IL46952A - Circuit for monitoring the loop state of subscriber stations in communication-particularly telephone-installations - Google Patents

Description

*yr fr stMtof jimopna o*»¾ii"»c cianij TO "zap" asE wmfln¥ Vara t¾s?B »naaaa ¾m»pa Circuit for monitoring the loop etate of subeoriber stations in communication, particularly telephone-installations The invention covers a circuit for monitoring in communication, particularly telephone installations, the loop state of subscriber stations having a subscriber loop which always comprises at least one coil with a rectangular hysteresis curve magnet core, where the magnet cores may respond on the loop state of a particular subscriber station according to its characteristic magnetisation status' by means of answering impulses over the control colls of the subscriber stations, and allow the emission of characteristic output impulses for the magnetisation status and thus for the loop state of the particular subscriber station over the selection coils of the subscriber stations.

A circuit of the type described above is already known (DT-AS- 1041098). In this known circuit it is however not possible to distinguish between the loop state of calling subscriber stations and the loop state of subscriber stations to be called. Such a distinction is often desirable since the loop state of calling subscri ber stations or subscriber stations to be called require the execution of different processes within a communication exchange.

A further circuit for monitoring the loop state of subscriber stations in telephone installations is know where each subscriber station is provided with two magnet cores with a row of coils (US - PS 3 157 746) . The two magnet cores have, in this case, always a rectangular hysteresis curve; but a different magnetic bias. The circuit is arranged so that, when at rest, the two magnet cores,always have a residual magnetism. When a responding impulse emanating from a responding impulse source is fed simultaneously to the responding coils, the residual status of only one magnet core is changed; if, as a result of not lifting the receiver, the loop current circuit of the particular subscriber station is open, the residual status of one of the magnet cores is changed whereas if, as a result of lifting the receiver, the loop current circuit of the particular subscriber station is closed, the residual statue of the other magnet core is changed. Even so, it is not possible to distinguish, in this known circuit, between the loop state of the calling subscriber station and that of the subscriber station to be called.

Furthermore, there is a known circuit (D2-AS 1140240) for time-multiplex telephone exchanges where in the course of monitoring the loop state of subscriber stations a distinction can be made between calling stations and stations to be called. In this known circuit, the call numbers of calling stations and the call numbers of stations to be called are stored in different call number circulation storage units.

A call number generator issues call numbers of subscribersstations to be tested for their loop state which are compared in isolated comparators to the call numbers of calling subscriber stations or subscriber stations to be called contained in the two call number circulation storage units. Depending on which of the two comparators emits a signal indicating concordance of compared call numbers, the central control device will release the required action. Establishment of the loop state of one of the subscriber stations of a system, i.e* a calling station or a station to be called or respectively a called station - occurs only by means of the call numbers circulating in the call number circulation storage unit or the call numbers of the calling subscriber stations. Whilst it is possible to establish* in the knox-m. circuit under discussion, by means of the above mentioned call number comparators, whether a connected subscriber station is a calling station or respectively a called station, it is not possible to distinguish in this circuit, simply by connecting the subscriber circuit of an individual subscriber station, whether the latter is a calling station or a station to be called or respectively a called station. This distinction is only possible in connection with the above mentioned call number comparators. However, the additional circuitry required to achieve, in the above mentioned circuit, a distinction of the loop state between calli g subscribers and called subscribers or subscribers to be called is relatively expensive.

The purpose of the invention is to show a way whereby in a circuit of the type described in the introduction, the loop state of calling subscribers can be distinguished in a relatively simple manner from the called subscribers or subscribers to be called.

The problem as stated above is solved according to the invention for a circuit of the type described in the introduction by providing two separate control colls for each subscriber station so that control impulses for monitoring the loop state of calling subscribers are fed to one of them, and control impulses for monitoring the loop state of subscriber stations are separately fed to the other, and that, upon the appearance of these control impulses emanating from the respective release coils of the magnet cores according to the loop state of subscriber stations upon special evaluation devices, output signals are produced by the latter. Thus, the advantage is achieved to differentiate, at relatively small expense, between calling subscriber stations and called subscriber stations or subscriber stations to be called when monitoring said subscriber stations.

According to one application of the invention, the circuit contains two separate magnet cores with a rectangular hysteresis curve for each subscriber station so that one of the magnet cores is fed, over a special control coll, control impulses for monitoring the loop state of calling subscriber stations, and the other magnet core is fed, over another control coil, control impulses for monitoring the loop state of subscriber stations to be called, and that each magnet core is connected over a special reading coil to a special evaluation device, thus the advantage is achieved to have a rel&tivel SL.CJ.1 number of windings over the magnet cores.

According to another application of the invention, only one magnet core with a rectangular hysteresis curve is used for each subscriber station ; this magnet core is provided with two control coils so that control impulses for monitoring the loop state of callin subscriber stations or respectively subscriber stations to be called are fed in separately, and to each control coll a diode Is connected in series; this diode being further connected to a series circuit consisting of the reading ^ coil of the magnet core and the primary winding of an output transformer, the secondary winding of which Is connected to the evaluation device, the control colls having the same winding sense as the reading coils.

Thus, the advantage is achieved that one magnet core is sufficient for each subscriber station.

According to a further application of the invention, the primary winding of each of the output transformers is connected in series, over decoupling diodes to reading coils pertaining to the magnet cores of further subscriber stations and in parallel to other diodes lying in the control windings of the above mentioned further subscriber stations ; with the decoupling diodes so polarized with respect to one of the other diodes, that under the same current direction they are stressed in the same forward direction as one of the other diodes. Thus the advantage is achieved of particularly small expenditure with respect to the manufacture of output transformers.

According to a further application of the invention, the reading coils of the magnet cores are connected to an integration element which will receive signals and impulses of only one polarity. Thus one can achieve advantageously a storage of the answering results of the magnet cores pertaining to the individual subscriber stations during a certain time period, which makes the evaluation of these results an easier task.

According to a further application of the invention the control cores of the magnet cores provided for each res-pective subscriber station are connected to a coll of an additional transformer which emits, at least over one output winding, actuation impulses for the operation o at least one time channel switch connecting the respective subscriber station with a multiplex bar. Thus, the equipment required for monitoring the loop state of the subscriber stations can also be advantageously used to operate the time-channel switches over which said subscriber stations can be switched into a time-multiplex bar of a time-multiplex system.

According to a further application of the in¬ vention, at least one winding of the above mentioned additional transformer can be short-circuited. Thus, the advantageous possibility is achieved to prevent the actu¬ ation of the above mentioned switch when the receiver is not lifted in the respective subscriber station. Further¬ more, occasionally occuring multiple connections can also be avoided.

According to a further application of the in- vention, the above mentioned additional transformer is provided with an additional winding for 0ach control coil of the magnet core of each subscriber sation; this addi- tional winding is connected in parallel over the secondary ! . winding of a control transformer to the diode! which is already connected to the respective control (soil of the magnet core of each subscriber station* this additional winding is connected in parallel over the secondary winding of a control transformer to the diode which is already connected to the respective control coil; the primary winding of the control transformer being connected in parallel to an electronic switch. Thus the advantage is achieved of a particularly inexpensive circuit with respect to short-circuit at least one winding of the above mentioned additional transformer.

According to a further application of the invention two control transformers ar provided for several subscriber stations, the secondary winding of one of the control transformers being connected in parallel, over the decoupling diodes and over one of the additional windings of the additional transformer pertaining to the respective subscriber station, to a corresponding number of several diodes connected to one of the control colls of the magnet cores pertaining to the respective subscriber station to a corresponding number ofsseveral diodes connected to one of the control coils of the magnet cores pertaining to the respective subscriber station, the secondary winding of the other control transformer being connected in parallel, over the decoupling diodes and also over one of the additional windings of the additional transformer pertaining to the respective subscriber station, to a corresponding number of several diodes connected to the other control coil of the magnet cores pertaining to the respective subscriber stations. Thus an advantageous saving is achieved in the utilization of the above mentioned control transformer.

According to another further application of the invention, the decoupling diodes connected in parallel to a diode lying in series with one control coll of a magnet core,as© BO polarized with respect to the particular diode, that under the same current direction they are stressed in the same forward direction as the particular diode. As will be seen below, this provides the advantage of a particularly simple means to control the influence of the above mentioned control trans ormer upon the other trans ormers serving for the release of actuation impulses to the above mentioned time-channel switch.

Perusal of the drawings depicting application examples of the invention will hel to further clarif the latter.

Fig. 1 shows one application example Of the circuit, according to the invention. ! Fig. 2 shows a second application example of the circuit, according to the invention.

Fig.3 shows a modification of the circuit depicted in Pig.l , according to the invention.

Fig.l shows a subscriber station Tl, the subscriber loop of which comprises two windings a and b of two magnet cores Ka and K which have a rectangular hysteresis curve. These magnet cores can, for example, consist of magnet ring cores. The winding a of the subscriber loop of the subscriber station is connected to a (+) terminal at Its far end (away from the subscriber station) whereas the other winding b is connected to a (-) terminal at its far end. Both windings a and b however, have such a winding sense that when the subscriber loop of the subscriber station Tl is closed, the loop current flowing In this subscriber loop will cause a magnetic reversal of the two magnet cores £& and Kb from one residual state - the one they acquire in rest position - to the other residual state.

So each of the two magnet cores Ka and Kb, which can actually be provided In quantity corresponding to the quantity of several subscriber stations, a control coll 1 or n and a reading coil k or m is attached. e conro co s connec e o an answerng evce marked ScA in Pig.1 and the control coil is connected to an answering device B marked ScB in Fig.l. She current circuit which includes the control coils 1 and n also comprises a diode and one winding of an additional transformer lie. Whereas the current circuit comprising the control coil 1 of magnet core 2a also includes a diode Dla and a winding wl of said additional transformer We. The importance of this additional transformer will be discussed in detail below.

The reading colls k,m of the two magnet cores Ka,Kb are connected to a special evaluation device, thus, the reading coll k of magnet core Ka is connected to the evaluation device A marked UA in Fig-.l, and the reading coil m of magnet core Eh is connected to the evaluation device B marked UB in Fig.l. She current circuits of these reading coils k,m also comprise in the above case, integration elements. Thus the current circuit including the reading coil k comprises the integration element with condenser Ca, and the current circuit including the reading coil m comprises the integratio element with condenser Cb.

Fig* 2 shows an embodiment of the circuit according to the -^r invention and which differs from the one described in Fig. 1 by the fact that now only one magnet core Ke with a rectangular hysteresis curve is provided. This magnet core is also provided with two windings a, b in the subscriber station loop of the subscriber station 1» In contradistinction to the condition described in connection with Fig. It the magnet core Ke is provided* in this case* with six windings. These windings are marked similarly to the corresponding windings in Fig. 1. Contrary to what has been shown in Fig.! 1, the reading coils k and m shown in the circuit of Fig. 2 are always connection in parallel over the primary winding of an output transformer Aue* or Bue respectively the diodes Dla or Dnb respectively which are provided in the circuits of the control coils 1 and n of the magnet core Ke. The control coils 1 and n and the reading coils k and m ere wound in the same sense. The secondary windings of the output transformers Aue* Bue are connected via a diode Sea or Deb respectively to a condenser Ca or Cb respectively forming an integration circuit to which the evaluation devices A and B» marked UA and WB are connected. The above mentioned diodes Dla and Dnb have such polarity that only answering or control impulses respectively emanating from the answering devices ScA or Scb will pass while they remain blocked for any other Impulse or current. Whaever the particular diode Dla or Dnb is conductive* a current may flow through it in the direction opposite to its conductivity as well as through the primary winding of the respective output transformer Aue or Bue. Current flow in the primary winding of the last mentioned output transformer occurs* however* only when a suitable voltage impulse is induced in the reading coil k or n respectively of the magnet core Ke as a result of a control signal current flowing through the appropriate control coil 1 or n respectively of the magnet core Ke. Should no such induction voltage be available in the reading coils k or m of the magnet core Ke since» as a result of tlie ,— receiver being in a rest position at the subscriber station Tl, the magnet core Ke will be in its residual position brought about by the occurrence of a control impulse emanating om one of the answering devices ScA or ScB* an insufficient current lows in the primary winding of the corresponding output transformer Aue or Bue when the respective answering device ScA or ScB emits a control impulse* The flow of such a current in the primary winding of the respective output trans ormer Aue or Bue not only results in the fact that the corresponding evaluation device UA or U3 detects the occurrence of this state* according to which the receiver at the respective subscriber station Tl is lifted; but mainly* the respective evaluation device UA or UB willevaluate the fact that the fereceiver of the corresponding subscriber station Tl is in a rest position* In the circuit of Fig. 2 the primary windings of the output transformers Aue* Bue are connected across two diodes Dkal, Dka2 or Drabl Dmb2 respectively* in parallel to one of the diodes Dla or Dnb.

These diodes only serve to produce decoupling when the primary windings of the respective output transformers Aue* Bue are connected in parallel through several diodes Dla or Dnb to several subscriber stations·< In this case the primary windings of the above mentioned output transformers Aue* Bue are connected* through several further decoupling diodes* in parallel to diodes corresponding to the diodes Dla* Dnb* These further decoupling diodes are depicted by broken lines and marked Dkl' , Dka2* or Stabl* * Dmb2' respectively* The polarity of diodes Dkal* Dka2 with respect to the diode Dla is so selected that the two diodes Dkal* ka2 are conductive in practically the same current direction as the diode Dla* Similar relationships are also valid for the diodes Bmbl, ttab2 and the diode Dnb*' Thus a control impulse current and a current induced by a voltage impulse in the corresponding reading coil will low through the decoupling diodes* With respect to the operation of the circuit depicted in Fig* 2 ^ it should be remarked that except for the above mentioned and differing production of reading voltage impulses* it is identical to the operation of the circuit depicted in Fig. 1 as previously described and therefore no further clarification is required.

Fig* 3 shows a modified form of the circuit depicted in Fig. 1. All the circuit elements which correspond to the ones of Fig. 1 are also marked identically* The circuit elements already described in connection with the circuit of Fig. 1 and also appearing in the circuit of Fig.3 are not described again. In contradistinction to the circuit of Fig. 1 the circuit of Fig.2 comprises an additional transformer Uem comprising two additional windings W^and These additional windings W5» W6 are eonnected in parallel with the secondary winding of a control transformer Stua or Stub of the diode Ola or Dnb which is situated In the control current circuit of the corresponding control winding 1 or n of the two magnet cores a and Kb. The primary windings of the control transformers Stua* Stub can be shortened by means of an electronic switch Wa or Wb. The control input of these switches Wa* Wb may be connected to the control output of the evaluation devices UA or UB» in order to provide» for example* a signal closing the respective switch 9 or Wb when the receiver of the corresponding subscriber station is in a rest posiion.

As explained above* it is possible to short circuit the respective windings W5 or W6 of the transformer Uem across the corresponding diode Dla or Dnb when the corresponding electronic switch W or Wb is closed by proper utilisation, of the additional windings W5 o W6 of the transformer Uem in conjunc ion with the control transformers Stua* Stub and the switches Wa* Wb. A short circuit occurring in the primary winding of the control transformer Stua or Stub Is transformed in the secondary winding of the control transformer and is thus across the diode Ola -w-r-or Dnb* in parallel to the additional winding W5 or W6 of the transformer Uem, which result in a control impulse current or control signal current flowing in the winding Wl or W2 of this transformer Uem not inducing a voltage in the winding W3 » W4 of this transformer Uem. This means that* in this case, answering or control impulses respectively emitted by the answering devices ScA, ScB will have no effect on the time channel switch connected to the windings 18» 94 of the additional transformer Uem* This is* as already mentioned* desirable when for exam le) the receiver of the subscriber station XI is not lifted*' The series circuits connected in parallel to the diodes Dla or Dnb and consisting on one side of the winding W5 of the additional transformer Uem end the secondary winding of the control transformer Stua and on the other side of the winding W6 of the additional transformer Uem and the secondary winding of the control transformer Stub* are supplemented in the circuit of Fig* 3» by another two diodes Dual , ua2 or Dubl, Dub2. These diodes» basically serving for decoupling* have such polarity in their circuit that* with respect to the conductivity of the diode Dla or Dnb they are connected in parallel. Thus the "the transformed short circuit" will be effective through them only when the diode> which is connected in parallel to the corresponding decoupling diodes* is conductive* i.e. will carry an impulse current* The diodes Dual* Dua2 or Dubl* Dub2 are required when the control transformers Stua or Stub are used for several transformers corresponding to the additional transformer Uem* In this case the secondary windings of the corresponding control transformer Stua* Stub are included* over further decoupling diodes Dua2'» Dual* or Dubl** Dub2', into the above mentioned corresponding circuits*.

Since the circuit depicted by Fig. 3 operates in a manner identical to the one of Fig. 1 and since this operation has already been explained in connection with the description of Fig.' 1» it is not necessary to explain this operation again.

In connection with the control of the electronic switches Via and VTb , it should be further remarked that this control may start at the central control device of Fig. l t since this control device has information which subscriber station is to be treated as a calling and which as a called subscriber station.

In conclusion it should be further remarked in connection with the drawings » that the short slanted lines appearing at the crossing points of the schematically depicted magnet cores and magnet core windings indicate the winding direction of the respective windings , so that when the slant of said lines is in the sane direction* the corresponding windings are also wound in the same direction. - -

Claims (10)

WHAT IS CLAIMED IS:

1. Circuit for monitoring in communication - particularly telephone installations « the loop state of subscriber stations having a subscriber loop which always comprises at least one coil with a rectangular hysteresis curve magnet core, where the magnet cores may respond on the loop state of a particular subscriber station according to its characteristic magnetization status by means of answering impulses over the control coils of the subscriber stations* and allow the emission of characteristic output impulses for their magnetization status and thus for the loop state of the particular subscriber station of the selector coils of the subscriber stations characterised by the fact that the magnet cores (Ka,Kb,Ke) are provided with two separate control coils (l,n) for each subscriber station (Tl), so that control impulses for monitoring the loop state of calling subscribers are fed to one of them, and control impulses for monitoring the loop state of subscriber stations to be called are separately fed to the other, and that upon the appearance of these control impulses output signals indicating the loop state of subscriber stations (Tl) are emitted from selector coils (k, m) of the corresponding subscriber stations (Tl) to special evaluation devices (UA, UB)

2. Circuit according to claim 1, further characterized by the fact that by using two separate magnet cores (Ka, Kb) with a rectangular hysteresis curve for each subscriber station (Tl) so that one of the magnet cores (Ka) is fed, over a special control coil (1), control impulses for monitoring the loop state of calling subscriber stations; and the other magnet core (Kb) is fed, over another control coil (n) , control impulses for monitoring the loopstate of subscriber stations to be called, and that each magnet core (Ka,Kb) is connected over a special reading coil (k,m) to a special evaluation device (UA,UB) .

3. Circuit according to claim 1, further characterized by the fact that by using only one magnet core (Ke) ¥ith a rectangular hysteresis curve for each subscriber station (Tl), this magnet core (Ke) is provided with two control coils (n,l) so that control impulses for monitoring the loop state of calling subscriber stations or respectively subscriber stations to be called are fed in separately; and that to each control coil (l,n) a diode (Dla,Dnb) is connected in series; this diode being further connected to a series circuit consisting of the reading coil (k,m) of the magnet core (Ke) and the primary winding of an output transformer (Aue,Bue), the secondary winding of which is connected to the evaluation device (UA resp. UB) , and that the control coils (n,l) have the same winding sense as the reading coils (k,m) .

4. Circuit according to claim 3» further characterized by the fact that the primary winding of each of the output transformers (Aue, Bue) is connected, in series, over decoupling diodes (Dka1 , Dka2 or respectively Dmbl, Dmb2) to reading coils pertaining to the magnet cores of further subscriber stations and in parallel to other diodes (Dla, Dnb) lying in the control windings of the above mentioned further subscriber stations; with the decoupling diodes (Dka1 , Dka2 resp. Dmb1 , Dmb2) so polarized with respect to one of the diodes (Dla resp. Dnb), that under the same current direction they are stressed in the same forward direction as one of the diodes (Dla,Dnb).

5. Circuit according to claim 1, further characterized by the fact that the reading coils of the magnet cores (Ka,Kb,Ke) are connected to an integration element (Dka,Ca; Dnb,Cb) which will receive impulses or signals of only one polarity.

6. Circuit according to claim 2, further characterized by the fact that the control coils (l,n) of the magnet cores (Ka, Kb; Ke) provided for each respective subscriber station (Tl) are connected to a coil (Wl resp. 2) of an additional transformer (Ue) which emits, at least over one output winding (w3,w4), actuation impulses for the operation of at least one time channel switch connecting the respective subscriber station (Tl) with a multiplex-bar.

7. Circuit according to claim 6, further characterized by the fact that at least one winding of the above mentioned additional transformer (Ue resp. Uem) can be short-circuited.

8. Circuit according to claim 7, further characterized by the fact that the above mentioned additional transformer (Uem) is provided with an additional winding (w5, w6) for each control coil (l,n) of the magnet core (Ka,Kb; Ke) of each subscriber station (Tl); this additional winding (w5, w6) is connected in parallel over the secondary winding of a control transformer (Stua, Stub) to the diode (Dla, Dmb) which is already connected to the respective control coil (l,n); and that the primary winding of the control transformer (Stua,Stub) is connected in parallel to an electronic switch (Wa;Wb).

9. Circuit according to claim 8, further characterised by the fact that two control transformers (Stua; Stub) are provided for several subscriber stations, that the secondary winding of one of the control transformers (Stua) is connected in parallel, over the decoupling diodes (Dua1, ua2, Dual ,,Dua2') and over one of the additional windings (w5) of the additional transformer (Uem) pertaining to the respective subscriber station, to a corresponding number of several diodes (i.e. Dia) connected to one of the control coils of the magnet cores pertaining to the respective subscriber station, and that the secondary winding of the other control transformer (Stub) is connected, in parallel, over the decoupling diodes (Dub1,Dub2; Dub1 ' ,Dub2' ) and also over one of the additional windings (w6) of the additional transformer (Uem) pertaining to the respective subscriber station, to a corresponding number of several diodes (Dnb) connected to the other control coil (n) of the magnet cores pertaining to the respective subscriber station.

10. Circuit according to claim 9» further characterized by the fact that the decoupling diodes connected in parallel to a diode (Dla; Dnb) lying in series with one control coil of a magnet core, are so polarized with respect to the particular diode, that under the same current direction they are stressed in the same forward direction as the particular diode. COHEN ΖΕΌΈ.Κ & SP1SBACH P.0. Box 331 16 , Te ! - A v i v Attorneys f o r Applicant