DE577225C - Circuit arrangement for telephone systems with dialer operation and preferred participants - Google Patents

Description

GERMAN EMPIRE

ISSUE Al
May 26, 1933

REICH-S EATENTAMT

PATENT LETTERING

M 577225 CLASS 21a ³ GROUP 36 oi

Patented in the German Empire on July 27, 1929

The invention relates to telephone systems with ■; Voter operation where preferred Participant by a special switching measure at the intercom station the occupied Influence the device in such a way that it switches to busy connections. Around To direct this switching measure to the occupied facility must usually be special Lines are led to the subscriber stations, for which in turn special Switching arms are to be provided in the selector. This different training of the Voters make it difficult to empathize with the option to connect in such systems, as, for example, in an existing system the Voters must be changed constructively, if a participant with the switching option should be provided. It can also happen that these additional switching arms of the voters are already available for transmission further switching measures, such as switching to consultation and the like, are used so that they can be used to transmit the switching measures are no longer available for activation.

To overcome these difficulties, the invention envisions the use of AC circuits, which are formed via the selector arms and lines local DC circuits, which are used to carry out other switching operations, superimposed will. If necessary, these AC circuits must be used with the aid of further lines are formed. However, the use of alternating current allows that those made in the direct current and in the alternating current circuit Switching operations do not touch each other, as it is easily possible to switch the relay in the Train the direct current circuit insensitive to alternating current, while on the other hand the direct current can be sealed off from the AC relays by capacitors. Through this it is possible to take additional switching measures without changing the design of the selector via switching means already used for other purposes.

The invention is explained in the drawing using an example circuit. The circuit shows only the essential parts necessary for understanding the invention - a telephone system with dialer operation, in which the subscriber T ¹ can connect to the subscriber T ² by means of the call finder AS and the line selector LW. When subscriber T ¹ calls, the connection set is ASILW. Blocked via the third wire c by the relays T and 5 by partial short-circuiting of the relay 6 * by means of the energized in the first stage contact si ³ in

*) The patent seeker stated as the inventor:

Karl Brendel in Frankfurt a. M.

lay the strongly drawn out holding circuit. The relay S switches through the connection to the line selector LW by means of its contacts si ² and si * , via which the further connection is established in a known manner under the influence of the subscriber T ¹ .

The calling subscriber is assigned buttons M and T, which he can use to initiate special switching processes. As a preferred subscriber, he can for example be authorized to intrude on existing connections or request the help of an officer in the exchange by activating an optical or acoustic signal.

The subscriber wishes to call the attention of an official on himself, he operates his key M, and thereby causes the holding current for the relay T and S is changed, amplified in this case, so that the constructed as a double-armature relay testing relais S in second Level can address. It closes its contact ss, which switches on the signal lamp ML. The officer recognizes by this sign that she is to enter the connection or to carry out some services.

If the participant T ¹ presses the button Γ, he closes the circuit shown in dashed lines, in which alternating current of any frequency flows, via the strongly drawn out holding circuit. The alternating current is drawn from an existing alternating current network via a transformer Tr. Without influencing the direct current of the holding circuit, this alternating current is superimposed on the direct current. It energizes the relay X located in the dashed circuit. If the calling subscriber has found when dialing the connection number of subscriber T ² that this subscriber is busy, he can switch to this connection by energizing relay X using his key T. The contacts x ² and x ⁱ switch through the connection even if the switch contacts p ″ and p * could not be closed due to the fact that the connection of T ^{2 was occupied.}

Claims (3)

Claims: 5 " i. Circuit arrangement for telephone systems with dialer operation, where preferred Participants can influence the occupied facility by means of a special switching measure at the intercom so that it switches itself on to occupied connections, characterized in that via selector arms and lines leading to Execution of local switching operations are provided, if necessary under the known direct current circuits With the help of further lines formed alternating current circuits for the execution of the special switching measures are superimposed. 2. Circuit arrangement according to claim i, characterized in that the Alternating current to the connection lines used for testing and imperfect blocking flowing direct current is superimposed. 3. Circuit arrangement according to claim ι for telephone systems with Voter operation, characterized in that the connecting devices of the Central office AC relays and alternators are assigned, which are constantly connected to the test arm of the call seeker are connected and their circuit by a button of the subscriber station can be closed for the purpose of using the signals already used for testing and switching on certain signals Initiate further switching operations. 1 sheet of drawings