DE2605540A1 - TELEPHONE SYSTEM, IN PARTICULAR KEY-CONTROLLED SERIES SYSTEM WITH LIS-TO-SPEAK DEVICES - Google Patents

Description

260554Q

DeTeWe

Deutsche Telephonwerke und Kabeifndustrie Aktiengesellschaft

Berlin, February 1976 E 4-3 Schz / sz P 2246

Telephone systems, in particular key-operated Series system with listening-in-speech facilities

The invention relates to a telephone system with listening devices, such as B. series system, anteroom system, broker system and the like, their connection and switching functions are advantageously controlled by buttons.

In telephone systems with several lines, listening in on calls on these lines is achieved by a'e listening in Lead one side of an eavesdropping transmitter firmly on the associated line is connected and a double line (monitoring line) from the other side of the monitoring transmitter leads all microphone units with listening rights.

Every call station with listening rights (listening point) can be switched to the listening line by means of switching means will.

Is in a known telephone system with z. B. four Trunk lines and ten remote units only require one listening point, but four listening transmitters with the associated ones are required Provide coupling capacitors and four double lines up to the listening point.

709832/0854

260554Q

In contrast, a circuit arrangement for telephone series systems (OS 24 35 045) a monitoring transmitter common to all lines per call station, waiving monitoring lines, on, "in which the internal and external calls over the eavesdropping transmitter run and carrion emitt el for eavesdropping per eavesdropping line available. It is not possible to prevent eavesdropping when making calls from certain microphone units. The eavesdropping transmitter must also be used for intercom stations that are not authorized to listen in. There is also a limit to the number of listening points required, because theoretically all monitoring transmitters at the same time z. B. could be switched to an exchange line, as a result of which permissible values of the insertion loss can no longer be adhered to, since technical measures allow simultaneous switching on do not prevent all monitoring transmitters.

The invention is based on the task of a telephone system, in particular key-controlled series system to create a listening-in-speaker arrangement with extended operating options, without to use special monitoring lines.

This is achieved by the fact that with one on different Operating modes like

a) Participation by the listening point,

b) privileged listening parts,

c) Prevention of eavesdropping for microphone units

depending on the call station and the respective line,

d) Prevention of eavesdropping on other eavesdropping points if a listening point is already listening in,

Adjustable listening-in-speech device for listening-in by pressing a button via switching means available for other purposes, an eavesdropping transmitter is switched to a line of the eavesdropping point will.

The invention is illustrated in the drawing, for example, the circuit details being shown only as far as it is is necessary to understand the invention.

709832/0854

Call station 1 with the addition "assembly A" is more detailed shown as call stations 2 and 3 · The relays 1A, 2A ... are the line connection relays. The relays 1R, 2R ... are Auxiliary relay of relays 1A, 2A ...

The operator switches with the 1AT, 2AT ... buttons of the intercom to the 1st line L1, 2nd line L2 ... The key switch ensures that only one Line can currently be switched to the intercom.

When the 1MT, 2MT ... buttons are pressed, one of the microphone units switched on for the purpose of listening in on the 1st line L1, 2nd line L2 ... Here, too, the button switching ensures that you can only listen in on one line at a time.

Line occupancy

If the 1st line L1 is free, the transistor 1Ta (in each speech point) receives negative base potential in a manner not shown. If, for example, "in the case of the St1 call station, the If button 1AT is pressed, the 1A relay responds in the following circuit:

1) Earth - 1AT - 1Ga - 1Ta - 1A - key circuit - minus. The relay 1A is in a hold circuit:

2) Earth - mIY - IaIII - 1A - key circuit - minus.

The contacts 1al and 1aII switch the 1st line L1 to the speech loop the call station St1.

3) L1a- 1a- 1al - ml - speech loop - mil - 1aII - 1b - L1b. Contact 1aIV switches on the 1R relay.

4) Earth - mlV - 1aIV - 1R -minus.

709832/0854

Via the contact 1rl the leading to all microphone units is sent Line 1Ms wired with ninus potential.

5) Minus - Mv - B1 - B2 - 1rl - 1Ms - line 1Ms.

The call station St1 is now connected to the 1st line L1 and in addition, the line 1Ms carries negative potential.

Listen in

For the description of eavesdropping, it is assumed that the intercom StJ is conducting a conversation on the 1st line L1 and the call station St1 should be able to listen in on this conversation.

In the case of the St3 intercom, the switching states described in the line assignment have been set and the line 1Ms receives negative potential from there.

To listen in, the operator of the intercom station St1 presses the 1MT button on the 1st line L1. Since the transistor 1Tm is negative Receives base potential from the line 1Ms, this transistor controls through and the common listening relay M responds.

6) Earth - 1MT - 1Gm1 - 1Tm - 1Gm2 - M - key circuit - minus. The 1A relay is also switched on via the transistor 1Tm.

7) Earth - 1MT - 1Gm1 - 1GmJ - 1A - key circuit - minus. Relays 1A and M bind.

8) Earth - mlV - 1aV - 1TM - - key circuit - minus.

The contacts 1al, 1aII and mill connect the primary side of the Monitoring transmitter MÜ1 with the 1st line L1.

9) L1a - 1a - 1al - mill -MtM-OI- 1aII - 1b - L1b.

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The contacts ml and mil switch the secondary side of the monitoring transmitter to the speech loop of the call station St1.

10) MÜ2 - ml - speech loop - mil - MÜ3 - 02 - MÖ2.

The conversation conducted by the call station St 3 on the 1st line L1 is now inductive on the speech loop of the call station St1 transferred.

Eavesdropping permission

A prerequisite for listening in on a line is that the associated line Ms carries negative potential, which is through the The call station conducting the call is created. This negative potential is applied to the corresponding Ms line, see Circuit 5) · The resistor Mv and the bridge points B1 and B2 are available in each microphone unit and per line.

Now a participant wishes that the conversations he for example on the 1st line L1 is not allowed to be overheard, the connection between the bridge points B1 - B2 is the 1. Line Li removed. If this subscriber is now conducting a call on the 1st line L1, circuit 5) cannot be established come, which means that other microphone units can also be listened to (due to the missing negative potential on the 1Ms line) is no longer possible. It can be seen that the listening permission can be set up separately per call station and per line.

Have a say

The microphone powering required for speaking is given to the microphone unit with listening rights via the resistors Rs1 and ßs2.

11) Minus - Rs1 - B4 - B3 - MÜ2 - ml - speech loop - mil MÜ3 - B5 - B6 - Es2 - earth.

709832/0854 _ ₆ _

26055A0

If you do not want to speak while listening in, the connections between the bridge points B3 - B4 and B5 - B6 removed. Because these bridging points are available for each intercom are, the prevention of speaking (in contrast to the known monitoring circuits) can be set up for each call station.

Listening in from, only one listening point at a time on one line

The listening device shown allows the connection of several listening points at the same time for the purpose of listening a line occupied by a call. The monitoring transmitters of the connected monitoring stations are located with their primary sides parallel in the respective line, which increases the insertion loss for this line when everyone is listening in hurry increased. However, this can lead to the permissible Insertion loss if the lines are trunk lines.

In the exemplary embodiment shown, one per line is used existing and as an additional assembly A, the device OM, RI, E2, R3, R4, 02, G1, G2 bordered by dash-dotted lines, the connection of Monitoring points regulated in such a way that only one monitoring point can be connected to a line at a time.

In the following description it is again assumed that that the intercom St3 is conducting a conversation on the 1st line L1 and the intercom St1 is listening to this line switches.

Relays iA and M are addressed in the Sti intercom.

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The line 1Ms, originally, from the call station
m i t Minuspoteritial "was beschältet, {is laid now iron the mithörenden St> computationally put St1 to earth.

12) Earth - mlV - 1aV - R4- - G2 - 1rl - 1MS - line 1Ms.

This gives the transistors 1 ¹ M of the other listening points
Super potential, so that no further listening is possible.

The R4 in the 12th circuit is dimensioned so that the base of T2 receives a sufficient negative voltage to turn on this transistor, whereby the transistor TI also in the
conductive state changes. This has the consequence that despite the blocking potential on the line 1Ms, the monitoring transistor 1Tm of the Sorechstelle St1 remains switched on, whereby the holding of the relays 1A and M described in the 8th circuit is still possible.

The listening option shown can also be used if in a Creation of a specific listening point in relation to other listening points should be given precedence in that one or more listening points switched on for eavesdropping automatically avoid eavesdropping switched off when the preferred listening point switches on to eavesdrop.

⁷ D 3 3 3? /

Claims (4)

Patent claims: 1) Telephone system, especially key-operated series system with listening-in-speech facility, characterized in that that with one on different modes of operation like a) Participation by the listening point, b) preferred listening point, c) Prevention of eavesdropping for call stations each according to the call station and the respective line, d) Prevention of eavesdropping on other eavesdropping points if a listening point is already listening in, Adjustable listening-in-speech device for listening-in by pressing a button (e.g. 1MT) using switching means (1A, 2A ...) available for other purposes Monitoring transmitter (MtH) is switched to a line (e.g. 1) of the monitoring station (e.g. 1). 2) Telephone system according to claim 1, characterized in that bridge points (B1, B2) per station and line are available, the connection status of which defines the eavesdropping authorization. 3) Telephone system according to claim 1, characterized in that by switching means (Ti, T2, R1 ... H4, G1, G2) listening in to only one listening point on a line is achieved. 4) Telephone system according to claim 1, characterized in that that the speaking while listening in is determined by the connection status of the bridge points (B3, B4, B5, B6) is. 7 0 9 B Ί 2 / Π Ρ 5 & ORIGINAL INSPECTED