing a potential in the bank of said connector upon any of said plurality of lines to which it is desired that said connector shall extend a connection, said potential effective if placed upon said seized line to operate said switching means in said primary circuit to complete a joint connection from said seized line and said control line over said wipers to said seized 7 17. In a link circuit such as claimed in claim 16, means for breaking the connection extended from said seized line to said control line by said finder, wherein said third means renders last said means responsive to the operation, in said primary circuit only, of said switching means.

18; In a switching control system, a plurality of lines, an automatic switch having access to said lines over its wipers, means for seizing said switch over any of said lines, means responsive to said seizure for marking the seizing line in the bank ofs aid switch, means for presetting'the wipers of said switch upon said seizing line in accordance with said marking, means for marking, in

the bank of said switch, any one of said lines to which it is desired that said switch shall extend a connection, a test relay in said switch fordetermining the condition of lines encountered by the wipers of said switch and for seizing a line which isdesired according to last said marking if said desired line is idle, means efi'ective only if the line upon. which said, wipers are'preset is" the line which is desired according to last said I marking for causing said relayto complete a connection over saidwipers to said desired line regardless of its condition. l

19. In a switching control system, a plurality of lines, an automatic switch having access to said lines over its wipers, means for seizing said switch over any of said lines, means responsive to said seizure for marking the seizingline in the bank ofsaid switch, means for marking,[in the bank of said switch, any one of said lines to which it is desired said switch shall extend a connec: tion to thereby direct the wipers of said switch to a setting upon the desired line, a test relay in said switch for determining the condition of lines encountered by the wipers of said switchand for 7 bank of said switch, a relay in said switch for testing simultaneously both said one bank and also another bank of said switch over the wipers of said switch and for extending aconnection to any of said lines with which said wipers are associated if that line is both idle and is also marked in said other bank, means for seizing said switch over any of said lines, means for setting said wipers upon one of said lines and for preparing a special circuit to said relay to cause said relay to extend a connection to said one line regardless of its condition if said one line is marked in said other bank, means for marking in said other bank any of said linesto which it is desired said switch shall extend a connectiommeans effective only if said one line is not so marked in said a other bank for causing said special circuit to be broken and to cause said wipers to be moved under control of said relay in search for a line so marked. i

21, In a switching system such as claimed in claim 20, wherein said second means marks the seizing line in said switch, and wherein said third means sets said wipers upon said seizing line in accordance with last said marking.

22. In a switching control system, a plurality of lines, an automatic switch having access to said lines over its wipers, a relay in said switch for determining the condition of lines encountered by said wipers and for completing connections over said wipers to idle lines only, means for seizing said switch, means for presetting its wipers upon one of said lines, a variably operable 3 register for characterizing any of said lines upon which it is desired that said wipers shall be finally set, and means efiective only if the line upon which said switch is preset is so characterized for causing said relay to complete a connection over said wipers to that line regardless of its condition.

23. In a switching system, a plurality of lines, a connector having access to said lines, means for seizing said connector over any of said lines, means in said'connector operated to prepare a connection to the seizing line, a register operated to characterize any one of said lines, and means in said connector for completing said prepared connection to the seizing line if it is the line characterized by said register, or, if some other line is so characterized, for abandoning said prepared connection and completing a connection to the characterized line only if said characterized line is idle. I

EDUARDWOCHINGER.

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