DE1015063B - Circuit arrangement for telephone extension systems in which a tracking switch prevents the establishment of unauthorized connections - Google Patents

Description

GERMAN

In telephone exchange systems with dialer operation it happens that after an exchange line has been occupied the calling subscriber sends out bursts of number current before entering the office via the preselection level or the preselection levels a number surge receiver has been assigned. Simultaneously with the occupancy the exchange line through the calling subscriber is assigned a follow-up switchgear assigned to the exchange line, which enables the establishment of unauthorized connections in traffic directions that are blocked for the calling subscriber prevented turned on. In the event of a premature current impulse, the control takes place of the tracking switchgear according to the number of power surges received, but not one with it matching setting of the number stream shock receiver in the office. This number shock receiver is either not set at all or only set by the last current impulses of the first series of current impulses.

As a result of the mismatched setting of the two switching mechanisms (tracking switching mechanism and first group selector) may be the calling party Participants reach a traffic direction that is blocked for them.

If all connection devices in the subscriber circuit that can be reached via preselection organs are blocked not an interception circuit via a drop-out delayed relay, e.g. B. isolating relay, the connecting cable is established, any temporary loop interruption (power surge) can reduce the occupancy of a group voter who has since become free. Since this current impulse is the tracking switchgear sets, but not a subsequently occupied group selector, can also be used in this case further impulses from the calling subscriber, a connection can be established in a blocked traffic direction.

The invention shows a simple way to adjust the tracking mechanism by not to prevent number surges from affecting a voter of the office.

The invention consists in that in the private branch exchange in bridge to the trunk line in per se known Way, a signal receiver is located, which responds to a dialing signal sent by the office, and a relay actuated via the signal receiver closes the impulse circuit via the trunk line initiated and the setting of the tracking mechanism prepared.

Although there are arrangements with signal receivers at the outgoing end of a line known that the Record free and busy signals and evaluate them accordingly, but these signal receivers are not able to accomplish the task of the present circuit arrangement

for private branch exchanges,

where a tracking mechanism

the manufacture of unauthorized

Connections prevented

Applicant:

Siemens & Halske Aktiengesellschaft,

Berlin and Munich,
Munich 2, Witteisbacherplatz 2

Fritz Villinger, Großhesselohe near Munich,
has been named as the inventor

finding with the features required for this fulfill.

According to a further embodiment of the invention, when an exchange line is occupied, a call stimulus is via the given to influence the signal receiver serving bridge. One of the control of the monitoring device Serving, when the trunk line is occupied, the surge receiving relay switches itself into a holding circuit while at the same time bridging the switch-on contacts that open when a current surge is given a.

Further details of the invention are as follows To be found in the description.

An exemplary embodiment of the invention is shown in the drawing. Only those to understand the Invention absolutely necessary switching means and circuits are shown. It shows

Fig. 1 the equipment of an exchange line in the private branch exchange with the between the speech wires switched signal receiver,

Fig. 2 the selection on the trunk line.

A signal receiver SE is connected to contact 3 c, capacitor Koe, the primary winding pr of a transformer and contact 4 c in a bridge between wires 1 and 2 of the trunk line AL. After the trunk line has been occupied by a line selector (not shown) in the office, the call relay AR responds to the call current created in the line selector, but not the relay Y located in the anode circuit of the tube Ro . The call current runs through the capacitors Koa or K ob.

The connection of the exchange line when the officer reports and the response to relay C is

7OJ «60/149

not described as these details are relevant to the invention are irrelevant.

When the trunk transmission AUe is occupied by a calling subscriber of the private branch exchange, the relay 5 ¹ in the feed circuit responds. The contacts for 5 s and 6 s close. Since the contacts 7 c and 8 c are open, no direct current bridge is established between the wires 1 and 2 when the contact is closed for 5 s. The relay /, which is placed in a holding circuit, is switched on by contact for 6 s:

Contact 6 ί is bridged. With the contact 11t a call incentive is given over the trunk line.

2. - (Fig. 2), Ii ?, 12 t, 1 (Fig. 1), 3c, Hi, pr, ± c,

2 (Fig. 2), 13 i, +.

Contacts 14 i, ISi open, contact 16 i closes. The call relay R of the preselector causes its setting in a known manner. After a free group dialer has been assigned, the dialing character is switched on. The signal receiver SE responds to this dialing signal, which is also transmitted to the calling subscriber. Relay Y is activated and switches relay C on with contact 17 y .

3. +, 17y, Wi, IC, JlC, -.

The winding I C is short-circuited by contact 18 c. Relay C receives dropout delay. By opening the contact 9 c, the holding circuit 1 is interrupted. Relay / is now under the exclusive influence of contact 6 s. Contact 19c bridges contact 17y. Contact 20 c prepares the activation of the control relay V. Contacts 7c and 8c close. Then the contacts 3c and 4c open. With the signal receiver SE switched off , a direct current bridge containing the impulse transmission contact 5 s is placed between wires 1 and 2 of the exchange line.

Nrnnmernstromimpuls transmitted by the calling subscriber are transmitted by means of the contact 5s to the current impulse receiving relay of the connected user current impulse receiver in the office. At the same time the relay / drops out in pulses. The rotary magnet D of a follow-up switching mechanism is actuated.

4. +, 19c, Hi, D, -.

At the same time the control relay V is switched on:

5. +, 19c, 15i, 20c, IV, UV, -.

Contact 21 ν short-circuits the winding I V , so that the relay V remains activated while a series of current impulses is picked up. Further, not shown f-contacts, which prepare the influence of the changeover relay, identification relay and a blocking relay, are switched over. If the code number of an unauthorized traffic direction is selected, the connection route is triggered in a known manner.

If the calling subscriber sends out number current impulses before he has received the dialing signal, i.e. at a point in time at which relay C is not yet energized, the relay / current impulses cannot follow, because the contact 6 s is bridged. A transmission of impulses over the trunk line does not take place either, because the contacts 7c and 8c are still open.

When the trunk line was occupied, a drop-out delayed relay Vl ( not shown) was actuated, which among other things closes contact 21 ν 1. If the relay 5 ¹ drops on the first current impulse, an auxiliary relay H responds.

6. +, 23s, 2SvI, 24c, H, -.

Contact 26 h in the circuit of relay F opens. This prevents that when the first group selector is occupied during the transmission of the first series of impulses in the signal receiver, the dialing signal becomes effective, the relays Y and C respond and thus the last current impulses of the series of impulses being sent cause the setting of the occupied group selector and the tracking switchgear .

Instead of the relay H shown, there could also be a winding of the blocking relay in the circuit 6. The locking relay responding when the circuit 6 is closed would then trigger the connection path.

In order to have a control for when and how often a calling subscriber ignores the dialing signal, the relay H can place itself in a holding circuit via a second winding, not shown, and switch on a signal. The Verbiwfetagsweg then remains, and the caller can be identified by the PBX staff. '

Finds the activated by the response of the relay R via circuit 2 preselector VW (Fig. 2) no free group selector, the preselector is shut down in a known manner in the overflow position uk . In the overflow position, the switching arm 30 has left the contact segment 31 and is on the contact uk 2. In this contact, since the contact 32 r is open, there is no negative potential directly on the rotary magnet Dvw. The following circuit is established:

7. +, Ru, Dviv, 33 1, 34r, II T, IT, 35, ukl, Gl, -. As a result of the high resistance of the relay G , the relay T and the rotary magnet Dvw have Fehlstrona.

If the calling subscriber sends out current surges while the preselector is in the overflow position, there is no interruption of the current flowing through the relay R , because the contacts 7c and 8c are still open, and the holding circuit 1 still exists for the relay / Relay / can therefore not follow the current surges sent by the subscriber.

By switching on the signal receiver is consequently prevents the person in the preselector from receiving the current impulse on the part of the calling subscriber existing circuit 7 is interrupted and the selection is stimulated to start again. He can So do not adjust to a group voter that has meanwhile become free. By preventing the dropping of the preselector from the overflow position is now further prevented that the tracking switching mechanism by a different number of power surges is set as the group selector that occupies 7 of the preselector when the circuit is interrupted will. Under certain circumstances, the group selector found during this second run of the preselection can through the first series of impulses cannot be set at all.

Claims (6)

Patent claims: 1. Circuit arrangement for telephone private branch exchanges in which a tracking switch prevents the production of unauthorized connections, characterized in that a signal receiver (SE) is located in the private branch exchange in a bridge to the exchange line (AL) in a manner known per se, which is sent to an office Dialing character responds, and a relay (Y ) actuated via the signal receiver (SE) closes: the impulse circuit via the exchange line (AL} _: -: initiates and prepares the setting of the tracking switchgear. 2. A circuit arrangement according to claim 1, characterized in that when the trunk line is occupied, a call stimulus is given via the bridge serving to influence the signal receiver (SE) (Hi) and that a surge receiver relay which is used to control the monitoring device and is switched on when the trunk line is occupied ( /) is in a holding circuit while at the same time bridging the switch-on contact (6 s) that opens when a current impulse is given (1 (H) 3. Circuit arrangement according to claim 1, characterized in that the relay (F) responding to the signal receiver (SE) switches on a relay (C) which opens the holding circuit for the relay (/) controlling the tracking mechanism and switches off the signal receiver (SE ) closes the surge circuit via the exchange line (AL) (7 c, 8 c). 4. Circuit arrangement according to claim 1, characterized in that in the event of a premature rush current on the part of the calling subscriber through the first rush current, an auxiliary relay H is switched on (23 s), which prevents the selection signal from taking effect during the recording of the series of rush currents (26 K). 5. Circuit arrangement according to claim 4, characterized in that the auxiliary relay (H) switches on a monitoring signal. 6. Circuit arrangement according to claim 1, characterized in that in the event of a premature impulse current on the part of the calling subscriber through the first current surge, the triggering of the existing connection path causing blocking relay is switched on. Considered publications:
German patent specification No. 945 256. 1 sheet of drawings © 709 650/149 8.