DE2624132A1 - Circuit detecting connection request in telephone system - scans subscriber lines by brief closing of contacts which remain closed if loop is unbroken - Google Patents

Abstract

The circuit detects a connection request in a telephone system. The request is detected by an indicator allocated to a subscriber and affected by the subscriber line state. The subscriber station can be connected to a connecting circuit supplying it and receiving its criteria. A central scanning and control device cyclically tests indication devices and processes switching states or criteria marking engagement state. A single switch can be connected to a group of subscriber lines as indication device through contacts individually allocated to each line of the group and operated in accordance with engagement state. Central control keeps the switch circuit open by operation of contacts until the "loop closed" state is registered during consecutive brief switching through of contacts by the connecting circuit.

Description

Circuit arrangement for a telephone system for detection

a connection request The invention relates to a circuit arrangement to determine a connection request by means of one of the subscriber station assigned and influenced by the switching state of the subscriber line Indication point in a telephone system in which the subscriber station has crosspoints a corresponding coupling stage to a subscriber station feeding and their Criteria-absorbing connection set can be switched on, with a central Scanning and control device checked the indication points in a cyclical sequence and processes the switching and criteria states that characterize a weighting process will.

For scanning the loop status of the individual subscriber stations becomes a centrally located scanning device in centrally controlled telephone systems used, which all subscriber stations one after the other with regard to their switching state checked, compares the result of this check with the previous switching status and if a change in the switching state is detected, corresponding new switching processes triggers.

During such scanning processes, that is to say by means of which, in particular, it is determined whether a subscriber wishes to establish an outgoing connection is a previous connection of the subscriber station to be scanned with the connection set not mandatory. However, it is necessary that the state of the respective Subscriber line in a subscriber-specific memory element is cached. For this purpose is in a subscriber circuit for each Subscriber at least one relay or

to provide an indication point. For a system with a central Place the addresses of the subscriber stations for the already incoming or outgoing one Connection exists, are saved, it is known that are not yet occupied marked subscriber stations cyclically one after the other with a free and provided Connect connection set.

This successive connection through-circuit then takes place as long as until a subscriber station is reached for which the production of a outgoing connection signaling loop closure is detectable. This finding is carried out by a loop status evaluation device in the connected connection set. In this way, the use of a subscriber circuit can be avoided. The prerequisite for this, however, is that for the cyclical connection of the connection set extremely fast switching to all subscriber lines marked as free Eoppelpunucte are available.

The object of the invention is, using a conventional Crosspoint system the subscriber-specific effort for the recognition of a connection request to reduce in the subscriber circuit.

This is achieved in that in each case for a group of subscriber lines a single switching means serving as an indication point through each line within individually assigned to this group, operable depending on the occupancy status Contact elements is effectively switchable that due to the central control device an activation registered during the check with the exception of the one as occupied marked lines of the group by controlling the respective for a while Contact elements the actuating circuit of the switching device is disconnected as long as until the subsequent one made one after the other via the connection set taking place short-term through-connection of the crosspoint of the line state "loop closed "is registered, whereby the connection of the Subscriber station upright with the connection set for further connection establishment is obtained.

For checking the loop status of a group of subscriber lines the switching status of an associated indication point is thus cyclically in each case scanned.

This group-wise assignment results in a saving of Switching means for the intermediate storage of the respective line condition. Through this that the access to the indication switching means is interrupted for the respective group is ensured that the supply for the requesting a connection Participant from the connection set. By using this connection set The crosspoints are then switched through by the central controller this participant can be clearly identified.

According to the invention, in those cases in which no registration of a When the loop closes, the assigned connection set is immediately activated made so that a stimulus recognition triggering glitch is not significant Delay time causes.

In the figure, an exemplary embodiment of the invention is shown.

The subscriber stations S11 to Snx of a private branch exchange are in individual participant groups S1 to Sx combined.

The subscriber circuit available in the telephone exchange for each subscriber station each has a switching means assigned to each participant. In the exemplary embodiment are these the bistable ones Relays Til to Tnx each when switched on Supply voltage by applying the counter potential to the circuit points A. or B can be controlled in one of the stable positions via diodes D11 / D21 to Dlx / D2x are.

Each of the subscriber groups S1 to Sx is now a switching means assigned in the form of relays R1 to Rx. Within each group, everyone is now the assigned relay via the switching means T assigned by the subscriber actuating contacts with the individual connection lines in the group combined subscriber sites connected. There is a Call connection so access to the assigned group relay R is prevented, since in such a case the respective contacts t are in the open state.

If there is no connection, for example, is out of the group S1 the subscriber station S11 via the contacts t11 / t21 and the subscriber station Sin connected to relay R1 via contacts tni / tn2. In the same way exists for the subscriber station S1x via the contacts tx1 / tx2 and for the subscriber station Snx establishes a connection to the participant group assigned to this participant group via the contacts tnxi / tnx2 Relay Rx. The state of the individual switching means R is determined by the cyclic scanning of the contacts r signaling this state by means of a central scanning device ZAT noted. Now wants a subscriber station, for example the subscriber station If you set up an outgoing connection, you will activate the fork changeover contact a loop is established at the station, so that the group relay R1 assigned to subscriber group S1 can respond. When scanning of all group indication points, this is initiated by the participant Input occupancy recognized and the central control device ZST a corresponding one Incentive transmitted. This then enables the assignment of a free connection set VS causes. In the event that no free connection set is provided can, the incentive remains as long as there is a loop closure is.

Depending on the information contained, for example, in an allocation memory The status of the individual subscriber lines is not yet carried out for them Participants marked as occupied in the group for which an incentive is registered was, an influencing of the assigned relay T in such a way that by the relay own contacts t the connection of the individual connection lines to the respective group indication switching means is separated. Determining which Participant within the group wishes to establish an outgoing connection, now takes place in that the connection to the connection set VS is used Coupling links k for this group of subscribers switched through briefly one after the other and then open again. This actuation of the coupling links, the conventional should represent mechanical coupling contacts, takes place via the connection set and is controlled by the central control device ZST. Will be successive in this case Switching through the coupling links marked as free within the respective Group by the evaluator assigned to the incoming side of the connection set If the loop closure is recognized, the connection set is activated via the central control device occupied for further connection establishment and that within the respective group ongoing search process ended. To control the individual double sections of the Coupling network KS can be based on a coordinate-like structure in a known manner lie.

When a loop closes, the assigned ones remain Coupling routes. k switched through, so that now a final connection of the subscriber station with the connection kit. The subscriber stations in the group that are not marked as occupied by a corresponding Control of the relay T assigned to these subscriber stations again with the respective Group indication point connected in the form of the relay R shown, since the respective Contacts t are switched back to their original rest position.

With the reception of the first impulse from the subscriber station given dialing code is the disconnection in the occupied connection record of the dialing character caused4 The recorded dialing codes either in the Connection set or evaluated centrally, then lead via the central Control device for setting the connection path to be established.

Used when scanning the individual group indication points Incentive recognized, but made within the assigned participant group Through the connection of the coupling links no loop closure is found, after when this group indication point is switched on again, the connection set in use unlocked. In such a case, a glitch is likely to be the cause of the triggered an incentive search.

L e r s e i t e

Claims (2)

P a t e n t a n 5 p r ü c h e Circuit arrangement for determination a connection request by means of one assigned to the subscriber station and indication point that can be influenced by the switching state of the subscriber line in a telephone system in which the subscriber station has a crosspoint corresponding coupling stage to a subscriber station feeding and their criteria receiving connection set can be switched on, whereby a central scanning and control device checked the indication points in a cyclical sequence and the an occupancy process characterizing switching or criteria states processed are, characterized in that each for a group of subscriber lines a single switching means (R) serving as an indication point through each line individually assigned within this group (S) and depending on the occupancy status actuatable contact elements (t) can be effectively switched that via the central control device (ZST) due to an activation registered during the check with exception of the lines marked as busy Fr group by controlling the respective Contact elements of the activation circuit of the switching means (R) are disconnected is carried out one after the other through the connection set (VS) taking place short-term through-connection of the crosspoints (k) the line status "Loop closed is registered, whereby the connection via these coupling points the subscriber station with the connection set for further connection establishment is maintained. 2. Circuit arrangement according to claim 1, characterized in that in those cases in which no registration of a loop closure takes place, a Activation of the occupied connection set is carried out.