DE1177690B - Circuit arrangement for in-house telephone systems - Google Patents

Description

Circuit arrangement for in-house telephone systems The invention relates to a circuit arrangement for in-house telephone systems with several call stations and one common power source for the voice and ringing currents, whereby this is achieved by pressing a Call button of the calling station triggered tone-frequency call signal of the called Intercom station is supplied.

In the known circuit arrangements for in-house telephone systems the common power source for the speech and ringing currents either through one or several batteries or formed by a power supply unit. The ringing signal is directed by the calling party to the called microphone units. This is usually a circuit closed, the signal buzzer or alarm clock of the called microphone units will sound leaves. However, systems are also known in which each subscriber has a ringing current modulator possesses, which is designed, for example, as a transistor oscillator. When calling This creates current impulses that are fed directly to the listener of the called subscriber will. The disadvantage of these known solutions is that they are relatively high Price of the individual microphone units.

The invention is therefore based on the object of a circuit arrangement of the type mentioned at the outset, in which this deficiency is avoided.

This object is achieved according to the invention in that for all Call stations a common call signal generator is provided, the. with the power source lies in a circuit that is optionally closed by the individual call buttons.

The call signal generator can be used in a manner known per se as a electromagnetic buzzer equipped with a self-breaker or be designed as a transistorized vibration generator.

The main advantage of the circuit arrangement according to the invention consists in the considerable reduction in the price of the in-house telephone system, as compared to the known designs, both the call signal generators provided for individual call stations as well as the DC call signal receivers (buzzer) provided for other systems can be saved.

The circuit design of the solution according to the invention leaves numerous variants too: For example, the in-house telephone system can be used in a well-known Work with parallel calls, whereby the individual microphone units only have one call button and each participant is assigned a special call sign for identification is; however, the system can also work with individual calls, with each participant a special call line is assigned.

Details of the invention can be found in the description of some in Drawing of illustrated embodiments. FIG. 1 shows the circuit arrangement an in-house telephone system according to the invention for four intercom stations with parallel calls and parallel connection of microphone and receiver, FIG. 2 shows a modification of the circuit according to FIG. 1 with a series connection of microphone and receiver, FIG. 3 the circuit arrangement an in-house telephone system for four intercom stations with individual calls and parallel switching of microphone and listener, F i g. 4 shows a modification of the circuit according to FIG. 3 with Series connection of microphone and receiver, FIG. 5 another according to the invention Circuit arrangement with parallel call, FIG. 6 shows a modification of the circuit according to FIG F i g. 5 with individual call, F i g. 7 the circuit arrangement according to the invention a In-house telephone system with two intercoms.

The in F i g. 1 shown as a first embodiment of the invention The circuit arrangement is intended for an in-house telephone system with four intercoms, of which only two call stations are shown for the sake of simplicity.

The call stations, which each have a microphone M, a receiver F, a limiting resistor R, a capacitor C , a hook switch contact Gu and a call button RT, are connected to one another via the lines La, Lb, Lc and Ld. The circuit arrangement also contains a battery Ba, a choke Dr, a capacitor C and a ringing current generator, which is designed as an electromagnetic signal buzzer and has a contact k.

This circuit, which works with parallel calls, works as follows: If subscriber 1 picks up his handset, contact Gu is actuated and microphone M receives supply current via Ba (-), Dr, La, Gu, R, M, Lb, Ba (+). If subscriber 1 now presses his call button RT, the buzzer Sai receives voltage via Ba (-), Su, k, Lc, RT, Ba (+).

As a result, the contact k of the electromagnetic buzzer Su is periodically opened and closed. The resulting tone-frequency ringing voltage reaches the line wires Lc and Ld via the capacitor C and is consequently fed to the other subscribers. The result is the following ringing circuit: C, Ld, Gu (subs. 2, 3, 4), C, F, Lb, RT (subs. 1), Lc, k.

Any participants who are already speaking are not affected by the call signal disturbed because her listenerF through the contact Gu of the hook switch from the line Ld is disconnected.

As shown in FIG. 1 and the above description, a common call signal generator Su is provided for all call stations, which is connected to the power source Ba in a circuit that is optionally closed by the call buttons RT of the individual call stations.

While in the case of FIG. 1, the microphone M and the receiver F are parallel to the lines La, Lb, is in the embodiment shown in FIG. 2 a series connection of microphone M and receiver F is provided. Otherwise, the circuit corresponds to the embodiment according to FIG. 1.

In Fig. 3 is a further embodiment of the invention Circuit arrangement shown with individual call.

In addition to the lines La, Lb, Lc and Ld, there are four other lines L 1, L 2, L 3 and L 4 in this arrangement, which represent the call lines assigned to the individual call stations.

Each call station is also provided with three call buttons RT, 'RT, and RT, which are connected to the call lines leading to the other microphone units.

The mode of operation of the circuit according to FIG. 3 is as follows: If the subscriber 1 picks up his handset, the two contacts GuI and GuII of the hook switch are actuated, whereby the receiver F is disconnected from the call line Ld and connected to the line La, Lb together with the microphone M. If the subscriber 1 now actuates the call button RTi, for example, the call signal generator Su receives voltage via Ba (+), RTl, Lc, k, Su, Ba (-).

The tone-frequency ringing signals resulting from the periodic opening and closing of the interrupter contact k are fed to the subscriber 2 via the following ringing circuit: C, Ld, GuI (subs. 2), C, F, GuII, L "RT, (subs. 1), Lc , k.

In this circuit arrangement according to the invention, too, a common call signal generator Su is provided for all call stations, which is connected to the power source Ba in a circuit that is optionally closed by the individual call buttons.

While in the circuit according to FIG. 3 the microphone M and the handset F of the individual subscriber stations is connected in parallel, the in F i g. 4, a series connection of microphone M and receiver F is shown. Otherwise, the circuit according to FIG. 4 the previously explained embodiment.

F i g. 5 shows, as a further embodiment of the invention, a circuit arrangement with parallel calling, in which the circuit containing the power source Ba and the call signal generator Su and which is closed by a pressed call button RT leads directly to the receiver F of the called speech stations. For example, if subscriber 1 picks up his handset so that the contact Gu is actuated and he presses his call button RT, the following call circuit results: Ba (+), Su, k, RT (subscriber 1), Ld, Gu ( Part 2), M, F, La, Ba (-).

In contrast to the exemplary embodiments, there is thus a flow in this circuit according to FIGS. 1 to 4 - the direct current used to excite the signal buzzer Su also via the handset of the called subscriber. For this, however, the one does not apply to the Circuits according to FIGS. 1 to 4 provided capacitors C.

Even with the circuit according to FIG. 5 are the rest of the already speaking subscribers are not disturbed by a call, since their listener is not disturbed by the contact Gu are disconnected from the line Ld.

F i g. 6 shows that of FIG. 5 corresponding circuit for an in-house telephone system with individual call. Accordingly, in addition to the lines La, Lb and Lc, four call lines L 1, L 2, L 3 and L 4 are also provided, as well as three call buttons RT1, RT and RT3 in each of the individual call stations.

If the subscriber 1 picks up his handset so that the contact Gu is actuated, and if he presses the call button RTI, for example, the following ringing circuit results: Ba (+), Su, k, R T1 (subscriber 1), L 2, Gu (TIn. 2), M, F, La, Ba (-).

In Fig. Finally, as a further exemplary embodiment of the invention, a circuit arrangement for an in-house telephone system with only two speech stations is illustrated in FIG. 7. The power source Ba is here directly in the speech circuit of the two speech stations, which runs as follows when the contacts Gu of both speech stations are activated: Ba (+), Gu (subscriber 2), M, F, F (subscriber 1), M, Gu, Ba (-).

The ringing circuit that is formed when subscriber 1 lifts the handset and presses the call button, runs as follows: Ba (+), RT (Subscriber 1), F (Subscriber 2), M, Gu, k, Su, Ba (-).

In this embodiment of the invention, too, a common call signal generator Su is provided for both speech stations, which is connected to the power source Ba in a circuit that is optionally closed by the call buttons of subscribers 1 or 2.

Claims (7)

Claims: 1. Circuit arrangement for in-house telephone systems with several call stations and a common power source for the speech and call currents, whereby the tone-frequency call signal triggered by pressing a call button of the calling call station is fed to the called call station, characterized in that a common call signal generator ( Su) is provided, which lies with the power source (Ba) in a circuit that is optionally closed by the individual call buttons (RT). 2. Circuit arrangement according to claim 1, characterized characterized in that the call signal generator in a known manner as a with an electromagnetic buzzer (Su) equipped with a self-breaker contact (k) is trained. 3. Circuit arrangement according to claim 1, characterized in that that the call signal generator in a manner known per se as a transistorized Vibration generator is formed. 4. Circuit arrangement according to claim 1, characterized characterized in that in which the current source (Ba) and the call signal generator (Su) containing, call signals generated by the pressed call button (RT) via a closed circuit a capacitor (C) is fed to the call line (Ld) common to all speech stations (Figs. 1 to 4). 5. Circuit arrangement according to claim 1, characterized in that the circuit containing the power source (Ba) and the call signal generator (Su) and closed by the pressed call button (RT) leads directly to the receiver (F) of the call stations (F i g. 5, 6, 7). 6. Circuit arrangement according to claim 1, characterized in that the power source (Ba) is connected in a manner known per se via a throttle (Dr) to the speech circuit (La, Lb) of the speech stations (F i g. 1 to 6). 7. Circuit arrangement according to claim 1 for in-house telephone systems with two intercom stations, characterized in that the power source (Ba) is in a manner known per se directly in the speech circuit of the two intercom stations (F i g. 7).