BE482011A - - Google Patents

Description

       

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  Restricted telephone service
The present invention relates to automatic telephony systems and relates especially to those in which different groups of subscriber stations benefit from different corresponding classes of service.



   In an automatic telephone system serving a central or urban office area and adjacent suburban areas, communications from subscriber stations in the urban area which are to terminate at subscriber stations in suburban areas usually arrive from first to an operator's table in the urban area and are then directed by the operators to the subscriber stations in the suburban areas. While functioning in a completely satisfactory manner, this system requires, in the central office, a large operator table served by a large number of operators, in order to establish communications emanating from the area. urban and intended for suburban areas.



   The present invention therefore aims to establish a system

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 telephony system comprising advanced switchgear, whereby first-class subscriber stations in the central office have a corresponding class of service which enables them to establish communications with subscriber stations in suburban areas, while second-class subscriber stations in the central office have a corresponding class of service which prevents them from establishing communications with subscriber stations in suburban areas.



   The invention further aims to establish an automatic telephony system of the aforementioned type, in which the aforementioned first and second class services are provided to the corresponding classes of subscriber stations, whether these are connected to individual lines or to shared lines.



   The invention further aims to establish an automatic telephony system of the type described and comprising first and second class subscriber stations connected to the same line and benefiting from corresponding first and second class services.



   The invention further aims to establish an automated telephony system in which the subscriber stations benefit from different classes of service, these classes of service being selectively established by an improved device comprising an apparatus provided at the subscriber stations.



   The invention further aims to establish an automatic telephony system in which the subscriber stations benefit from different classes of service, these classes of service being selectively established by an improved device comprising different types of numbering mechanisms provided. to subscriber stations.

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   The invention further aims to establish a telephony system comprising a series of automatic switching steps, in which an advanced switching step supplies current of a polarity opposite to that of a previous switching step, a improved device comprising an asimetric or one-way current conductor member arranged at restricted service subscriber stations in order to prevent these stations from controlling the operation of the advanced switching stage.



   The other characteristics of the invention relate to the particular arrangement of the circuit elements of the system which make it possible to achieve the operational features indicated above and others.



     The invention will be better understood, as regards its design and its operation, as well as its other objects and advantages, if one refers to the description below considered in conjunction with the appended drawing, the single figure of which represents the details. of an automatic telephony system comprising the characteristics of the present invention.



   This drawing shows an automatic telephone system comprising a main office or exchange 10 and a remote office or exchange 20. The main office 10 is connected to the remote exchange 20 by a group of suburban (or trunk) lines including the suburban line 1400.
The main office 10 can serve a group of several hundred subscriber stations comprising both private or individual subscriber lines and grouped subscriber lines, both provided with subscriber stations benefiting from both. servioe olasses including unrestricted servioe and restricted service. A first

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 The group of these subscriber lines comprises the individual subscriber lines, 30 and 40, and the grouped subscriber line 170.



   To the individual subscriber lines 30 and 40 are connected the subscriber stations T1 and T2 respectively benefiting respectively from an unrestricted service and a restricted service. To the grouped subscriber line 170 are connected in the ordinary way the subscriber stations PT1 and
PT2 which respectively benefit from an unrestricted service and a restricted service. T1, PT1 etc. with unrestricted service, are equipped with identical and conventional telephone sets, while subscriber sets
T2, PT2 etc., with restricted service are equipped with identical but special telephone sets.

   For example, the unrestricted service subscriber station T1 is provided with a subscriber station apparatus comprising a circuit, a telephone set 11, a hook switch 12 and a dialing dial.
13; the latter comprises a pulse contact 14 in series with the circuit of the subscriber station connected to the line conductors C31 and C32 of the subscriber line 0. Similarly, the subscriber station T2 with restricted service comprises a switchgear. subscriber station comprising a circuit, a telephone set 21, a hook switch 22 and a dial dial 23; the latter comprises a pulse contact 24 interposed in the subscriber station circuit connected to the line conductors C41 and C42 of the subscriber line 40.

   In addition, the apparatus of the subscriber station T2 comprises an asymmetric current-conducting apparatus 25 in the form of a copper oxide rectifier bypassing the impulse springs of the dial 23, associated and designed so that it cannot be crossed by an appreciable current of determined polarity. In particular, the device 25 opposes the passage of an appreciable current when the line conductors C41 and C42 of the subscriber line

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   40 are negative and positive respectively; it can be crossed by an appreciable current when the line conductors 341 and C42 of the subscriber line 40 are respectively positive and negative.

   When the line conductors of the subscriber line 40 have a polarity such that the device 23 blocks the passage of an appreciable current, the pulse contact 24 of the dial 23 can transmit the pulses of one digit through the line of. subscriber
40 following the operation of the dial 21. On the other hand, when the line conductors of the subscriber line 40 have a polarity such that an appreciable current can flow through the device the impulse springs 24 of the device. dial 23 are effectively bypassed and cannot transmit one digit pulses through subscriber line 40 as a result of dial 23 being actuated.

   In addition, each subscriber line ends on a preselector which is individual to it; subscriber lines 30, 40 and 170 respectively terminate at preselectors 35, 45 and 175.



   Further, the main office 10 includes several groups of first selector switches, the first group of first selectors comprising the first selector 50 which terminates the junction 60 accessible to the preselectors 35, 45, 175, etc. associated with the subscriber lines of the first above-mentioned group. Further, the main office 10 includes several groups of local connectors, the first group of local connectors comprising the local connector 70 which terminates the trunk 80 accessible to the different groups of first selectors.



  The local connectors 70, etc., of the first group have access to the subscriber lines 30, 40, 170, etc., of the first group.



  In addition, the main office 10 comprises a group of second selectors including the second selector 110 which terminates the junction 130 accessible to the different groups of first selectors.

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   On the other hand, office 10 comprises a group of suburban circuits which terminate the suburban lines of the group terminating at the remote exchange 20; the suburban circuit 150 terminating the suburban line 140 and being provided with a junction 160 accessible to the second selectors 110, etc. On the other hand, the office 10 includes an operator position 100 terminating a bundle of junctions, the junction 96 of which. Junctions 96, etc., terminate with suburban circuits .95., Etc., respectively provided with incoming junctions. 90, etc., accessible to different groups of first selectors.



   The remote exchange 20 serves a group of subscriber stations including the T3 station; this exchange comprises an automatic switching apparatus 145 of the Strowger type on which the suburban lines 140, etc. terminate and which has access to the subscriber lines 146, etc., respectively terminating at the subscriber stations T3, etc. . On the other hand, the switching apparatus 145 is accessible to the subscriber stations T3, etc., via the subscriber lines 146, etc.,
Preferably in the main office 10, each of the first selectors is identical to the first selector 50, which is of the usual Strowger type oomporting a line relay R51 and a remote switching relay R55.

   Preferably, each of the local connectors is identical to the local connector 70, which is of the usual Strowger type comprising a line relay R71 and a supply reversal relay R75. Preferably, each of the second selectors is identical to the second selector 110, which is of the usual Strowger type comprising a line relay Rlll, a remote switching relay R115 and a signaling relay R120, as well as a counter. 125.



   The connection mode and the arrangement of the telephone system according to the invention will be better understood thanks to

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 the following description relating to the operation of the equipment forming part of this system, operation resulting from the establishment of the various connections from the subscriber stations belonging to the main office 10.



   URBAN COMMUNICATIONS IN THE MAIN OFFICE 10
Assume first that a call is initiated at any subscriber station in main office 10, eg, unrestricted service T1 subscriber station. When the call is initiated at the subscriber station T1 by removing the handset 11 of this station from its switch hook, the switch 12 of this hook closes making an obvious connection passing through the contact or the springs. pulses 14 of dial 13 in shunt with the line conductors C31 and C32 of subscriber line 30 leading to the preselector 35. This initiates the actuation of this preselector, which acts automatically to select a junction leading to a first selector free of the associated group.

   For example, the preselector may select junction 60 leading to the first selector 50, thereby closing a loop circuit between the calling subscriber station T1 and the line relay R51 of the first selector 50. More specifically, a potential earth is applied via the lower winding of the line relay R51 and the pads 59 to the line conductor C62 of the junction 60 and, through the preselector 35, to the line conductor C32 of the subscriber line while a battery potential is applied via the upper winding of the line relay R51 and the pads 6 to the line conductor C61 of the junction 60 and, through the preselector 35, to the line conductor C31 of subscriber line 30.

   When this loop circuit is closed, the line relay R51 of the first selector 50 attracts in order to condition the first selector 50 so that it can react to the first digit formed at the calling abbnne station T1.

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   The subscriber of the calling station Tl then operates the dial 13 to form the first digit of the call number of the called subscriber station; therefore, the pulse springs 14 of the dial 13 are controlled so as to transmit a corresponding number of pulses through the above-mentioned loop circuit to the line relay R51 of the first selector 50.

   This last relay obeys the first digit, thus determining the operation of the first selector 50 to select the corresponding group of local connectors, and then, a free local connector in that group. For example, the first selector 50 can be operated to select the junction 80 terminating at the local connector 70, so that the remote switching relay R55 of the first selector 50 attracts to cut at the pads, 56 and% the loop circuit previously established between the calling subscriber station T1 and the relay of line R51 of the first selector 50; and in closing at the pads 57 and 58 a variant loop circuit extending between the calling subscriber station T1 and the line relay R71 of the local connector 70.

   The aforementioned circuit-loop extends from the source of earth potential through the lower winding of line relay R71 and pads 79 to one of the line conductors of junction 80. and thence through it. via the pads 58 to the line conductor C62 of the junction 60, then via the pre-selector 35 to the line conductor C32 of the subscriber line 30, and finally to the calling subscriber station T1;

   and, from the source of battery potential, via the upper coil of the line relay R71, and the pads 77, to the other line conductor of the junction 80, and from there, via the pads 57, to the line conductor C61 of the junction 60, then through the preselector 35 to the line conductor C31 of the subscriber line 30, and finally to the calling subscriber station T1.



  When this variant loop circuit is closed, the line relay R71 of the local connector 70 attracts to condition the

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 local connector 70 so that it reacts to the next two digits of the call number of the called subscriber station formed at the calling subscriber station T1. Assuming that the call in question is intended for the called subscriber station T2 , the calling subscriber T1 operates the dial 13 to form the next two digits of the calling number of the called subscriber station T2, so that the line relay R71 of the local connector 70 operates according to these two digits.

   More specifically, the local connector 30¯ operates first to select the group of subscriber lines comprising the subscriber line 40 terminating at the called subscriber station T2, and then to select the individual subscriber line 40 in the previously selected group. The subsequent operation of the local connector 70 depends on whether or not the subscriber station called T2 is occupied or not at that moment, in accordance with the usual method.



   Assuming that the called subscriber line T2 is free at this time, inrush current is sent from the local connector 70 by the subscriber line 40. When the called subscriber T2 announces himself by picking up his sombined 21 of the switch hook 22 associated with the called station, the switch 22 of this hook closes establishing an obvious connection comprising the pulse springs 24 of the dial 23 in shunt on the line conductors C41 and C42 of the subscriber line 40. When this connection is established, the local connector 70 operates to interrupt the sending of inrush current on the subscriber line 40 and performs remote switching to determine the operation of its power reversal relay. R75.



  When operating, this last relay inverts at pads 76, 77, 78 and 79 the polarity of junction 80 with respect to the upper and lower coils of line relay R71 and, consequently, the polarity of line conductors C31 and C32 of the subscriber line 30 terminating at the calling subscriber station T1.

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  This reverse polarity in the loop circuit extending between the calling subscriber station T1 and the line relay R71 in the local connector 70 has no particular effect while still being able to be used for counting purposes.



  At this time, a connection is established between the calling subscriber station T1 and the subscriber station T2.



   Subsequently, when the calling subscriber T2 hangs up the receiver of his telephone apparatus 21 on the hook-switch associated therewith, the switch 22 of the latter opens by cutting the loop circuit extending between the telephone set. subscriber called T2 and the local connector 70, so that the supply reversal relay R75 of the local connector 70 drops out by reversing again, at the pads 76, 77, 78, and 79, the polarity in the loop circuit s 'extending between the calling subscriber station Tl and the line relay R71, all having no effect at this time.

   When the calling subscriber Tl hangs up the receiver of his telephone apparatus on the associated switch hook, the switch 12 of this hook opens by cutting the aforementioned loop circuit terminating at the line relay R71 of the local connector 70, from so that the latter relay drops out by determining the release of the local connector 70, the first selector 50 and the preselector 35. At this moment, the connection between the calling subscriber station T1 and the called subscriber station T2 is inter - broken and the equipment which took part is completely relaxed and available for a new job.



   By considering the above description relating to the establishment of an urban call from a private subscriber station T1 with unrestricted service, it is understood that the establishment of an urban call from a station

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 shared subscriber to unrestricted service is performed in an identical manner. By way of illustration, it will be noted that the establishment of an urban call from a shared subscriber station calling unrestricted service PTI on the shared subscriber line 170, the associated pre-dialer 175, the junction 60, the first selector 50, the junction 80, the local connector 70 and the subscriber line 40 to the called subscriber station T2 is identical to that described above.



   It will now be assumed that a call is initiated from a subscriber station in the main office 10, for example the restricted service subscriber station T2. In this case, when the call is initiated at the subscriber station T2 by removing the receiver 21 of this station from the associated hook switch, the switch 22 of the hook closes, closing an obvious connection passing through the pulse contact. 24 of the dial 23 by shunt on the line conductors C41 and C42 of the subscriber line 40 leading to the preselector 45. The latter is actuated to act automatically in order to select a junction leading to a first free selector of the associated group.

   For example, the preselector 45 may select the junction 60 terminating at the first selector 50, thus closing a loop circuit between the calling subscriber station T2 and the line relay R51 of the first selector 50. More specifically, a ground potential is applied. via the lower coil of the line relay R51 and the pads 59 to the line conductor C62 of the junction 60 and, through the preselector 45, to the line conductor C42 of the subscriber line 40; on the other hand, a battery potential is applied via the upper winding of the line relay R51 and the pads 56 to the line conductor C61 of the junction 60 and, via the preselector 45., to the C41 line conductor of the

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 subscriber line 40.

   When this loop circuit is closed, the line relay R51 of the first selector 50 is actuated to condition the first selector 50 so that the latter can react to the first digit formed at the calling subscriber station T2. It should be noted in passing that, at subscriber station T2, the asymmetric or one-way current conductor device 25 bypasses the pulse contact 24 of the associated dial 23;

   however, this device has no effect in the case considered, since the line conductors C42 and C41 of the subscriber line 40 are respectively marked with a positive and negative polarity by the line relay R51 of the first selector 50, so that the passage of an appreciable current through the device 25 is blocked so that the pulse contact 24 of the dial 23 is able to transmit the pulses of the first digit formed to the calling subscriber station T2 through the subscriber line 40 to line relay R51 of the first selector 50.

   The calling subscriber T2 then operates the dial 23 to form the first two digits of the call number of the called subscriber station, so that the pulse contact 24 of this dial is actuated to transmit a corresponding number. of pulses through the aforementioned loop circuit to the line relay R51 of the first selector 50. The line relay R51 of the first selector 50 operates according to the first digit by determining the actuation of the first selector 50 to select the corresponding group of local connectors and then a free local connector in this group.

   For example, the first selector 50 can be actuated to select the junction 80 terminating at the local connector 70, so that the remote switching relay R55 of the first selector 50 is actuated.

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 to cut at the pads 56 and 22 the aforementioned loop circuit extending between the calling subscriber station T2 and the line relay R51 of the first selector 50; and to close to the pads 57 and 58 a variant loop circuit extending between the calling subscriber station T2 and the line relay R71 of the local connector 70.

   The aforementioned circuit-loop extends from the source of earth potential, through the lower winding of the line relay R71 and the pads 79. to one of the line conductors of the junction 80, and from there, through the 'through the pads .58., to the line conductor C62 of the junction 60, and then, through the preselector 45, to the line conductor C42 of the subscriber line 40 and finally to the calling subscriber station T2 ;

     and, from the source of battery potential, via the upper winding of line relay R71 and pads 77, to the other line conductor of junction 80, and from there, via the pads 57 to the line conductor C61 of the junction 60, then, via the preselector 45, to the line conductor C41 of the subscriber line 40, and finally to the calling subscriber station T2. When this variant loop circuit is closed, the line relay R71 of the local connector 70 operates to switch this local connector 70 to react to the next two digits of the called subscriber station number formed. at the calling subscriber station T2.

   As the conductors C42 and C41 of the subscriber line 40 are respectively marked with a positive and negative polarity by the line relay R71 of the local connector 70, the passage of an appropriate current through the devices 25 of the calling subscriber station T2 is blocked, so that the pulse contact 24 of the dial 23 can transmit the pulses of the next two digits formed at the calling subscriber station T2, through the subscriber line 40, to the line relay R71 from local connector 70.

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   If the call in question is intended for the call subscriber station? T1, the subscriber of the calling station T2 operates the dial 23 to form the next two digits of the call number of the called subscriber station T1, so that the line relay R71 of the local connector 70 operates according to these two digits . More specifically, the local connector 70. operates first for select. the group of subscriber lines comprising the subscriber line 30 which terminates at the called subscriber station T1 and then to select the individual subscriber line 30 from the previously selected group. The subsequent operation of the local connector 70 depends on whether the called subscriber station T1 is busy or unoccupied, in accordance with the current method.



   If the called subscriber set T1 is free at this time, inrush current is sent from the local connector 70 on the subscriber line 30. When the called subscriber T1 answers the call by picking up the phone. combined 11 of this station of its hook switch, the switch 12 of the hook closes making an obvious connection comprising the pulse contact 14 of the dial 13 shunted on the line conductors C31 and C32 of the subscriber line 30. When this connection is thus established, the local connector 70 functions to interrupt the sending of the call current on the subscriber line 30 and performs a remote switching to determine the operation of the supply reversal relay. R75 of this connector.

   When it is actuated, this last relay reverses at pads 76, 77, 78 and 79 the polarity of junction 80 with respect to the lower winding of line relay R71 and therefore the polarity of line conductors C41 and C42 of line d subscriber 4 - terminating at the calling subscriber station T2.



  This reverse polarity in the loop circuit extending between the calling subscriber station T2 and the line relay R71

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 of the local connector 70 makes the line conductors C41 and
C42 of the subscriber line 40 respectively positive and negative so that an appreciable current flows through the device 25 of the calling subscriber station T2, thereby effectively shorting the pulse contact 24 of the dial 23 in order to emit - fishing for the formation of subsequent digits at the calling subscriber station T2.

   However, the bypassing of the pulse contact 24 from the dial 23 to the calling subscriber station T2 has no particular effect in the present example, since no more digits need to be formed at this station, since that communication has already been established with the called subscriber station
T1. Also, this reverse polarity in the loop circuit extending between the calling subscriber station T2 and the line relay R71 of the local connector 70 can be used for counting purposes. A communication is now established between the calling subscriber station T2 and the called subscriber station T1.



   In the following, when the called subscriber Tl hangs up the receiver of the telephone apparatus 11 of its installer, the hook switch associated with it, the switch 12 of the hook is opened by cutting the loop circuit which extends. between the called subscriber station T1 and the local connector 70, so that the supply reversal relay R75 of the local connector 70 drops back again by reversing, at the pads 76,77,78 and 12, the polarity in the loop circuit extending between the calling subscriber line T2 and the line relay R71, all of which has no effect at this time.

   When the subscriber of the calling station T2 hangs up the receiver of his telephone device on the associated switch hook, the switch 22 of this hook opens by cutting the aforementioned loop circuit terminating at the line relay R71 of the connector. local 70, so that the line relay R71 drops, thereby determining the release of the local connector 70, of the first selector 50 and of the preselector 45.

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 the communication between the calling subscriber station T2 and the called subscriber station T1 is interrupted and the equipment which participated in it is completely released and available for new use.



   Considering the above description relating to the establishment of an urban call emanating from a restricted service private subscriber station T2, it is understood that the establishment of an urban call emanating from a station of The shared (restricted service) subscriber will take place in an identical manner. By way of illustration, it should be noted that the establishment of an urban communication emanating from a shared subscriber station calling PT2 with restricted service, by the shared subscriber line 170, the preselector 175 associated therewith, the junction 60, the first selector 50, the junction 80, the local connector 70 and the subscriber line 30 to the called subscriber station 13, is identical to that described above.



   INTER-URBAN (SUBURBAN) CALLS FROM THE MAIN OFFICE 10 TO
REMOTE CENTRAL 20
Assume first that a call has been initiated at the unrestricted T1 subscriber station at main office 10; that the preselector 35 has operated to select the junction 60 leading to the first selector 50; that the first selector 50 is conditioned to obey the first digit formed at the calling subscriber station T1; and, that the call is intended for the called subscriber station! 1 of the remote exchange 20. In this case, the subscriber c of the calling station T1 forms the first digit of the call number of the called subscriber station T3 of the central / remote 20, so as to re-operate the first selector 50 for the purpose of selecting a junction resulting in a second free selector.

   For example, the first selector 5-3 may operate to select junction 130 leading to the second selector 110, after

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 what the connection relay R55 of the first selector 50 attracts to cut at the pads 56 and 59 the above-mentioned loop circuit extending between the calling subscriber station T1 and the line relay R51 of the first selector 50 ; and to close at the pads 51 and 58 a variant loop circuit extending between the calling subscriber station T1 and the line relay R111 of the second selector 110.

   More specifically, an earth potential is applied via the upper winding of the line relay Rlll and the pads 116 to one of the line conductors of the junction 1 0 and, through the pads 57, to the conductor. line C61 from junction 60 and from there, via preselector 35, to line conductor C31 of subscriber line 30 terminating at calling subscriber station T1, while battery potential is applied by the intermediate to the lower winding of the line relay R111 and the pads 119 to the other line conductor of the junction 130 and, through the pads 58, to the line conductor
C62 from junction 60, and then,

   via the pre-selector 35 to the line conductor C32 of the subscriber line 30 terminating at the auxiliary subscriber station. Therefore, the line conductors C31 and C32 of the subscriber line 30 terminate at the extension calling subscriber T1 are respectively applied a positive and negative polarity by the line relay R111 of the second selector 110, this polarity of the subscriber line 30 having no effect on the calling subscriber station T1.

   When this variant loop circuit is thus closed, line relay R111 operates to condition second selector 110 to obey the second digit formed at the calling subscriber station T1; and to close to the pads 112 a circuit passing through the pads 119 'and intended to apply an earth potential to the counter 125, so as to initiate the operation of the latter.



    It should be noted here that, if the second digit of the called subscriber station T3 telephone number of the remote exchange 20 is not

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 formed in a determined time interval, the counter 125 intervenes to determine the operation of the signaling relay R120 for a purpose which will be explained more fully below.



   The subscriber of the calling station T1 then forms the second digit of the call number of the called subscriber station T3 of the remote exchange 20; the line relay Rlll obeys by determining the operation of the second selector 110, first in order to select the group of trunk or suburban lines provided between the main office 10 and the remote exchange 20, and then to select a line of free junction in this group.

   More specifically, the second selector 110 may select the trunk 160 terminating at the trunk or trunk circuit 150 which terminates the trunk line 140 terminating at the switching apparatus @ of the remote exchange 20, after which the switching relay remote R115 of the second selector 110 pulls to cut at the pads 116 and 119 the loop circuit previously established between the calling subscriber station T1 and the line relay Rlll of the second selector 110.

   Further, the remote switching relay R115 closes at pads 117 and 118 a variant loop circuit extending between the calling subscriber station T1 and the line conductors of junction 160 terminating at junction circuit 150. , so that this circuit ensures the occupation of the junction line 140 and therefore of the switching device 145 of the remote exchange 20, with the result that this device is put in a state to obey a series of digits transmitted by the junction line 140. Finally, the remote switching relay R115 of the second selector 110 cuts at the pads 119 'the circuit previously established to apply the earth potential to the conductor ending at the counter 125, in order to stop the circuit. operation of the latter at this time.



   The subscriber of the calling station Tl then forms the numbers

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 of the call number of the called subscriber station T3 of the remote exchange 20, so that these digits are sent by the above-mentioned loop circuit to the trunk circuit 150 and are repeated therein by the trunk line. junction 140 to the switching apparatus 145 in order to cause the latter to establish the connection to the subscriber line 146 terminating at the subscriber station called T3 of the remote exchange 20. Subsequent operation of the apparatus Switch 145 depends on whether or not the called subscriber station T3 is busy or not at that time, in accordance with the usual method.

   If the called subscriber station T3 of the remote central station 20 is free at this time, the switching apparatus 145 operates to send inrush current through the subscriber line 146 to that station.



   When the subscriber of the called station T3 announces himself by removing the receiver of the telephone apparatus of this station from the associated hook switch, the switching apparatus 145 performs a remote switching in order to establish a connection. between the calling subscriber station il¯ of the main office 10 and the called subscriber station T3 of the remote exchange 20.



   The interruption of the connection thus established is subordinated to the subscriber of the calling station T1 of the main office 10 and, when the receiver of the telephone apparatus of this station is hung up on the associated hook switch, the switch 12 of this hook opens so as to interrupt the previously indicated loop circuit extending between the calling subscriber station T1 and the junction circuit 150. This latter circuit is interrupted, which determines the release of the second selector switch. 110, of the first selector 50, of the preselector 35 of the main office 10. as well as the release of the switching apparatus 145 of the remote office 20.



    Considering the above concerning the establishment of a suburban call from the private subscriber station T1 with unrestricted service, it is understood that the establishment

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 of a suburban call from an unrestricted service shared subscriber station is carried out in an identical manner.

   By way of illustration, it should be noted that the establishment of a suburban toll call from a shared subscriber station calling PT1 from the main office 10, with unrestricted service, via the telephone line. shared subscriber 170, of the associated preselector 175, of the junction 60, of the first selector 50, of the junction 130, of the second selector 110, of the junction 160, of the junction circuit 150, of the junction line 140, switching apparatus 145 and subscriber line 146, with the called subscriber station T3 of remote exchange 20, is identical to that described above.



   It will now be assumed that the call has been initiated at the restricted service subscriber station T2, main office 10; that the preselector 45 has operated to select the junction 60 leading to the first selector 50; that the latter has operated to select the jonotion 130 leading to the second selector 110 and that the latter is conditioned to obey the second digit formed at the calling subscriber station; and, that the subscriber of the calling station T2 still tries to establish a communication with a called subscriber station of the remote exchange 20.

   At this time, the first selector 50 has already reacted to the first digit of the call number of the subscriber station called from the remote office 20 to select the junction 130 leading to the second selector 110 as indicated above, so that the line relay 1111 of the second selector 110 will have operated to initiate the operation of the counter 125 incorporated in this second selector. On the other hand, the line conductors C41 and C42 of the subscriber line 40 are respectively applied a positive and negative polarity by the line relay R111 through the loop circuit extending between the station. calling subscriber T2 and the second selector 110.

   Therefore, the device 25 which shunts the pulse contact 24 from the dial 23 to the

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 calling subscriber station T2 allows an appreciable current to flow due to the indicated polarity of the line conductors of the subscriber line 40, printed by the line relay
Rlll of the second selector 110, so that the device 25 bypasses the pulse contact 24 of the dial 23. Therefore, this contact is disabled from transmitting subsequent pulses from the dial 23 of the calling subscriber station. T2 via the subscriber line 40. Thus, the subscriber of the calling station T2 cannot control the line relay Rlll of the second selector 110, and any subsequent operation of the dial .23. at the calling subscriber station T2 has no effect.



   Shortly thereafter, the counter 125 of the second selector 110 completes its counting operation to determine the operation of the signal relay R120, so that the latter closes an obvious circuit to the pads 121 to apply a hum current, supplied by the buzzer transformer 122, to one of the line conductors of the junction 130, which buzz current is returned by the loop circuit to the calling subscriber station T2, indicating to the subscriber from this station that the communication in question cannot be established with the called subscriber station of the remote exchange 20.



  When the subscriber of the calling subscriber station 12 then hangs up the receiver of the telephone apparatus of this station on the associated hook-switch, the switch 22 of this hook opens, interrupting the extending loop circuit. between the calling subscriber station T2 and the line relay Rlll of the second selector 110. The line relay R111 drops out, thus determining the release of the second selector 110, of the first selector 50 and of the preselector as explained previously.



  On the other hand, on falling, the line relay Rlll of the second selector 110 cuts to the pads 112 the circuit indicated above in order to apply an earth potential to the lead conductor.

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 weaving to counter 125, so that the latter is released causing the release of signaling relay R120.



   On falling, the latter cuts to the pads 121 the circuit previously established for the return of the humming current to the junction 130. At this moment, the connection between the calling station T2 and the second selector 110 is cut. and all the devices that participated in it are completely released and can be used again.



   Considering the above description of how a suburban call initiated at the restricted service private subscriber station T2 of the main office 10 is blocked in the second selector 110, it is understood that a suburban call initiated. at a shared subscriber station calling with restricted service of the main office 10, for example the shared subscriber station PT2, will be blocked in the second selector 110 in an identical manner.



  In addition, it is understood that, in the case where the subscriber of a calling station with unrestricted service initiates a suburban call and determines the transmission of this call to the second selector 110 and then omits to form the second digit of the number of the called subscriber station of the remote exchange 20, the counter 125 of the second selector 110 is actuated in the manner described above in order to determine the operation of the signaling relay R120 of this second selector, with, as a result, the forwarding of the buzzing current at the aforementioned calling subscriber station, all in the manner described above.



   CALLS TO OPERATOR POSITION 100 OF THE OFFICE
MAIN 10.



    Private subscriber stations T2, etc., with restricted service and PT2, etc., with restricted service do not have the option of establishing suburban calls directly from the main office 10 to the subscriber stations called from

 <Desc / Clms Page number 23>

 remote office 20, but can obtain such communications only with the assistance of the operator in the operator position 100. Such subscribers must establish communications directly with the operator position 100 and request the intervention of the operator. the operator of this position with a view to establishing communications with subscriber stations requested from the remote exchange 20.

   However, the subscriber of any calling station of the main office 10 can establish a communication with the operator position 100 in order to obtain the assistance of the operator of this station for the establishment of a call. interurban (suburban) communications or for any information or other services.



   For example, the subscriber of the calling station T1 unrestricted service of the main office 10 can establish a connection through the subscriber line 30, the preselector ± ±, the trunk 60, the first selector. 0¯ and incoming junction 90, with junction 95 on which junction 96 terminates leading to operator position 100, as is self-evident. When the connection is thus established up to the junction circuit, a signal is transmitted on 96 to the operator position 100 and, when the operator of this position announces himself, a connection is established between her and the set. 'T1 subscriber.

   In the following, when the subscriber of the calling station Tl hangs up the receiver of the telephone apparatus 11 of this station on the switch hook associated with it, the switch 12 of this hook opens to cut a loop circuit substantially. identical to that established previously between the calling subscriber station Tl and the suburban circuit 95, so that the latter is interrupted by determining the release of the first selector 50 and the preselector On the other hand the junction circuit transmits a signal release on junction 96 has the operator position 100 and the operator of this last position removes the connection

 <Desc / Clms Page number 24>

 with junction 96.



   Considering the above description relating to the establishment of a communication between the calling subscriber station T1. unrestricted service from the main office 10 and the operator position 100 of that office, it will be understood that calls from subscriber stations T2, PT1, PT2, etc., from the main office 10 can arrive from a identical to the operator position 100 of this office. It should be noted in passing that calls from subscriber stations with restricted service, for example stations T2 and PT2 of the main office 10, destined for the operator position 100 of this office can end in this position, being; given that the sending of such calls does not require dialing beyond the first selector 50.

** ATTENTION ** end of DESC field can contain start of CLMS **.


    

Claims (1)

CONCLUSIONS Considering the foregoing, it can be seen that both restricted and unrestricted subscriber stations, whether connected to individual lines or to shared lines, can selectively control the automatic switching apparatus for establish city calls in the main office 10. However, only subscriber stations with unrestricted service, whether connected to individual lines or to shared lines, can selectively control the telephone set. automatic switching to establish long distance (suburban) communications with subscriber stations in the remote office 20. In addition, it is conceived that any subscriber station, whether connected to an individual line or to a shared line, can easily be transformed from an unrestricted station to a non-restricted station. service restricted by the only modification of its dial, that is to say by providing the subscriber station with a dial whose impulse contacta is shunted by a one-way current conducting device Although an embodiment of the invention has been described here <Desc / Clms Page number 25> As currently considered to be preferable, it goes without saying that this execution is susceptible of various variations, the following claims being intended to cover all modifications which may be justified by the spirit and the real scope of this invention. CLAIMS 1.- In a telephone system comprising a first or central office with subscriber stations benefiting from first and second class services and a first switch accessible to these subscriber stations and a second accessible switch at the first switch and having access to these subscriber stations and a third switch accessible to the first switch, a second office or central, and a junction provided between these exchanges and accessible to the third switch; each of these subscriber stations comprising a circuit and a dialing mechanism provided with a pulse contact in series in this circuit, each of said subscriber stations of said second class further comprising a current conducting device asymmetric or one-way bypassing the pulse contact of the associated dialing mechanism and established so as not to pass through an appreciable current of determined polarity, means comprising the dialing mechanism of a calling subscriber station to actuate said first switch to selectively establish connections with said second switch and said third switch, means included in said second switch, for supplying current of said determined polarity to the subscriber station circuit connected caller, so that this second switch can be operated under the control of the numbering mechanism of a calling subscriber station of one or other of said classes, in order to establish a connection with a station of 'a- bonne called, and means incorporated in said third <Desc / Clms Page number 26> switch and intended to supply current of the opposite polarity, to the circuit of the calling subscriber station connected, so that this third switch can be actuated under the control of the dialing mechanism of a subscriber station first class calling for establishing a connection with said junction, but cannot be operated under the control of the dialing mechanism of a subscriber station of said second class for setting up a connection with said junction. 2.- In a telephone system comprising first and second class subscriber stations, a first switch accessible to these subscriber stations, and a second and third switches accessible to the first switch; each of these subscriber stations comprising a circuit and a dialing mechanism provided with a pulse contact in series therein, each of the second class subscriber stations further comprising a device. one-way current conductor bypassing the impulse contact of the associated numbering mechanism, and established so as not to deliver an appreciable current of a given polarity, means comprising the dialing mechanism of any calling subscriber station for actuating said first switch to selectively establish connections with said second switch and said third switch, means incorporated therein switch for supplying current of said determined polarity to the circuit of the connected calling subscriber station, so that this second switch can be actuated under the control of the dialing mechanism of a calling subscriber station of either any of said classes, and means included in this third switch and intended to supply current of opposite polarity to the circuit at the connected calling subscriber station, so that the third switch <Desc / Clms Page number 27> be operable under the control of the numbering mechanism of a calling subscriber station of the first class, but not operable under the control of the dialing mechanism of a calling subscriber station of the second class . 3.- In a telephone system comprising a subscriber station, a first switch accessible to this station, and a second and a third switch accessible to the first switch; this subscriber station comprising a circuit and a numbering mechanism provided with a pulse contact in series in this circuit and a one-way current conducting device bypassing this contact and established so as not to allow passage of an appreciable current of determined polarity, means comprising said numbering mechanism for activating the first switch in order to selectively establish connections between this subscriber station and this second switch and this third switch, means included in this second switch for supplying current of said determined polarity to said circuit when a connection is established between this subscriber station and this second switch, so that this second switch can be operated under the control said numbering mechanism, and means included in said third switch and intended to apply current of opposite polarity to said circuit when a connection is established between this subscriber station and this third switch, so that this switch cannot be actuated under the control of said dial mechanism. 4.- In a telephone system comprising a subscriber station, a first switch accessible to this station, and a second and third switches accessible to the first switch; this subscriber station comprising a circuit and a dialing mechanism provided with a pulse contact in series in this circuit and with an asymmetric current conducting device shun- <Desc / Clms Page number 28> both this pulse contact and established so as not to allow passage of an appreciable current this determined polarity, means comprising this numbering mechanism and intended to control the first switch, to selectively establish connections between said station subscriber and the second switch and the third switch, means including a line relay in the second switch, for supplying said circuit with a current of said determined polarity, so that the line relay is actuated when a connection is established between the subscriber's station and the second switch, and can be selectively controlled by the numbering mechanism and means including a line relay provided in the third switch, to supply current of the opposite polarity to this circuit, so that the line relay last mentioned is activated when a connection is established between the subscriber station and the third switch, but cannot be selectively controlled by this dialing mechanism. 5.- In a telephony system comprising a subscriber station, a first switch accessible to this station, a second and a third switch accessible to the first switch; this subscriber station comprising a circuit and a numbering mechanism provided with a pulse contact in series in this circuit, while a one-way current-carrying device bypasses this contact and is established so as not to provide passage to an appreciable current of determined polarity, means comprising this naming mechanism and intended to actuate the first switch to selectively establish connections between the subscriber station and the second switch and the third switch, means included in the second switch for supplying current of said determined polarity to said circuit when a connection is established between the subscriber station and this second switch, so that this switch can be operated under the control of the numbering mechanism <Desc / Clms Page number 29> tion, means included in the third switch for supplying current of opposite polarity to said circuit when a connection is established between the subscriber station and this third switch, so that this third switch cannot be operated under the control of the dialing mechanism, and of the duration counting means controlled by the non-operation of the third switch in a determined time interval after a communication has been established up to this switch, in order to return a signal on the connection going to said subscriber station. 6.- In a telephone system comprising a subscriber station, a switch accessible to this station and a first and a second path accessible to this switch; this subscriber station comprises a circuit and a numbering mechanism provided with a pulse contact in series and an asymmetrical current conductor device bypassing this contact and established so as not to allow passage of an appreciable current of a determined polarity, means comprising this numbering mechanism and intended to actuate this switch to selectively establish connections between said subscriber station and said first channel and said second channel, means included in said first channel, to supply current of said determined polarity to said circuit when a connection is established between the subscriber station and this channel, so that a next digit of the numbering mechanism can be transmitted to said first channel, and means included in the second channel for supplying current of opposite polarity to said circuit when a connection is made between the subscriber stations and this second channel, so that a subsequent digit of the dialing mechanism cannot be transmitted to said second channel. 7.- In a telephone system, a subscriber station at the <Desc / Clms Page number 30> which terminates a two-conductor line, and comprising a circuit branched off from these line conductors, a numbering mechanism provided with a pulse contact in series in this circuit, and an asymmetric current-carrying device bypassing this contact . 8. - In a telephony system comprising a shared line serving first and second class subscriber stations, a first switch accessible by the intermediary of this shared line to said subscriber stations and a second and a third switches accessible after the first switch; each of these subscriber stations comprising a circuit and a dialing mechanism provided with a pulse contact in series therein, each of these second class subscriber stations comprising an asymmetric current-carrying device bypassing the contact to pulses of the associated dialing mechanism, and established so as not to give passage to an appreciable current of determined polarity, means comprising the dialing mechanism at any calling subscriber station, for actuating, through this line shared, said first selector, in order to selectively establish connections with said second switch and said third switch, means included in said second switch, for supplying current of said determined polarity to said shared line, and beyond to the circuit of the connected calling subscriber station, from; so that this second switch can be operated by this shared line under the control of the dialing mechanism of a calling subscriber station of any one of said classes, and of the means included in said third switch, for supplying current of polarity opposite to this shared line, and beyond to the circuit of the connected calling subscriber station, so that the third switch can be operated by this shared line under the control of the dialing mechanism of a subscriber station <Desc / Clms Page number 31> calling from said first class, but cannot be operated by this shared line under the control of the dialing mechanism of a subscriber station calling from said second class :. 9.- In a telephone system, a shared line of the two-conductor type, first and second-class subscriber stations, each of these stations comprising a branch circuit on said line conductors and a mechanism numbering device provided with a pulse contact in series in this circuit, each of the second class subscriber stations further comprising an asymmetric or one-way current-carrying device bypassing the pulse contact of the associated dialing mechanism .