DE1042668B - Circuit arrangement for telephone sets provided with number current pusher - Google Patents

Description

GERMAN

In telephones for automatic ZB-Ämter there are capacitors with the following three functions used :

a) as an alarm clock or ringer capacitor, the task of which is to pass the direct current through the signaling device (Alarm clock) to block, in order to prevent that the call relay of the central office responds;

b) as a spark quenching capacitor, which has the function of the voltage at the pulse contact of the dial trained number current pulse generator, including the capacitor, for example in Series is connected with a resistor;

c) as a speech capacitor, the task of which is to block part of the speech circuit for direct current. This capacitor can e.g. B. be arranged so that the entire line current through the microphone flows while the remote handset is protected against direct current. With uninterruptible microphones the electrode system and the carbon chamber are designed so that regardless of the position in which the Microphone is held, no power interruption occurs in the microphone. When using carbon grain microphones, which are not uninterrupted, for example, the speech capacitor becomes such Switched in such a way that direct current flow through the handset is definitely prevented.

The functions of the ringing and spark extinguishing capacitor are usually fulfilled by one and the same capacitor by means of switching by the hook switch (cf. the known circuits shown in FIGS. 1 and 5). So you have a total of two capacitors in these circuits. The switching elements are: the two branches La and Lb ₁ the hook switch HU ₁ the signaling device (alarm clock) W ₁ the dial D ₁ the microphone M ₁ the receiver T ₁ the speech transformer IC ₁ the spark extinguishing resistor r _v the combined ringing and spark extinguishing capacitor C. ₁ , the speech capacitor C ₂ and a symmetry or compensation resistor r ₂ . In a circuit according to the type disclosed in FIG. 1, the balancing resistor r _{2 can be contained} in the right winding of the speech transformer IC . When the telephone set is switched to the ringing state (as shown in Fig. 1), the capacitor C _{1 is} connected via the contact springs 2 and 3 of the hook switch HU in series with the signaling device W between the two branches La and Lb , while in the speech state Contacts 1, 2 of the hook switch HU are closed. The capacitor C ₁ is then connected via the contact springs 1 and 2 of the hook switch in series with the spark extinguishing resistor T ₁ via the pulse contact springs 12 and 13 of the dial D.

Telephone stations are also known in which the circuit arrangement

for with number current pusher

equipped telephones

Applicant:

Telefonaktiebolaget LM Ericsson,
Stockholm

Representative:

Dr.-Ing. H. Ruschke, Berlin-Friedenau, Lauterstr. 37,

and Dipl.-Ing. K. Grentzenberg, Munich 27,

Patent attorneys

Claimed priority:
Sweden 17 February 1955

Hans Gösta Thames, Hagersten (Sweden),
has been named as the inventor

Handset is not connected galvanically, as in Fig. 1 and 5, but inductively to the speech circuit. then a capacitor to block the handset is not required; therefore one comes to these places with just a single capacitor. On the other hand, call stations are also known in which the ringing capacitor also serves to protect the remote receiver against direct current flowing through it; then but no spark extinguishing function is provided.

Finally, circuits are also known in which the listener against direct current flow through a Capacitor is blocked, which is connected so that it is in series with a winding of the speech transformer is connected to the pulse contact, so that this circuit as a spark extinguishing circuit serves. In order to obtain an optimal effect of the function of such a spark extinguishing circuit, would have to measure the resistance of this winding with regard to the property as a spark extinguishing resistance will. Since this resistance in the known circuit is from one winding of the speech transformer is formed, this winding must of course also with regard to the property a transformer winding. It is therefore not possible with this known Circuit an optimal effect of the spark extinguishing

«09677/100

circle with regard to the spark extinguishing properties ^; obtain.

The object of the invention is to provide a spark extinction for the pulse contact in such circuits and DC blocking for the listener using a single capacitor to give a · To create circuit, which an optimal effect of the spark extinguishing circuit with regard to the spark extinguishing properties enables.

According to the invention, this is achieved by adding an additional set of contact springs to the current material transmitter is assigned, through which the second assignment of the single capacitor when the handset is removed in the idle state of the number current pusher with the handset and in the working state of the Number current pusher is connected to a specially provided spark extinguishing resistor, the in turn lies on the second contact spring of the pulse contact.

FIGS. 2 to 4 and FIGS. 6 and 7 are exemplary embodiments of the subject matter of the invention shown.

The circuit of Figure 2 shows the apparatus in the ringing state; then a plate of the capacitor C to the line branch La and its other occupancy of the hook switch HU is connected in series with the signal device W via the contact springs 2 and 3, which is connected to the other branch line Lb.

When the apparatus is switched to the speaking state by lifting the microtelephone, the hook switch HU moves upwards, whereby the contact between the springs 1, 2 and 4, 5 is closed (Fig. 3). The capacitor C causes the DC line current through the branch line La, the pulse contact springs 12-13 and the Kurzschlußfedernil and 15 of the dial disc D _1, the microphone M ₁ part of the speech transformer IC and the contacts 4-5 of the hook switch HU flow to the branch line Lb got to. On the other hand, the alternating voice current can flow through the capacitor C via the springs 1-2 of the hook switch, the additional contacts 17-16 of the dial!?, The handset T _1, the voice transformer IC and the contacts 4-5 of the hook switch HU .

If current surges are given over the line La, Lb by the fact that the pulse contact springs 12-13 of the dial are alternately opened and closed depending on the position of the breaker disc, the spring 14 and the additional spring 17 are bent to the right, whereby the contacts between the Springs 14 and 15 or 17 and 18 are closed and at the same time the contacts between springs 15 and 11 and between springs 16 and 17 are interrupted. The position of the contact springs at this point in time is shown in FIG. The spark quenching circuit, which consists of the capacitor C and the spark quenching resistor T ₁ connected in series with it via the contact springs 2, 1 and 17, 18, is thereby connected to the pulse contact springs 12, 13 of the dial.

4 shows a modified form of the apparatus circuit according to FIGS. 2 and 3, in which the signaling device W is constantly connected in series with the capacitor C between the line branches La and Lb , but in which only partial use is made of the invention, since the handset is not completely blocked from direct current. In this case, too, the entire supply current runs through the microphone M ₁ but then branches off into the speech transformer IC , with a part in the receiver T and further via the springs 16-17 in the dial D and through the signaling device W, which are in series with the handset T runs, while the majority of the current flows through the transformer IC and via the contacts 8,9 to the line. The ratio between the resistance of the speech transformer IC and the total resistance of the receiver Γ and the signaling device W is such that such a small part ( ¹ ZsO to V100) of the supply current runs through the receiver T that it is negligible with regard to the receiver T.

In Fig. 5, a known circuit of a telephone set is shown again; Fig. 6 shows a circuit diagram of an apparatus of the same type, but in which - according to the invention - the circuit is converted so that the function of the capacitor C ₂ (in Fig. 5) is taken over by the single capacitor C. The call circuit is closed via La ₁ C ₃ contacts 2-3 from HU ₁ W to Lb. The hearing circle is connected via T ₁ IC (right part), r ₂ , contacts 13-12 parallel to contacts 15 and 11 in D ₁ contacts 4-5 of HU ₁ C ₁ contacts2-1 of HU ₁ contacts 17-16 of D closed after Γ. The spark extinguishing circuit is closed via C, springs 2-1 of the hook switch HU _1, springs 17-18 from D ₁ T ₁ , pulse contact springs 13-12, springs 4-5 from HU to C.

Fig. 7 shows the circuit of an apparatus in which there are no signal devices (which is the case, inter alia, in so-called secondary apparatus). In the drawing showing the circuit diagram of the secondary set, LaI and Lb 1 relate to the line to the office and LaZ ₁ Lb2 to the line to a main set, which is not shown and can be designed in any known manner. HU is the hook switch of the auxiliary machine. An incoming call signal from the exchange via the branches LaI, LbI runs through the closed contact springs 20, 22 via the line La 2, L & 2 to the main telephone. When the slave set is to be used and its microtelephone is lifted, the contact springs 20 and 22 move upward until the spring 22 makes contact with the spring 21. However, the spring 20 continues to move upward until contact between it and the spring 22 is broken. The secondary set is thus connected to the exchange via the lines LaI, L & l and via the contacts 21, 22. The capacitor C is then connected via the contact 17 either to the receiver T or to the spark quenching resistor T ₁ in a manner analogous to that described in the explanation of FIG.

Claims (1)

Claim: Circuit arrangement for telephone sets provided with number current pulse generators, in which the receiver, which is galvanically connected to the microphone, is blocked against direct current flow by the single capacitor provided in the apparatus, one of which is located on a contact spring of the pulse contact, characterized in that the number current pulse generator has an additional contact spring set ( 16, 17,18), via which, when the handset is removed (contacts from HU closed), the second assignment of the single capacitor (C) in the idle state of the number current generator (contacts 11-15, 16-17 closed) with the handset (T) and in the working state of the number Impulse generator (contacts 11-15, 16-17 open, 17-18 closed) is connected to a specially provided spark extinguishing resistor (T ₁ ) , which in turn lies on the second contact spring (13) of the pulse contact (12, 13). Documents considered: German Patent No. 880 152; Swiss patents No. 302 743, 277 499; British Patent No. 665 081. 1 sheet of drawings