DE2541092B2 - CIRCUIT ARRANGEMENT FOR THE ASSIGNMENT OF A TYPE OF AUTHORIZATION IN EXTENSION SYSTEMS - Google Patents

Description

It is known to assign types of authorization to the subscriber of a private branch exchange to allow only certain voice connections. For example, a participant can only take a tour of calls in the local area or in addition to the local area only in part of the remote area be entitled. This blocking or release of certain speech connections can now be done by a one or Multi-digit control of the number dialed by the subscriber can be carried out. You can do this mechanical locking systems adjustable in the manner of a voter are used. By manipulation of the subscriber on the telephone set and special properties of a private branch exchange system there are now possibilities for bypassing such locking devices. To the security against such Increase bypasses, it is known for a tampered remote connection that is considered by a non remote authorized subscriber is set up, the arriving at the beginning of a long-distance call to use the first charge clock pulse for the forced release of this connection. Such a control however, it is used in systems in which, "iir a connection In the local area, the required charge pulse is already sent at the start of the conversation. The transmission of the billing pulse at the beginning of the call would, for example, be in the area of the Deutsche Bundespost during the planned introduction of local transport areas. Call connections in such a local transport area are to be processed with the facilities of the self-dialing remote service, but for a fee Local call.

The security against bypassing the locking device due to the forced release with the first charge pulse, it cannot then be used either if there is no general blocking of the self-dialing remote service, but a specific one The remote area should be accessible by the subscriber.

A similar case exists if the planned introduction of local time counting also occurs during a local call, counting pulses with a predetermined time interval during the call to be sent for billing and a subscriber to make such local calls should be made possible.

It is now the object of the invention to provide a circuit arrangement for allocating a counting pulse-dependent Type of authorization for a call station that can be set up in private branch exchanges and for trunk transmissions to create running connections through the call connections for the subscriber within a freely selectable tariff range to be specified and at the same time a security against circumvention of this respective authorization is given.

This is achieved by the fact that, on the basis of a connection that has been established, to determine the charges created time cycle is checked whether it is within an exclusively for this intercom Approved tariff range is that at a limit value thereby predetermined in comparison to this a higher clock frequency having a time cycle, the disconnection of the connection is effected immediately.

According to the invention, there is an evaluation of the time cycle output for an established connection, whereby the authorization of the subscriber for such a conversation can be determined immediately can. The arrangement for checking the timing is in this case every exchange transmission of a private branch exchange assigned. Different tariff areas can therefore easily be used for the individual microphone units can be assigned, with one free connection option within each of these areas given is. Since the time interval to be charged for the connection is selected as the criterion for this, there is a reliable control option, so that this time cycle can be recognized at the earliest with the point in time is, the forced release can be initiated for an unauthorized connection. aside from that This gives a high level of security against bypassing that of the known locking device in Connection with the evaluation of the first registered counting pulse. Since not the principle of There is synchronicity between a blocking device and the voters of the exchange system Compared to this known arrangement, none was caused by a deliberate disturbance of this synchronization Bypass possibility, so that without additional measures an increased security even with only one Part of the remote area including clearance is available.

According to a further development of the invention, the check is carried out by a with the message pulse following pulse of the applied clock cycle and the shortest time interval of the Clock pulses of the respectively approved tariff area coordinated time step, with the separation in Depending on the further clock pulse arriving within this period of time is triggered.

A monostable multivibrator or an internal clock can be used as the timing stage switched counting stage are used. In this way, the time span which corresponds to the smallest distance of the Clock pulses corresponding to the time interval assigned to the released tariff area, can be specified. Meets now no further clock im-

pulse, it is a sign that the connection is released for the intercom and therefore no forced release is required.

In the drawing, an embodiment of the invention is shown in the form of a block diagram.

It is now assumed that a secondary Still subscriber of the station 5p, for which, retained in a Unlock ^r echenden authorization Reviewer limitation of Verbindungsinöglichkeit is to consist, builds on the Koppelnelzwerk KN, and via the exchange transmission Alje a paid trunk call A. The restriction can consist, for example, in the fact that only part of the remote area is released for this intercom, which is defined in the time pulse counting by the smallest possible distance between the individual clock pulses of the time pulse for this area.

Assuming a local time count, the same way for this call station could only making local calls, which in turn is assigned a predetermined time interval, is permitted will.

The device provided with the reference sign LJ and assigned to an Amis transmission is now used to check whether the subscriber is crossing the area specified for him or is establishing a connection within this area.

The clock pulses incurred for the call connection are fed to the devices available for billing and at the same time to the device U via the addition Z assigned to the exchange transmission. In order to enable an exact assessment of the timing, the start impulse triggered with the reporting of the called subscriber and simultaneously evaluated as the first counting impulse is not used for the evaluation. The evaluation should only be carried out with the second charge pulse, so that an unauthorized call connection incurs a maximum of two charge units. This means that the time stage in the form of the counter Z 2, which is matched with the internal clock supplied by the clock generator TG , is only released when this second charge pulse arrives.

This is now done in the following way. The counter Zl, which represents a binary counter, for example, is to assume the logic potential H or L with the first pulse supplied via the coincidence gate G 4 at the two outputs Qi and Q 2. The output Q 3 should supply the potential L corresponding to the output potential in the idle state, so that the coincidence gate GA is permeable to the pulses applied to its input El via the reversing stage U 2. With the second charge pulse, the counter Z1 should assume the logic potential L at its output Qi and the logic potential H at its output Q 2. As a result, logic potential H is applied to the input £ 2 and the input £ 3 of the gate G 1 via the inverter LJ 1. As a result, the gate is opened with the charge pulse applied to the input £ 1 of this gate and a pulse is given to the input 5 of the counter Z 2 used as a timer. This is supposed to assume the logic potential H at its output A. As a result, the coincidence gate G 3 is enabled via the input E \ , so that the clock pulses supplied by the clock generator TG are sent to the counter Z2

ίο are supplied as incremental pulses. This internal cycle can be, for example, a second cycle. The counter Z2 is preset in such a way that, via this input clock, it reaches the end position specified thereby in a time which corresponds to the smallest time interval between the clock pulses for the released tariff range. Until this fixed period of time has elapsed, there is logic potential H , triggered by the second charge pulse at output A of the counter, which is also present at the same time at input E of the bistable multivibrator FF . This toggle stage can be brought into the initial position shown, triggered by actuation of the fork changeover contact GLJ. In the case of a predetermined period of time in the minute range, two stages can be provided for the counter Z2, assuming a driving second cycle, of which the second then receives the transmission pulse triggered, for example, at a full minute.

If a further charge pulse arrives during the specified period of time, this is a sign that a call has been set up to which the respective subscriber is not authorized. By this third pulse, both the output Qi and the output Q2 of the counter Zl

3S assume logic potential H , which is then applied to the inputs E2 and E3 of the gate circuit G2 . The pulse still present at the input Ei of the gate circuit G 2 then leads, when this gate is enabled, to a signal fed to the clock input T of the flip-flop FF, so that the flip-flop is switched to the other stable position. The resulting signal at output A then z. B. the isolating relay TR effectively switched and in not shown! ' Way causes the forced release of the established connection. This can happen after a short delay, during which the extension subscriber is prompted to end the call with an alert. If no further charge pulse arrives within the specified period of time, this is to be interpreted as a sign that the call connection has been set up in the tariff range permitted for the intercom. In this case, after the time has elapsed, ie when the final value of the counter Z1 has been reached, the output A will assume logic potential L , whereby the gate C 3 is blocked via the input £ "1.

For this purpose 1 smooth drawings

Claims (2)

Patent claims: 1. Circuit arrangement for allocating a counting pulse-dependent Authorization type for a call station that can be set up in private branch exchanges and Connections in telephone systems via office transmissions, characterized in that that the time cycle applied on the basis of an established connection to determine the charge is checked to determine whether it is within a tariff area released exclusively for this intercom is that with an im Compared to this predetermined limit value having a higher clock frequency Immediately the connection is disconnected. 2. Circuit arrangement according to claim!, Characterized in that the check is carried out by a time step (Z 2) which is triggered by the pulse of the applied line clock following the message pulse and is matched to the shortest time interval between the clock pulses of the respectively permitted tariff range and the separation (TR) is triggered depending on the further clock pulse arriving within this period of time.