US1870997A - Printing telegraph exchange system - Google Patents

Description

Aug.9,1932. A. JIPFA'ET AL 1,870,997v

PRINTING TELEGRAPH EXCHANGE SYSTEM Filed Jan. 4, 1950 4 Sheets-Sheet 1 Aug. 9, 1932. A, PP ET AL x 1,870,997

PRINTING TELEGRAPH EXCHANGE SYSTEM Filed Jan. 4, 1930 4 Sheets-Sheet 2 u 'l W v .um l I ALJ-Snug:

Aug. 9, 1932. A. .uPP ET Al.

PRINTING TELEGRAPH EXCHANGE SYSTEM 4 sheets-sneu 5 y Filed Jan. 4, 1950 Aug. 9, 1932. A. JIPP ET Al.

PRINTING TELEGRAPH EXCHANGE SYSTEM 4 Sheets-Sheet 4 A Filed Jan. 4. 1930 MMN @MW mmm.

Patented Aug. 9, 1932 UNITED STATES' AUGUST J' IPP, OF BERLIN-SPANDAU; E-H'RHARD ROSSBERG, OF BERLIN -SIEME-NSSTADT;

PATENT FRANZ SIMON AND .ALFRED SCHEUNERT, OF BERLIN-CHARLOTTENBURG, AND WILLY SKAWRAN, OF BERLIN-NIEDERSCHONHAUSEN, GERMANY, ASSIGNORS T0 SIEMENS tv HALSKE, AKTIENGESELLSCHAFT, OF SIEMENSSTADT, NEAR BERLIN, GERMANY, A CORPORATION OF GERMANY PRINTING TELEGRAPH EXCHANGE SYSTEM Application led January'4', 1930, Serial No. 418,460, and in Germany December 28, 1928.

Our invention relates to improvements in systems of communication, and more particularly tele-printers, tele-writers and the like.

It is well known in the art to design communication systems for tele-printers, telewriters and the like in such a manner that the apparatus is always ready to receive a message and the transmitted signs are automatically printed or recorded by the receiving apparatus. Neither for switching the receiving apparatus on or off nor duiing the' transmission of the messages is any attendant required at the receiving` end.

It is, however, a drawback that .in particular in extensive systenis'and such for automatic connection the calling subscriber has no means at his disposal of ascertaining at once whether the correct conii-ection has been made and that the receiving apparatus is really ready to receive the message. This uncertainty is particularly disagreeable if a Y message is to be kept secret or is of great importance.

The object of our invention is to provide an automatically operating return signaling device or indicator which becomes operative when a call is received and transmits a Signal to the calling subscriber. This may in the simplest case consist of a. signal indicating readiness, but preferably a special signal identifying the called up subscriber will be transmitted, for instance, his name. The return signaling device is in its mode of operation preferably adapted tothe tele-printer so that the return signal can be written down by the receiving apparatus of the calling subscriber. l

An impulse transmitter of suitable construction is therefore employed, such as a transmitter for standard perforated paper tapes, or a step-by-step mechanism of the nature of dial selectors, or a contact mechanism with cam control.

` Preferably the return signaling device is connected with a contact of the receiving relay in such a manner that said device is released by the relay as soon as the calling impulse arrives. The receiving relay is preferably connected in such a way that its armature is operated once by the calling imdcpresses` a calling key 'whereupon at the' called station the armature ofthe receiving relay is reversed and the return signaling de vice or recorder rendered operative. It will be understood that instead of the key other means may be provided which start the return calling device automatically after the through connection has lbeen effected.

The return report is now Written down by the receiving apparatus of the calling subscriber so lthat this subscriber knows that he is correctly connected and that the station called up is ready to receive his message. The return signaling device is then automatically rendered inoperative again and switches in the receiving apparatus at the called station if this should not already have been done by the calling impulse. No attendants whatever are thus needed at the called station.

During .the transmission of messages whichl then begins the return signaling device remains inoperative and is made ready for service again only when the connection lis interrupted. On the other hand it might be desired that the return signaling device should -not start at all when a message is sent out, i. e. at the calling' station. Switching means are therefore provided which are indirectly or directly rendered operative by the subscriber prior to or when Certain difficulties arise, however, in me-- -orifice chanically operating apparatus working without revolving distributor brushes, as for instance the mechanical apparatus operating on the start-stop principle. In this appara- 5 tus the combination of current impulses (as a rule iive impulses) corresponding to the signal or symbol to be transmitted at the time is set in such a manner that Contact.

springs which are controlled by a controller shaft and which can be closed consecutively during each revolution of the control shaft, are partly locked in a mechanical manner by key-operated levers.

In one embodiment of our invention these contacts are electrically connected with the signal transmitter serving ,for return signaling. The arrangement is preferably such that during the return signaling the run of the control shaft depends upon the operation of the signal transmitter in such a manner ythat the signal transmitter controls the mechanism which releases the control shaft for one revolution at a time.

In the circuits of the contacts controlled by the controller shaft areincluded the contacts of the signal transmitter, for instance the contact arms andcontacts of a dial selector of known design, the bank of contacts of which is wired in accordance with the return symbol or si nal. Instead of a dial 0 ates, for instance, in such a manner that the receiving relaylof the called Asubscriber is first reversed by the calling impulse. After switching in the motor theV signal transmitter provided for the return Areport performs its first step and releases the control shaft transmitter.

of the main transmitter for its first revolution by, for instance, a tripping magnet acting on the blank letter key being energized across a contact controlled by the 'signal control shaft a contact controlled by this shaft causes the signal transmitter. to advance by a further step for the purpose of transmitting the next signal. In this way the signal transmitter and the control shaft of the main transmitter cooperate alternately by controlling each other alternately.

It is easily possible to combine the return signaling device or indicator with the tele- 0 printer or tele-writer in a self-contained unit and, if desired, to use different switchgear in common. In many cases it is, however. preferable to use the return signaling device as a separate appliancewhich may be readily 35 connected with standard apparatus .and thus -ing itself from the called up line.

After the revolution of the form a valuable supplement to existing systems. v

A further considerable simplification may be brought aboutby providing at the exchange station one or a plurality of return signaling devices for one group or all the lines combined and by using automatic switchgcar to effect the connection of a return indicator disengaged at the time.

After a connection has been made by dispatching series of current impulses in a well known manner the return signaling device is automatically switched in and transmits t'ne return signal, which may consist of the name of the town and the name or the numberof the called subscriber, to the receiver of the calling subscriber and then again renders itself automatically inoperative by disconnect- Simultaneously the line tothe called subscriber is connected through and is now ready for transmitting messages. The return signaling device returns to the initial position of rest only after the two subscribers have been dis'connected.

Thestarting ofthe return signaling ,device in the case of outgoing 4tratiic is, however, impossible since the lswitchgear which initiates the operation of the naine transmitter is so arranged that it can be rendered operative by arriving current impulses only.

. The drawings aiiixed to our speciiication illustrate various embodiments of our invention.

In the drawings:

Fig. 1 is a return signaling device connected with the distributor ring of an electrically operating tele-writer according to the startstop principle,

-F ig. 2 shows a. special construction for a 105 mechanically operating start-stop apparatus the contacts of which are controlled by cams or tappets,

Fig. 3 is a detail of the apparatus shown in i110 Fig. 2, and

Figs. 4, 5 and G'illustrate various systems of connection for the application of a return signaling device in tele-printer systems with selector operation. In particular various systems of the interlinking ofthe return signaling device with connecting apparatus, such as selectorsof exchanges, are shown in these v figures.

Referring to Fig. 1 of the drawings it will b e seen that a dial selector is utilized as a return signaling device, the arms of which are indicated by the reference letters d1 to da. E is the receiving relay the armature e of which is reversed as soon as a calling impulse arrives.

This causes the relay X to respond which by 1 means of the contact m1 connects in circuit the relay Y. Y now responds and by means of the contacts fz/1 and y2 connects the source of current S to the apparatus so that its driving motor M starts. Simultaneously the J -relay is energized in the following circuit: battery, rest contact a, relay J, key A712, selector arm d1, reversed contact ya, battery. The contact l connects .the stepping magnet D in circuit so that the selector performs its first ste-p.

Simultaneously there is energized the time lag relay V which by means ofthe contacts c. and

'v2 disconnects the keyboard contacts (T) of lthe apparatus. During the step-by-step mothat the circuit for the relay J remains closed even when a break takes place during the passage of the arm (Z1 from'one contact to the other.

The arms d2 to ZG are now according to the signalto be transmitted; connected .partly to l, partly to `of the battery so that a corresponding series of impulses (for instance -las shown) is sent into the line when the brush B sweeps across the transmitter disk O.

The brush in known manner, is released, for a complete revolution at each time,

by the charging current of the condenser C across the contact i3 when the J -relay responds.

During the revolution the contact .a is open and is closed only after the revolution is completed. In this way the relay J is connected in circuit=anew so that the magnet D is energized again and the selector makes another step forward. Through the transmitter disk the sequence of impulses corresponding with the second selector step, for instance -l- ..is now sent into the line. The cycle described is repeated until the dlarm of the selector engages the last contact. I-Iere it stops since the contact m3 is -still open.

During the return signaling the time lag relays X, Y and V are permanently energized. `As soon as theselector has reached the last contact the relay V drops open and by the contacts 'v1 and 'v2 which were open during the return signaling, connects the keyboard contacts again to the battery or the network.

The return signaling is now finished and the ordinary traffic may commence.

During the trafiic the relays X 'and Y con-A tinue to remain energized. traiic is finished the. armature e of thev receiving relay is reversed into the inoperative position shown. X and Y are then deenergized so that ac3 is closed again. Through w3 the relay J is made to respond once more, D

receives a fresh impulse and advances they selector into the zero position. The control magnet St is then no longer'energized because 6@ me is already open.

The system is now ready for another call. In the case of outgoing traffic the switch An, for instance a key, is reversed either prior to or simultaneously with the switching in of the main transmitter. The Y-relay is then tion of the selector the contact is closed soby the control magnet St which is energized Only after the energized across the switch Anl, so that the contacts y1 and y2 are closed. Simultaneously A712 is, however, opened so that the J -relay does not respond and the return signaling device does not become operative.

Fig. 2 illustrates va return signaling device operating in a similar manner in conjunction with a tele-printer the contacts of which are controlled by a bank of cams and thus render necessary a special connection of the return signaling device.

The first calling impulse arriving over the line Ly energizes the receiving relay E across the following circuit: line battery (not shown), line a, relay E, closed contact Ico, line b, line battery. The relay E by closing the switch or contact e causes the relay Y to respond. The relay Y reverses its contacts yl to g4. Through the contacts y1 and '1 2 the driving motor M is connected to the supply N and thus the main transmitter started. Through contact ya there is energized the stepping magnet'D which moves` the signal transmitter, designed as a dial selector, forward by one step. ya is designed as a follower contact and in the attracted stateof ys D would have been deenergized again if the relay J had not been simultaneously energized f through contact .g/i and had not closed the con-l tact z'. The relay Y has a time lag and remains permanently attracted during the return sig- 'naling as well as during the entire trafIic since it cannot be made to drop off by the short interruptions of the contact e.l

When the stepping magnet D is attracted the contact d is closed and the tripping magnet A made to respond. The blank letter key BT,'for instance', is thusy pulled down l and the control shaft released for one revolution. cois open so thatl D is deenergized and the contacts cl to 765 close in succession. One group of current impulses is then sent into f the line, in correspondence with the combination set up at the contacts of the dial selector. As soon as the revolution is completed the contact ko closes so that the relay J -is energized anew and causes the stepping magnet Dto respond again. The stepping magnet D advances the Contact arms Z0-d3 115 by a further step and causes the control shaft to revolve as before, for instance by operating the blank letter key BT. In this way the current impulse combination corresponding with the signs to be returned are sent into the line until the dial selector has attained its last step infront of the starting position. In this position the contact arm do short circuits the relay J across the contact f so that i remains open and thel stepping .125 magnet receives no further current impulses. The return signaling is now finished and the ordinary traffic can commence.

lVhen the transmission is finished the relay Y is made to drop ofi if the line of the During the revolution the contact 105 relay Y is permanently interrupted since the contact e of the receiving relay E remains open. The contacts y1 and y2 are opened again and the motor switched off. The follower contacty3 is closed fora short time so that the stepping magnet receives a last impulse and advances its contact arms iO-d5 into the starting position. u

In case of outgoing 4trafiic the switch S is reversed either automatically or by hand.

The relay Y is then energized across Sl and.

thus the driving motor M switched on. The contacts @/3 and g4 which serve for connecting'up the return signaling device remain, however, inoperative since the relay J is shortcircuited across the contact S2 of the reversed switch and the circuit for D was also interrupted by the contact S3.

Fig. 3 of the drawings illustrates a construction of the contacts k1 to h5. The contact spring 7c is during a certain part of the revolution of the control shaft moved into the closed position by a cam n mounted upon the shaft. This movement can, however, take place then only when the locking lever hr is located in the release positionlshown in the drawings. If, for instance, said lever is moved towards the left when the transmitter keyboard is operated, it locks the contact and prevents it from moving. The locking levers 7L, lone of Awhich is provided for each of the contacts c1 to 765, are reversed by keys in deiinite combinations during ordinary traiic. lVhen the blank letter,key is 'depressed, on the other hand, all the levers are in the release position. Since the correct working of the return signaling device clemands this position of the levers, t-he blankletter key BT must either be moved by a release magnet A, as shown in Fig. 2, or the reversal of the locking lever into the release position must be brought about by other means, for instance by a special rail, bar or lever which forces all locking levers back simultaneously and is adapted to be'operated by a magnet.

Fig. 4 of the drawings illustrates the system-of connection of an exchange for teleprinter systems with dial selector operation in conjunction with a return signaling device by which the name `of the town and the name of the called up subscriber is adapted to be indicated at the transmitter station. The transmitter consists of a controller shaft which revolves continuously and a cani shaft which is 'operated electro-magnetically. To each transmitter is apportioned a dial selector which sets itself automatically on the line called. The sequence --of the current impulses for the individual letters is con- I. trolled by a dial selector coordinated to each pre-selector. The number of the transmitters can be chosen according to the size of the oiice.

It may now be assumed that a calling sub- -After the line selector has set itself on the i called subscriber the following circuit for the Hl-relay and Tl-relay is established in the pre-selector of the called subscriber: ground, battery, P3-relay at the line selector, c-arm of the line selector, o-wire, Hl-relay, c-arm of the pre-selector at the calledfsubscribers station, Tl-relay, ground. i The Tl-relay connects the two lines through to the called subscriber with its contacts l .t1 and 2 tl. The Rl-relay of the call line linder responds in the following circuit: ground, contact 3 h1, contact 4 el, contact 5 @1, winding of the Rl-relay, battery, ground. Contact 6 rl closes and establishes a circuit for the stepping magnet D2 of the call finder: ground, delayed action circuit-breaker LUl, contact 6 r1, contact 7 p1, winding D2 of t'he stepping magnet, battery, ground. The retarded or delayed-action circuit breaker LUl energizes the stepping magnet repeatedly until the arm asl of the call finder encounters the dial lselector of the called subscriber. The following circuit is then established for the relays Pl and El: ground, battery, windings Land Il of the Pl-relay, arm asl of the call finder, winding of the El-relay, contact 3M, ground. The contact 461 interrupts the circuit for the Rl-relay, the contacts 7191 and the contact 61 disconnect the stepping magnet D2 from the time lag circuit breaker LUl; the contact 8d2 which responds every time the stepping magnet responds prevents a premature de-,energizing of the stepping magnet when the test relay is energized. The contact 9201 shortcircuits the high-resistance winding I of the Pl-relayd and thus blocks the call finder against a further engagement.

After the remaining arms as2 to L88 of the call findery have set themselves on the contacts to which is connected the dial selector coordinated tothe called subscriber, in the example illustrated the third contacts, a circuit is prepared for the stepping magnet D1 through the arm or wiper cs2 and the contacts 17 h1 and 12M. The control shaft StWl which revolves continuously, now operates the 'contact 16k by means of a cam whereby a circuit is completed for the stepping magnet Dl, viz.: ground, contact 16k, wiper as2, contact 17M, wiper dwl, magnet winding Dl, battery, ground. The dial selector performs one stepand remains on the contact reached next since the control shaft StlVl has meanwhile continued its rotation and has broken the contact 16k.

The control shaft then operates the contact 18k by a second cam. A circuit for the magnet M1 is then established, viz.: ground, battery, winding of the magnet M1, contact 1870, ground. This circuit operates by the aid of a clutch, not illustrated, the cam shaft los NWlwhich performs one revolution. The camshaft NlVl closes in succession the contacts 197s to 257e.l` The contact bank'of the dial selector D1 the contacts of which are directly connected to the negative or positive pole of a battery is wired in correspondence with the name and the town of the called subscriber. O ne letter consists of 5 different current impulses which are sent to the calling subscriber through the wipers 0h02 to (i106 of the dial selector D1 standing on the second Contact, the wipers of the call inderllasc to L88 standing on the third contact, contact 24rd and b-wire. The'rst letter consists in the example illustrated of thel current impulses: l -l. Apart from this a current impulse is sent both at the beginning and at the end of each letter, which impulse passes over the contacts 19k and 2570. After the cam shaft NlVlhas completed one revolution the slowly rotating control shaft StlVl closes the contact 16k and thus completes the circuit for the stepping magnet Dl afresh, the magnet Dl performs another step and again remains on the'contact reached after the control shaft has continued its rotation and opened the contact 167:. The sending of the impulse for the second letter takes place in the saine manner as described before.

l/Vhen the last letter has been dispatched the lll-relay responds across the last contact of the dial selector D1 in the following circuit: ground, winding of the lll-relay, Contact lkl, wiper or Contact arm (Z101, winding of the stepping magnet Dl, battery, ground. rlhe stepping magnet does not respond in this case owing to the high-resistance of the winding of t-he lll-relay. By means of the contact 241A the call finder is disconnected from the called line and by the contact 25rd the o-line to the called subscriber is connected through to the called subscriber so that the line becomes free for the transmission of the telegraphing impulses. Until the next connection is made, the call finder remains in the position attained; the dial selector Dl is turned back into its starting position by interrupting the circuit for the Ul-relay, after the calling subscriber has hung up land has thus caused the connecting gear to effect the release. rlhe stepping magnet Dl is made to respond again through the following circuit: ground, time lag circuit breaker LU2, contact 14M, wiper (Z101, winding of the magnet Dl, battery, ground, and performs a further step 'so that the initial position is attained again.

In the system illustrated in Fig. 5 of the drawings by which town and name of the called subscriber may likewise be given, the transmitter equipment at the exchange station as in Figa) consists of a control shaft continuously rotated, and a camshaft which is operated electromagnetically. The camshaft is, however, designed in such a manner that to each letter is apportioned a disk provided with corresponding cams, the disk being able to Connect the positive or the negative pole of a battery to the transmitting de- Vice. To each pre-selector Vl/V is apportioned a dial selector, as in the embodiment described above, the control of which takes place across its own contact arm or wiper while the connection to the called line is effected across its second wiper. By a corresponding connection of the individual contacts of the second bank of contacts of the dial selector to the contacts operated by the camshaft the correct sequence of letters is obtained for each subscriber. s

If a ycalling subscriber has established a connection the H2- and T2-relay in the preselector VW of the called subscriber responds, as in the arrangement according to Fig. 4 of the drawings. Simultaneously a relay not shown in the drawings is. energized wh-ich closes its contact 2151'. By means of a cam, the control shaft Sil/V2 operates contact 2067s and completes the following circuit for the stepping magnet D3 of the dial selector: ground, contact 20670, contact 2 05t2, wiper (Z107, winding D3 of the stepplng magnet, battery, ground. The magnet moves a step forward and remains stationary on the contact reached since the control shaft has continued its revolution and has again opened the contact 20670. l

The control shaft then operates the contact 207k by means of a second camand comple-tes the following circuit for the magnet M2: ground, battery, winding M2, Contact 207k, ground. lhe magnet M2 throws 1n a suitable clutch and4 thereby causes the camshaft N`W2 to perform a revolution. Across the plus or minus pole, contact 209/0, which is closed by the cam of the letter wiper (Z108, which in the example assumed would stand on the second contact, -line, the series of current impulses of the first letter is sent over the wire to the calling subscriber. rlhe sending of the further letters takes place in the above described manner after the Contact 206k has been closed again by the control shaft. After the last letter has been dispatched the dial selector performs a further step and remains stationary on the last contact since the opened Contact 204712 has interrupted. the circuit to the time lag circuit breaker LUS. Across the wiper zZ/w8 of the dial selector, the last contact of the dial selector, Contactl 2157', contact 213t2, subscriber N2, contact 21422, the line is connected through to the called subscriber and is thus ready for the transmission of the telegraphic impulse.

After the completion of the transmission the connecting gear, such as pre-selector, group selector, line selector are tripped in the usual manner by the calling subscriber hangin conjunction with a relay chain.

ing up his instrument whereby the circuit for the T12-relay in the pre-selector of the called subscriber is broken. The I-I2-relay drops ofi" and connects with its Contact 204712 the time lag breaker LU3 to the stepping magnet D3 ,which makes another step forward and thus returns into the starting position.

In Fig. 6 a further modification of the system is illustrated in which town and number of the called subscriber is reported back to the caller. The central transmitting equipment consists again of a control shaft and a camshaft, the latter with V11 cams, appor- ,tioned respectively to the name, the town and the figures 0-9. The connection to the called line as well as the correct sequence of the figures is obtained by a lift rotary selercltor he number of the lift rotary selectors depends upon the traiiic which the exchange has to handle, but for each group of 1000 subscribers at least one lift rotary selector is necessary. The selection of an idle lift rotary selector is effected by dial selectors with preidjustment apportioned specially to each It may now again be assumed that a calling subscriber sends current impulses in the usual manner across pre-selectors and group selectors for setting the line selector to a desired subscriber line. In the line selector the A3-relay is thus energized by current impulses. p

The rotary selector with pre-adjustment which in a fairly large exchange may, for instance, be located in the 7th hundred of the 8th thousands group, is already set to connect with an idle lift rotary selector since its turning magnet is permanently energized across earth, battery, winding D4, contact 304253, contact 305t3, locking key SpTl, relay WK3, ground. During each 'response of the stepping magnet the contact 306d4 completes a circuit for the relay T3, viz. ground, battery, winding I of the T3-relay, Contact 306d4; locking key SpTl, WK3 relay, ground. The T3-relay interrupts with its contacts 304t3 and 305t3 t@ circuit for the stepping magnet D4 whereby contact 306d4 1s opened and the T3-relay caused to open again. The contacts 304153 and 305153 close the circuit for the stepping magnet D4 afresh. The magnet responds and takes a step forward. This cycle is repeated until the Wiper cia/)15 of the rotary selector encounters an idle lift rotary selector and completes the following circuit: ground, battery, winding II of the T3-r-elay, locking key SpT2, wiper`dw15, Contact 30704, head contact 30870, ground. The T3-relay is energized and finally arrests the stepping magnet by opening the contacts 304253 and 30553. By closing the contact 309153 the @-Wire is connected through between the group selector and the line selector.

tery and ground, in order to prevent a response of the stepping magnet D4. This is necessary since in the above circuit the-C3re lay in the line selector also responds and energizes the (E4-relay of the lift rotary selector across the following circuit: ground, winding of the (I4-relay, wiper 51014, contact 31503, contact 316103, resistance W3, battery, ground, which relay opens its contact 30704. The winding II of the T3-relay would then become dead and due to the dropping of the contacts 304zf3 and 305253 complete anew a circuit for the stepping magnet D4. The relay C3 connects itself with its contact 51103 in the following holding circuit: ground, P4-relay in the group selector, c-arm of the group selector, winding III of the 'T3-relay, contact 309133, 0-wire, Winding I of the C13-relay, contact 31163, resistance `W2, battery, ground.

By the response of the A3-relay in im-A pulses owing to the current impulses sentout by the calling subscriber there is effected the setting of the line selector on the desired subscriber line. If the subscriber line is idle the P5-relay in the line selector is energized and with itso contacts 301195 and 302295 connects through the two connecting lines; by closing the contact 317725 a circuit is prepared for the Kl-relay.

By the response of the A3-relay in the line selector the A4-relay coordinated to the lift rotary selector is likewise energized in impulses across: ground, contact 303a3, wiper cl'w9, winding of the 14A-relay, battery, ground. In this way the lift rotary selector is adjusted in the same manner as the line selector on the contact. corresponding with the number of the called subscriber. The circuit for the lift magnet of the lift rotary selector is then as follows: ground, battery, winding H3 of the lift magnet, Contact 32611;, contact 325u4, winding of the VS3-relay, contact 319a4, Winding of the relay VVK/l, ground. The V-3 relay being a time lag relay remains energized during the sending of impulses and prevents a premature response offthe stepping magnet D5 by opening its contact 321v3. After transmission of the first series of impulses the V3-relay is shortcircuited by the Contact 318a4, it drops o and completes a circuitfor the U4-relay, viz.: ground, winding of the WK4-relay, head contact 32070, which has closed during the first lift step ofthe lift rotary selector, contact 321/03, contact 32204, winding I of the Uli-relay, Contact 32610, Awinding H3 of the lift magnet, battery, ground. The lift magnet does not respond in this circuit owing to net, battery, ground.

The V3relay again remains energized durlng the transmission of the impulses and closes a holding circuit for the U4-relay Y across ground Contact 328u3, contact 327%4,

Winding II of the Uli-relay, battery, and ground so that the Uli-relay is likewise unable to drop open during the sending of impulses.

After the transmission of the impulses and the testing of the line selector for an idle subscriber line is linished,a circuit for the relay K1 is prepared by the contact 317375, as already mentioned; the control shaft StI/V3 Which is continuously rotated closes by the aid of its cam y1 this circuit across: ground, contact 353s, Winding I of the Kl-relay, wiper (71013, contact 317 p5, contact 316u3, resistance 73, battery, ground.

. The relay K1 connects itself across ground, contact 351705, Contact 342701, Winding II of the Kl-relay, battery, ground in a holding circuit so that it remains energized during the entire duration of the call answer after it has once responded, like the remaining relays of the chain of relays. rIhe control shaft SV3 now continues to revolve and establishes by mcans'of a cam af, which closes the contact 352s, the following ci'rcuit for the magnet M3: ground, battery, winding of the magnet M3, contact 352s` and ground. This magnet causes the -camshaft NIV3 to perform a complete revolution by means of a clutchv not shown in the drawings.

By means of the cam which corresponds with the name of the town of the called subscriber and which connects the positive or the name of the town are thus sent out along the following circuit: positive er negative pole of the battery, contact 358s, contact 331702, contact 329701, contact arm (71011, contact 369u3. contact 302125, b-Wire to the receiver of the calling subscriber. After the camshaft NW3 has completed a revolution the Cam/2 of the control shaft SWS closes the contact 354s and thus the following circuit for the relay K2: ground, contact 354s, contact 338701, Winding I of the relay K2, battery, and ground. The relay K2 connects itself across ground, contact 347701, contact 343702, Winding II of the K2-relay, battery, ground, in aholding circuit. The control shaft StWB, continueslto revolve and again closes by means of a further cam w the above described circuit for the release magnet M3,

which brings about a second revolution of the camshaft NW3. Let us assume that the subscriber called has the number 8719. Since the lift rotary selector, as assumed is situated in the group of the 8th thousand, the 8th contact bank designating the figure 8 ofthe one contact set, the contacts of which are connccted With one another, can be firmly connected t-o the contact 332703. During the second revolution of the camshaft NW3 the cam coordinated to the figure 8 closes the following circuit for sending out the current impulse corresponding to thisl number, viz.:

positive or negative pole of the battery, contact 329701, contact arm dwll, contact 369103, contact 302295, b-Wire to the receiver of the calling subscriber.

The contact series corresponding to the number 7 cannot be connectedv to adelinite contactl like the thousands number because in this case a special lift rotary selector would be necessary for each hundreds group.

This series of contacts is for this reason con` nected by the rotary selector arm 12 With the respective hundred to which the rotary selector is coordinated. The contact arm 71016 belongs to a rotary selector, not shown,

Relay K3 connects itself into a holding cir-4 cuit across ground, contact 348702, Contact 344703, Winding II of the relay K3, battery, ground. The cam 00 of the control shaft SLVV3 controls the release'magnet M3 and again causes a revolution of the camshaft N`W3. The circuit for current impulses corresponding With the number'7 which the corresponding cam fof the camshaft NW3 connects to the change-over contact is as follows :positive or negative pole of the battery, contact 333703, co-ntact 330702, contact 329701,

contact arm 71011, Contact 369173, contact 30229-5, ZbWire to the receiver of the calling subscriber. rI`he issue of the tens and units of the number of the called subscriber is obtained by a coordinate-like wiring of the' contacts of the lift rotary selector.

In the contact set designating the tens the contacts are Wired in horizontal rows, in the second contact set, o n the other hand, which designates the units, in vertical rows. To each of the Wired Contact rows is coordinated a number from 07 to 9 respectively and connected to the respective change-over contacts 359s to 368s operated by the cams of the camshaft NW3.

Since the arms of the lift rotary selector contact 351765.

already stand on the contact corresponding to the number of the called subscriber, in the example assumed on the 9th Contact of the irst decade, the following circuit is established for the issueof the tens number after the control shaft StV3 has energized by its cams y 4 and the relay K4 and the release magnet M3, respectively, viz.: positive or negative pole of the battery, change-over contact 368s, vertical row of contacts 1, horizontal row of cont-acts 1, contact 9, contact arm g1 ofthe lift rotary selector, contact 336705, Contact 3357u4, contact 333763, contact 33072, contact 329761, contact arm (71011, contact 369u3, contact 302125, h-wire, to the receiver of the calling subscriber. For the release of the unit number, after the control shaft StlV3 has again energized the relay K5 and the magnet M3 by the cams ?/5 and respectively, the circuit is as follows: positive or negative pole of the battery, contacts 360s, vertical row of contacts 9, contact arm g2 of the litt rotary selector, contact 337765, contact 335704, contact 33373, contact 3307c2,con

tact 329701, contact arm d'w11, contact 369103,.

contact 302225, 7 wire t0 the receiiger of the calling subscriber. This completes the call return or answering of the name of the town and the number ot the called subscriber.

When the relay K5 responds the holding circuit for the relay -Kl is broken by the The relay K1 drops off with time lag so that the last ligure is still issued with certainty. By the release of the relay K1 there is initiated the stepwise drop of the relay chain K1 to K5 by the contact 342761 opening the holding circuit for the relay K1; relay K1 drops ott and opens through contact 347701 the'holding circuit for the relay K2, the latter drops oit and opens the holding circuit for relay K3 and so on until relay K5 drops oil and the chain of relays is thus deenergized again. When the relay K5 re- -sponds the relay K1, being a time lag relay, does not drop otf at once; in this way the following circuit is completed for the relay U3 in the line selector LW: ground, Contact 371765, contact 370761, Contact arm (Z1010,- winding I of cthe relay U3, head contact 3137s, resistance 72, battery, ground. The relay U 3 responds and on the one hand switches the b-line through to the called subscriber by closing its contact 373u3 and on the other hand disconnects the rotary selector from the connecting line. The line is now ready forthe transmission of the telegraphic impulses. For the relay U3 the following holding circuit is completed: ground, winding 1I of the relay U3, contact B14/a3, head contact 31370, resistance W2, battery, and ground. The contact 316173 has opened the circuit of the relay C4, relay C4 drops open and closes the contact 307 c4. The stepping magnet D5 of the lift rotary selector is again energized by the dropping of the contact 32304 along the following circuit: l

ground, winding of the relay WK4, head contact '32070, contact 321/03, Contact 32304,

contact 374%, winding D5 of the steppingn4 magnetLbattery, and ground.

The contact 37 3675 is closed in consequence of the attraction of the stepping magnet D5 and establishes a circuit for the relay U4, viz.: ground, Contact 373675, winding Il of the U4-relay, battery, ground. Contact 374274 then opens againfand interrupts the circuit for the stepping magnet. rlhe stepping magnet D drops ott and interrupts the circuit for the relay U4, whereupon the said -magnet D5 is again energized across the ing telegraph transmitting and receiving `mechanisms at each of the stations, a central oiice, means at said otlice for establishing connections between said subscribers stations as desired, and automatic means operating on extending a connection to a desired station for sending back to the calling station signals which characterizel the desired sta-- tion, said automatic means being arranged to operate said receiving mechanism at the calling station.

2. In a printing telegraph exchange system, a plurality of subscribers stations, printing telegraph transmitting and receiving mechanisms at each of the stations, a central otlice, means at said otlice for establishing connections between said subscribers stations as desired, and automatic means operating on extending a connection to a desired station for sending back to the calling station signals which characterize the desired station, said automatic means consisting of a stepping mechanism adapted to produce groups of impulses for operating said receiving mechanism at the calling station.

3. In a printing telegraph exchange system, a plurality of subscribers stations, printing telegraph transmitting `and receiving mechanisms at each of the sta-tions, a central oiice, means at said office for establishing connections between said subscribers stations as desired, and automatic means operating on extending a connection to a desired station for sending back to the calling station groups of impulses which characterize the desired station, said automatic means consisting of a selector-,like stepping switch whose bank conimpulses.

4. In a printing telegraph exchange system, a plurality of subscribers stations, printing telegraph transmitting and receiving mechanisms at each of the stations, a central oiiice, means at said oice for-establishing connections between said subscribers stations as desired, and automatic means which upon the extension of a connection to a desired station will produce groups of impulses characterizing the desired station for operating said receiving mechanism at the calling station, said automatic means'comprislng a se- Jlector-like stepping switch whose contact bank is wired according to said groups of im` pulses, and a printing telegraph transmitting mechanism whose contacts are connected with' the wipers of said stepping switch.

5. In a printing telegraph exchange sys.-

tem, a plurality of subscribers stations, printing telegraph transmitting and receiving mechanisms at each of the stations, a central office, means at said oiiice for establishing connections between said subscribers stations as desired, and automatic means which upon the extension of a connection to a desired station will produce groups of impulses characterizing the desired station for operating said receiving mechanism at the calling station, said automatic means comprising a selector-like stepping switch whose contact bank is wired according to said groups of impulses, and a printing telegraph transmitting mechanism whose contacts are connected in series with the corresponding wipers of said stepping switch.

6. In a vprinting telegraph exchange system, a plurality of subscribers stations, printing telegraph transmitting and receiving mechanisms at each of the stations, a central oiiice, means at/said office for establishing con- ,y nections between said subscribers stations asffp/l desired, and automatic means comprising a stepping mechanism. land a printingy telegraph transmitting( chanism whose contacts are connected 'wv ylteach other, which mea-ns, upon the extension'of a connection to a desired station, will produce grqups of impulses characterizing the desired station for operating said receiving mechanism at the calling station, the stepping-on of said stepping mechanism and the rotation of said transmitting mechanism being dependent upon each other.

7. In a printing telegraph exchange system, a plurality of subscribers stations, printing telegraph transmitting and receiving mechanisms at each of the stations, a central oiiiee, means at said olice for establishing connections between said subscribers stations as desired, and automatic means comprising a stepping mechanism and a printing telegraph transmitting mchanism whose contacts are connected with each other, to prothe stepping-on of said stepping mechanisml being effected by a contact which is controlled by said transmitting mechanism.

8 In a printing telegraph exchange system, a plurality of subscribers stations, printing telegraph'transmitting and receiving mechanisms at each of the stations, a central office, means at said oiice for establishing connections between said subscribers stations as desired, and automatic means comprising a stepping 'mechanism andl a printing telegraph transmitting mechanism whose contacts are connected with each other, to produce, upon the extension of a connection to a desired station, groups of impulses `characterizing the desired station for operating said receiving mechanism at the calling station, said transmitting mechanism consisting ofV a plurality of contacts and a common cam spindle controlling them..

9. In a printing telegraph exchange system, a plurality of subscribers stations, printing telegraph transmitting and receiving mechanisms at each of the stations, a central oiice, means at said office for establishing connections between said subscribers stations as desired, and automatic means comprising a stepping mechanism and a printing telegraph transmitting mechanism whose contacts are connected with each other, to produce, upon the extension of a connection to a desired station, groups of impulses characterizing the desired station for operating said receiving mechanism at the calling station, contacts, a common cam spindle controlling said contacts, and a continuously revolving control '),/',l/,Q y,In a' printing telegraph exchange systenta/f` la plurality of subscribers stations, printing telegraph transmitting and receiving mechanisms at each of the stations, a central oflice, means at said oiiice'for establishing connections between said subscribers stations as desired, and automatic means which, upon the extension of a connection to a desired station, will produce groups of impulses characterizing the desired station for operatingl said receiving mechanism at the calling station, the operation of said automatic means being effected when engaging the desired station.

11. In a printing telegraph exchange system, a plurality of subscribers" stations, printing telegraph transmitting and receiving mechanisms at each of the stations, a central o iiice, means at said oiiice for establishing connections between said subscribers stations as desired, and automatic 'means which, upon the extension of a connection to a desired station, will pro'duce groups of impulses characterizing the desired station for operating said receiving mechanism at the calling station, the operationof Vsaid automatic means being effected by means of a relay becoming operative when engaging the desired station. e 12. In a printing telegraph exchange system, a plurality of subscribers stations, printing telegraph transmitting and receiving mechanisms at each of the stations, a central oice, means at said ollice for establishing connections between said subscribers sta- 4 tions as desired,and automatic means which,

upon the extension of a connection to a desired station, will produce groups of impulses characterizing the desired station for operating said receiving mechanism at the calling station, said automatic meansbeing arranged at said central oliice.

13. In a printing telegraph exchange system, a plurality of subscribers stations, printing telegraph transmitting and receiv- 1 ing mechanisms at ,each of the stations, a

central olice, means at said olce for establishing connections between said subscribers stations as desired, and automatic means which, upon the extension of a connection to a desired station, will produce groups of impulses characterizing the desired station for operating said receiving mechanism' at the calling station, said automatic means being arranged at said central olice and assigned to a plurality of subscribers stations.

14. In a printing telegraph exchange system, a plurality of subscribers stations, printing telegraph transmitting and receiving mechanisms at each of the stations, a central oice, means at said oiice for establishing connections `between said subscribers stations as desired, automatic means at said office for producing, upon the extension of a -connection to a desired station, groups of impulses characterizing the desired station to operate said receiving mechanism at the calling station, and automatic contact devices for cutting through said connection to the desired station after the answer back is inished.

15. In a printing telegraph exchange system, a plurality of. subscribers stations, printing telegraph transmitting and receiving mechanisms at each of the stations, a central office, means at said office for establishing connections between said subscribers stations as desired, a plurality of automatic devices at said oliice for producing, upon the extension of a connection toa desired station, groups of impulses characterizing the desired station to operate said receiving mechanism at the calling station, and yselector switches for automatically lswitching onto said connection an idle one of said automatic devices.

16. In a printing telegraph exchange system, a plurality of subscribers stations,

' printing telegraph transmitting and receivthe operation of said selector switches being effected by a relay becoming operative when engaging the desired subscribers line.

17. In a printing telegraph exchange system, a plurality of subscribers stations, printing telegraph transmitting and receiving mechanisms at each of the stations, a central oiiice, means at said office for establishing connections between said subscribers stations as desired, and automatic means at said oiiice for producing, upon the extension of a connection to a desired station, groups of impulses characterizing the desired station to operate said receiving mechanism at the calling station, said automatic means comprising a plurality of stepping switches each of which is assigned to, and has its contact wired inaccordance with, one of the subscribers stations, a plurality of transmitting mechanisms adapted to generate groups of impulses for operating the printing telegraph receiving mechanisms at the subscribers stations, and a plurality of selector switches each of which upon the extension of said desired connection, automatically connects an idle one of said transmitting mechanisms with that of said stepping switches which is assigned to the desired station.

18. In a printing telegraph system, a plurality of subscribers stations, printing telegraph transmitting and receiving mechanisms at each of the stations, a central office for establishing connections between L. said subscribers stations as desired, and automatic transmitting means operating on extending a connection to a desired station for sending out to a calling subscribers station a predetermined series of impulse combinations characterizing a called station, said automatic transmitting means consisting of signal producing means representinyen a series of impulse combinations in a fixed fo m, and of'distributing means for sending. out said impulse combinations in identical manner corretures.

AUGUST JIPP. t EHRHARD ROSSBERG. FRANZ SIMON. ALFRED SCHEUNERT. WILLY SKAWRAN.

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