DE767334C - Circuit arrangement for control switchless line selectors in telephone systems - Google Patents

Description

ISSUED MAY 29, 1952

RE I'S PATENT OFFICE

PATENT LETTERING

CLASS 21a ³ GROUP 2820

S 143382 Villa / 21a ³

. Walter Mai, Berlin-Siemensstadt and Franz Etzel, Berlin-Frohnau

have been named as inventors

Siemens & Halske A. G., Berlin and Munich

(Ges. V. 7/15/51) Grant of patent announced on March 20, 1952

In telephone systems with dialer operation, it is often necessary to use number current surges through the look-through corrcts of a line dialer, eg. B. switching arms and bank contacts to pass on to subordinate, in the same office as the line selector or in another office, such as a sub-office, located number stream tioßemp receiver ei η to s tel len.
■ After the number surge receiver (s) subordinate to a line selector has been set, the line selector sometimes still records number current surges caused by the caller in error or by playing on the surge transmitter, which are then also transferred to the busy connection line to be continued. In many cases, the transmission of these number current impulses has no or no serious consequences, ζ. B. when the surge receiving device, e.g. B. the drive magnate, des

last Xu m m ernst rom bump e nip catch rs so fο rt is switched off after its setting; In other cases these cause nervous surges, if no shutdown of the Shock receiving device takes place after dialing the number, only one caused by the calling subscriber himself Incorrect connection if the connection line reached is free or disconnected can be determined.

In other systems, however, the transmission can take place after the connection path has been established from number trumpets to those from the line selector occupied connection line Ixachtliche Have consequences, is z. B. the last number surge receiver in one only with the setting elements of the voter and a few relay-equipped sub-office and will be checking whether an elected Connection line is free or occupied in the office in which the line voter is includes. carried out by a follower, so can transferring the subsequently recorded Xummer thrusts on the Liaison lending to the cancellation of the conversation to lead. That is the case when the follower from operational engineering and for economic reasons, it is switched off immediately after dialing the number and checking and -lie metallic veins be switched on. A subsequent sequence of numbers transmitted to the connection line then adjusts the last number stream stopper again. If the connection is reached, but occupied, so the calling subscriber is switched to the existing connection.

A line selector with a control switch is known, through whose switch arms Xummer current surges to hire a voter in one only via a single training line connected sub-office. Participants in this sub-office can there is intercourse between the subscribers is not provided. when the connection line to this sub-office is occupied not be occupied. After setting the number current receiver In the sub-office, the Stromstoriempfangsrelais is switched off by switching the control switch, see above that further power surges in the line selector are no longer recorded and therefore also cannot be transferred to L'nteramt.

There is also a control switchless line selector known in which a Core of an occupied connection line leading to a number current surge receiver a relay is energized, which the Rmanssendung prevents and further the surge transmission circuit closes. This relay is activated by disconnecting the potential on the connection line " or to the subordinate voter ineffective, if this is set.

The object of the invention is in a control switchless Line voter the transmission of number stream impulses to a J> elegte Connection line. after the numbered surge receiver (s) subordinate to the line selector have been assigned, to prevent, without influencing the control relay of the line selector through Switching means on the connection line or a downstream number surge receiver. This is achieved by the fact that after choosing the code number for a \ * erkehrsrichtunsj. in which the line selector at least one additional number surge receiver is subordinate, the current surges on the line selector relaying circuit and the circuit of the l> ei each Recording of series of current impulses in the line selector to be energized control relays of two parallel contacts are dependent. of which the one of one of the choice of named code number to switch the line selector, but when one becomes effective relay switched off to be passed on and the other relay from Control relay is controlled by itself.

The invention is a from the operational Point of view from ■ flawless system created in which the Number of special relays, which the control switchless line selector for Implementation of the special operating conditions that occur when connecting to downstream Number stream outgoing shock receivers Blocking lines on the line selector occur, - toggle, not yet increased by further relays, which the Prevent transmission of number power surges after dialing is finished. The number of control relays on control switchless ones Keeping line voters as small as possible is very important, not only for economic reasons, but also to increase the size of the line selector frames to avoid enlarging the relay sets.

Due to the inventive arrangement will the Weitergalx also? of number flow surges on the occupied connection line also avoided in cases in which er / oiyt a shutdown of the surge receiving relay in the line selector. However, this shutdown only takes place after a waiting period in which viii possible Waiver of the caller affects the established connection. The Strömst.-iJempfan ^ srdai.-. is only then settled

switches when the call of the selected subscriber is initiated after the waiting period has expired will.

The invention can be applied to all line selectors without control switches, be it> Rotary selectors, lever-operated rotary selectors, rod selectors, relay selectors, etc. can now be used. Since the Control of the two 'circuits takes place locally in the line selector, is the application

to the invention further independent of the equipment and circuit of the weiterf leading connecting lines and the downstream Number surge receiver.

The impulse transmission circuit and the circuit of the control relay can each be controlled by a pair of contacts. A complete ¹ separation of the two circuits is then achieved. Both circuits can, however, also run over one and the same contact pair. In terms of behavior, both circuits are not completely separated if a common series resistor is used for them, but an inadmissible influence on the current surges to be passed on by the control relay is then avoided by suitable dimensioning of the common series resistor. This arrangement is advantageous when both or one of the relays controlling the contact pair is already heavily loaded.

In Fig. 1 are a line selector and

Switching means on a connecting line to a downstream voter, as far as it is necessary for understanding the invention ¹ , shown.

Fig. 2 shows a further embodiment of the invention. Only that is shown Part of the circuit of the line selector, which changes with respect to FIG.

When the line selector » LW ^- 1 is occupied by a group selector upstream of it, the occupancy relay C 1 is energized: + in the occupying group selector, contacts ici, 2 k (head contact of LWi), winding I of relay C 1, -. The relay C 1 opens, among other things, the contact in and closes the contact c 1. The winding I of the relay Ci is now independent of the head contact 2 k on the incoming occupancy wire.

To set the line selector LW 1 , + is applied to the upper speech wire at an upstream point on the connection path during the transmission of each current impulse, thereby energizing the StromstoBempfangsrelais E 1: + at the previous position of the connection path, upper Spreehader, contacts. 5 s, 6 g 1, relay E 1 winding I, -. The relay: E 1 transmits these current impulses to the lifting magnet HIw 1:

+, Contacts 7 e 1, winding I of relay V 1, contacts S it 1, 9 m 1, 10 w (shaft contact of LW 1), lifting magnet HIw 1, -. While the line selector LW 1 is a hasty part *, the relay V 1 keeps its armature attracted because it shorts its winding III by closing the contact iiwi: +, contacts 11 ν I ₁ 12 g i, winding III of the relay V i, -) -, and thus receives anchor dropout delay.

After completion of the group selection and prolonged opening of the contact J e ι , the relay V 1 drops out. The reversing relay U 1 responds to: +, contacts 13 k (at the 1st stroke of the line selector, closed), 14 c 1, 15Wj 16 ν i, relay Ui winding ι, -. By opening the contact 8 u 1, the lifting magnet HIw 1 is switched off and the rotary magnet DIw ι at contact 17 u 1 is brought under the influence of the impulse contact 7 e ι. After receiving the first current impulse in the next row and opening the contacts 15 w and i6wi, the relay U 1 is kept excited via its winding II: +, contacts, 13 k, 14 ei, 18 u i, 19 ^ 1, winding II of the relay U i, resistance 20, -. After the end of the StromstO'ßgabe relay V 1 drops out.

Assuming that the individual subscriber Tn 1 directly connected to the line selector is selected. The closing of the test circuit in the line selector is delayed for a short time (waiting period) in order to avoid a call from the selected subscriber if the calling subscriber should hang up his handset immediately after dialing the number and thus forego the connection.

Some time after the contact 16 vi is closed, the relay G 1 receives a current surge from the slow breaker LU ι: +, slow breaker LU 1, winding I of the relay) G i, contacts 22 s 1, 23 ^ 1, 24 a », 16 ν i , Winding I of relay U 1, -. -The relay G 1 opens, among other things, the contact 4 £ 1 and thereby puts its own winding II and the winding II of the relay .S "1 in series with the winding I of the relay C ι in the incoming assignment wire. At contact 6 g 1 the winding is I relay e 1 off and it created the inductor Dr 1 to the upper intercom wire via contact 47 g 1. From the calling party sent out by mistake or by playing on number switch power surges now have no influence on the line selector. the relay g 1 is hooked. The relay Si responds. The excitation circuit is interrupted at contact 22 s 1 via winding I of relay G 1. The test circuit is closed at contact 25 s 1 , and the test circuit is opened at contact 19 ι of the holding circuit for the relay U1, whose

Winding II is short-circuited at the same time at contact 26 ί ι. As a result of this short circuit, the relay U 1 receives a strong drop-out delay.

When the selected subscriber line is free, the test relay P 1 responds to: +, contacts 13 k, 14 t · i, 18 α ι, 25.S ¹ I, windings I and II of the relay Pi. Test arm and test contact of the line selector, isolating relay T 1, -. The relay P 1 blocks the selected line by closing its contact 28 /> 1: this is because · + is applied directly to its own low-resistance holding winding II via the contact 2Q α ι. A local holding circuit is established at contact 30 /> 1 via winding III of relay P 1: +, contacts 30 p i, 31.1-1, winding III of relay Fi, contacts 32, ·; ·, 33 c 1, Resistance 34, -. The speech wires are switched through at contacts 35 ρ ι and 36 / "1.

The drop-out delay of the relay U 1 is so strong that its armature is still in the work si age after the relay P 1 has responded. The first call is sent out. Relay E ί receives a current impulse from slow interrupter LU 2: +, slow interrupter LU 2, winding III of relay U 1, contact 3S u 1, winding II of relay E i. Contacts 36.1-1, 37 τ'1, 38 α ι, 39 g · i. 40 ρ i, rotary magnet Dki ' 1, -. The rotary magnet Dks 1 is not excited in this circuit. The contact 41 e ι is opened, and the contact 42 e 1 is closed. The call power source is applied to the upper voice wire.

After the end of the current impulse from the slow interrupter Lu 2 , the relays E ι and U ι drop off one after the other. By closing the contact 43 u 1, the winding II of the relay E 1 is connected to the wire leading to the call switch RS . The call switch RS puts in! »Agreed time intervals + on winding II of relay £ 1. So that this relay can respond and initiate the transmission of ringing current. If the selected subscriber answers, relay A 1 in the microphone feed circuit responds. It interrupts contact 38 α ι the circuit of the winding II of the relay e 1, turns on the. contacts 143 α ι and 79 ff the speech wires ι by, opens at the contact 29 a 1 the short circuit of the winding I of Zähleinleiterelais Z. which thus in series with the holding winding II of Re- 'Iais P 1 is placed, and by closing the contact 44 a 1 switches the winding II of the relay Z parallel to the winding II,'! Es relay F i. The relay Z is connected to the Gu contact 4 ^ ^ in a holding circuit is: +. Winding III of the relay Γ ι. Winding III of relay Z, contacts 45 z, $ 3 c 1, resistor 34, -. The relay V 1 responds. By opening the contact 5 ~ and closing the contact 46 ζ , the winding I of the choke coil Dr 1 is placed on the lower voice wire and the counting initiation criterion is thereby given. At the contact }, 2 ζ the winding III of the relay P 1 is switched off. j If the calling subscriber sends j after setting the line selector LW 1, but before the relay G 1 responds, i.e. within the waiting period mentioned above, further power surges erroneously or as a result of playing at the number switch. so the relay E 1 is actuated again.

The current surges are transmitted to the rotary magnet Dki ' ι, so the line selector is switched on, and the relay V 1 responds. At contact 16 ν ι the prepared excitation circuit for the relay (χ ι which marks the expiry of the waiting period when it responds) is opened. if the switching arms ülier the bank contacts are moved out by the additional current surges, triggered in a known manner, and the busy signal is switched on.

As already mentioned above, there are no problems some systems have much more serious consequences if the calling subscriber for connections that have at least one subordinate to the line selector Number surge receivers are running, after number dialing they still have power surges sends out.

Such a connection runs, for example, via the connection line VL 1 and the line selector LW 2 in the sub-office UA. After setting the line selector LW ι to the first contact of the contact group to which connecting lines to the sub-office UA are connected, the collective contact sku is closed. If the relay U ι drops after the end of the current impulse and closes the contact 67 ν ι, no, the relays M 1, S 1 and X 1 respond: +, contacts 6 ~ ν 1, sku. Winding II of relay J / i, contact 70; / 1, winding I of relay S 1, relay X 1, contacts 71 g 1, c I, resistor 34, -.

The relay M 1 closes the contact 72 m 1 lying parallel to the contact 70; / 1 and prepares a circuit of the rotary magnet DIw 1 at the contact 50 m 1.

The relay S 1 immediately closes the test circuit at contact 25 s ι, because after setting the line selector to one

Individual participant may not start waiting period after selecting the code of the sub-office UA , but only after setting the line selector LW 2. At the contact 22 s ι the excitation circuit is opened via the winding I of the relay G ι. At the contact 26 s 1, the winding II of the relay U ι is short-circuited. Contact 19 is opened. Since the relay X 1 responds somewhat delayed, ie the contact 27 χ ι only opens after some time, the relay U ι keeps its armature still attracted during the time required to test the first line going to the sub-office. If the first of the outgoing connection lines to the sub-office UA is free, the test relay P 1 responds, blocks, switches the speech wires through and opens the excitation circuit of the rotary magnet DIw ι at contact 21 p 1 before the relay U 1 drops out.

But if the connecting line is blocked, ^one of the line selector LW 1 seeks an idle trunk with high pace. The relay U 1 is used as a current impulse generator, which opens the test circuit when it opens the contacts 19 s 1 and 27 χ ι th drop at contact 18 ul and closes the circuit of the rotary magnet Dhv 1 at contact 53 u 1: +, contacts 50 m 1, 53 u 1, 21 p 1, rotary magnet DIw ι, -.

The rotary magnet DIw 1 switches on the winding I of the relay U 1 at the contact 54 dim I, which at the contact 53 u 1 interrupts the circuit of the rotary magnet DIw 1, which drops out and the relay U 1 switches off. This drops off quickly and closes the circuit of the rotary magnet DIw 1 at the contact 53ti.i again. If the switching arms of the line selector LW 1 come to the contacts of the free connecting line VL 1, the test relay P 1 responds and opens the circuit of the rotary magnet DIw i at contact 21 ρ ι. The occupied connection line VL 1 is blocked at the contact 28 p 1 , and the voice wires are switched through at the contacts 35 p 1 and 36 p 1. At contact 30 ρ ι the holding circuit prepared at contact 73 χ ι for relay X ι is closed: +, contacts 30 p 1, 73 χ i, resistor 74, relay X 1, contacts 7 ¹ g ^x > 33 ^{c τ} > resistor 34, -.

In addition to the already described the relay X 1 has carried out in the following switchovers line selector LW 1: By opening 'of the contact closure of the local holding circuit is ι χ 31 have been prevented through the winding of the relay P III. 1 Both windings I and II of the feed bridge relay A 1 are switched off at the contacts χ i, j6 χ ι. At the contact T] χ τ the transmission of number current surges to the occupied connection line VL 1 is prepared by switching on the impulse contact 78 e 1.

On the connection line VL 1, the relays Y 2, Q 2 and Γ 2 in the test circuit are excited: +, contacts 13 ε, 14 c 1,

^{68 dlw τ} , 25JI, relay P 1, windings I 18 μ ι ' ^D ' ^s

and II, test switch arm, test contact, relay Y 2, contact 81 «2, relay Q 2 winding I, relay T 2 windings II and I, break contact and switch arm of the preselector VW 2, -. The relay T 2 performs the known Umschalturagen. Relay Y 2 switches the speech wires through to contacts 82 y 2 and 83 y 2 and, by closing contact 84 y 2 , prepares to determine whether the subscriber to be dialed is free or busy. The contact 85 q 2 lying parallel to the contact 81 η 2 is closed. At contact 86 q 2 , winding II of relay V 2 is switched on, and at contacts 87 q 2, 88 q 2, 89 q 2 , circuits are connected via relay A 2 winding I, relay P 2 or relay Q 2 winding II prepared.

The relays in the sub-office, which are not of interest in the present case, as well as on the connection line VL 1 in the main office, which, among other things, enable connections to be made by a subscriber of the sub-office, are not shown. ,

The connecting line VL 1 is assigned a switching mechanism ML 1 , which is set with a connection to the sub-office by the line selector LW 2 setting number current surges. In this connection, it acts as a follower. The switching arm 90 of this follower is used to determine whether the selected subscriber is free or busy after the last number of bursts has been sent.

The number current series used to set the line selector LW ^{2 transmits the relay 1} E 1 to the relay B 2 on the connecting line: -, resistor 150, contacts 151 si, 78 e 1, γγ χι, 36 p 1, switching arm and bank contact, contact 93 p 2, relay ¹ B 2, relay V 2 winding I, +. At the same time, relay V 1 in the line selector is also excited: +, contact 1 each , winding I of relay V 1, contact 153 .r 1, winding II of relay V 2, contact 94.1-1, lifting magnet HIw 1, -. The lifting magnet does not respond in this circuit. By opening the Kontalitee 67 ν ι drop the relays M 1 and S 1 in the line selector. But there are the current impulse transmission circuit through the parallel ztim contact 151 s 1 lying contact 152 ν ι and the circuit of the

Control relay V 2 is kept closed by ^{contact 154-C 1} I lying parallel to contact 153.'ι. The relay X 1 is in the circuit: -, contacts 30 p ι, 73 .ri, resistor 74, relay X 1. Contacts 71 ^ "1. SS c i, resistor 34, -.

The relay IJ 2 at the Yerbindungskkting VL ι transmits the current impulses to the rotary magnet Dkc 2 : - .. Contacts 95 p 2, üo q 2. 97 l> 2, S3 _v 2, lower Spreehader, rotary magnet DIv 2. Contact 155 // 2. Earth (_— >. At the same time, the follower ML 1 is set; because every time relay B 2 responds, the drive magnet DmI 1 at contact 9S b 2 is switched on.

After the first switching step of the follower, the relay X 2 is switched on via the switching arm 99, which opens the contact Si 11 2 in the occupancy circuit of the connection glue / 'Li. The contact 100 n 2 is closed. The relay J'2 receives drop-out delay because its winding Ii is short-circuited when the relay B 2 disconnected; fall and contact 101 / * 2 is closed.

Home first response of the Drehmagiieten Dnil i ι is on contact 102 Dall ι the _Wick-: lung I of the relay A 2 is turned on: -. Kon-! clocks N7 q 2, 103 p 2, 102 dml 1, relay A 2 j winding I, -. The contact 104 t; 'lying parallel to the contact 102 dy.il 1 2 is closed. Are also closed Kontakte105 a 2 and 107,172th open, the contact 100a of the contact 2. 1051/2 the counter II winding is applied the relay A 2 to the switching arm 90 of the follower. If, during the setting of the follower ML 1, the switching arm 90 leaches to the contact assigned to an occupied subordinate, current flows through the counterwinding II of the relay A 2. The relay A 2 then drops out temporarily. but this does not affect the completion of the connection that is being established. After the end of the series of rushes for setting the line selector LW 2 , the control relay V 1 in the line selector LW 1 and the control relay V 2 on the connecting line VL 1 drop. Before the latter drops, the relay A 2 determines whether the desired subscriber is busy.

The switching arm 90 of the follower ML 1! stand on the contact io'6: j

If the subscriber is busy, contact 10S is at contact - via switching means the one with dein

.j ?. selected subscriber in connecting connecting line I 'L 2: -K contacts- ^l] 116 ρ 2'. 117 ν 2 ', switch arm 118, contact ί iiy. Wire 120, contactless. The relay A 2 \ is thrown off by counter currents and conducts:

6u the release of the Yerbindungskitung VL ι ; one, which is not of interest here. ,

If the selected participant is free, there is no potential at contact 10N. About the counter winding J Γ of the relay. I 2 iiiei.lt therefore no current, so that the Re- ■ ais_-i2 remains excited. X When relay V 2 drops out and the toy contact closes, relay P 2 is energized: -. Contact 109; · 2. 10702, relay P 2, contact SS q 2. -. At the contact 110 p 2 , the Gegencnwickking II of the relay. -J 2 switched off by the switch arm tjo. By closing the contact 111 p 2 , ~ - is applied to the switching arm 00 as a blocking potential.

The contact \ 12p2 in the circuit of the counter winding II of the relay Q is opened. Opening the contact 93 p 2 disconnects the relay B 2 and the winding I of the relay V 2 from the lower voice wire. This voice wire is switched through at contact 113, -2. The relay / 2 is switched off by opening the contact 103 p 2 and drops out. The closing of the contact ioötr 2 after the closing of the contact 109 ν 2 has no influence on the state of excitation of the relay (J, since the contact H2 ρ 2 is open.

After the last number dialing is finished, the waiting period begins, during which the calling subscriber can still do without the connection without the selected subscriber being called. Since the connecting line VL ι is switched through metallic immediately after the selector IJV 2 has been set and the rotary magnet Dlz 2 is still on the lower speech artery in the lower arm UA 2, the line selector LIV 2 advance. A test of the subscriber line reached does not take place, however, since the follower ML ι has already been switched off in the main office. If the subscriber line reached is busy, the calling subscriber is connected to the existing connection, so the conversation security is not maintained.

Without the need for at least one special relay, the delay possible by dialing is prevented by immediately disconnecting the impulse transmission circuit in the line selector after the total number. The contacts 151, which operate in parallel, serve this purpose. i ~, 2 ζ- ι in the impulse transmission dry circuit and 153 ^ 1. 154: · ι in the circuit of the control relay Γι, which responds during each recording of Xummerustromstöfien in the line selector. The relay 5'1 is a relay which Txe-i selection of a communication direction. in which \ ^r onnectivity over the line selector demand

orderly selectors run, the line selector switches over to meet special operating conditions, because it closes the test circuit at contact 25 s ι immediately, not only after a waiting period, and switches off the Haltewickluhg II of relay U 1 at 19 s 1, so that this relay as Current surge generator can act. The relay ό * ι is switched off at the beginning of the current impulse transmission to the selector LW 2 by the control relay V 1 that responds with every recording © of number currents in the line selector. It then opens the contacts 151 s ι and 152 j i. If the relay V ι drops out and the contacts 152 ν ι, 154 ^ ι opens after the end of the passed number current impulse series and prolonged dropping of the relay E 1, no number current impulse recorded in the subsequent waiting period in the line selector ¹ LW 1 can influence the relay V ι and also cannot be transferred to the connection line.

After the waiting period has expired, the relay G 1, but not the relay U 1, responds when the slow interrupter LU ι is connected to earth. The relay G 1 switches back its own winding II and the winding II of the relay S 1 by opening the contact 4 £ ι in series with the winding I of the occupancy relay C 1 ammonium contact 71 g 1, the holding circuit equipped of with strong anchor fall delay Relay X 1 open. The following circuit of relay U 1 is established at contact 39 g 1: +, slow breaker LU 2, winding III of relay U 1, contacts 115x1, 37 ν ι, 38 a 1, 39 gi, 40 ρ i, rotary magnet DIw 1, - . The rotary magnet DIw 1 does not respond. By closing the Kbntaktes 35 u 1, the relay U 1 prepares the excitation of the relay E 1 via its winding II by means of a current surge from the low-speed interrupter LU 2. If the relay X 1 drops out, the relay E ι responds. The first call is sent.

It should also be mentioned that the connection λ'οη + by the slow breaker LU 2 only takes place after the contact 39 g "1 is closed and that the release time of the relay X 1 is such that it occurs after the contact 35 u 1 closes at a point in time drops, at which the earth which excites the relay U 1 is still connected to the low-speed interrupter LU 2 , so that this current surge also causes the relay E 1 to be excited.

If the relay U 1 drops out, the relay E ι is excited at certain time intervals by applying + via the call switch RS and applies the call current source. When relay X 1 drops out, the local holding circuit at contact 31x1 is closed again via winding III of relay P 1.

• Report to the desired party, the relay A 1 and U 2 speak to: Earth (+) Contact 155 u 2, relay U 2, shifting and bank contact of LW 2, telephone sets, bank contact and shifting of LW 2, upper wire of VL 1, contact ν 2, bank contact and switching arm of LW 1, contacts 35 ρ ι, 75 χ ι, winding I of the relay A i, contact 41 e 1, resistance; 150, -. the relay A 1 carries out the switchings already described. The relay U 2 switches! at the contact 156 μ 2 the lower wire of the connecting line VL ι and separates the contact 155 μ 2 earth (+) from this wire.

While in the exemplary embodiment shown in Fig. 1, the impulse transmission circuit is completely separated from the circuit of the control relay V 1, since each of these circuits has a pair of contacts connected in parallel (151 s 1, 152 ^ 1 or 153JI, 154W1), is in the arrangement according to FIG. 2 - on both circuits üibereiini and the same Kontali te 151 s 1, Vi. In spite of the fact that the two circuits are not completely separated, suitable dimensioning of the common ballast resistor 150 prevents distortion of the current impulses transmitted to the connecting line, which becomes noticeable in a disturbing manner.

Claims (3)

Patent claims: i. Circuit arrangement for control switchless line selectors in telephone systems, via which both subscriber lines directly and connection lines to downstream number current surge receivers can be reached, characterized in that, after the code number for a traffic direction (UA) has been selected, the line selector (LW 1) has another number current surge receiver (LW 2) is subordinate to the Sitiromstoß over the line selector (LW 1) passing circuit and the circuit of the control relay (V 1) to be excited with each recording of series of current impulses in the line selector of two parallel contacts (151 s 1, 152 ν ι; 153 s 1, 154 vi) are dependent, of which one of the line selector (LW 1) switching over after selecting the specified code, z. B. enabling the immediate test, but when the relay (S 1) becomes ineffective again when the relay (S 1) to be passed on becomes effective, and the other is controlled by the control relay (V 1) itself. 2. Circuit arrangement according to claim i, characterized in that the surge circuit and the circuit of the control relay (F l) run via separate pairs of contacts (151 J i, 152- ' ¹ I or 153 .τ i, 154Ϊ · 1; Fig. Ii . 3. Circuit arrangement according to claim i, characterized in that the Impulse circuit and the control relay circuit (F 1) have the same contact pair (151 ** 1. 152 γι, Fig. 2) run. To differentiate the subject matter of the invention from the state of the art, the granting process is in progress the following publication has been taken into account: German patent specification Xr. 645 375. 1 sheet of drawings O 5050 5.52