TELEPHONE NETWORK WITH SWITCHING PLANTS, WHICH ARE OVER FEEDER LINES WITH ONE ANOTHER GROUP, IN PARTICULAR BRANCH NET WITH A MAIN PLANT, WHICH IS OVER NEBENANSCHLUSSLEITUNGEN WITH WAEHLUNTERANLAGEN GROUP

The invention refers to a telephone network with Vermitflungsanlagen, which are connected by feeder lines, in particular branch net with a main plant, which is connected with selecting documents by Nehenanschlußleitungen, whereby the signal system of the telephone network does not contain absolutely necessary, by alternating current characteristics, in particular 50-Hertz-Wechselstromkennzeächen, formed main characteristics and additional, for the connection establishment and the clearing necessarily necessary for the connection establishment and the clearing Nehenkennzeichen formed by audio frequency characters, whereby a Nebenkennzeichen is sent always immediately after a main identifier and whereby the respective Nebenkennzeichen directly preceding the Haupt_kennzeichen is intended also for the control of for sending, admission and evaluation lo of the Nebenkennzeichens serving Sendeund receipt mechanisms. The use of doubly arranged feeder lines in connecting traffic, in particular in telephone networks, is well-known. If it concerns thereby connecting traffic between Fernsprechnebensteltenan] agen itself and if the PABX are equivalent, then generally of cross connection traffic one speaks. If it concerns against it the telephone transmission between a main plant and a so-called selecting under plant, by which from connections to the public office only over the Hauptaniage can be manufactured, then generally of Nehenanschlußleitungen and selecting under plant traffic one speaks. With each traffic between telephone systems and in particular between main plant and W, an extension net, characteristics between the two plants *ihlunteranlagen are exchanged. These indications can e.g. as Gleiehstromkennzelchen, when inductive characters, when alternating current characteristics, when audio frequency characteristics are sent and also as multi-frequency clay/tone choice characters. Which classification of signals is used, is not only from the respective telephone system of the telephone system and the Betrfehsart of the used line transmissions, but also dependent on the number of characteristics which can be transmitted. With the transmission method for the characteristics over the feeder lines, which can be transmitted, it is generally insignificant, which choice procedure is used in each case in the plant existing at an end of the Verbindungsleitnng. It is ün general insignificant whether at a feeder line end impulse choice or push button selection or both kinds of choice are intended. The respective choice procedure can be selected freely. The respective transmission method for the choice characteristics over the feeder line can be selected likewise freely. Can be transmitted from there both impulse choice characteristics and Mehrfrequenztonwahlkeunzeichen and also different indications. With impulse choice it is usual to pass these on in the character font of the used upper carrying procedure of the feeder line simply. With the available telephone network it acts over additionally to the choice characteristics alternating current characteristics and audio frequency characteristics which can be transmitted, whereby the audio frequency characteristics s can be also Mahrfrequenzzeichen. The alternating current characteristics are called Hanptkennzeichen and the audio frequency characteristics (multi-frequency characters) as Nebenkennzeichen. This use from main identifiers and Nehenkennzeichen to transferring characteristics over blocked Verblndungsleitungen is already well-known from the DE-OS 2233764, whereby one can also assume that it admits is to assign to the main identifiers depending upon transmission direction different lengths in order reached through a transmission direction to secure. With from the aforementioned DE-OS 2233764 well-known procedures for transferring characteristics over between Fernsprechhauptund to a Fernspreehunteranlage process do not end abgeriegeite feeder lines for the Aufund dismantling of a connection necessary characteristics, as for example allocation characteristic, choice impulse, free characteristic and release characteristic as 50-Hertz-Wechselstromkennzeichen of different length and all for the actual connection establishment necessarily necessary characteristics, like authorization flag, lane occupation characteristic u.dgl., as audio frequency characteristic of different frequency between the two plants are e.g. exchanged. With this procedure also multi-frequency clay/tone choice characteristics can be used. An audio frequency characteristic directly preceding the Wechselstromkennzelchen serve also s0 for it, one free for the admission to turn evaluation and/or sending on of audio frequency characteristics necessary audio frequency receipt mechanisms and/or transmission mechanisms to the Verbindungsleltung. With that well-known procedures managing however not in every case the perfect transmission and evaluation Hauptund Nebenkennzeichen are guaranteed specified. There is with this procedure in particular the possibility that main identifiers and/or Nebenkennzeichen from same and/or opposite direction into one another-run and that disturbances of the Nebenkennzeichen take place via Sprachsignale. The task of the invention consists of guaranteeing in a telephone network with a signal system consisting of Hauptund Nebenkennzeichen while maintaining the reaching through protection of characteristics of a certain Verkehrsrichtung the perfect transmission of the Nebenkennzeichen. This is reached by the fact that the respective Nebenkenn sent after a main identifier calibrate immediately after a following second main identifier one repeats. Hiedurch is guaranteed in simple way at small expenditure under utilization of the same Nebenkenuzeichens that, even if a Nebenkennzeichen following on a first main identifier is disturbed or destroyed but the information contents of the Nebenkennzeichens remain unchanged. Another gleichfferichtetes or main identifier moving in opposite directions can shorten a Nebenkennzeichen, but the repetition of the latter guarantees its evaluation. This is for example with impulse choice the case, if choice impulses are already passed on over the feeder line, before that was transferred to the allocation characteristic (main identifier) the following Nebenkennzeichen in full length. Since such Nebenkennzeichen cannot only be lost, but by Sprachsignale, u.zw also in the instance of repetition to be falsified, consists a favourable further training of the invention can of that each main identifier both to Sendeals also at the receipt side of one between main plant and selecting under plant process end to feeder line an interruption of the Sprechwege introduce and that a following Nebenkennzeichen extends this interruption at least for its complete duration. It is reached that a main identifier for causing the disconnection and a directly following Nebenkennzeichen are used for the extension of this disconnection of the transmission path for Sprachsignale. Hiemit is then the troublefree transmission and evaluation Hauptund Nebenkennzeichen guaranteed. A further favourable execution of the invention lies that the interruption only according to completion of one with a main identifier and/or a Nebenkennzeichen determined time delay is waived. From it the advantage results that e.g. then, if a Nebenkennzeichen consists of several clay-frequent single characters no unnecessary short turning of the Sprechwege on takes place. A further favourable execution of the invention consists of it that the time delay is longer than the Pausenzeit between two following each other, belonging together main identifiers, in particular a choice pulse series (impulse break time t). From it the advantage results that e.g. between two Wahllmpulsen each of a choice pulse series no redundant Ansehaltung of the Sprechwege takes place. On the basis the Fig. a remark example of the invention and the details standing thereby in connection are descriptive 1 to 7. Fig. 1 shows from the main plant --Ha-- outgoing Hauptken - indications --HK1 to HK4-- and Nebenkennzeichen --NK1 to NKI'"--, which are sent in connection with the occupying of the feeder line and the following first choice pulse series with for example three impulses with the connection establishment over the feeder line. The Nebenkennzeichen --NKI' to NK1'r…. place, as still one describes, in each case the repetition of the Nebenkennzeichens --NK1-- . Fig.2 shows from the selecting under plant --WUA-- outgoing main identifiers and Nebenkennzeichen 4s with the connection establishment to a main plant --Ha--, whereby Fig.2a for occupying necessary main identifiers --HK5-- , Fig.2b points to occupying necessary main identifiers --HK5-- and a directly following, e.g. a code choice indicating Nebenkennzeichen --NK2-- , Fig.2c points to the main identifier --HK5-- from two audio frequency characters of different lengths an existing, e.g. an office without direct distance dialing indicating Nebenkennzeichen --NK3-- shows and whereby Fig.2d to so the main identifier --HK5-- from three audio frequency characters an existing, an office with direct distance dialing indicating Nebenkennzeichen --NK4-- shows. Fig.3 shows the main identifiers --HK7 to HK10-- a first choice pulse series inclusively the allocation characteristic --HK6-- for the connection establishment of the selecting under plant --WUA-- to the main plant --Ha-- without use of Nebenkennzeichen. Nr.348B97 Fig.4 shows both of the Hauptaulage --Ha-- and the Wählunteranhge called of --WUA-- delivered Hauptund Nebenkennzeichen with the procedure “locking on”. Fig.5 shows from a selecting under plant --WUA--outgoing characteristics for the procedure “further inquiry” toward Hauptaulage. Fig.6 shows the characteristics for the dismantling of one between a main plant --Ha-- and a Wä, hlunteranlage --WUA-- existing connection by the participant of the W hlunteranlage --WUA-- introductory releasing. Fig.7 shows the necessary characteristics for the dismantling of one between a main plant --Ha-- and a Wählunteranlsge --WUA-- existing connection with by the participant of the Hauptanhge --Ha-- introductory releasing of the connection. It is accepted that it itself with the descriptive remark example around a main plant --Ha-- and several selecting under plants turn onable to it --AUA-- acts. The substations of the Wählunteranhgen can manufacture only over the Hanptanhge connections to the public office. The dung lines between the main plant and the W hlunteranlagen are final at the dung line ends by appropriate line transmissions both in the main plant and in the W'ählunteranhge in each case. In these transmissions become in each case from the respective plant (main plant --Ha-- and/or selecting under plant --WUA--) over the feeder line received characteristic in indications converted, which are adapted to the line signal transmission procedure and/or the installation internal Signaaverfahren. Further is accepted that over a dung line in each case either normal dekadisehe Wah) mpulsserien or in addition, multi-frequency clay/tone choice characteristic to be transferred. For the connection establishment and the connection clearing and/or for the data ur WegeeinsteUung as well as for the data concerning Wegeund of conversation and the supplementing data, as e.g. concerning kinds of discussion and authorizations for transferring characteristics become as Hauptkenn2eichen (see. --HK1 to HK4-- in Fig.1) and/or as Nebenkennzeichen (see --NKI-- transfer into Fig.1). Used as main identifiers 50-Hertz-Wechselstromsignaae will become, as Nebenkennzeichen 2 audio frequency signals within the range of the frequency spectrum of the usual clay/tone choice procedures used. The Tonfrequenzsign8! e can be transferred thereby also carrion multi-frequency characteristic, e.g. as combination of several frequencies. If however only a smaller number from indications is to be transferred to, it is favourable to use only one audio frequency. If in the latter case of the 425-Hertz-Ton one uses, for its production in each plant the necessary mechanisms anyway are present, then one has in addition the advantage of the multiplex operation and D nit saving at otherwise necessary additional means for the signal frequency production. In the following is still beschriehen, in which way with this audio frequency used for other indications can be formed by 425-Herr a larger number of Nebenkennzeichen. As Hauptkennzeiehen 50-Hertz-Wechselstromsiguale are used. By the main identifiers, e.g. --HK1 to HK4-- into Fig.1, the more important vermittlungsteehnischen information, e.g. the data is transmitted for way attitude as well as over Wegeund Gespräehszustand. By the Nebenkennzeichen, e.g. --NK1-- transferred authorizations into Fig.1, supplementing data, for example data concerning the Gespr ehsarten, u.dgl.. The Nebenkennzeichen is sent always directly afterwards to the main identifiers and/or a given time to the main identifier, whereby the latters take over thus the additional function of a key symbol. The main identifier transmitted in each case does not only steer as so-called key symbol the Ansehaatung Empfangsund evaluation mechanisms for by means of the Nebenkennzeichens to transferring audio frequencies, but it steers also at both dung ends during sending main identifiers and Nebenkennzeichen an interruption of the transmission of language to avoid 4s around a disturbance Hauptund/or clay-frequent Nebenkennzeichen. This interruption “of transferring the language is introduced by the Nebenkennzeichen preceding the main identifier and extended in each case, if a Nebenkennzeichen follows the main identifier, at least for its complete duration. The abolition of this interruption takes place after Hauptbzw. Nebenkennzeiehen with a certain time delay, which is longer carrion the so greatest possible break between a main identifier and following Nebenkennzeichen and/or between two frequency sequences and which belonging to a Nebenkennzeichen it is longer than the greatest possible impulse break time in the latter case, thus between two following each other, main identifiers US-mmengehörenden. From the managing also it follows that the main identifiers will receive at any time from the Gegenanlage be able to have and that it in addition, like the Nebenkennzeichen, by other indications, as for example Sprachsignale to be not interruptible to be allowed. During sending the main identifier (and Nebenkennzeichens) and for the time the following cable back TLA dung (return) no receipt may take place at the appropriate sending end. Those managing mentioned time delay during the disconnection of the interruption of the language transferring prevents unnecessary Anund switching the interruption of the language transferring off. With the arrival of a main identifier in the Gegenanlage a receipt mechanism is held ready there for the admission of the clay-frequent Nebenkennzeiehen. This holding ready time extends I0 automatically after the arrival of the Nebenkennzeichens to the maximally possible duration of this indication. In that managing suggested way one reaches: 1. that an enterprise is possible over blocked lines, 2. that by the addition of the Hauptkenn2eichen with Nebenkennzeichen the need of alternating current characters of under ski roofs length substantially is reduced, 3. reached through that with simultaneous sending from both plants for the longer in each case main identifier is guaranteable, 4th that mechanisms for the frequency production are sharable with multi-frequency palpation choice procedures, 5. are usable that the main identifiers as key symbol, which is called that the receivers planned for NIehrfrequenzwahl for the receipt of Nebenkennzeichen only during a certain time interval to be made available to need and from there on a small number is not limitable and 6th that receiver own voice protection planned for the multi-frequency choice to need. 2s the received Nebenkennzeichen are transmitted to the central control. This Nebenkenn calibrates gives either for itself however or in addition, in connection with the preceding main identifier and in dependence of the existing in each case, certain switching conditions during the connection establishment and/or the different connections characteristic Zustandskennzeichen of the central control equipment information, which causes the development more intended for the further 3e connection establishment and/or for certain change-overs and such instructions. In the following the individual phases, in which during the connection establishment and/or during the existing connections an indication exchange takes place, are more near descriptive. 1. Proofs. Around traffic, that of the Hauptaniage --Ha-- to the selecting under plant --WUA-- , opposite 3s opposite traffic, that runs of the Wähiunteraalage --AUA-- to the main plant --Ha-- runs, one through reached to assign (Fig.1 and 2), those are in each case as main identifiers for allocation transferred 50-Hertz-Wechselstromsignale depending upon sending plant (--HK1-- in Fig. 1 opposite --HK5-- in Fig. 2) differently long. This means that with the simultaneous occurrence of an allocation impulse on the same line, u.zw once e.g. of the main plant --Ha-- (longer main identifier --HK1--) and once e.g. of the selecting under plant --WUA-- (longer main identifier --HK5--), only the allocation signal of the main plant --Ha-- due to his larger temporal length to reached through to arrive may. This means thus that the allocation signal of the main plant --Ha-- by simultaneous sending of the shorter allocation signal (HKS) of the selecting under plant due to overlay to be only in such a way shortened it can that in any case (of the main plant) a coming 4s allocation of the selecting under plant --WUA-- one causes. With beginning of receipt of the allocation characteristic in the feeder line transmission of the selecting under plant --AUA-- becomes closed this transmission for another, outgoing allocation. In addition it is in the selecting under plant --AUA-- guaranteed that signals, which are longer than a certified can lead the length of the proof characteristic exceeding maximum length, not to an arriving allocation of the transmission. If this fixed maximum length is in such a way exceeded, then becomes an obligatory de-energizing for from the selecting under plant --WUA-- to the main plant --Ha-- going allocation and the release of the transmission of the Gegenanlage guaranteed. At the same time with the allocation of the transmission of the selecting under plant --WUA-- taken place also the connection of the receipt means for the expected clay-frequent Nebenkennzeichen, since the allocation causative ttauptkennzeichen at the same time as conclusions] indications of such Nebenkennzeichen works there. The Nebenkennzeichen now following in direct connection to the main identifier serves the kind of discussion and/or a selected connecting direction and/or the authorizations of the calling substation for the marking. Depending upon number that information contents of a characteristic which can be transferred at the same time has the Nebenkennzeichen the only Nebenkennzeichen or the combination of Neben_kennzeichen assigned frequency, which can be transmitted which can be transmitted. The indication length of the Nebenkennzeichens is so limited that into the Gegenanlage arriving Mindestantefl lo of the Nebenkennzeichens with consideration of a carrier frequency section operated over intermediate transmissions (short-circuit of the Sprechweges in the intermediate transmission during and to about 40 ms after completion the conclusions] indication) for receiver evaluation is sufficient still perfectly. If only in each case a certain Nebenkennzeichen is to be transferred, like already mentioned, the 425-Hertz-Ton of the signaling devices of the respective plant for the formation of the Nebenkennzeichens is enough out. I5 being supposed however several different indications of different substations as Nebenkennzeichen to be available, then is possible it to transfer by means of the 425-Hertz-Tones Nebenkennzeichen which itself from long and short audio frequency characters zusurùmensetzen (e.g. Fig.2c), interrupted by certain breaks. Also hiebei the main identifiers have the function of a key characteristic. If the number of Nebenkennzeichen the available is to be still larger beyond that, then it is appropriate to plan an additional Nebenkennzeichenv.ariation by multi-frequency clay/tone choice characters. Main identifiers and Nebenkennzeichen can be sent not at the same time in a direction and also not opposite arranged effectively. Becomes for example, in particular in the direct election procedure, those for the communications attitude in the selecting under plant --AUA-- necessary first 2 number of the desired participant characteristic number too fast after choice that the Verkehrsrichtung to the selecting under plant --AUA-- selected, then the possibility exists specifying index that and/or the first choice impulses intended for the further connection establishment first choice pulse series itself the Nebenkennzeichen transmitted after the allocation main identifier overlaid and so that this Nebenkennzeichens cuts a part off (e.g. --NK1 to HK3-- in Fig.1). In such a case is a perfect evaluation of the Nebenkennzeichens transferred after the allocation main identifier (HK1) --NKI-- no more guaranteed. From there the Nebenkennzeichen (NK1 as NKY to NK'") must be repeated in such a case. This repetition of the Nebenkennzeichens (NK1) can only in the direct connection to the last choice impulse (last main identifier --NK4--) the first choice pulse series to be transferred in such a way that it can be evaluated with security. Over however the expenditure for the determination of the last choice impulse --HK4-- the first Wahllmpulsserie to keep as small as possible, is again started transferring the Nebenkennzeichens at the end of each main identifier of a choice pulse series, so that after the last main identifier of the Wahllmpulsserie automatically transferring the Nebenkennzeichens (--NKI'"-- in Fig.1) in his full intended length takes place. In the regarded case the allocation main identifier is the first main identifier and the second Hanptkennzeichen is at least the last choice impulse of the choice pulse series following on the availability indicator. Regarding sending of the Nebenkennzeichens renewed with each choice impulse each choice impulse can be called second main identifier. In this connection it is still important to state that the Nebenkennzeichen is in any case temporal längsr as one impulse break time each between two choice impulses. The vostehende treated repetition of Nebenkennzeichen has always with operating cases meaning, which do not exclude a destruction of the Nebenkennzeichens. A repetition of the Nebenkennzeichens after the first choice pulse series is not necessary, if an intermediate storage into the selecting under plant --WUA-- to transferring choice characteristics, since in such a case transferring the choice characteristics steered by the centralized control takes place only then, o is intended if with security both the first main identifier and the following Nebenkennzeichen is fully evaluablely stored. If for economy reasons for several line transmissions of a selecting under plant --AUA-- for example common multi-frequency clay/tone choice mechanisms to be planned, which are turned on to the Nr.348597 feeder line transmissions only for the time of the respective genuine need (so-called flying connection), then must when transferring Tonfrequenzslgnalen on losses are counted. This would mean that Nebenkennzeichen can be lost due to disturbances. If due to such a trouble the Nebenkennzeichen is missing, the Verbinduag becomes by being missing the Nebenkennzeichens the connection with the most extensive restriction, by see thereby for example the Berechügungskennzeichnung of the calling substation or the marking of kind of discussion or the direction authorization marking changes, if such a marking were assigned not from the beginning. Furthermore becomes with connecting traffic, in particular from the main plant --Ha-- to the selecting under plant --WUA-- and with being missing one itself normally to the Hauptkennzeiehen --HK1-- following Nebenkennzeichens --NK1-- due to a disturbance the main identifier --HK! -- a certain meaning for a kind of discussion assigned. With that managing mentioned change of the priority and Nichtweiterwahl within a before determined maximum intermediate choice time for example the engagement of a call marking takes place to an operator's position. In the case of change of the priority and choice of more than in the internal traffic necessary indices a change-over can likewise take place on the operator's position. On change of the priority and choice of one as not to the internal traffic to the main plant --Ha-- recognizable characteristic number becomes a renewed authorization signaling of the calling substation of the selecting under plant --WUA-- requested and the centralized control of the main plant --Ha-- identification of a Amtsbereehtigung of the substation of the Wählunterantage transfers with Erz0 --AUA-- as not to the main plant --Ha-- recognized, buffered characteristic number after change-over of the occupied feeder line on a free office transmission to the public office further. A condition hiebei is naturally the intermediate storage, which can be planned either in principle in the system, or however it is valid due to the change of priority off then the selected index. If in the case of 2s results that indices were lost, a automatic connection of place can likewise be intended. Following the allocation main identifier for the allocation of a transmission of the Gegenanlage with the connection establishment of the selecting under plant --WUA-- to the main plant --Ha--, thus to the allocation of a transmission of the main plant --Ha--, main identifiers become (--HK6 to HK10-- Fig.3) transferred those substantially shorter are than the allocation main identifier (--HK1-- in Fig.1), that for allocation with the connection establishment of the main plant --Ha-- to the selecting under plant --AUA-- one uses. It acts with the allocation characteristic of the selecting under plant --WUA-- to the main plant --Ha-- around internal traffic, then no Nebenkennzeichen following on the main identifier is necessary (Fig.2a and 3). Only if it concerns the production of a resuming connection for example to the public plant, further Nebenkennzeichen is transmitted following the main identifier. In accordance with Fig. it can concern 2 thereby three different Nebenkennzeichen. (Fig.2a shows the allocation main identifier which can be sent by the selecting under plant.) Fig.2b shows the Nebenkennzeichen --NKZ--, which, if a participant of the selecting under plant --WUA-- the automatic call distributor of the main plant --Ha-- selects (code choice), of 200 to 300 ms long audio frequency beside characteristics consists. Against it the participant of the selecting under plant is --WUA-- in the main plant --Ha-- a Amtsleitungsbiindel without entrance to the direct distance dialing reach, or acts it see around a direct-access branch, then also the Nebenkennzeichen (NK3) can be transmitted as a pulse rate, for example two seaweeds or also two differently is enough for audio frequency characteristics following the main identifier (HK5). In the case represented in Fig.2c it concerns 4s two characteristics of different lengths, between which a certain, defined break is intended. Is the participant of the selecting under plant --WUA-- in the main plant --Ha-- with a local loop bundle with entrance to the direct distance dialing to be connected or it concerns an entitled branch, then the Nebenkennzeichen (NK4) can be enough also of and consist two short s0 impulses same frequency. In the available example the 425-Hertz-Ton of the signaling devices for the formation of the Nebenkennzeichen, planned for hearing indication gift, is then sufficient. From the managing it follows that a multiplication of possible characteristic statements is reached by it that several from an appropriate clock mechanism produced and from the Nr.348597 respective switching status characteristic, those differently or directly] angen characteristics (Fig.2d) depending upon need Schaltmitteln lining up steered Nebenkennzeichen (e.g. --NK4-- into Fig.2d) to be transferred. On a repetition of the Nebenkennzeichen following the last main identifier of the first choice pulse series can with the traffic of the selecting under plant --WUA-- to the main plant --Ha-- are done without, if it concerns, as in the available case, office traffic and far-truely into the public plant only take place may, if a selection signal of the public office were received. If the selection signal of the public office is not waited for and is not further-selected prematurely, then it is usual to release the connection. It concerns on the other hand a house connection between one lo participants of a Wählunteran] age --AUA-- and a participant of a main plant --Ha--, then transferring of a Nebenkennzeichens is necessary for upper means of special information about the calling branch, for example their authorization, likewise not. For the by-election from there also no special condition exists concerning the waiting period for the far choice. Following the allocation head the ennzelchen sent Nebenkennzeichen is lost in office traffic (e.g. --NK4--), because for example in the main plant the Rmpfangseinrichtung was not in time turned on, then the kind of discussion is changed and the connection is considered as house connection. Also in this case with the choice by more indices, than for the production of an internal connection are necessary, and/or with choice of a characteristic number deviating from the internal numbering, either the connection to the operator's position is switched or in addition, by the centralized control of the main plant --Ha-- a renewed authorization check of the substation of the selecting under plant --AUA-- arranged and further during office authorization recognition in the main plant --Ha-- the Umstenerung on a free office transmission and the transmission of the buffered indices over the local loop arranges. 2. Lane-occupied. The condition “lane-occupied” can be signaled either by main identifiers or by Nebenkennzeichen. If the condition is sent “lane-occupied” as main identifier, then this takes place under the condition that also the main identifiers for “end of selection” are intended, branch-freely”, “branch-occupied” and “announcing” in the plant, since otherwise on the receiver side no distinction between lane-occupied and in relation to releasing because of “Nichtberechtigung” is possible for the actually identical characteristic for the release characteristic of the called participant place which can be transmitted into backwards direction and further no distinction (S. also sections 4 and 8). This is transferred meant that the lane occupation characteristic and the release characteristic, however this characteristic transmitted into backwards direction are alike depending on whether it before or after the end of selection characteristic and the following branch free characteristic and/or branch occupation characteristics, the meaning as or as “Rückwärtsauslösung” keeps “lane-occupied”. The dominant in each case switching status best {rnrùt therefore the meaning of the transferred characteristic also. The aforementioned release characteristic is called in the sections 4 and 8 de-energizing characteristics. The recognition of the Gassenbesetztzustandes in the main plant --Ha-- can for example to a automatic, renewed Wegesuche and thus to a repetitive connection establishment to lead. Likewise this can lead also to a special signaling or a connection of place. The Gassenbesetzt Kennzeiehen could be transferred also as Nebenkennzeichen following the main identifier branch-occupied ". Thereby is however a condition that the condition “lane-occupies” automatically also a branch occupation characteristic releases and that this Neben4s position occupation characteristic, which is given as main identifier is supplemented by “lane-occupied” - a specific Nebenkennzeichen. 3. End of selection. The Wahlendesignal has with enterprise with impulse choice for traffic between main plant --Ha-- and selecting under plant --WUA-- apart from the actual characteristic function the additional task, for from the Wählunteraniage --WUA-- the following signals branch free characteristics and/or Nebenstelie occupy characteristics reached through make possible, if the participant of the main plant --Ha-- further-selected. If thus in select under nlage --WUA-- it is determined that all Wab] information for the connection establishment in the selecting under plant --WUA-- selected are, becomes of the centralized control of the Nr.348597 selecting under plant --WOA-- from transferring the Wahlendesignals as main identifiers over the feeder line toward the main plant --Ha-- arranged. With receipt of the Wahlendesignals in the main plant --Ha-- becomes there transporting further from choice impulses to the choice under plant --WUA-- prevented. Hiedurch is up to the connection clearing for all from the selecting under plant --AUA-- the following signals a so-called “competitive enterprise” with Wahlhnpulsen from the main plant --Ha-- excluded. The temporal distance between transferring the Wahlendesignal of representing main identifier and transferring the main identifier for branch-occupied " and/or branch-freely " places at the same time in the selecting under plant --WUA-- a watch dog time for impulse receipt. The I0 Wahlendesignal could for his part already with a following choice pulse series from the main plant --Ha-- meet and are lost. In this case the so-called “competitive enterprise” must with the following signals branch-freely” and/or Nebenstelle-beset2t” from the selecting under plant --WUA-- with security to be excluded. Became following from the main plant --Ha-- transferred choice pulse series with the end of selection characteristic and became thereby following choice impulses in the selecting under plant meet --WUA-- arrives, then it is there guaranteed that the signals “itfrei't and/or branch-occupies” only at expiration of a certain dead time after arrival of the last choice impulse from the main plant --Ha-- readdressed choice pulse series into backwards direction to be transferred know. Both by the end of selection characteristic --HK11-- ala also when being lost this characteristic due to further by-election and by the substation free characteristic --F-- and also by the substation occupation characteristic --B-- in the Gegenanlage becomes transferring further choice pulse series at least up to the there arrival of a reporting characteristic --M-- prevented. The loss of the Wahlendesignals by competitive enterprise is for the main plant --Ha-- without effect. It becomes this thereby balanced that during missing end of selection characteristic transferring the characteristic for “branch-freely” and/or “branch-occupied” additionally also as “end of selection” is evaluated. In this connection is to be still mentioned that the characteristic “Nebenste] le-free” a long alternating current Irish Republican Army pulse from for example 200 to 300 ms is, during branch-occupied” from two alternating current impulses of for example 50 ms exists, for a wozwischen break of likewise 50 ms is appropriate. This break (HK12 to HK13) is shorter, than the distance between the end of selection characteristic (HKII) and the first main identifier (HK12) of “itoccupies” with which the characteristic is branch-occupied” also when being lost the end of selection characteristic (HKll) recognizable “. Further the time between the end of selection characteristic and the following branch free characteristic and/or branch occupation characteristic (watch dog time) may do, as well as the dead time for the 3s passing on of the characteristics branch-freely " and/or branch-occupied " after arrival of in the main plant --Ha-- further-selected Wählimpulse not more largely than the intermediate choice time its, in order to prevent that still another second index from the main plant, which can be expected --Ha-- to be after-selected can. This means thus also that in any case before the possible far choice in the main plant --Ha-- and sending of a further pulse series due to it with security at least branch-freely " and/or branch-occupied " this far choice to have prevented must. This is valid also, if with the end of selection characteristic “colliding” choice information from the main plant --Ha-- from only one choice impulse and from there neither this exists a choice impulse nor the end of selection characteristic their goal plant reaches and in the main plant --Ha-- after this impulse and the following intermediate choice time one further-selects. The reporting characteristic, which follows after the branch free characteristic, is to be transmitted as promptly as possible after the end of selection characteristic. Also for this reason a firm time is fixed after the end of selection characteristic for following transferring of the branch free Kennzeiehens. Hauptund Nebenkennzeichen can consist of several single characters separated by breaks. 4. Select an unauthorized branch of the selecting under plant --AUA-- by a participant of the public office. Becomes from a participant of the public office an unauthorized Nebenstene of the selecting under plant --AUA-- selected and this Nichtamtsberechtigung in the selecting under plant becomes --WUA-- determined, then is forwards or also after recognizing branch frefl' and/or branch-occupied " to release at the latest however before announcing this unauthorized branch the connection. For this purpose the protection in the selecting under plant becomes after recognizing --WUA-- and transferring the end of selection characteristic and for example after transferring branch free " and/or branch-occupies ", but in any case before transferring the reporting characteristic from the s selecting under plant --WUA-- a back release characteristic to the Hanptanlage --Ha-- transferred and thus the release of the connection arranges. This back release characteristic corresponds to the appropriate indications in accordance with the sections 2 and 8 and as Frelschaltekennzeichen is designated there. Since this back release characteristic can as Rfickauslösezeichen (de-energizing characteristic) at another time, which means in another connecting condition will transfer, with this characteristic in the main plant --Ha--, the plant, those regarding the selecting under plant --WUA-- also for office traffic as calling plant to be regarded” a connection of the operator's position can be steered to the local loop. It is to be noted that in this connection for office traffic the main plant continuous to the selecting under plant (WUA) --Ha-- also as calling plant one designates (patent claims). In this way einund the same indication can serve different plant in each case depending upon connecting condition for the different marking in that. A such Rfiekauslösung is natural with a Rückfragevcrbindung between a participant of the main plant --Ha-- and a participant of the selecting under plant --WUA-- not necessarily. Also with a further inquiry with an unauthorized substation of the selecting under plant --WUA-- transferring and/or evaluating characteristics given in backwards direction is necessary, u.zw. , even if it does not concern “releasing” here. It is referred hiezu to section 6. By-election and locking (Fig.4 on). Combination signals (HK14, NK6, HK15) may only after transferring the branch occupation characteristic (HK! 2, HK13, NKS) receptible its, whereby the latter is sent to the characteristic for “end of selection” (HKll). This is guaranteed from the centralized control. Only after being present the branch busy condition the admission of combination signals (HK14, NK6, HK15) is possible. Locking on can take place via transferring a combination characteristic, for example via earth depressing the key or however via Nachwählen. Takes place locking on via by-election, for example from the main plant --Ha-- out, then becomes in the centralized control of the main plant --Ha-- guaranteed that in place the Impulsfole of the after-selected number will transmit a special main identifier (HK14 and/or HK15) to representing main identifiers, which introduces for example the combination (HK14). A depressing the key end identifier (HK15) can serve to indicate the length of depressing the key in order to make as it the distinction possible of a short depressing the key of a long Tastendruek in reverse and. Long depressing the key will for example switching on of a signal on at the operator's position, e.g. “place-call for” or in addition, “knocking” (additional ticking ore oaks with on scolded) to mean to be able. Appropriate is the case during further inquiry introduction and “place-calls for”, where also more briefly and/or a long depressing the key is usual. Subsequently, to the main identifier with depressing the key beginning (HK14), delivered with delivery of a depressing the key characteristic on the part of a substation, in particular the authorization is also transferred the depressing the key characteristic delivering substation characteristic Nebenkennzeichen (NK6). Additional Zeitschaltmlttel of the receiving Leitungsühertragungsseite determines the temporal duration of depressing the key on the basis the temporal distance first (HK14) and the second (HK15) main identifier. In addition, it is possible that the length of the Nebenkennzeichens e.g. --NK6-- corresponds to the depressing the key length, in order to let determine time sports club stop means of the receiving line transmission side the temporal duration of depressing the key from it. In the Zusùmmenhang with that vostehend it mentioned conversion of the after-selected index and/or characteristic number, which is selected a pre-determined time after evaluating a substation free line condition and/or a substation busy condition of a calling and/or called substation, is to be still mentioned that this in dependence of the switching status existing in each case for the introduction of a certain shifting process, for example on schals0 tung, evaluated and as Hauptund deviating from the index and/or characteristic number/or Nebenkennzeichen of the origin plant over the feeder line to the Zie] plant is transferred. It is in this way guaranteed that both of the participant places no increased expenditure is not necessary for the indication delivery, and in the transmissions and in the centralized control additional expenditure for transferring and the evaluation of the characteristics. At one to the selecting under plant --WUA-- transferred main identifiers as Auischaltebeginnkennzeichen itself following Nebenkermzeichen --NK6--, which contains further switching-oriented information, for example different Auischalteberechtigungen can indicate in the case of locking on. If the participant is after the outer/scolded, to whom one outer/switched, by presenting the listener again freely, then a branch free characteristic (HK6, NKT) and a following reporting characteristic (HK17, NK8) become as main identifier (HK16, HK17) with if necessary following Nebenkennzeichen (NKT, NK8) the main plant --Ha-- transferred. l0 the combination characteristic (HK14, NK6) could also with a branch free Kennzelchen (e.g. --HK16--) meet. In this case however the branch free ability character (F) became to reach through, since it is longer than the combination characteristic (e.g. --HK14--). Thus the Aufschaltevorgangda it would then be will-terminated also automatically redundantly and the lining up connection would be connected through. This evaluation takes place in the centralized control of the main plant --Ha--. The combination procedure is afterwards deleted. In order reached through the longer branch free characteristic (F) to guarantee, must the minimum distance between two combination signals as main identifiers be so large that the branch free characteristic (F) only with one of the combination signals (combination branch printing beginning and/or - ends) meets and thus only by a signal to be shortened can. This means thus that signal of beginning of combination (HK14) and combination end signal (HK15) must have a certain minimum distance. If locking on is introduced by operation of a Flash key, in addition, then by simultaneous manipulation of the Flash key and a figure key another switching procedure than “Aufscha can! ten” to be introduced. During the early recognition of the free line condition with combination procedure final yet and, the early completion of the combination procedure following from it thus the branch free characteristic (F) in the main plant becomes --Ha-- as “testing characteristics” rated. 6. Meaning Wahlendeund of the reporting characteristic. The marking of the Nichtberechtigung of a branch of the selecting under plant --WUA--, to arrange which is called without justification by the office, is only for connections possible, which in the normal connecting expiration also the main identifier “announcing”, since otherwise no distinction with a Rückwärtsauslösung is possible by the calling. Further also the Hauptkennzeichan “end of selection” must be transferred and “branch-freely” and/or branch-occupied”, in order to be able to differentiate at the receiver side between releasing because of “Nichtberechtigung” and releasing because of “lane-occupied” before the connection clearing. The characteristic “end of selection” alone is not sufficient hiebei, since it can be lost by competitive enterprise. In addition a condition with the managing procedure is that the reporting characteristic with unauthorized Spreehstellen of the selecting under plant --W-JA-- in the main plant --Ha-- one does not need. As reporting characteristic after the branch free characteristic eln short Wechselstromlmpuls will transfer. For this reporting characteristic no competitive enterprise exists. Following the reporting characteristic a Nebenkennzeichen can be transmitted (S. Fig.4 --HKI7, NK8--). Usually however such Nebenkennzeichen (NK8) is not necessary after announcing. 7. Further inquiries (Fig. 5). The transmission of characteristics over the communications for Riickfrage is only from the 4S selecting under plant --WUA-- to the main plant --Ha-- necessarily, there only for the participants of the selecting under plant --WUA-- office traffic over the feeder line takes place. The signal ring printing for the further inquiry by a participant of the selecting under plant --WUA-- becomes by a characteristic of firm length, a main identifier (HK18) and thus an alternating current characteristic, transfer. The length of this characteristic is so limited that the further inquiry characteristic (HK18) can be differentiated at the receiver side from in such a way choice impulses. Since the choice impulses have usually a length from 50 to 70 ms, as Rückfragekermzeichen (HK18) a characteristic is used from 200 to 300 ms. The further inquiry characteristic is not bound at certain phases of the Verbindungsauibaues. It is still mentioned that the allocation characteristic (HKI9), that of the selecting under plant --WUA-- to the main plant --Ha-- is sent, likewise a short main identifier is. If the length of depressing the key is to be along-evaluated, then this - as previously mentioned - can take place, as a Nebenkennzeichen (NK9) will transfer for the duration of depressing the key following the main identifier (HKI8). Usually however the Nebenkennseichen is transferred as characteristics of certain firm length, but they are used and evaluated for the marking of the authorizations and the respective condition of its connection. Accordingly they are necessary here also only with introducing the further inquiry. The Empfangseinriehtungen of the main plant --Ha--, which serve for the receipt of the Nebenkennzeichen, thus with receipt the further inquiry of characteristic main identifier turned on. This is also a simplification for the selecting under plant --W/JA--, there the selecting under plant --AUA-- not to know it needs whether it concerns a first or second depressing the key in the process of a further inquiry discussion. From the understanding thus that although the duration of the signal ring printing will transfer must, the audio frequency signal of the Nebenkennzeichens (NK9) up to releasing the Is key follows to be transferred can. This can be however only of importance, if the further inquiry characteristic with another characteristic were confusable, for example “calling for the switching person”. The IIauptkennzeichen still shown in Fig.5 --HK20 to HK23-- are first and the represented main identifiers --HK24 to HK27-- are a last choice pulse series to represent. The long main identifier --HK28-- meant “Rüekfrageende”. Becomes in further inquiry a not direct-access branch of a participant of the main plant --Ha-- selected, then this must in the main plant --Ha-- are marked. This takes place via that the selecting under plant --WUA-- the I do not eldekennzeichen transfers. Also transferring of other main identifiers and concomitantly transferring 50-Hertz-Wahlimpulsen the selecting under plant become simultaneous --WUA-- to the main plant --Ha-- up to the complete release of the further inquiry connection prevents. Hiemit is guaranteed that only one further inquiry between the two substations (Sprechstelie of the main plant --Ha-- and unauthorized substation of the Unteranlage --AUA--) possible and thus surrounding the direct trunk call to the unauthorized Spreehstelle to be prevented can. Hiedurch is also possible it to turn on and/or signal the backasking substation and/or the local loop and thus the place there. From the managing it follows thus that the centralized control of the main plant --Ha-- the introduction of the rating of a direct trunk call on a participant of the selecting under plant --WUA-- to only permit may, if the reporting characteristic (m) of the participant of the selecting under plant --AUA-- in the main plant --Ha-- it arrived to which a storing of this characteristic (m) in the occupied office transmission of the main plant --Ha-- is intended. Transferring the authorization flags of the called substation takes place in form of a Nebenkennzeichens of Hauptund Nebenkennzeichen consisting of the characteristics for “branch-freely” (F) and “branch-occupies” (B). 8. Connection clearing. It tar distinctive between releasing the connection clearing by the participant of the selecting under plant --WUA-- and releasing the connection by the participant of the main plant --Ha--. First it is accepted that the participant of the selecting under plant --AUA-- the existing connection with the public office and/or with a participant of the Hanptanlage --Ha-- by presenting terminates 4s of the listener (Fig.6). In this case becomes from the selecting under plant --WUA-- a very long main identifier (HK29), which in its length both from the allocation characteristic and from the free characteristic and/or occupation characteristic and from the Rüekfragekennzeichen differs, as Freischaltekermzeichen (HK29) to the main plant --Ha-- sent. This de-energizing characteristic (HK29) may be shortened through none of the other main identifiers in such a way that the meaning of another could be assigned to it in such a way main identifier. It may thus also after a possible shortening not the order of magnitude one of the before-regulatory indications attain and must always as de-energizing characteristics be evaluable. After the transmission of the Freisehaltekennzeichens (HK29) Rückkennzeichenein becomes so-called unblocking characteristic (HK30) from the main plant (ha) - expects. Between this two characteristics which is appropriate watch dog time it is to be measured in such a way that also during a retarded release, i.e. with returning the unblocking characteristic (HK30) at expiration of a certain, determined time, but the evaluation and thus the release to surely take place can. With sending the unblocking characteristic (HK30) in the main plant --Ha-- becomes the release both the line transmission, and the release of the other appropriate Schaltmittel of the main plant --Ha-- and the selecting under plant --WUA-- made. A if necessary necessary transporting of an initiation signal further over the local loop becomes from the centralized control of the main plant --Ha-- already with being present the de-energizing characteristic (HK29) made. After receipt of the unblocking characteristic (HK30) in the selecting under plant --AUA-- are the there line transmission and the further RST if necessary still needed mechanisms for a further connection establishment again provably. It is now accepted that the release of the participant of the main plant --Ha-- and/or from the participant of the public plant proceeds (Fig.7), then becomes with the main plant --Ha-- a separation characteristic (HK3!) over the feeder line toward the selecting under plant --WUA--sent, u.zw itself this separation characteristic (HK31) of the other mentioned so far must of the main plant --Ha-- to the selecting under plant --WUA-- sent indications, as for example the allocation characteristic, differentiate. This is reached by that one it for example a length from 1200 to! 700 ms assigns. This separation signal (HK31) arranges in the line transmission of the selecting under plant --WUA-- the Rückwärtsübertragen of the de-energizing characteristic (HK29), which as managing (S. also Fig.6) mentions, to be so long must that it does not come also with characteristics moving in opposite directions into the order of magnitude one of the other long characteristics. This de-energizing characteristic (HK29) arranges then in the main plant --Ha-- like already described, after a certain watch dog time sending a Entsperrkcnnzeichens toward the selecting under plant --WUA-- and afterwards the release procedure runs as when presenting the listener by a participant of the selecting under plant --WUA-- off. From the managing it follows that thus the release of the mechanisms of the main plant --Ha-- 2s always with by the main plant --Ha-- sent unblocking characteristics (HK30) and the mechanisms of the selecting under plant --WUA-- always by the there arrival of the main plant --Ha-- sent unblocking characteristic (HK30) to be released. Thereby it is alike whether a participant of the selecting under plant --WUA-- or a participant of the main plant --Ha-- and/or the public office the release by presenting the listener introduced. It leads thus with other words of a calling and from a called substation introductory clearing independently of the direction of the connection establishment and the direction of the clearing to different, the respective feeder line sides firmly assigned characteristic sequences (S. Fig.6, --HK29, HK30 and/or Fig. 7, --HK31, HK29, HK30--). A final de-energizing of the feeder line an introductory first characteristic (--HK30--, Unblocking character) proceeds thus always from a certain Verbindungsleitungsselte (ha), during in the respective characteristic sequence (HK29, HK30 and/or HK31, HK29, HK30) with the certain feeder line side outgoing first characteristics (HK30) always this first characteristic (HK30) releasing second characteristic (--HK29--, De-energizing characteristic) precedes. When releasing the aforementioned characteristic sequence (HK29, HK30 and/or HK31, HK29, HK30) contains third, the second characteristic (HK29) of the connection from the certain connecting side releasing characteristic (HK31) as separator. First (HK30) and the third (HK31) characteristic from the certain feeder line side (ha) and the second characteristic (HK29) is always sent always from this opposite feeder line side (WUA). The second characteristic mentioned (HK29) is temporally so long that it is perfectly evaluable also with a receiver shortening by the third characteristic (HK31) or by a choice pulse series arriving from its direction. 9. Remote barriers. Both for connecting traffic Hauptanlage Ha Wählunteranlage WUA, and for connecting traffic Wählunteranlage WUA Hauptanlage ha a remote disable flag is intended, which has s0 one duration of for example more largely equivalent 1 s and which is then sent by a transmission, if this is not ready for use for a coming allocation and/or also for the receipt of back characteristics. If necessary the remote disable flag can the receiving plant by this remote disable flag in, if it itself for example around the selecting under plant --WUA-- , the Freischaltekenn2eichen acts or if it itself around the main plant --Ha-- , the separation characteristic acts to be arranged around so also the release of the disturbed transmission to reach and with it the disturbance and/or the “Nichtbetriebsbereit” - condition to waive.