US2258854A - Automatic telephone system - Google Patents

Description

Oct.y 14, 1941.

J. KuczHLJsYv ETAL AUTOMATIC TELEPHONE SYSTEM Filed Dec. '17, 1938 sheets-sheet 1 J. KUCHLEY ET AL AUTOMATIC TELEHONE SYSTEM oct. 14, 1941..

4 sheets-sheet 2 Filed Dec. 17, 1938 y c NSN J.

J ww zw 5.9.... m vh `v w my 4 m mu a o waw EN NSQN m mm m I gil K .SQ @www mx m .u NSEM @am wm Z T ull @QN Nnw Oct. 14, 1941. J, KUCHLEY ErAL 2,258,854

AUTOMATIC TELEPHONE SYSTEM Filed Deb. 17, 195s 4 sheets-sheet a FIG.5

INVENTORS Jau-'F /fl/CHL fr ATTORNEY.' l

Oct. 14, 1941. l J, KUCHLEY ET AL 2,258,854

AUTOMATIC TELEPHONE SYS TEM ATTORNEY.

Patented ct. 14, 194i AUToMATio TELEPHONE SYSTEM Josef Kuchley, Berlin-Siemensstadt, and Walter Pinell, Falkensee, near Berlin, Germany, assignors to Fides Gesellschaft fr die Verwaltung und Verwertung von Gewerblichen Schutzrechten m. b. H., Berlin, Germany Y Application December 17, 1938, Serial No. 246,336

In Germany December 23, 1937 16 Claims.

In distance communication, in particular telephone systems, it is known that connections in a remote exchange extend over connecting paths for the trafc having junction lines which are connected to the exchange set of the calling sub: scriber. This arrangement can be uneconomic When the traflic in the remote exchange sets require special auxiliary devices, for example, for the purpose of sending out impulses, supervising, etc., since in such cases all the connecting paths for the internal trailic must be provided with these. With a large concentration of traffic in extraneous exchange sets a large number of connecting paths must be provided especially when the principal trafc peaks or internal and connected traffic coincide.

Connections in remote exchanges can be passed over connecting lines for the internal tralc within the exchange sets of the calling subscriber while the connections themselves extend over special connecting paths. By this arrangement after seizing of the connecting path for internal connections for the calling set the desired remote exchange set is characterized Whether by selection of a characterizing digit or by the execution of a particular switching measure (pressing ofthe key) and thereby connected with a free junction line over the associated selector in the desired direction which is connected with the calling junction line. The connecting path seized by the call is thus freed for internal trahie. This arrangement has the advantage that the connecting path serving for the internal trafic need not be provided with the devices which are necessary solely for the traii'ic in the extraneous exchange sets. The number is further not increased or only increased to an insignificant amount compared with the number necessary for dealing with internal traic.

If selectors with multiplied contacts are associated with the junction lines to the exchange sets the connection of the junction lines to the calling junction line requires a certain period of time during which the calling subscriber cannot send out impulses for setting the selector in the remote exchange set. He must await the connection or disappearance of an exchange signal from which he recognizes that impulse receivers are now ready to receive the impulses. This arrangement is specially disadvantageous in the characterizing of the remote exchange set by the selection of a characterizing circuit. Storage devices can now be provided which receive the impulses so that the calling subscriber need not desystems having selectors which are directlyset on the calling set it is not desired to provide such auxiliary devices.

The present invention shows a way in which at the same 4time special instructions for the subscriber (wait until an exchange signal is heard or disappearance) on the initiation of a connection from an extraneous exchange after seizingV of a junction line to external connections by a call and further storage or the provision of in-v ternal junction lines with devices for fuliilling special requirements for junction traiiic (e. g. the signalling devices) are avoided. 'Ihe invention attains this result in that the outgoing junction lines to the extraneous exchange sets are provided with special access which is obtained over the internal connecting path seized after the characterizing of the remote exchange, and vover which dial impulses for setting the selectors in the extraneous exchange can be sent out previous to the connection of a junction line to the calling exchange line resulting when the connection path is switched over.

By means of the arrangement according to the invention the calling subscriber has the possibility of sending out impulses for setting the impulse receiver in the desired exchange directly after characterization of the desired exchange in a particular manner (selection of characterizing digits or pressing of a key). The use of the connecting devices serving for internal traic continues only until the connection of the junction line to the calling junction line of a special selector serving merely for the junction traflic.

A further advantage of the arrangement according to the invention is that large group selectors can be used for traiiic with the remote exchange without an especially high operating velocity or specially constructed testing devices or storage devices being necessary, while the subscriber need not delay the sending out of impulses.

A special access to the junction line can be obtained over an impulse receiver for internal connections but also over another station of the internal connecting path seized by the call e. g. following a selecting stage.

According to the invention the special access of the junction line can be metallically connected with the speaking conductors of the internal connecting path. It is then possible 'whenthe junction line to the remote exchange cannot be made over the connecting selector e. g. as a result of lay sending of dial impulses. Especially with disturbances, to by-pass the speech traine over the internal connecting path by the special means of access.

According to another feature of the invention the present switching means are provided which when a desired line becomes disengaged prevent the switching back of the call to an engaged subscriber having call storage facilities, but cause the call to be switched back when the subscriber who has stored the call becomes free. The switching back of the call to the waiting subscriber only results then when the required line and the waiting subscriber who has stored the call are both free.

This has the advantage that the waiting subscriber only has the called line at his disposal when he himself is also free. The subscriber in another conversation is thus not disturbed. The

required line can be placed at the disposal of a further subscriber in the interval in which the waiting subscriber is engaged in another conversation.

In arrangements with call storage when a called line is engaged and the storage of the call is maintained through further outgoing and incoming connections the subscriber does not need to undertake the selection of the desired line again after receiving the automatic switching back of the call when the desired line becomes free. He is connected in preparation to the called party by means of the call storing operations of the selector which has operated previously.

In order that the subscriber'shall determine whether the selection of the required line shall take place immediately or only after switching back further features are provided according to the invention which are associated with the called line and decide whether the required line is to be reached immediately or after the call has been stored. The selection of the desired line can then take place independently of whether the call is stored or whether the desired line is immediately free. The subscriber also has to perform the necessary switching measures after selecting the desired line again after the switching back of the call. For example, he has to select the characteristic digits of a required line in each case even after call storage before the selection of the digits of the required subscriber is undertaken. If after the switching back of the call no further digit selection takes place the subscriber receives the engaged signal.

In the drawings systems are shown as embodiments in which the selectors serving the tralc to the extraneous exchange are associated with the outgoing junction line. It is understood that the invention can also be used for the purpose of connecting traffic, the junction lines being provided with a special discriminating selector for junction traffic.

Figs. 1 and la relate to a circuit for a fully automatic rural exchange with local and main exchanges and characterizing digit selection and call storage.

Fig. 2 shows an arrangement in which in contrast to Fig. 1 on seizing of a free connecting line VL the other connecting lines are not` guarded.

Figs. 3 and 4 show further embodiments for impulse receivers serving to send out impulses over internal routes.

In Figs. 5, 6 and 7 various possibilities for sending out impulses to the junction lines having directive selection by the pressing of a key are represented.A

Only the details necessary for understanding the invention are represented and described. Thus in the gures a local group AS, L-W and a line VL and a remote group AS only are shown.

Internal routes extend over selectors OAS-OLW and the incoming exchange trailc over FAS and FLW in the usual way. For the purpose of the invention only the outgoing cxchange traillc is of interest.

In Fig. 1 initiating of an outgoing exchange connection to another exchange takes place as follows:

When the subscriber N lifts up his receiver thc subscribers relay R operates over contact It, subscribers loop, contact 2t, winding I of relay R, battery, By means of a Contact 31- the seizing circuit for the selector OAS is closed over contact lit. The relay RA operates over contact |211 and by means of its contact Era completes a circuit for relay Q, winding I, over contacts 6c and 1v. Over contact Bq the rotary magnet AS is connected. The selector OAS rotates its wiper in alternate play between the relay Q and contact Sas until the relay C tests on the subscribers connection characterized by means of the contact l8r over the c-Wiper of the selector OAS over the following path: earth, contact Hra, windings I and II of relay C, c-wiper of selector OAS, contact |81, winding II of relay R, operated contact IMT winding I of relay T, battery. Relay C operates and stops the selector at contact 6c and switches through the talking conductors over contact |80 and |90. Over contacts |3c and |4o| relay C holds, short-circuits its winding II and guards the nder switch against further seizure. Over the contact |50 the relay V operates, and over contact |611 the d-conductor of selector OAS prepares a circuit for the relay F associated with thesubscriber. Contact 'lv causes the relay Q to restore again.

Over contact HUI in its normal position, upper windingv of the repeater, a-conductor, operated contact-|80, a-wiper of the selector OAS, subscribers set, b-conductor, b-wiper of the selector OAS, operated contact |90, lower winding of the repeater, contact 200|, and earth, the relay A operates. Contact 2|a operates the relay J and contact 227' the relay V|'. Relay VI holds during the sending out of impulses. Relay A holds over operated contact |'lv|, relay J holds over earthen the choke coil Dr after the operation of Contact 200|. Over contact 23a and off-normal contact 24u) of the selector OLW the subscriber receives the exchange signal or dial tone WZ.

It will be assumed that the subscriber who wishes to make a local or remote call, will select the digit Or for this purpose. By the interruption of the loop the relay J restores. Over contacts 37:1' and 3Ec| relay V2 operates and during the impulse transmission this relay holds and shortcircuits the choke Dr by means of its contact 21122. Over the operated contact 2812!, contact 247' in its normal position, contact 25u and offnormal contact 26u; of OLW, the vertical magnet H of the selector OLW operates. The wipers of the selector OLW are now raised by a number of steps corresponding to the numberlof interruptions in the loop.

After the switch has been stepped up, i. e., in

the case assumed, after it has reached the setting epesses-l rotary'magnet D of the selector OLW is operated. The rotary oil-normal contact 34d of the selector OLW energizes the relay U and the relay U interrupts the circuit for the rotary magnet D at contact 32u. This alternate control causes the rotary magnet D to rotate the wipers of selector OLW over the bank contacts to hunt for a free junction line. Relay P testover the c-Wip'er of the selector OLW, contacts 35u, 38112, 36a and 29k to the battery potential on the cconductor.

Junction Zine free It will rst be assumed that a connecting line, for example selector FAS, is free and the contact 48g is in the normal position. The relayv G, which is common to all selectors FAS, operates when one selector FAS is seized and guards all the remaining junction lines by operating all the contacts corresponding to 40g until selector FAS has been set on the subscribers junction line.

In this way cross connections to a subscribers junction line by the simultaneous testing of several selectors FAS is avoided.

The relay P of the selector OLW operates over: battery, off-normal contact 39M of FLW, contact 130g, winding of relay CI, contact M2171, and cconductor. By means of contact 42p the winding I of relay P is short-circuited and the line on which the selector OLW is tested is guarded. Over contact 33p the magnet D is disconnected and the selector OLW is stopped. Over contacts 43p and Mp the talking conductors of the selector OLW are switched through. Over contacts 45p and 46g earth is connected to the z-wiper of the selector OAS over the conductor Bes,

and thus the subscribed N is characterized by a multiple connections to the selector FAS.

4By means of the short-circuiting of winding I oi relay P the relay CI associated with the connecting line VL operates and holds independently of contact 40g over its contact 410|. Contact 480| energizes the relay G which opens contact 40g. Over contact 560| earth is disconnected from the c-conductor of the selector FAS so that vthe relay PI can no longer test. At contact |c| the test circuit of relay Pr is vprepared. Over contact 52e! the starting relay An of the selector FAS operates and over contacts 53am, 55m and 56m the rotary magnet DFAS operates and rotates the selector FAS under con-l Further selection After the selection of the characterizing digit the subscriber can immediately begin to dial thenext impulse series. He need not delay the im.

pulselsendingntil a connection'gto the junctionj line-VLis V.completed over the selectorfFiiS;

c If the connecting line VL is free, selector OLW has direct access -to the impulse relay Al, associated with- VL, which is operated over the a.- conductor, OLW, contact j, 43p and 8|q. ContactA 9Ia| brings up the relay V3 which holds during the impulseseries. Contact 92113 cuts off the relay J serving for incoming traffic from the a-conductor of VL. Contact S'Ial connects battery to the a-conductor of the exchange line over the coil DTI.

v`-On-tl'ie operating of the dial the relayv J of the local connection is' restored as well as in the characterizing digit selection and at its contact gfdisconne'cts earthv from the a-lead over contactslq, 82jv2, 43p. InY this way the relay Al in the a-conductor of the junction lineA VL is restored and at contact 91a| removes battery from the a-lead in synchronism 'with the impulses.A On the release of the relay A| relay V4 operates over contacts 93113', S4a| and 957| and holds during the impulse series andthe coil DTI is short-circuited by its contact 96114.

In order to ensure that the impulses are not mutilated the arrangement is such that the switchingthrough of the selector FAS associated with the connecting line VL is only possible at the end of an impulse train.

For this purpose it is arranged that in dependence on the relay V4 which, is operated by an impulse train, an additional relay Tr is inuenced which controls the switching through relay PH.

In Fig. 1 the circuit of the relay Tr is interrupted -by means of contact 6h24. At the end of the impulse train thecontact 6h24 is restored to normal. Meanwhile -therelay Pr of the selector FAS has tested on the subscribers junction line, as described previously, and the relay Tr operates over contacts Blvd and 62221 and holds over its own contact 63tr. Contact 6413?' connects earth to the c-wiper of the selector FAS, so that the switching through relay C of the selector OAS is short circuited and the internal connecting path is released. By means of contact 65h" the switching through relay PH is energized and effects the switching through of the talking conductors of the selector FASr by vmeans ofits contacts v'mph and 1 5ph.'

Over contact 131m earth is connected to the dwiper of theselector FAS and is connected to the d-wiper of the line leading to the selector OAS. The relay F which maintains the storage of the impulses isthus short crcuited and restores. The impulses are no longer stored. Over contact 4|ph and c-conductor tothe selector OLW is interrupted.v Relay C| associated with the connecting line is restored.

Relay H2 which operated over contact '180| holds over contact 19111'. Contact 8'8'h2 closes the a-conductor of the selector FAS and over contact 89h2 and choke DTZ connects earth to the b-conductor of the junction line VL. The relay P1' holds over the contacts 58m' and 6|v3 which is operated during the impulse transmission.

After the closing of the final connecting path from the connecting VL over the selector FAS to the subscribers connection and release ofthe local apparatus OAS-OLW, the dial impulses arel transmitted as loop impulses over earth, choke DrZ, contacts 89712, 83114, '|5ph, b-wiper of FAS, b-conductonrsubscribers station N, a-conductor, a-.wiper of FAS-,contact '|4ph, 88h2, reA-M laylAi. Tha-delay in'4 the operationfofthe switching through i relayl PH .of selector FAS andthe release period lof'. the switch through relay C of selector IOAS is sov arrangedinviewA of the short-circuiting, that ndimpulse'.` gets lost. In

order tov avoid controlling the .impulse relay' Ai simultaneously at VL over the internalas Well as i' over the final connecting path,v both Aperiods are made substantially the same.

No junction Zine' free If no junction line to the extraneous exchange is .free a subscriber receives the-'engaged signal Bes over contacts 45p, 24111, 23a, He can hang up and hold an internal .conversation during the` waiting period., His call remains stored over the relay F during .the localconversation of the subscriber. Junction lines which became. free are at the disposal of: other subscribers. j

If several subscribers calls are stored-but: are not engagedin local-.conversations and therefore are ready toseize the connection, the subscriber whose associated selectorrst Yreaches the junction line VL seizes the-connection to the remote exchange.

It will be assumedl that the subscriber N with a stored call is the first who is ready to seize the line.

Revertioe calling 'When on the release ofa junction line VL, the subscriber Nis free andhashungup, the selector FAS associated with the free connecting line over contacts tilllfV and lll lt'starts up in that the relay An operates.

The selector FAS of the junction' line VLtherefore comes under the control of-two call receiving devices in the first placeiunder the control of the seizing relay CI Iwhich' is reached only over the internalV connecting path with special access to VL, and in the other case under the influence of relay F storing the call when all connecting lines VL are engaged.

Over contacts 53cm, 55101' and 55p! the -rotary magnet DFAS operates and rotates thel selector FAS with the aid of the interrupter UI until-the test relay PI tests over contacts 50cl and I03an, c-wiper of the selector FAS, contact 12j, winding 'II of relay R, contact' BSt, winding I of relay T. The contact 50cl is in its normal position when the correspondingv junction` lineA is free.

By testing on the call of the subscriber `N stored over the contact .12j relay Pi operates and again stops the selector FAS over contact 56p! `and. short circuits its Ysecond-winding byr means of contact' |05pl.

Over Vthe operated contact 56p| .theA relay PH operates and switches through the talking conductors of the selector 'FAS over the contacts Mph and '151311. Over the contacts? 8111.2 and 89h2and .the windings I and II of relay RI: the subscriber N receiveszcalling. current, over the talking conductors. vThe call from the `exchange is conveniently difIerentiate'dfrom anfinternal call bythe length of the ringingzsignal exchange signal from selector'FAS.

The subscriber can, after lifting up `his receiver, `send out the number of 'the desired subscriber `corresponding to the characterizing' digits of the resulting impulse train. Then infknown manner the selector in the main exchange is set corresponding to .thef impulse train andthe conue'ction to the desired subscriber isset up.

'-65 Thel subscriber N after receiving theicalllifts up his receiver and immediately receives the The arrangement can, however, also be coriveniently such that the' subscriber after the switching backlofthe call has to select the complete'number. of. the vcalled party again, i. e., he must carryout the digitselection again. He need then,A 'noti differentiate between the selection without callf storage and the selection after call storage. If the: subscriber in the last arrangement described forgets to dial the characterizing digit again, he receives the engaged signal.

Further selection according to this arrangement will be described in detail with reference to Figs. 1 and '1a.

The arrangement is such that switch means having access to the junction line differentiate between the various arrangements for reaching the'mainzexchange from the junction line, as to whether the connection extends over internal connecting devices and the special access means (when a connecting line is free), or (after the junction lines have all been engaged) directly over selectors serving only the connecting trafo to the remote exchange.

In the selection over the internal connecting path to the other exchanges the dial impulses are transmitted freely by means of the switch means affecting the differentiation, while by the selectionldirectly over the selector of the junction line the impulses are freely transmitted only on the selection of the characterizing digit. The testing occurring on the selection of the characterizing digit is performed by a discriminator which by means' of the switch means carrying out vthe differentiation on the selection is brought directly under the control of the dial impulses over selectors of the junction lines. On selection of the characterizing digit switch means are controlled by means of the discriminator which makes it possible to send on the impulses to the main exchange. On the selection of digits which do not correspond to the characterizing digit the impulse transmission to the main exchange is prevented, however, and the calling subscriber receives the engaged signal.

It will be assumed that the number of the desired subscriber at the main exchange is O 365. The calling subscriber in the sub-exchange then must 'always select this subscribers number whether the connecting line of the remote exchange is free or is first engaged.

Connecting Zine free If the connecting line is free on the settingup of the connection to Athe main exchange over the internal connecting path the calling subscriber receives the exchange signal after the digit selection, as described, over the internal connecting path. On the selection of the following characterizing digit 3 then, as already described, the relay Al of the access means to the junction line is controlled in synchronism with the impulses and the impulses are transmitted over contact Slal. Over contacts 96114, Q'lal and 26502 relay A2, (Fig. la) is controlled in synchronism with the impulses. One the energization of the relay A2 the relay V5 operates over contact 20Ba2 and holds during an impulse train.

On the seizing of the junction line to the remote exchange over the special access means relay C! was energized and operated the relay DI over contact 2000i. Over resistance Wi, the operated contact 20ldl, and contact 202a| which is set back to its normal position by each impulse, battery is connected to the b-conductor of the connecting `line to the main exchange whereby over contacts 203c2 and 204h3 which are in their normal positions, relay S is operated. Over contacts 201125 and 208s the relay U2 is operated. Over contacts 209u2 and 2I0125 the impulse transmission to the group selector GW in the main exchange is made possible. By the controll of contact 2I|a2 positive .potential is connected to the a-conductor to the main exchange and the group selector, which is not shown, is stepped up to the third bank after the digit has been selected. Over contact 2|2u2 the rotary magnet DM of the discriminator is disconnected andthe setting of the discriminator is prevented. ,Relay U2 holds over its own contact 2|3u3 and contact 201125. The discriminator DM is therefore not operated in this case.

Junction lines all engaged at rst,

Recertvzve calling If all junction lines are engaged the calling subscriber receives the engaged signal from the local connecting path after selecting the characterizing digit 0. He hangs up. His trunk call is stored. The subscriber is free for local traiiic. If in the meanwhile a junction line to another exchange becomes free and in addition the calling subscriber is free, as described, the revertive call is made automatically over the selector FAS of the junction line whereby the calling subscriber is switched through to the main exchange. The subscriber lifts up his receiver and receives the revertive call signals. The relay Rl of the junction line VL operates and connects the relay H2 (Fig. l) with contacts 22,014 and 22ml. By the operation of the contacts 88h2 and 8911.2 the relay Rl is disconnected from the conductors a, b of the junction line VL.

'I'he subscriber must now select the number of the subscriber 0.365 again. After the transmission of impulses the relay Al of the junction line VL which is operated by the operation of the contacts 88h2 and 89722 restores in synchronism. with the impulses. Relay V3 holds in the manner described over contact Slal and the relay V4 over contacts 93123, 94a! and 9571. The impulses are transmitted in the manner already described over the contact 91a! to the relay A2 (Fig. 1A). On the release of the relay A2 the relay V5 operates over contact 206er?. in the manner already described and holds during an impulse series. Relay U2 does not operate. The rotary magnet DM of the discriminator is therefore controlled in synchronism with the impulses over contacts 206112, 220125, 22|el and H2112 i. e. on the selection of the digit 0 it is brought into the position O.

In the position O the relay U2 operates over contact 201125 and wiper 208dm of the discrimi nator. Over contact 2l2u2 the rotary magnet DM of the discriminator is disconnected. Over contact 2I5125 the relays H3 operates and connects earth on the c-conductor of the group selector GW in the main exchange, by means of its contact 21th.?. Contact 209112 which `previously prevented transmission of impulses to the group selector GW is closed. Over contacts 209112, H0115 and 2 l |112 impulses following on the' digit characterization are transmitted to the group selector GW in the main exchange. The group selector GW is stepped on to the third contact bank as previously corresponding to the selection of the digit 3.

If the subscriber instead of selecting the complete subscribers number 0 365 only selects the digits 365 after Vreceiving the reverted call he receives the engaged signal.. The transmission 0f impulses to the main'exchange is prevented.

I'nrorderA to obtain this resultthe relay U2 effecting the impulse transmission is not operated if the discriminator is not set in its position O.

On the selection of the digit 3, after receiving the revertive call, the rotary magnet DM of the discriminator as described, is controlledv over contacts 206112, 220125, 22|a| and 2|2u2 and brings the wiper 208dm into positionV 3 correspondingto the digit 3. In the positions 1 -9 lower down than the position O of the-wiper 20801111' the relay ZI operates over contact 201125 and wiper 20812111 vand locks up over contact 2|1zl. Contact 22|zl'interrupts the circuit for the rotary magnet DM. The relay U2 cannot operate as in the digit selection. Y The impulse transmission to the group selector GW isi prevented by means ofA the contact 209112'. in its normalposition. The calling subscriber receives the engaged signal over windings II' of therelays S and'AZA and wiper 2|9dm. L

In'this way the calling subscriber is compelled to select the complete number of the desired subscriber.'l Y 5 In the embodiment shown in Fig. 1 on the seizing of a junction-line (VL) overa iinal selector OLW ofthe internal connecting path by means of the operating relay Cl the blocking relayv G common to all junction lines, is energiz'ed, and as describedybyope'ning theconta'ct corresponding tov the contact 40g in'the access means to the other junction line VL'prevents a further junction line from being seized until the selector FAS of the seized junction line has reached the line of the calling subscriber N. vvThe' arrangement can also besuch, however, (Fig. 2') that after the; seizing of an' internal junction' line over connecting paths of the internaltraic, thelseizing of another `free junction line is not prevented but so long as the 'free june; tion lines canstill be'reachecL all the ifreejunction lines canV be seized over connecting'paths for internal-traiiicQbut the connecting devices can never hunt'for different connecting lines atthe same time as thg'e'callingline. y Y

For this purpose the arrangement according to Fig. 1 is provided with an auxiliary connecting path.v Two auxiliary selectors are providedof 'which' one sets itself. Vonthat local connecting path overwhich a connecting line h'as been seized' and a second auxiliary selector sets itself on the seized junction line.' The setting of these two auxiliary selectors can be made dependent in known manner onl the closing of an individual testing circuit which is only completed 'when over connecting devices ofthe connecting path for internal trailic, taken into use over the two auxiliary selectors and the Seized junction line, a circuit containinga particular current source is completed. Furthermore. a test circuit for the selector oi the seized junction line is extended over the auxiliary connecting path and over ini ternal connecting `devices taken' into use, and

test potential is connected to the test Wiper of the selector of the junction line as Well as tothe internal connecting path used` bymeans'of the auxiliary selector. It is convenient to set the rotary magnets of these two auxiliary selectors over a further wiper.

v In Fig. 2 it is shown diagrammatically how the testingAcan beperformed with the aid of two auxiliary selectors Wl and W2 withoutA all ofthe junction lines being blocked when a junction line is seized over the internalA connecting `path and several junction lines are free.

When the selector OLW tests on a free junction line VL relay P associated lwith the selector OLW operates and, over the. contact Ic; operated by the seizing 'of a selector OAS, contact 2160 of the selector OLW'operated when the selector steps up to the tenth contact bank, contacts lllp and Uhr the relay An. .Operates and over con-- tacts |3an, |6p| operates the rotary magnet DWI of the auxiliary selector Wl over an interrupter U. Contact 3p short circuits a winding vof the relay P and brings the` relay Cl of the special access means ZL tothe junction line VL. When the auxiliary selector W| 'tests on positive potential over thecontacts Ic, A27m, lpyand winding of the relay vI-Ir, relay PI of the auxiliary selector operates Yand over contact |6p| disconnects the rotary'magnet DWL The auxiliary selector Wl is stopped.

Over contactslHpL 22e., |8pw the auxiliary selector W2 is rotated overrits rotary magnets DW2 and the interruptor U until in the circuit: c-wiper of the auxiliaryselector W|,dwiper of the selector OLW, contact |5c|, c-Wiper of the auxiliary selector W2, contact 4e and alternating current repeater Tr, the relay PW is operated. Over contact lpw the rotaryqmagnet DW2 is disconnected and the auxiliary e selectorWZ is stopped on the position :characterized by means oficontact |5cl. Over contact |9pw the relay E operates and holds over contacts 20p| and 2|e. Contact 4e interrupts the lalternating currenttestcircuitand contact, 22e,'the circuit for the rotary magnet-DW2.. Contact 23e' connects the rotary magnetV DFAS of the selectorFAS to the .junctionfline Vllover;thed-.wipenof` the auxiliary selectOrrWZ' and contactV 23e., Over-contacts .24e Vand A25el test potentials are connected tontheswipersa' of` theauxiliary selector W; W2'. FASoperates -until the following testY circuit is completed for therelay Pr: negative, contact 24e, z-wiper `of the auxiliary selector W2, relay Pr, zwiperof theselector FAS, e-wiperjof theselector OAS,-e-wiper of theA auxiliaryselectorWl, `coni tact 25e, positive. Over contact 26111' the magnet DFAS is disconnected." The connection between the-junction line VL andthe subscribers line is set up.A

The "impulse transmission overthe internal connecting devices and the special access means ZL (Figfl) extending to a junction line VL can alsoibe arranged according to Figs. 3 and 4.

Fig; 3 relates to theimpulsetransmission of an internal group selector and a bridge relay as an impulse-repeater lin the special access means to the junction line VL. Inthis case after the testing operation,'e. g. of the group selector OGW the contacts Ip and 2pareoperated, the bridge relay A disconnected, -and` over' Contact 40| vthe impulses aretransmitted `to the relay AI of the junction line by means offtherelay A2 and contact-3a2.

In-Fig'. 4 is representedthe disconnection of the bridge' relay A on :the seizing of the junction line over a` lineV selector OLW and metallic switching through over' special access means to the junctiomline. When the-relay P tests over .the c-wiper` of. the selector OLW on to the relay CI of the junction-line VL which in contrast to the relay of the subscribers line,-is of a 4low resistance, the relay P| operates and disconnects the bridge relayAby means of its contacts' Ipl, 2pl, 311|- and 422| and sWitchesthrough the talking conductors a, b.

The loop interruptions on the dial impulse transmissions can be transmitted in Figs. 3 and 4 directly to the relay Al of the junction line VL after the switching through. This case is shown in Fig. 4.

The loop interruptions can, however, be transmitted to a bridgerelay A2 of the special access means of the selector OLW and OGW as shown in Fig. 3. Contact 3a2 closes the circuit for the relay AI of the junction line prepared by means of the contact 40|. In the second case no metallic switching through of the internal connecting path to the free junction line takes place. No talking can occur over the outgoing line.

In Figs. lit is assumed that connecting devices in particular dial impulse receivers of the internal connecting path hunt freely for access to a free junction line. A free junction line can, however, be hunted for over a special auxiliary selector in particular when junction lines in another exchange cannot be set up over internal dial impulse receivers with free hunting. The selector OLW is then set on a particular contact by means of a charactem'zing digit. The auxiliary selector with free hunting which is arranged further on is either started by the characterizing digit selection or it is preset. A

In Figs. 5, 6, 7 circuit arrangements are shown in which the connections to another exchange are set up over points which have access to internal connecting devices in particular to dial impulse receivers and to a special access means to a junction line in another exchange. Over the points, impulses can be transmitted to another exchange until a connection is set up between the seized connecting line extending to the other exchange and the subscribers line. The switching operation results convenientlyby the pressing of the key at the subscribers station. In order to hunt for a free junction line an auxiliary selector HW is used which either operates by means of pre-setting (see Fig. 5) so that when a junction line is free indirect impulses can be transmitted to the junction line connected to the other exchange, or the auxiliary selector is only started up after the operation of the points (see Figs. 6 7). The arrangement according to the preceding figures can be suchthat over the points a metallic connection to the special access means in thejunction line is set up (Figs. 5 and '7)'. The arrangement, however, can be such Athat over the internal connecting .path only dial impulses for setting dial impulse repeaters can be transmitted to the other exchange without a talking connection being setup. (see Fig. 6).

In Fig. 5 after the selector OAS has been stepped up and has tested on the subscribers line in known manner the relay C is energized (not shown).` By the pressing of the key at the subscribers stationA for` setting `up a connection to another. exchange theV relay X is energized, and by means of its Contact |23:` energizes the relay E over the rotary oil-normal contact Slclw of the selector OLW. The point contacts |e and 2e aret'opel'ated. Relay E'hclds over contacts Me and llo independently of the pressing of the key. Aiurther contact, not shown, of the relay E interrupts the setting circuit of the selector OLW so-that this can no longer be iniluenced by the impulses which follow.

The auxiliaryy selectorIIW is provided with a pre-setting arrangement and when a junction line is free it sets itself on this free junction line. The auxiliary selector HW is rotated until the operation of' its test relay Pl over contact 20m,

rotary magnet DHW and interrupt'er U2, when the test relay PI operates by testing on a resistance Wi associated with a free junction line VL. It is arranged that one winding of the test relay is only short circuited when the access means ZL to the junction line VL is seized by the operation of the relay E. By the operation of the relay E the second winding of the Nrelay PI is short circuited over contacts 2| pl and 22e. This has the consequence that the other auxiliary selectors whose test relays are also operated over their d-wipers and the resistance Wi and are stopped on the same contact, again restore since by the short-circuiting of one'winding of the relay Pl over contacts 2 I pl and 22e they are disconnected. The remaining auxiliary selectors are, therefore, connected again to the interrupter and stepped on to the next free junctio-nline. After the operation of the relay Pl the magnet DHW of the auxiliary selector is disconnected over contact Zpl. 'Ihe contacts 3011i and 3lpl switchthrough the talking conductors aand b. Over contacts 32pl, 33e, wiper c of the auxiliary selector HW, relay Cl of the junction line operates.

If the auxiliary selector is not pre-set on ak free junction line, it is started in dependence on the operation of the points ,whichv in the present case is done by relay E. Fig. 6 represents this arrangement. When this is used the rotary magnet DHW of the auxiliary'selector is energized over the interrupter U3 until therelayPl tests on a free junction line (relay C) .over contact 54e and d-wiper of the auxiliary selector HW. The contact 5710i disconnects the rotary magnet DHW. Contacts 55p| short-circuits a winding of the relay Pl. The contacts EZpI and 53p| switch through the conductors a and b'of the auxiliary selector HW.

The impulse transmission to the relay Al of the junction line VL takes place in Fig. 5 Vover contact 35a of the relay A of the internal connecting path. During the impulse transmission the relay Vl holds and the relay V2 operates over contacts llvl and 9a. Relay V2 holds during an impulse train.

In Fig. 6 the impulses .are transmitted over contact Ela after the contact 50cl has been closed. Relay Al of the junction line is restored in synchronism with the loop interruption and as in Fig. 1 transmits the impulses over the junction line.

The initiating ci" a connection from theseized junction line to the subscribers line by vlay-passing the local connecting path (OAS) can take place in Figs. 5 and 7 directly after the direction selector e. g. by means of the relay E, or by seizing of the junction line (VL, relay Cl) as shown in Fig. l. After the icy-passing of the local connecting path the impulse transmission as in Fig. l follows directly over the selector FAS.

In Fig. 7 a further embodiment is shown for Fby-passing by means of points and selection of a free junction over'an auxiliary selector. The impulses are here transmitted to the relay AI of the junction line VL directly without using internal impulse repeaters. After the pressing of the key and operation of the relay X the relay Xl is operated over contacts like and 9c. On release of the key, i e. the release of relay X, the switching relay E is operated over contacts 8x and i212! and holds over contact |30 and lite. Over contacts x and 2010i the rotary magnet DHW is energized over the interrupter Ud. VThe operating circuit is maintained after the release of relay X over contact I Bxl and after the disconnection of the relay Xl over contact lle.

. When the auxiliary selector HW tests on relay CI associated with a free junction line VL relay PI operates, and disconnects the rotary magnet DHW at contact 20p! and stops the auxiliary selector HW. Over contacts 21p! and 22p! the talking conductors of the auxiliary selector HW are switched through. Contacts 'le and 8e control the access means to the junction line VL.

The loop interruptions caused by the dialling of the subscriber N directly control the relay Al; associated with the junction line.

What is claimed is:r

1. In a telephone yor'like system,v a first exchange having one or more trunk lines outgoing to a second exchange, a calling subscribers line in the rst'exchange, lmeans localto said first exchange controlled over said calling line at times to extend a connection from said calling line to the line `of `another subscriber in the same eX-f change and at other timeslto extend a'temporary connection from said calling line to one of said trunk lines,a callingdevice at the calling station operated by the subscriber thereat at said other times to control switching apparatus at the second exchange over said temporary connection and said trunk line,` and means for .releasing said temporary connection before completion of the controlling of said switching apparatus at the second exchange'and, at substantially the same time, substituting another connection for said temporary connection, said calling device thereafter controlling the 'switching apparatus at said second exchange over said other connection and said trunk line. i ly 2. In a telephone system, afirst exchange having a trunk line extending to a second exchange, subscribers lines terminating 'at the firstv exchange, switching apparatus at the first ex- Y change having access to said trunk line and to said subscribers lines, means for seizing said switching apparatusover a calling one of said subscribers lines and at times controlling same to seize said trunk line, means insaid switching apparatus responsive to impulses received over the calling line forcontrolling the transmission of corresponding impulses -over the trunk line to operate switches in said second exchange, other switching apparatus in the rst exchange terminating said trunk line and operated to connect with the calling line responsive to said seizure of the trunk line, means for releasing said rst switching apparatus rwhen said other switching apparatus Yhas connected ,with the calling line,

said impulse responsive means in said rst switching apparatus being disabled upon said `release thereof, Aand means in said other switching 'apparatus vthereafter responsive to impulses received over the calling line for controlling 'the transmission'of corresponding impulses over the trunk line to' continue the operation of the :switches insa'id second exchange. f Y

3. In a telephone system,ia local exchange having trunklines outgoing to a distantexchange', subscribers lines terminatingat the localexchange, a local switch train for completing connections lbetween said subscribers lines, means for at times controllingxsaid switch train over a calling one of said subscribers lines'to extend a temporary'connection from said calling line to a trunk line, means for vsubsequently completing another connection between said calling line and the trunk line and for thereupon releasing said temporary connection, means controlledl oversaid temporary'connection from the calling Vstationbefore said release thereof vfor transmitting impulses over said trunk line, said last means being controlled over said other connection from the calling line' after .the release of said temporary connection.

4. In a telephone system, a local exchange having trunk lines outgoing to a distantfexchanga subscribers lines terminating atz'the `local exchange, a local switch train for completingv connectionsbetween said` subscribers lines, means for at times controlling said switch ytrain over a calling one of saidsubscribersV lines to extend a temporary connection from; said calling line'to a trunk line, said means including a calling device at the calling station thereafter operated by the subscriber thereat .to transmit impulses over said temporary connection and said trunk line to set switches atthe distant exchange, and means for releasing said temporary connection` before completion of the setting of said switches at the distant exchange and, at ,substantiallyv the same time, substituting another connection for said temporaryconnection, the,V impulses from said calling device thereafter being transmitted over said other connection and the trunk line` to the distant exchange.

5. In a telephone system, a local exchange having trunk lines outgoing. .to-a distant exchange. subscribers lines terminating. at the local exchange, a local switch .train for completing connections between said subscribers lines, means for at times controlling said switch train over a calling one of said subscribers lines to seize one of said trunk lines, a finder switch in said local exchange terminating said trunksline and voperated to connect `with the, calling linefresponsive to said seizure of the trunk line, means for releasing said local switch train when said nnder has connected with the calling line, Vmeans responsive to impulses transmitted over said call ing line and said local switch train before said release thereof for transmitting` corresponding impulses over the trunk: line toccontr'ol the lsetting of switching apparatus inithe 4distant exchange, said lastmeans beingl responsive to* impulses transmitted over said. calling line and said finder switch vafter Jsaid release `of said `switch train for `transmitting corresponding. impulses over the trunkline to continue controlling the setting of the switchinglapparatus in the distant exchange.

6. In a telephone system, a locallexchangelhaving trunk lines outgoing toa distant exchange, subscribers4 lines terminating vat the localV exchange, a local switch train for completing connections vbetween said subscribers lines, said. train includinga numerical switch, means controlled by the initiation of' a call from one of said subscribers lines for extendinga connection from the calling line to said numerical switch, acalling device at the calling station operated 'at times after a connection has been extended to said numerical switch to control said switch to extend a connection .to awanted subscriberslinefinA the local exchange, other means at the calling station operated at other times aftera connection has been extended to said numerical switch `to seize one of said trunk lines without operating -said switch, switching apparatus in' the ,local exchange terminating said one trunk line and operated to connect with the calling line responsive to said seizure of the trunk line, means for releasing the connection from saidA calling li'neto said numericalV switch when saidswitching zapparatus has connected with the calling line, and means controlled bythe calling device at the calling station both before said switching apparatus has connected with the calling line and after said connection from the calling line to said numerical switch has been released to control the setting of ,switching apparatus in the distant exchange.

7. In a telephone system, a local exchange haiing trunk lines outgoing to a distant exchange, a calling subscribers line terminating at the local exchange, means at times controlled over said calling line to extend a local connection therefrom to another subscrbers line in the same exchange, a key at the calling station operated at other times to control said last means to extend a temporary connection to a trunk line, a calling device. at the calling station thereafter operated by the `subscriber thereat to transmit impulses over said temporary connection and said trunk line to set switches at the distant exchange, and means `for releasing said temporary connection before completion of the setting of said switches at the distant exchange and, at substantially the same time, substituting another connection for f said temporary connection, the impulses from said calling device thereafter being transmitted over said other connection and the trunk line to the distant exchange.

8. In a telephone system, a local exchange having trunk lines outgoing to a distant exchange, subscribers lines terminating at the local exchange, a plurality of 'link circuits for completing local calls between said subscribers lines, means for controlling one of said link circuits over a calling one of said subscribers lines to seize one of said trunk lines, means for controlling another of said link circuits over another calling one of said subscribers 'lines to seize another of said trunk lines at substantially the same time, switching apparatus in the local exchange controlled by the seizure of said one trunk line to extend a connection therefrom to said one calling line, other switching apparatus in the local exchange controlled by the seizure ofsaid other trunk line to extend a connection therefrom to said other calling line, and means for preventing said rst switching apparatus from extending the connection from said one trunk line to said other calling line and preventing said other switching apparatus from extending the connection from said other trunk line to said one calling line.

9. In a telephone system, a first exchange having a trunk line to a second exchange, means for engaging vsaid trunk 'line for an inter-exchange call, a plurality of calling lines in the rst exchange, means controlled over each calling line toldesignate a call to the second exchange, means for storing said calls, means controlled at times over one of said calling lines while its call is in storage for extending a local call to the line of another subscriber in said first exchange, a finder switch in said first exchange terminating said trunk line and operated responsive to said trunk line becoming available for another inter-exchange call to search for and seize one of said callingr lines, and means for preventing said nder switch from seizing said one calling line while same is engaged in said local call.

10. A telephone system as claimed in claim 9, wherein said last means comprises means individual to said one calling line and operated while same is engaged in said local call to characterize said one line inthe bank of said finder switch.

11. In a telephone system, a rst exchange having trunk lines outgoing to a second exchange,

a calling line in the rst exchange, means in said rst exchange operated over the calling line to designate a call to the second exchange, means for thereupon storing said call if no trunk line to the second exchange is available, means at times controlled over said calling line While said call is in storage for completing one or more local calls to the lines of other subscribers in said rst exchange, and means effective responsive to a trunk line becoming available While said call is in storage for connecting that trunk line to said calling line only if said calling line is not engaged in a local call.

12. In a telephone system as claimed in claim 11, means responsive to the designation of a call to the second exchange for seizing a trunk line outgoing thereto substantially at once if one of said trunk lines is available, and discriminating means operated dilerently in dependence upon whether a trunk line is seized for the call at once or after becoming available While said call is in storage.

13. In a telephone system, a rst exchange having trunk lines outgoing to a second exchange, a calling line in the rst exchange, means in said first exchange operated over the calling line to designate a call to the second exchange, means for thereupon storing said call if no trunk line to the second exchange is available, means thereafter responsive to a trunk line becoming available for seizing the calling line and signalling the subscriber thereover, means at times controlled over said calling line While said call is in storage for extending one or more local calls to the lines of other subscribers in the first exchange, and means for disabling said third means at said times.

14. In a telephone system, a rst exchange having trunk lines outgoing to a second exchange, a calling line in the rst exchange, means in said first exchange operated over the calling line to designate a call to the second exchange, means controlled by said designation for seizing a trunk line to said second exchange substantially at once if one is available, means for storing the call if no trunk line to the second exchange is available, means effective responsive to a trunk line subsequently becoming available while said call is in storage for connecting that trunk line to the calling line, a calling device at the calling station operated to control the transmission of impulses over the trunk line to set switching equipment in the second exchange, and means in said second exchange for at times absorbing certain of said impulses depending upon Whether the trunk line Was seized substantially at once or after becoming available while said call was in storage.

15. In a telephone system, a rst exchange having trunk lines outgoing to a second exchange,

a calling line in the first exchange, means in said first `exchange operated over the calling line to designate a call to the second exchange, means controlled by said designation for seizing a trunk line to said second exchange substantially at once if one is available, means for storing the call if no trunk line to the second exchange is available, means eiective responsive to a trunk line substantially becoming available While said call is in storage for connecting that trunk line to the calling line, a calling device at the calling station operated to control the transmission of trains of impulses over the trunk line to operate switching apparatus in the second exchange, and means in said second exchange eiective at times in dependence upon whether the trunk line was seized substantially at once or after becoming available While said call was in storage for preventing the operation of the switching apparatus in the second exchange if a predetermined one of the trains of impulses received over said trunk line does not contain a predetermined number of impulses.

16. In a telephone system according to claim 15, means for absorbing said predetermined one train of impulses at times depending upon whether the trunk line was seized substantially at once or afterbecoming available while said call was in storage.

JOSEPH KUCHLEY. WALTER PINELL.

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