DE972568C - Circuit arrangement for telephone extension systems with dialer operation - Google Patents

Description

ISSUED AUGUST 13, 1959

S 40621 VIIIa j21 a ^s

The invention relates to a circuit arrangement for telephone private branch exchanges Voter operation and production of a waiting state for the transfer of the office by the night station at Free or busy intercom called on inquiry. For such arrangements it is already known, with the establishment of the waiting state by the night station, the public dialer to adjust to the requested position. The Inquiry connection path used.

Furthermore, it is known to assign a special follower to each transfer of office, who at Establishing the inquiry connection is set with and the inquired position on the exchange dialer indicates. The follower is controlled by each intercom, so it can also be used if necessary can be set by a night station.

The invention now aims at the exchange dialer in the switching activity by the night station set to a requested intercom and at the same time the waiting state of the exchange transfer to produce in such systems, where probably with a completed inquiry connection the House connection path is available for the identification of the requested position, but at

909 574/1

incomplete consultation call cannot be used. This is achieved according to the invention by that in the production of the inquiry connection path through the night station only the Night station transmission of specially assigned followers is set, which the queried intercom station on the public dialer indicates, and that also with the establishment of the waiting state of the Office transmission through the night station, through ίο relay of night station transmission and relay of Transfer of office, the elector of office to the questioned one identified by the follower Station is set.

The invention ensures that even in systems in which, for example, the test path of the Outside line voter via the house connection device not only from the free status of the inquired Call station is dependent, but also only through a special measure at the inquired Intercom for the transfer of an existing exchange connection is established with the establishment of the waiting state of the transfer of office by the night station of the office voter alone a follower assigned to the night station transfer to the intercom station in question is set. This creates the conditions for it in a private branch exchange the establishment of the waiting state by the night station without significant intervention in to retrofit the existing system.

An exemplary embodiment of the invention is shown in the drawing. It is a private branch exchange in which internal and inquiry connections are made via the dialers ^ 4, S ", LPF. Office connections in both directions of traffic run via the dialers AW I and AWII Closing the contacts 1 NS and 2 NS prepares the setting of the exchange dialer AWI for the intercom station marked as night station. When calling via the exchange line AL · the alternating ringing current switches on relay A. Relay H is made to respond via the following path :

i. H-, 3 ir, Ii7, 4a, 5kl, 6kll, -

The following holding circuit is established for relay H:

2. +, 3ir, ΙΗ, -jas, Sh, -.

Relay H creates a circuit for relay N :

3. +, 9ir, ioum, iiu, 12h, N, iNS, ■ -.

The drive magnet DAWI of the exchange dialer AWI is switched on by the relay Λ ^Γ:

4. Relay breaker RU, 13 p, 14z, 15 c, 16fell, I7r2, i8we, 19 », DAWI ₁ .-.

The public office voter AWI begins to turn. After the first switching step of the selector A WI , the head contact 5 k I is opened and thus the circuit 1 of the relay H is interrupted. The night station N 1 is identified by switching on the Λ "+ potential on the switching arm set e of the exchange dialer AWI . If the exchange dialer AWI reaches the contact of night station N 1 marked by K + potential, the test relay P is switched on:

5. K +, elAWI, elAWII in positionO, 20z <i,

21 Υ I, 22 71, 23 /? I, IP ₁ 24JIi ?, / C.

The P relay interrupts circuit 4 of the DAWI drive magnet at contact 13 / ». The AWI dialer is shut down.

The following holding circuit exists for relay P:

6. +, 9 tr, 2Sb, IIP, 26p, 27c, -.

The relay P creates a circuit for the relay P 1:

7. +, 28 ^ Pi ₁ 2gn, 30 / t, -.

The relay P 1 opens the contact 23 pi the circuit 5 of the relay by the relay P. P 1, a circuit for the relay C, NV, C, R and T is prepared:

8. +, distributor PV, 31 pi, IC, II C, 32tr, 33 MW or 34 ", cJÄWII in position 0. clAWl, NV, C x, 35 knw, R, T, -. '

When night position N 1 is free, relays C, NV, Ci ₁ R and T are energized. Relay C creates the following blocking circuit:

9. +, 36c, IIC, 32ir, 33MWI or 34 ", cjAWII in position 0, cJAWl, NV, Ci. 35 knw or 37 c 1, R, T, -.

Relay C interrupts the holding circuit 6 of relay P at contact 27 c. For the Relay P ι consists of the following holding circuit:

10. +, 38 p I ₁ Pi ₁ 29 n, 30Ä, -.

Through the relay C1 of the transmitter assigned to the night station N1 , direct access to the office selector AWI is switched off by opening the contacts 39cι, 40ei and the night station A ^r i is switched on via the contacts 41 ei, 42ei to the transmitter of the night station. Relay Hi is switched on by relay Ci:

11. +, 43ί i,

I, IHi ₁

A holding circuit is established for the relay H τ:

12. +, 49/11, IiTi, -.

The following ring circuit exists for the night station Α ^{Γ ι:}

13 · +, 45 ^ 1 »41CI, JVi, 42Ci ₁ 46/11, Il / ii. Ringing current source RQ.

If the participant of night station 2V1 answers, the reverse winding II of relay Hi in ringing circuit 13 becomes effective. The relay H 1 drops out. The following supply circuit is established:

14. +, ISi ₁ IZi, 47 hl, 41 ei, JVi, 42CI, ^la 5 48 / ii, IIXi, IISi, -.

The relay Si switches on the relay V 3:
15. +,

The speech wires are switched through via contacts 51 ^ 3, 522/3. The relay 6 * 1 switches via contact 53.? 1 the reverse winding II of the relay H of the transfer of office:

16. +, 54A 55c, bjAWll in positionO,

bjAWl, Dn, 53SI, ajAWl, afAWll,

56Π, 57c, 58 Ä, UH, ringing current source RQ.

The relay H comes to waste and interrupts the circuit 3 of the relay N at contact 12 h. The holding circuit 10 of the relay P 1 is interrupted by contact 30 h. The relay P 1 falls back into the rest position. After relay H has dropped out, the following loop circuit exists for relay S:

bjAWIl in Stel a / AWl, 57c, 6oh,

17. +, IS, IX, sgh,

lung O, bjAWl, Dn,

ajAWII in positionO, 56η,

IIX.IIS, -.

The relay S switches on the relay V 1:
18. + ,. όΐί, Vi, -.

The trunk line AL is switched through via contact 62 s. The ringing current of the office is switched off by the loop formation. The subscriber at night station N1 is now connected to the subscriber calling via the exchange line AL and can find out the desired extension subscriber from him. To establish a connection to the desired intercom, ζ.Έ. N 2, the subscriber at night station N 1 temporarily presses the Ta 1 key. The differential relay X 1 in the feed circuit 14 is temporarily excited. The relay Zi is switched on in the transmitter of the night station:

19. +, 63 c i, 64x1, 65 vi, Zi, -.

If the button Ta 1 is released, the differential relay X 1 drops out. The circuit 19 of the relay Zi is opened at contact 64x1. The following holding circuit exists for the relay Z ι:

20. +, 63CI, 66x1, 6721, Zi, -.

After the relay Z1 has dropped out, when the Relay Zi also switched on relay Fi:

21. +, 63CI, 68jtri, 6921, Yi, -.

In the inquiry state, the relays Z1 and F1 are energized in the transmission of the night station. By relay X 1 is turned on while the button is pressed + potential via contact 70x1 and thus transmitted the inquiry incentive to the difference in Relay X loop circuit 17th The relay X controls an inquiry switchover device YjZ with contact 71 Jtr. The switchover from the exchange line AL to the consultation line 72/73 takes place by opening contacts 743 '»75 V and closing contacts 763 /, 77 y.

Via contact 783; and resistance Wi the exchange connection is held.

The current surges sent by the subscriber of the night stationΛΓΐ are received by relay 51 in the feed circuit 14 and passed on through contact 53 s ι to the feed bridge relay S of the office transmitter. The relay S transmits the current impulses with contact 62 s, after the call seeker AS is set in a known manner on the inquiry line 72, 73, to the feed bridge relay A ι of the house connection set AS / LW. The line selector LW , designed as a lever-operated rotary selector, is set in a known manner. With the setting of the line selector LW , the follower NW, which is assigned to the transmission of the night station, is also set. The first series of current impulses sent by night station N 1 acts on the lifting magnet HM of the follower NW, which is designed as a lever-operated rotary selector:

22. +, 79J'i,
HM, -.

80 /, 81 s ι, 82ΜΙ, 83 www,

Relay V 4 is switched on during the series of impulses:

23. +,

, 841/3, V4,

After the first series of impulses has ended, relay V4 drops out. The relay Ui is switched on:

24. +, 85 /, 863/1, 872/4, 88 www, 89 knw, Ui, -.

The circuit for the magnet DM is prepared via contact 90 u 1. The second series of impulses sent by the night station, which is transmitted to the line selector LW , now acts on the rotary magnet DM of the follower NW :

² 5 +> 79Y i. 80 /, 81 si, goui, DM, -.

After the first turning step, the circuit 24 of the relay U 1 is opened at the contact 88 wnw . The relay U 1 remains energized during the second series of impulses in the following way:

26. +, 85 /, 863/1, 912/4, 92MI, Ui, -.

After the end of the second series of impulses, relay V4 drops out. The holding circuit 26 of the relay Ui is opened at contact 91 ν4 . The relay U ι drops out.

Not only is the line selector LW set to the desired intercom station N2 via the inquiry path, but also the follower NW for identifying the inquired subscriber is set to the corresponding contact.

If the intercom station N 2 is free, the test relay P 2 and the subscriber relays R 3 and T 3 are energized in the test iac circuit via the line selector LW. About Contact 93 /) 2 2. If the participant of the speech ^la 5 stelle done the blocking of telephone N 2. There is the call of the telephone N immediately, then the night station N 1 via the

Inquiry path connected to the interrogated call station N 2 and can offer the subscriber to this call station the exchange connection. In order to take over the exchange connection, the subscriber of the station N 2 temporarily presses the Ta2 key. The differential relay X 2 in the supply circuit of the call station Nz is temporarily excited. The transfer incentive is transmitted to the relay U of the exchange line with contact 94 ^ 2:

27.-, 95 a, 94 # 2, Z 2, djAS, 96, 97 um, I! 7, +.

The relay Z 2 and the relay U are energized. The relay U establishes a holding circuit:

28. +, gtr, 10um, g8u, UU, 992, -.

The circuit of a switching device Um vorao is prepared by contact 100 «of relay U.

If the participant of the station N 2 releases the button Ta 2, the relay X 2 drops out. The relay P 3 is switched on:

29. +, 10122, 1023/2, IP $, 103.ΛΓ2, 95 «, -.

The relay P 3 remains independent of the excitation circuit 29 via the winding II in the test circuit of the Leituagswählers LW. When relay X2 drops out , circuit 27 of relays Z2 and U is interrupted. The switching device Um is now effective and interrupts the contact 10 to the holding circuit 28 of the relay U. When the switching device UM is energized, the circuit 9 is interrupted via switching arm c of the selector AWI at the contacts 33 um and 34 M in the fall time of the relay U.

Relays C ₃ NV, Ci, R and T drop out. The following holding circuit exists for relay Y:

30. +, 9ir, 104MOT, HF, 27c, -.

The relay Z belonging to the inquiry switchover device YIZ comes to waste.

When the relay C ι drops in the transmission of the night station, the feed circuit 14 is opened. The relay 5 "1 drops out. The circuits 20 and 21 of the relays Zi and Y are opened at the contact 63 c ι . The relay F is switched on:

31. +, io $ knw, 1063/1, 107g ·, F, -.

The DM solenoid is actuated by relay F:

32. +, 108 f, 109MI, DM, -.

When the rotary magnet DM is actuated, the contact 110 dm is closed and the relay Ui is switched on:

33. +, izodm, iii'f, Ui, -.

The circuit 32 of the Dfehmagneten DM is opened at the contact 109 Mi. The magnet DM interrupts circuit 33 with contact 110 dm. The magnet DM and relay U1 work together in an interrupter circuit until the follower NW has reached the rest position in which the contact 105 knw is opened and thus current circuit 31 of the relay ^{7 is} interrupted. The switching means of the transformer of night station N1 are again in the rest position.

In the exchange transmission, the drive magnet DA W I is switched on after relays Z and C have dropped out:

34. Relay breaker RU, £ 13, 14 ^, 15 c, i, DAWl, -.

The public exchange dialer AWI is switched on until it has reached the rest position. In the rest position, contact ii2 £ i is open.

It is assumed that the station A> ^r 2 is connected to a contact of the sixth row of contacts of the line selector LW . The directional contact 11.3 rk 6-0 is thus closed. Relays R1 and R 2 of the exchange transmission are switched on:

35. +, 113 r £ 6-0, 114/13, d / AS, 96, 115hot, R2, Ri, -. ⁸ p

The drive magnet DAWH is switched on by relay R 2:

36. Relay breaker RU, 13/1, 140, 15 c, n6fei, iijr2, DAWII, -.

The office selector AW 2 is switched on until it reaches the connection of the intercom N2 identified by the line selector LW . In this case the relay Γ is energized in the following way:

37. if + the external voltage, n8w, 119 «» », 72, a / AS, 120p 3, ajLW, 121, a / AWII, 122Π, 123 w i, IIIC, K - the external voltage. The exchange dialer AWII is stopped by opening contact 15c.

In order to check the exchange dialer AWII for the intercom station requested, the connection to the interrogated intercom station must be completely established and then the transferring stimulus must be brought about, through which relay P 3 becomes effective and relay P 3 via contact 120 / »3 the test circuit of the to be switched Office voter prepared.

When relay C responds, holding circuit 30 of relay Y at contact 27 c is interrupted. There is a switch back from the inquiry line 72/73 to the exchange line AL. The house connection set ASJLW is triggered.

When the exchange dialer AWII is set to the interrogated intercom station N 2 , the transfer device UM is switched off. At the contact 115 to the circuit of the relays R 2 and i? I is opened. The following blocking circuit exists via the switching arm c of the exchange dialer AWII:

38. +, 36c, IIC, 32ir, 33 um or 34w, c / AWU, 124, R3, Γ3, -.

The connection takes place via the contacts 57 c, 55 c. It is the feed bridge relay S via

the JV 2 intercom switched on. The relay 5 produces the Sirom circuit 18 of the relay Vi .

If the subscriber of intercom station iV 2 is free after the consultation call has been established by night station JV1 and if the subscriber of intercom station JV 2 does not answer or if intercom station TV 2 is busy, night station JV1 can call the outside line dialer AWII independently of the house connection set by hanging up the receiver Set by the follower NW to the interrogated intercom and at the same time establish the waiting state of the office transmission. By hanging up the receiver, the circuit 14 of the relay S 1 is opened. The relay S 1 drops out and interrupts the circuit of the relay V 3 at the contact 50 j ι. In the fall time of the relay V ¹ J, the relay V4 in the circuit 23 is switched on temporarily. After the relay V3 drops out , the circuit 23 of the relay V4 aiming at contact 84 ^ 3 is opened. When the relay S 1 drops out, the loop circuit 17 is opened. The relay S of the exchange transmission drops out. The circuit 18 of the relay V ι is opened at the contact 61 j. During the release time of relay V 1, relay V2 is switched on:

39- +. 9 ^tr > ionm, iiu, 125h, 1262/1, 127 s, V 2, -.

If relay Vi returns the contacts to the rest position, relay Tr is switched on during the release time of relay V 2:

40. +, 128 © i, 129 ^ 2, ITr, -.

The following holding circuit is established for the relay Tr:

41. +, 130ir, ITr, -.

The relay Tr interrupts the contact 32 tr the circuit 9 of the relay C, NV, Ci, R, and T.

At contact 63 c ι the circuits 20 and 21 of the relays Zi and Yi are opened.

During the release time of the relays NV and V2 , the relay NE is switched on in the inquiry state of the exchange transmission:

42.

2, INE,

, 1342, 135 Hz>,

The relay NE creates a holding circuit:

43 +. 136 ne, 137 nu, IIJV E, 138www, blNW (wiring of authorized call stations), 139M, 140CI, G, -.

In this circuit, the relay G is also excited as an official authorization identifier, which maintains the holding circuit 43 independently of contact 140 c ι via contact 141g ". The relay FL was excited in the following way:

44. +, 131 /> i, 132VI, 133V2, 134.3, FL, -.

The relay "FL" remains independent of the contacts 133 ^ 2 and 134 ζ via contact 142 //. After the relay V2 drops out, the inquiry switch YjZ is returned to the rest position. The inquiry line 72/73 switches back to the exchange line AL . the voters ASjLW the query path can be triggered. the official compound and / maintained regardless of contact 62 s 783 via contact 143 //.

When relays C and Z drop out, the DAWI drive magnet in circuit 34 is switched on. The public office voter AWI returns to the rest position. If the exchange dialer AWI reaches the rest position, then winding II of relay A is switched on:

45 +. 141 ft HA, ski, 6 * 11, -.

When the AWI dialer has reached its rest position, the reverse winding II of the isolating relay Tr is also switched on:

46. +, I42tr, UTr, 5kl, 6kll,

The relay Tr returns the contacts to the rest position. The relay H in circuit 1 is switched on and held in circuit 2. The relay JV comes into effect in circuit 3.

By responding to the relay G in the circuit 43, group identification is carried out according to the energized relay NE. Since the participant of the interrogated call station is connected in the sixth row of contacts, the switching arm α of the follower NW is in position 6. Relays R2 and Ri are switched on:

47. +, 143 g ·, a / NW in position 6, 144η, 145 ne, R ₂ , Ri, -.

The relays J? 2 and Ri can also be controlled via the code number connection KZ of the line selector LW to identify a calling station.

The drive magnet DAWIl is switched on by relay R2 in circuit 36.

If the exchange dialer AWYI reaches the interrogated intercom JV 2 identified by the switch arm c of the selector NW , the test relay P in the discharge circuit of the capacitors Co i, Co 2 is energized. This circuit runs in the following way:

48. +, 148g, Co i, 149g-, c / NW, 150, elAW II, 20V1, isine, 22η, 23 pi, IP, i52ne, 153g, C02, +.

The relay P stops the selector AWII through contact 13 p and establishes the holding circuit 6. The relay P1 is switched on in the circuit 7 and held in the circuit 10. The following circuit exists for the relay NU:

49. +, 2% p or 38 /> i, iS4fie, NU, 29 », 30 h, -.

⁰

When relay NU responds , circuit 43 of relays NE and G at contact 137 nu is interrupted. The relay NU is independent of contact 154 ne via contact 155 nu.

When relay G drops out , relay F in circuit 31 is switched on. The drive magnet

909 574/1

DM and relay U ι of the night station transmission are actuated in the circuit 32 and 33 and thus the follower NW is returned to the rest position. When relay NE drops out , circuit 47 of relays R 2, Ri at contact 145 we is opened. When the relay G drops out, the capacitors Co i, Co 2 are charged again via the contacts 145 g, 146 g and 147 g.

If the intercom station N 2 called in inquiry was busy and it terminates this connection, the test relay C of the exchange transmission is switched on in the following circuit:

50. +, distributor PV, 31 pi, IC, HC, 32ir, ₃₃ um or 34 u, switching arm el'AWII, 124, is R ₃ , T ₃ , -.

The blocking circuit 38 is established for the exchange dialer AWII. The following ringing circuit now exists for intercom station N 2:

51. +. S ₄ A, 55c, b / AWII, 156, ΛΓ2, 121, alAWII, 56 r 1, 57 c, 58 h, HH, Rufstromquelle RQ.

When relay C responds, circuit 6 of relay P at contact 27 c is open. The relay P drops out.

If the subscriber of the intercom station N 2 answers, the opposite winding II of the relay H in the ringing circuit 51 becomes effective and causes the relay H to drop out. The relay H opens the holding circuit 10 of the relay Pi and the circuit 49 of the relay NU at the contact 30 h. After the relay H drops out , the relay ^ is switched on via the subscriber loop of the call station N 2 . The relay Vi in the circuit 18 becomes effective. When relay Vi responds, the holding circuit of relay FL is opened via contact 142/7 on contact 1322/1. The relay FL drops out. The subscriber to the intercom station N 2 that has been queried is now connected to the exchange line AL . The subscriber can set up inquiry connections in the manner already described and also arrange for an exchange connection to be transferred to an inquiry station. If the relay G is switched on in the circuit 43, the thermal relay Th is switched on via contact 143 g parallel to the circuit 47 of the relays R1 and R 2. If, after a certain period of time, the exchange dialer AWYI has not reached the connection of the interrogated intercom station for whatever reason, then contact 157 th of the thermal relay Th is closed. Relay G is short-circuited via contact 157 th. The relay G drops out. The relay F in the circuit 31 is switched on. The relay F switches on the magnet DM in the circuit 32. Relay U1 in circuit 33 becomes effective. The follower NW is returned to the rest position in the manner described. This interrupts the holding circuit 43 of the relay NE. The circuit 47 of the relays R1 and R 2 is opened at contact 145 we. The circuit 36 of the drive magnet DAWII is opened at contact 117? "2. The drive magnet DAW II remains switched on:

52. Relay breaker RU, i ₃ p, 14z, 15 c 158kl !, DAWII. -

If the exchange dialer AWII reaches the rest position, the drive magnet DAWI is switched on in circuit 4 and the exchange dialer AWI is thus set again to night station N1 in the manner described.

If the follower NW is set to an unauthorized position, the excitation circuit 42 of the relay NE can be established in the fall time of the relays NV and V 2. The holding circuit 43, in which the relay G is also located, does not come about because for such a point the wiring on the switch arm set b of the follower NW is missing. The relay G remains in the rest position, and the relay NE will return the contacts to the rest position after the relay NV has dropped out.

In the rest position of the relay G , the follower NW is returned to the rest position by the circuits 31 to 33. The relay FL is switched on in the circuit 44 and the drive magnet DA W I in the circuit 34. The public office voter AWI goes to rest. Relay A in circuit 45 and, after relay Tr has dropped (through circuit 46), relays H (circuits 1 and 2) and iV (circuit 3) are activated. The drive magnet DAWI is switched on again in circuit 4 and the office selector AWI is set to night station N 1 in the manner described.

If, on the other hand, the exchange dialer A W1 1 has reached the interrogated telephone station N 2, the relay NU in the circuit 49 is switched on, as already described. A circuit is established for the THW thermal relay by means of relay NU:

53- +. i59nu, THW, -.

If the relay H is not released within a certain time by reporting the interrogated 'intercom station N 2 , the thermal relay THW becomes effective. The relay FL is kept energized:

54th +, 160 thw, FL, -.

The isolating relay Tr is still switched on by the THW thermal relay:

55- +, 161 thw, ITr, -.

The relay Tr remains in the circuit 41. The relay TR returns the exchange dialer AW II to the rest position in the manner already described. Subsequently, the exchange dialer AWI is set again to the night station N1 in the manner already described.

Claims (12)

PATENT CLAIMS: i. Circuit arrangement for telephone private branch exchanges with voter operation and creation of a waiting state. the transfer of office by the night station with free or occupied call station called in inquiry, characterized in that during the establishment of the inquiry connection path (ASI LW) by the night station (JVI) a follower (NW) assigned only to the night station transmission is set, which the queried station (N 2) on the exchange dialer (AWlI ) and that in addition, with the establishment of the waiting state of the office transmission by the night station, through relays of the night station transmission (NV) and relays of the office transmission (NE, FL, P, Pi), the office dialer (AWII) to the follower (NW ) marked consulted call station (N 2) is set. 2. Circuit arrangement according to claim 1, characterized in that in the inquiry state of the office transmission (relay YIZ energized) by hanging up the receiver of the night station (iVi) switching means (relay Tr, NE, FL) of the office transmission come into effect, which the night station ( Ni) return the selected dialer (AWl) to the rest position, keep the exchange connection (via contact 143 //) and set the exchange dialer (AWIl) to the intercom station (N 2) requested. 3. Circuit arrangement according to claim, characterized in that the examination of the public office dialer (AWH) on the by the follower (NW) characterized by the queried call station (N 2) is carried out by a relay (P) , which also the public office dialer (AWl) on incoming office call on the night station stops. 4. Circuit arrangement according to claim 3, characterized in that the relay (P) with the setting for the night station by an external power source (K - / K +) and with the setting for the queried call station by a second external power source (Co 1 / C02) current receives. 5. Circuit arrangement according to claim 4, characterized in that the discharge circuit of capacitors (Co 1, C 02) is used as an external power source for setting the office dialer (AWIl) to the interrogated call station (N 2). 6. A circuit arrangement according to claim 2, characterized in that after the setting of the office dialer (AWIl) on the requested call station (N 2) by switching means (relay NU) of the office transmission of the followers (NW) is returned to the rest position. 7. Circuit arrangement according to claim 3, characterized in that the check of the public office dialer (AWIl) on the queried call station (N2) is dependent on the office authorization check carried out via a switching arm (b) of the follower (NW). 8. Circuit arrangement according to claim 7, characterized in that the test circuit of the office selector (AW II) is prepared for shutdown on the queried call station (N 2) by the authorization test relay (G) (via the contacts 148g ·, 149 g, i53g ') · 9. A circuit arrangement according to claim 7, characterized in that when a non-authorized, consulted call station is identified, the follower (NW) is brought to the rest position and the office dialer (AWT) is set again to the night station (N 1). 10. Circuit arrangement according to claim 1 for systems in which the exchange transfer two exchange dialers are assigned to different subscriber groups, characterized in that the identification of the exchange dialer (AWTT) of the requested call station via the switching arm (a) of the follower (NW) (N 2) is transmitted to the relay (Ri, R 2) assigned to the office transmitter. 11. Circuit arrangement according to claim 10, characterized in that the identification of the group of the queried call station (N2) via the switching arm (α) of the follower (NW ) is transmitted to the relay (Ri, R 2) , which is also the dialer of a calling party Determine the call station. 12. Circuit arrangement according to claim 1, characterized in that after the setting of the office dialer (AWlT) on the requested call station (N 2) a time switch device (THW) is switched on, which after a certain time and no response from the requested call station (N 2) brings the exchange dialer (AWTT ) set to this intercom station (N 2) to the rest position and then sets the exchange dialer (AWT) again to the night station (N 1) . 100 Considered publications: German Patent Specifications No. 683778, 707541. 1 sheet of drawings ) 509 627/80 12.55 (909 574/1 8.59)