DE1259404B - Circuit arrangement for telecommunications, especially telephone systems, with traffic monitoring by listening - Google Patents

Description

Circuit arrangement for telecommunications, in particular telephone systems, with traffic monitoring by listening in. The invention relates to a circuit arrangement for telecommunication systems, in particular telephone systems, with traffic monitoring through eavesdropping.

For the quality monitoring of telephone calls finds - in particular in smaller systems - in addition to or in addition to the newer automatic quality testing devices still using the older method of monitoring conversations from a control person allow. The disadvantage here is that the telephone is secret when eavesdropping cannot be safely maintained in a connection if the control person has their Failure to observe confidentiality.

One of the above-mentioned known, newer automatic monitoring devices, for example according to German patent specification 958 577, contains an optical display means which can be controlled by the audio-frequency currents occurring in the speech and signal paths. This display means, in particular a light indicator tube (magic eye), has a fluorescent screen on which the observed currents are visible in the same rhythm as a function of their size. The result determined by this device is only of limited use, because background noises, z. B. loose contacts on the transmission path, calls taken over by shunts from other lines, etc. simulate a flawless conversation. In addition, it cannot be determined with certainty whether the displayed frequencies are from a conversation between the two subscribers who requested the connection, or whether a faulty connection to a third subscriber was established or even three subscribers were interconnected. Even conversations with oneself or conversations when the connection is not or not yet switched through are made visible on the luminescent screen like a regular conversation. In addition, speech distortions and similar disturbances cannot be detected.

The object of the invention is to show a circuit arrangement which allows the supervisor to disregard the proper course of a conversation and to convince of the technical quality of the established connection and still as far as possible - according to the purpose of eavesdropping - the telephony secret to protect.

This is achieved by the fact that the measuring and listening point of the traffic observation device a time switch is assigned, which is started when the listening devices are switched on becomes and after a; pre-set listening time the eavesdropping organs of the Disconnects the connection again. The circuit arrangement according to the invention has the The advantage is that eavesdropping on entire conversations can be prevented.

For how long the monitoring person is connected to the connection remains depends on the purpose of this traffic observation. So sets, for example The observation of the speech communication assumes that the observer overheard parts of it Understanding the conversation so that he can infer the circumstances surrounding the conduct of the conversation can. In such a case, the duration of the possibility of eavesdropping is extended to z. B. limited to 25 seconds. After this time interval has elapsed, the Monitoring device from the connection in question again free. One of a kind On the one hand, there is enough time to cover one or more sentences of a conversation understand, on the other hand, generally not, the entire content of the conversation capture.

According to a further development of the invention, the call duration can be in special cases by pressing an additional switch will. In order to keep these cases to a minimum, this is done at the same time an alarm device is switched on, which indicates this fact to the superintendent.

In another embodiment of the invention, after reporting of the called subscriber only after a few seconds have elapsed the eavesdropping organs switched through to the connection. After the listening time has expired, it will be back disconnected. This type of eavesdropping ensures that participants mostly remain anonymous, as the mutual introduction of the participants is hidden will. The interceptable part of the conversation then generally has no particular informational value more.

According to an expedient development of the inventive concept with or without start-up time, the time interval from z. B. 25 seconds in listening times and breaks divided. This results in intermittent listening without special Information content. The disconnection of the device from the connection to be observed then happens after several time intervals have elapsed.

If a connection for fault tracking is to be maintained, then must the timer for the limitation of the listening time remain effective or an acoustic one Display for the supervisory authority and / or an alert sign, e.g. B. Ticker symbol, the Participants are forwarded at the same time.

Automatic switching chains or flip-flops or also the incoming counting pulses registered by the observation device to be used. The listening time can also be extended by the arrival of special, selected ones Counting pulses are controlled.

With this timer, the listening time is to be used for the assessment the absolutely necessary amount of the transmitted goods are limited. On the one hand will so the confidentiality of the conversation is preserved in the best possible way and on the other hand the number of the connections to be observed increased as much as possible, since the observer yes only a certain time is available and he through the information content the conversations fail of its real purpose, the connection on their goodness to control, being distracted. The observer is thus given the freedom of choice, when he wants to start the next observation, withdrawn. Sufficient in exceptional cases If the listening time set for the quality determination is not exceeded, this has no effect on the overall result of the investigation. In statistical measurements, the individual is Measured value against. anyway insignificant over the collective of measured values.

The invention is based on the illustration in an exemplary embodiment explained in more detail.

When switching through the telephone connection from the telephone exchange FA to the subscriber station Tln , a pulse, for. B. signal pulse, given via the connection elements DS 1 to the timing circuit ZS, which can be designed as a relay or electronic circuit and which in turn enables the connection of the listening organs L of the measuring and listening station -MP via connection elements DS2 by means of contacts a for a certain period of time Actuation of a relay A makes.

To catch a connection to be monitored for the purpose of troubleshooting If a key F1, F2 is pressed in the measuring and listening position, a Signal W to the supervisory authority and! Or a ticker signal via connection elements DS3 the monitored line is given to display the monitoring for the participants.

Claims (5)

Claims: 1. Circuit arrangement for telecommunications, in particular Telephone systems, with traffic monitoring through eavesdropping, d u r c h e k e n n -z e i c h n e t that the measuring and listening place (MP) of the traffic observation device -A time switch (ZS) is assigned which, when the monitoring devices (L) are switched on, is started and after a preset listening time has elapsed the listening organs disconnects from the connection (FA) again. 2. Circuit arrangement according to claim 1, characterized in that the time switch (ZS) delays the co-organs (L) the connection (FA) switches on. 3. Circuit arrangement according to claim 1, characterized characterized in that the connection of the listening organs (L) depending on the start of the conversation (e.g. from the message pulse) takes place automatically. 4. Circuit arrangement according to claim 1, characterized in that for special measurements after pressing an additional Switch (F1, F2) the listening time with activation of a signal (W) for the supervisor and / or a ticker to the connection (FA) is extended. 5. Circuit arrangement according to one of the preceding claims, characterized in that the listening organs (L) intermittently connected to the connection (FA). Considered Publications: German Patent No. 958 577; Siemens publication SH 1802 2512, Müller, Hermann, operational monitoring of telephone systems.