DE513804C - Telephone line voting system with blocking circuit - Google Patents

Description

There are already line dialing systems with locking or secret circuit known at which by means of test and through switch relays and test potential a double connection is impossible is made. In these systems, which are set up in different ways, a constant test voltage of at least 8 to 12 volts are required, which is not always available for line dialing systems hold, especially in PBXs fed by the exchange. Consume such plants but also a high operating current, since the relays have to remain under current during the connection, which means high operating costs arise. The well-known test circuit with locking relay and without special power consumption would be better; but it has several disadvantages (Deactivating the secret circuit, switching off the test relay and others Shift handles) so that it is not used. But about her the rest of her Advantages because of (no power consumption, no constant test voltage) for line dialing systems to be able to use, switching devices are used according to the present invention, by certain working methods, mainly by switching off and switching over of the 'test relay of the calling station to a secondary switch of the selector made selection, whereby the test relay when the line is busy and when changing the The voter is excited after switching off the same and makes the speech device ineffective, eliminate the disadvantages and ensure excellent operational safety. By association the test current source with the call battery, it is not possible to switch off the test voltage. Otherwise, the failure the test voltage and the test equipment do not shut down the system, since the same then continues to work without a secret circuit. Also an important safety factor. The test relay only responds when the line is busy and makes the intercom ineffective. It therefore consumes very little electricity. The occupancy signal is given by a flag in the relay circuit or the clear message by an alarm tone during the call.

Such a device is shown in the example for three points a, b, C in such a way that point α is connected to b , while point c is at rest.

Each intercom consists of the intercom 44, 45, 46 and 47, 48, 49, one Hook switch 28, 29, 30, a similar apparatus 44, 45, 46 and 47, 48, 49, a Call and changeover switches 50, 54, 58, a test relay 15, 16, 17, an indicator 24, 25, 26 or a capacitor or the like 63, 64, 65, the test choke coils 37, 40, -38, 41- and

39, 4 ² as well as the voters 9, 12-10, 13-11, 14 of any kind and accessories. There is a common call and test battery 85 along with lines 1, 2 and a single line 3, 4, 5 or a double line 6, 7, 8 with 3, 4, 5 for each point.

All parts can be tracked in their activity on the basis of the operating mode. the Setup can be for single or double iQ lines are needed; It is intended initially for single lines, which of course must consist of the best induction-free cable.

Point α picks up the receiver, whereby the alarm clock 31 is switched off at 28 and the speaking set 44, 47 is switched on at 34. If the selector 9 (12 is omitted for a single line) is now set on line 4 to point b , the choke coil 37 or ao is placed in its place with a resistance of 1, 37, 76 on its own line 72, 3 and thus the test voltage for their own position switched on. At the same time the test relay 15 is connected to the selector 9 at j "j (current path 2, 51 [not open], 15, 24, 77, 9 and 4). If the call button 50 is now pressed, the disconnection of the takes place Test relay ι s at 51 from the selector 9 and its connection to a contact 78 at the selector 9 (current path 2, 51, 78 [open], 18 [open]). This contact is now only when the selector is not allowed to continue or switch 9 closed, whereby the relay 15 would be energized and would remain switched on continuously over 18. About this later. By pressing the call switch 50 a call current of 2 over 50 (normally open contact), 19, 9, 4 after position b, here over 73, 29, alarm clock 32 and ι sent, causing the alarm clock 32. Likewise, a choke coil 40 was switched on at 52 as test potential for point b (current path i, 40, 52, 19, 9, 4 to b). The switch parts 52, 53 remain but by a locking bar 53 or the like. In their working position, while the calling part 50 is in rest position g goes and can be pressed as often as required to call. Point b picks up its receiver, whereby the alarm clock 32 is switched off at 29 and the speaking set 45, 48 is switched on at 35. The speech stream is then closed from 1 to 34, 47, 44, 50, 19, 9, 4, 79, 10, 54, 45, 48, 35 to 1. Both positions are now protected against eavesdropping. If, for example, point c on line 3 (or 4) wanted to switch on (dialers set to 86 [87] after 3), relay 17 would respond (current path 1, 37, / ö, 3, 86, 11, 60, Relays 17, 89, 2) and switch off the intercom 46, 49 at 23.

If position α has found position b occupied before calling, relay 15 responds (current path 2, 15, 24, 9, 4 at b, now 73, ² 9i 3 ^ ^and d 0 ^and at 19 switches the intercom 44, 47 are off, and indicator 24 indicates that it is busy. If this indicator is not provided, the ringing current is also cut off at 19. When the call switch 50 is pressed, an alarm tone cannot be heard in the receiver as a dial tone 51 (55 and 60) must be follow-up contacts so that the relay circuit does not break. If relay 15 (or 16, 17) has been energized once and even then the call switch is pressed, it now remains via holding contact 18 (20 , 22), which otherwise does not work, is excited until the handset is hung up. As a result, after the call has been made and the test relay has been disconnected from the test line, the voter cannot be changed, since it is excited and remains in the working position Activation in an occupied line any other switching process, for example: change the selector after the call switch has been pressed, i.e. the test relay has been switched off from the test line, to block the intercom.

The capacitor 63 (64J or the resistor 65 is available to help with calls to make the dial tone perceptible in the handset, otherwise the same at 50 (54, 58) is separated.

When the receiver is hung up, all connections and the Rest position occurs; accordingly, the relay is also de-energized as soon as it is energized.

In the same way, any point can connect with any other, whereby the mutual relays are made effective or remain de-energized. The relays speak at every practical test voltage (from 4 volts upwards) and do not need a constant Tension. Their power consumption is quite insignificant and can be neglected. If the test voltage has become too low, the system continues to work without a blocking circuit.

With single line operation, there is a separate return line for the speech streams use to avoid the cracking noises that occur during testing; the lines of 47, 48, 49 are connected to a common return line at 34, 35, 36 or the lines 6, 7. 8 are combined into one line.

In the case of double-line operation, the lines 6, 7, 8 come with the selector parts 12, 13, 14 added. Then only the return of the speech flows via lines 6, 7, 8 done separately, while the rest of the facility remains. The speech stream course

between α and b would then be: from 44 to 47j 69 (34 and 91 omitted), 12, 7, 13, 70, 48, 45, 54, 10, 79 = 4, 9, 19 = 5 ° to 47. To; To adjust the double lines, inductors 66, 67 (68) can be switched on so that crosstalk does not occur. The paired choke coils (40, 66-41, 67-42, 68) can also be used to set up a central microphone feed. The choke coils 66, 67, 68 are not absolutely necessary. The design and more detailed switching type of the call stations a, b, c can be any. So have z. B. the points a, b foot contacts 76, 77-79, 80 on the voter, while the point C does not need such. At c , its own line 74 is connected to the selector 11 via a capacitor 82 which shuts off the test current, or directly via one of these, 83, to the speech circuits. The relay 17 is switched off immediately at 60 or the selector line 88 is switched over. The position c is therefore a bit simpler. 75 does not apply to double lines. The choke coil 39 can be omitted if the own line is disconnected when dialing, i.e. as 76 at α or 79 at b or 82 at 11.

The test chokes 37, 38 are switched on when dialing via 76, 79; You can also can be switched on when the receiver is picked up, i.e. at 90, with contact 79 not applicable. The test choke for your own line can also only be switched on when you call (39 at 59).

The contact 78, Si, 84 can advantageously be connected via a special switch-on contact at switch 61 to prevent any malfunctions.

If a preferred position in a busy line can be switched on, as is required for private branch exchanges, the test relay is only temporarily switched off by a switch 89 at c.

The intercom can be short-circuited by the test relay (21 at point b) or switched off (19 at a, 23 at c). The switch-off or short-circuit can be set up as required.

The speaking apparatus of each or only one specific point can be used in the well-known way can be switched using a toggle switch for public and house calls.

The line selector can be a crank, lever or push-button selector.

Claims (7)

Patent claims: ι. Telephone line dialer system. with blocking circuit, in which two in connection standing microphone units are protected against eavesdropping by the fact that the Test leads or one of the speech lines of both locations during the connection occupied with a test voltage and a third connection seeking point ineffective by its own test relay is made, characterized in that the test and blocking relay of the calling Place after dialing from when dialing or calling in a known manner with a test voltage the occupied test line of the remote station is disconnected and assigned to the voter, with each election and each change of the voter entering activity is connected in such a way that switching on to a busy line and forwarding or changing the dialer after disconnecting the with a test relay provided with a holding contact this brings to response and the intercom until the handset is hung up or Resetting the voter in the rest position makes ineffective. 2. Telephone line dialer according to claim 1, characterized in that the activation of the test voltage for the remote station initiating when a common call and changeover switch is operated (50, 51-54, 55-58, 59), which also switches the test relay (15, 16, 17) from the test lead to the Secondary switch (78, 80, 84). After the test has been completed, causes the switch to be switched on the test voltage for the calling station as soon as the receiver is picked up or when setting the selector or when pressing the call button. 3. Telephone line selector system according to claim 1 and 2, characterized in that that the changeover switch for the test relay is combined with the call switch that the former (51, 55, 59) means The lock (53, 57, 60) remains in the working position until you hang up the receiver while the latter (50, 54, 58) does not have a lock. 4. Telephone line selector system according to claim 1 to 3, characterized in that that the test and the call to the remote station via only one voice line (3, 4, 5). 5. Telephone line dialer system according to claim 1 to 4, characterized in that that preferred places a connection in a busy line with the help of a special relay disconnector (89) is made possible. 6. Telephone line selector system according to claim 1 to 5, characterized in that that the busy message by a flag (24, 25, 26) when responding to the Test relay or the clear message in a manner known per se via a voice line is indicated by the buzzer sound of the alarm clock in the handset. 7. Telephone line selection system according to claim 1 to 6, characterized in that a separate return line from the battery is used for the speech currents in single line operation in order to avoid cracking noises when checking. For this purpose ι sheet of drawings