DE740991C - Circuit arrangement for telephone systems with double-directional sealed connecting lines - Google Patents

Description

Circuit arrangement for Ferrnsprechanlagen with bidirectional Sealed - Interconnection Lines The present invention relates to a posture arrangement for intercom systems with cordoned off in both directions usable connecting lines, over which the switching processes of the transmission at one end of the line through inductively generated direct current surges and from the Transmission at the other end of the line can be transmitted by alternating current surges the switching means in inductive transmission are opposite each other at the same time Participant @ ermel @ deimpuls enforcing the tripping current transmitted via the line from the opposite direction initially bridge to after the end of the alternating current surge to send out further triggering impulses.

For such systems, in order to secure the release of the connection, if the inductive trigger pulse is accompanied by a character arriving from the opposite direction, in particular the subscriber message pulse, which coincides in time, has already been proposed have been to provide switching means in the outgoing transmission, which on arrival of the participant's message immediately after initiation of the triggering bridge the duration of this feedback and then the transmission of the to trigger induce serving induction pulses. According to this proposal, in in this case always the subscriber signaling pulse transmitted backwards by the alternating current against an inductive trigger pulse transmitted in the direction of the connection establishment by; However, it is after the end of the alternating current return pulse in the inductive transmission the transmission of further inductive dissolving impulses is ensured.

The present invention provides improvement and improvement in several respects of the previous proposal. While the older proposal is up, it is up simply directed traffic and therefore only on the avoidance of disruptions, Which by running against each other of the backward subscriber message impulse and the forward Directed trigger pulse arise, this idea is according to the present invention extended to bi-directional traffic, in which apart from running against each other of the subscriber registration and triggering impulses as well as opposing of the occupancy impulses with simultaneous assignment of the connection line at both ends as well as one The S: chliu: ßzeichen.imp: tilses of the calling participant in Direction of the connection establishment and a release pulse running in the opposite direction the called point as well as a counter-running of the backward directional sign impulse of the called subscriber and this forward trigger pulse of the calling party Position is possible. In all of these cases, 'according to the invention is the basic one Thought this. Older proposal applied in such a way that apart from the participant avoidance pulse also the: occupancy pulse and end signal pulse, also transmitted by alternating current this calling or called subscriber to each other: one at the same time in enforce the inductive occupancy or release pulse transmitted in the opposite direction and when they are included in the inductive transmission, create holding circuits for relays, which. in the one case (occupancy) bring about a switching state, the one Release of inductive transmission without emission inductive: generated direct current surges and a repeated assignment (queries) by the one documenting office (civil servant) causes in the other case (final sign) a switching state for transmission : Another inductively generated direct current surge after the end of the alternating current surge bring about, The invention achieves the advantage over the proposal mentioned, that ria.ch does not report the called subscriber several inductive triggers: eimpuls: e, but only a single trigger pulse has to be sent out, as there is a penetration the trigger pulse: e on - opposite the line somewhat simultaneously in the opposite direction transmitted AC final signal pulses is no longer necessary.

Another advantage of the invention is in comparison with the aforesaid Suggestion still in that the bridging of the alternating current rrimpu, ls @ es in the inductive transmission not by the short circuit of a relay and thus by the indefinite fall time this relay is achieved, but by 'd.aß' the alternating current in the pulse its inclusion switches on the bridging relay in a hold circuit and thus the bridging in any case ensures as long as the return signal lasts.

In Fig. I is the transmission associated with the trunk in the handset U (, which is assigned via the latch OB-KL. From the transmission Ue, the switching processes are switched off by inductively generated direct current surges via the Transfer connection line.

In FIG. 2, the VL arranged at the other end of the connecting line is shown Transfer Ue.> arranged. The transfer can be used for both Connection in outgoing direction from a group selector as well as through a from Incoming connection to a group dialer in incoming handset Direction to be occupied. The switching operations adorn the L'bertraguing Ue.> From All transmitted via the connecting line by alternating current.

In the following description, the transmission Ue, as AC 3-current transmission and L-transmission Ue, referred to as inductive transmission.

First, a connection in Riclitu @ ng voter office-hand office is described.

When the transmission (Te, (Fig. Z) is occupied by a group selector, Be-1, egu: ngsrelaisC. Speaks via the c-wire, Ko: itakte_; 5 (l.7, 36j2 # 37l`7. # 371e 38ni : ... 391 ;. 4o ('"MIcklu: ng II of relay C .. Battery, earth @in. Relay C, switches a second winding in the occupancy circuit in a known manner via contact 41c. R ° -lais C;,> also closes the following circuit for relay D,: earth, contacts r ; 1n_. - i4 c ,, winding of relay D,. Battery, Ft-de. The relay &. Now responds in the following circuit: earth , Contacts 53 (1., 52c_. 541m. 57v-, winding of relay B: battery, earth. Relay B. # applies alternating current source GVQ through its contacts 71 b, and ; 2 b. To transmit this occupancy pulse. The alternating current surge is terminated by the fact that relay B., via its contact 2S b = relay L ,: switches on, whereupon relay L =, via its contact 621 , switches on the delayed response relay V ', relay V huh Can be reached via its contact 21 v., independently of relay B .. Relay V "interrupts the circuit for relay B> at contact 57 v.. Relay B, drops out and disconnects the alternating current source WQ from the connection line. After the response of the R ° -la.is V, the following circuit for the relay M2 is closed: Earth, contacts 63 ('=. 64 v ,, winding I of the relay M:>, battery. Earth. Relay M. holds via its contact 65m2 independent of relay V2. Relans M2 opens its contact 54 m2 and closes contact 55m2, which prepares a circuit for the transmission of the trigger pulse. After the relay B2 drops out, the relays L2 and V2 drop out. When contact 13M2 responds when relay M2 responds, relay D2 is held in the following circuit: earth, contacts 17 x2, 1 5 d2, winding of relay D2, battery, earth.

In the inductive transmission Uel (Fig. I), the receiving relay 11 is briefly excited by the alternating current impulse. Relay J1 closes a circuit for the drop flap relay AI (. The circuit for the relay AI (runs as follows: -f- 6 volts (-E- 6 V), Kon .- "clocks 6o dl, i il, 6'i Cl , Winding of relay AI (, - 6 volts (= 6 V). Relay J1 also closes the following circuit for relay Hl .: + 6 V, contacts 2 i1, 1 5 o1, winding of relay Hl, contact 68. o1, - 6 V. After the occupancy pulse has ended, it responds to the relay 0 connected up to then via the contacts 671t1, 2 il, 1 5 o1, via contact 671t1 and the winding I in series with the relay Hl. - After the response of relay 0, the short circuit for winding II is opened at contact 68 o1; furthermore, contact i 5 .o1 is opened and contact 140, closed in order to prepare a short circuit for relay Hl.

The officer goes to the fall of the Eallklappe with its plug in the latch 'OB-KL. At the same time she puts back the drop flap. You can tell the caller the number of the desired subscriber for the purpose of connecting. When the jack OB-1 (L is plugged in, the jack contact hli and thus the following circuit for the relay Rl are closed: @ - 6 V, contact Fzli, winding of the relay I (1, - 6 V. Relay I (1 closes the following Circuit for relay Cl: + 6V, contacts 34h1, 37-'i winding_ of relay Cl, - 6 V: Relay Cl closes the following circuit for -relay V ,: -f- 6 V, contacts 2 i cl, 45 d1 Winding of the delay relay V1, - 6 V. In parallel with relay V1, the delay relay NI -an also speaks via contact 2 i cl, but this a little later than relay V1. After relay N1 has responded, a circuit for the relay Dl is closed. The relay Dl responds with a long delay, so that the following excitation circuit for the relay A1 is closed beforehand: -, '6 V, contacts 1 8 dl, 6 n1, 42 g1, winding of relay Al, = 6 V. The relay Al responds. The following circuit is closed-. -F- 6 V, contact 31 a "winding I of the transformer l ' r, - 6 V. By closing this circuit, a positive induction shock is transmitted via the connecting line VL. Relay A1 had also energized delay relay F, via Korntakt 49 a1, see above. that the winding II of the transformer is connected to the connection line via the contacts 8 n1 and 23 f1. After relay Dl responds, the circuit for relay A1 at contact 1 8 dl is interrupted. The relay A1 drops out and interrupts the circuit via the winding I of the transformer Tr at the contact 31 al, as a result of which a negative induction surge is transmitted via the connecting line VZ. After the end of this induction, the following relays are energized in the inductive transmission Uel I (1, Cl, NI, Dl, Hl, oil, relay V1 comes after the response of the relay Dl due to the opening of the contact 45 dl to fall.

In the AC transmission Ue2 (Fig. 2), when the positive induction surge arrives, the armature of the polarized receiving relay P2 is turned over and the relay J2 is excited via contact 52 p2. Due to the negative induction shock, relay P2 puts its armature back shortly afterwards and -tineer breaks the circuit of relay J .. While the relay J2 is energized, the following circuit for relay G2 is closed: earth, contacts 8 12, -7 4, winding of the Relay 02, resistor, battery, earth .. Relay G2 responds and closes the following circuit for relay X2: earth, contacts 2o g2, 1 9 i2, winding of delay relay X2, battery; Earth. For the duration of the occupancy: current surge, relay X2 is held via contact 1 8 x2. Relay D2 is held via earth, contacts 1 6 g2, 15 d2, winding of relay D2, battery, earth after contact 1 7 x2 has opened. Relay G2 is short-circuited via contact 3 i x2 :; however, the short circuit does not last long enough to cause the relay to drop out. After relay J2 drops out, relay X drops out again. Relay G2 is held by: earth, contacts 12 m2, II g2, winding of relay G2, resistance; Battery, earth. The following circuit is closed for relay H2: earth, contacts 12 m2, ii g2, 6 4, io d2, winding I of relay H2, battery, earth. Relay H2 responds and applies counting voltage to the b-wire to the calling subscriber via contact 43 h2 and winding II 'of the choke coil DY2. Earth for the final signaling is applied to the a-wire via grain bars 44 h2, 42 d2, winding I of the choke coil Dry.

The two participants can now speak to each other.

If, after the end of the conversation, the calling subscriber initiates the release by hanging up his receiver, the c-AJer becomes the transmission Ue. interrupted by the group selector. The occupancy relay C2 comes to waste. After relay C. drops out, the following circuit is closed for: relay B. closed: earth. Contacts 53 d # 5 t c. #. Winding II of relay M2, contacts 55171. #, 57v2, winding of relay B2, battery, earth. In this circuit, relay M.-, the hold circuit of which is interrupted via winding I at contact 63 c2, is still kept energized. B2 relay energized via its contact 28, the relay b2 L .. After the operation of the relay L2 is about the contacts 25 b2, 621. The time-lag relay V. excited. Relay V2 interrupts the circuit for relays B and M at contact 57 v2 .. The two relays come to waste. While the relay B2 was energized, a longer alternating current surge was transmitted over the connection line VL for triggering. After relay B. has dropped out, relays L @ and V. also drop out again. There are Ue in the transmission. thus only the relays G2, H2 and D2 are energized.

In the transmission Uel (Fig. I). is due to the arriving long. Trigger pulse energizes relay I ". Relay J, shorts relay Hl via its contact 2 il, so that it drops out and turns on indicator SZ: +6 V. Contacts 66 k1, 761t1, indicator SZ_, -6V. As soon as after relay Hl relay J1 drops out, relay 01 also drops out. The officer disconnects the connection by pulling the plug from the latch OB-I (L. Opening the latch contact kli opens the circuit of relay I (1. After relay I (1 drops out, the circuit for relay Cl is interrupted at contact 34 k1. Relay Cl drops out and interrupts the circuit of relay N1 at contact 21 cl. Relay NI drops out with a delay The following circuit is formed for the relay Al: + 6 V, contacts 2o cl, 1 9 dl, 6 ttl, 42. "-1, winding of the relay Al, - 6 V. The relay Al responds and switches the Relay F1 on. Relay F1 switches winding II of the transformer via contact 23 f1 s Tr to the connection line. When the relay Al responds, a circuit is closed again via the winding I of the transformer Tr. As a result of this current short-circuit, a positive induction surge is transmitted via the connecting line VL. After relay N1 drops out, relay Al drops out, which opens the circuit via winding I of transformer Tr? however, the negative current impulse induced in winding II of the transformer is not transmitted via the connecting line, since the secondary winding 1I of the transformer at contact 8 11 has already been switched off. After the relay AL has dropped, the relay Fr comes with a delay and then finally relay Dl, which was previously held via the contacts 72d " 71 f1, drops with a delay.

In: the alternating current transmission Ue. t Fig. 2) the armature of the relay P2 is switched over by the positive triggering induction shock arriving from the transmission Uel and the relay J2 is thereby initially continuously energized. The relay X. is now energized for a longer period of time via contact i9! 2. The relay G. is short-circuited for a long time via the contacts 31X2, 7 4 and caused to drop. By opening contact 6 i. Relay H. had come to waste. After the relay G2 drops out, the following circuit is established for winding II of the polarized. Receiving relay P2 formed: earth, contacts 2C2, 19-, 32x2, winding II of relay P2, battery, earth. In this circuit, the armature of the polarized relay P2 is returned to the rest position. This causes relay Lr and thus relay X. to drop out. Again, the relays are all in the rest position.

- In the event that after the end of the conversation the clerk of the handset pulls the plug out of the jack before the calling subscriber hangs up his receiver, a positive trigger impulse is also sent from the transmission Uel to the Cbertra, -ung Ue @. As already described, this short-circuits relay G "in transmission Ue2, so that the relay drops out. Since relays C2 and M are still excited in this case, the hold circuit of relay D_2 is on the one hand Contact 1692 interrupted; relay D. drops out. On the other hand, relay H2 is held above-earth, contacts 3c2, 4h2. Winding II of relay H2, battery, earth .closing sign controlling earth at the contacts 42d2, 44h, disconnected; on the other hand, the counting voltage remains on the b-wire via the contacts 431z2. The calling subscriber also receives the contacts 75d._ ,, 76m via the winding III of the choke coil Dr2. The officer has activated herself. She can, even if the calling subscriber does not hang up at first, establish an outgoing connection via the connecting line VL. If the calling subscriber then also hangs up, relays C2, H2 and M2 come on to waste.

It is now the establishment of a connection in Direction of the hand office voter office bleschrieb: en.

When the latch OB-I (L is plugged in by the clerk of the manual office, relay 1 (l is first excited via latch contact hli. After relay KI has responded, the following circuit is established for relay Cl: + 6 V, contacts 34 hl, 37 er winding of the relay Cl, - 6 V. The relay Cl responds and switches the relays V1 and N1 leg via contact 2 i ei After the relay Nl responds, the relay Al responds again via contact 6 ni. Relay Al energizes relay F1. Relay Al is switched off again after the response of relay D on contact 1 8 dl, same as relay V on contact 45 dl. The closing and opening of contact 3 i a1 results in the transmission of a positive and negative 'IndLlk% LOnlS impulse via the connection line. After the induction impulses have been emitted, relays 1 (1, Cl, NI and Dl excited.

In the alternating current transmission Ue2 (Fig. 2), the polarized receiving relay P2 and thus the auxiliary relay J2 dependent on it are briefly activated by the arrival of the positive and subsequent negative induction surge. Relay J2 energizes relay G2 via its contacts 7 i2 and 8 12. After relay J2 has dropped, relay 02 is held. In addition, in this case relay 92 is energized in the following circuit: earth, contacts 2 c2, II g2, 6 4, 9 d2, winding I of relay 1 <2, battery, earth. Via the contacts 82 g2 and 8 i h2, the c-wire leading to the group selector is grounded and .that is used. Furthermore, the connection line VL is occupied via the contacts 67 h2 and 69 k2. Group selector switched through.

The officer in the hand office (Fug. I) now presses the WT dial button and actuates their number switch. i Via the number switch contact hsi, the following becomes pulsed Circuit for relay 41 closed: -} - 6 V, contact nsi, select button WT, contact 56 hl, winding of the relay Au, - 6 V. The relay F1 is switched on via contact 49, a1, which persists during a series of current impulses. When the relay Al is triggered a positive, and if it drops, a negative induction surge via the connecting line VL given.

In the transmission Ue2 (Fug. 2), the relays P2 and 12 respond in pulses when dialing. Relay 12 switches on delay relay X2 via contact 1 9 12, which is held during the selection and interrupts the incoming a-wire at contact 77 x2. The impulses are passed on by applying earth through contact 78 i, 2 via the a-wire to the group selector. The relay 1 (2, whose current circuit is interrupted during the election at the contact 6 i2 pulsed manner is kept energized through .the in the c-wire lying winding II. Relay G2 is indeed short pulse, during the choice comes j e not -Yes to waste.

If the called subscriber answers, the relay S2 located in the bridge between the line wires is activated in the transmission Ue2. Relay S2 closes the following circuit for relay L2: Earth, contacts 2612, 29s2; Winding 1I of relay L2, battery, earth. Relay L2 responds and closes the following circuit for relay B2: Earth, contacts 66h2, 564, 57i'2: winding of relay B2, battery; Earth. Relaus B2 responds in this circuit and gives: an alternating oil current pulse backwards via the connecting line VL. At the same time as relay B2, the delayed response relay F2 is also energized: earth, contacts 2312, 24s2, winding of relay «F2, battery, earth. Relay F2, which is held independently of relay L2 via contact 22f2, switches off relay L2 at contact 26f. The alternating current surge over the connecting line -is' terminated by the fact that the relay L2 switches on the delay relay V2 via contact 6212. Relay V2 interrupts the circuit of relay B2 at contact 57v2. Relay B2 drops out. After the relay has dropped. B2 and L2 relay V2 also drops out.

In the transmission U-1 (Fug. I) "the subscriber signaling pulse: energizes relay Ji, which energizes relay Hl via contact 2 il. After the end of the pulse, relay Ni stays in series with relay 01 By activating the relay HI, the indicator SZ disappears as a result of the break contact of the contact 76. The officer now establishes the connection to the calling subscriber.

When the call is over, the called subscriber places first his listener opens, so the relay S2 comes first in the transmission Ue2 (Fug. 2) to waste. When relay S2 drops out, the holding circuit of the is set at contact 24 s2 Relay F £ interrupted. Relay F2 drops out with a delay. During the fall time of the Relay F2 responds to relay L2 in the following circuit: Earth, contacts 27f2, 3o s2, winding II of relay L2, battery, earth. Relay B .. is connected via contact 5612. excited again. Relay B2 and relay L2 switch on the delay relay V2, which the latter brings the relay B2 back to waste. Relay B2 gave during his arousal as End signal an alternating current surge backwards over the connecting line VL. After relays B. and L. have dropped out, relay V. # also drops out.

In the transmission Uel (Fig. I) responds to the final signal arriving via the connecting line, the enimpuls relay f. Relay Hl is short-circuited via contacts 2 il, 140 and brought to waste; The indicator SZ appears again via contact 761t1. After the relay J. ' Relay 01 also drops out.

Now releases the officer in the hand office by pulling the plug out of the If the connection is released, the relays come one after the other in the transmission Uel I ("Cl, Ni- to fall. During the fall time of the relay Ni, the relay speaks Al turn on. Relay F1 is also energized by relay A1. When responding of the relay Al - a positive induction surge is sent over the connecting line. After relays A1 and F1 have dropped out, relay D1 also drops out.

In the transfer Ure. (Fig. 2) the relays P. and J. are energized by the positive tripping induction shock. Relay J. switches on relay X. As a result, the relay G. is short-circuited and brought to waste. After the relay G. drops out, the c-wire to the occupied group selector is interrupted, which initiates the triggering of this and the subsequent selector. This means that relay I (2, which was previously held by winding II in the c-core, also drops out. Relay S. also finally drops out. Finally, after relay G2 drops out, polarized relay P. becomes over its winding II and the contact 32 x2 returned to the rest position.

In the event that the connection line VL is seized by the hand office and the voter office at the same time, the following switching processes occur: When the latch OB-I (L (Fig. N1, A.1, F, Dl energized; the relays A: 1, F-, V1 are released again, relay V1 with a delay does not come into effect in the transformer Ue., since, assuming a simultaneous outgoing occupancy, an alternating current impulse runs against the induction surges, which is, however, longer than the total duration of the induction surges.

In the transmission Ue. # (Fig. 2), the relays C .. D. ,, B.,. L.>, V., 1Y1. at. Relays B., L., V. come to fall, which stops the transmission of the occupancy pulse.

In the transmission Uei (Fig. I) becomes. after relays Al and F1 have come to a drop after the induction impulses have been emitted, relay Jl is energized by the opposing occupancy and current impulse. Since the relay V1 drops out with a delay, the following circuit is now closed: = 6 V, contacts 2 il, 64 v1, winding of the relay G1, - 6 V. In this circuit, the relay G1 responds. Relay 01 binds itself after the end of the alternating current pulse and relay J1 drops out via contacts 66 k-, 65 J1. The AK drop flap relay is switched on via contact 63 ä-. The trap flap falls and signals to the officer that a call has come in. At the same time, the relay C1 is brought to drop by opening the contact 37 g1; As a result, the relays Ni and Dl also drop out. A response of the relay A1 during the release time of the relay Ni is prevented by the open contact 42.ul@. Finally, the two speech wires are opened by the contacts 74-1 and 7-5-1. Since putting back the drop flap is unsuccessful as a result of the continued excitation of the drop flap relay AL , the officer is prompted to pull the plug out of the latch and insert it again. When the plug is pulled, the relays 1 (l, G1 drop out. As soon as the pawl is reinserted, relay I (1 responds again. Relay I (1 causes the relays Cl, V1, Ni, D1 to be excited. During the response time of the relay Dl, the relays A1 and F1 are temporarily excited, as a result of which a positive and negative induction surge is sent to the transmission Ue. # After the relay V1 has dropped out, the switching state for an incoming connection is established in the transmission Uei.

In the transfer Ue. are temporarily due to the inductive signal impulses the relays P- "J., X,. and lottering the relays G., f are energized.

With this connection, at the end of the call, the calling Participant and the officer in the hand office give the final signal at the same time, so play The following switching processes are canceled If the caller hangs up his receiver, he comes in the transmission Ue., (Fig. 2) first the relay C., to the waste. The relays B., L., V. speak - temporarily. Relay M. "comes to waste. Through the relay B.> y an alternating current surge is given over the connecting line, which is due to its length in the transmission Uel compared to that when pulling The induction shock emitted by the plug is penetrated.

In the transmission Uel (Fig. Z), when the plug is pulled from the latch OB-I (L, the following relays drop one after the other: 1 (l, Cl, N1, Dl. During the drop-out time of relay N1, relay A1 and depending on this the relay F1 on. When the relay Al is energized, a positive induction shock is emitted, but this has no effect due to the opposing alternating current surge held via: -i- 6 V, 72 dl, 5 il, winding of the relay Dl, - 6 V. Furthermore, the relay Cl is again: excited via: + 6V, 35 ie 4 iv 3791, winding of the relay Cl, - 6 V. Relay Cl again energizes relay N, relay Jl also short-circuits relay Hl, which drops out. As soon as: the alternating current surge is over and relay J, drops out, relays Cl, N1 drop out one after the other, during the drop-out time of relay NL Relay AL speaks in turn att and from this .dependent also relay FL. "Relay Al bewi rkt the transmission of a positive. ven tripping induction shock via - the connecting line. As soon as relay F1 has dropped, relay Dl also drops. After relay Z1 has dropped out, relay 0 also dropped out.

The positive trigger: induction in the transference Ue2 brought relays H2, G2, D2 to drop and thereby the connection line released for another occupancy.

If at: a connection in the direction of the hand office voter office by chance the final sign of the called partÜiehm @ ers and the release sign of the officer of the hand office. coincide, sch will prevail through the transference Ue2 for the transfer; g Uel to the reverse transmitted alternating current pulse in the transfer U: ei kept the relay Dl energized in the same way as described above, which in turn: energizes the relay Cl. This establishes the switching status which, after the end of the alternating current pulse, causes the automatic transmission of the passive Off: the release induction surge on the part of the transmission Uel ensures.

In the transmission Ue2, the relays are activated by this tripping current surge G2,1 (2 brought down, which initiates the release of the connection.

The same switching processes, which, as described above, in the two transmissions with a G.eg, the concluding characters occur, also occur: if the transmitted backwards over the connection line Participant message impulse randomly with a premature release of the connection on the part the officer in the hand office should collapse '.

Claims (1)

PATENT CLAIMS: r. Circuit arrangement for telephone systems with sealed,: in both directions usable connection lines, over which the switching operations are transmitted from the transmission at one end of the line by inductively generated direct current surges and from the transmission at the other end of the line by alternating current surges, with the switching means in the inductive transmission To a tripping current that is transmitted simultaneously via the line, the subscriber reporting pulse from the opposite direction is initially bridged in order to send out further tripping induction pulses after the end of the alternating current surge, characterized in that, in addition to: the subscriber reporting pulse, the occupancy pulse and the final character pulse of the calling or called party, which is also transmitted by alternating current Participant himself. enforce against an inductive occupancy or release pulse transmitted simultaneously in the opposite direction and, when they are received in the inductive transmission (Uel), establish holding circuits for relays (G1 or Dl, Cl), which bring about a switching state when the legs fall (occupancy), which triggers a release of the inductive transmission without emitting inductive: generated direct current surges and a repeated occupancy (inquiries) by the one occupying office (officer), in the other case (final sign): cause a switching state to emit another inductively bent direct current surge after the end of the alternating current surge . z. SchaltungsatnoMnung according to claim t, characterized in that with simultaneous occupancy of the connection line from both directions, the long change of occupancy, enforcing against the inductive occupancy pulses, current surge from the opposite direction in the inductive transmission (Uel) via: an auxiliary relay (Vl ) a holding circuit for: a relay (G1), which on the one hand cancels the holding circuit of the relay (C,) which controls the impulse transmission circuit, on the other hand by interrupting the speech wires (at contacts 74 '0'', 75: i) and switching on a Continuous signal (Alb over 63rd, u.) Causes the official to release (pull the plug) and repeated assignment (interrogation) of the inductive transmission. 3. Circuit arrangement according to Anspru @ ch2, characterized in that when the inductive transmission is released, the holding circuit of the relay (G1) which continues to exist after the end of the alternating current pulse is opened and, as a result, the relay (Ci, N1, A., D1, F1) dominating the current impulse transmission circuits. released for the transmission of inductively generated impulses by the repeated occupancy of the inductive transmission on the part of the officer. 4. Circuit arrangement according to claim r, characterized in that when the release bziv is sent. Trigger pulse on the part of the inductive transmission Wei) and simultaneous transmission of the subscriber reporting or final note pulse on the part of the alternating current transmission (Ue.) In the inductive transmission «depending,) after the end of the transmission of the induction surges by the alternating current surge, a delayed releasing auxiliary relay - (Dl) kept excited and via this and the surge receiving relay - (. h) recently a circuit for the relay (C1) dominating the surge transmitting circuits is closed, which automatically initiates the emission of an inductive triggering current after the end of the alternating current pulse. Legs literature references according to h9 rr, paragraph t of V.0. from May 12, 43