DE592666C - Circuit arrangement for coin telephones - Google Patents

Description

GERMAN EMPIRE

ISSUED ON
February 2nd, 1934

REICH PATENT OFFICE

PATENT LETTERING

CLASS 21 a 3 GROUP 80

Telephone apparatus factory E. Zwietusch & Co. G. m. B. H.

in Berlin-Charlottenburg *) Circuit arrangement for pay phone

Patented in the German Empire on November 12, 1929

The invention relates to a circuit arrangement for payphones that are connected to a Self-connection office are connected. Such payphones are usually set up in such a way that that only after the fee has been inserted the setting of the voters with the help of the. Dial can be made. By inserting the coin, the microphone is short-circuited so that the

ίο Participant is forced to, after reporting the desired subscriber to press a number key through which the short circuit for the Microphone is picked up again and the money is transported to the coin collecting container will. If the connection is not established, hang up the handset or press a special Return button, the inserted money is returned to the speaking guest.

With this mode of operation there are two possibilities of fraud:

1. The participant can by briefly moving the hook switch up and down without prior to inserting a coin, set the selector so that when the number key is pressed no coin is conveyed into the collecting container,

2. There is the possibility of the inserted money by briefly hanging the hook switch to get back without the voters collapsing.

In order to rule out this possibility of fraud, a brake is already on Hook switch and a time switch suggested that when the money is returned the Exchange loop interrupts a certain time so that the established connection is destroyed.

It has also become known a circuit arrangement in which one of a local battery Powered auxiliary relay in connection with a mechanical locking device is used to prevent selection by the hook switch. The present invention makes particular Mechanical devices in the coin operated remote speaker to prevent unauthorized dialing by means of a hook switch are unnecessary. The invention uses instead an auxiliary relay, which in contrast to the known Arrangement does not require any additional mechanical device and its actuation current from the official battery. According to the invention these advantages are achieved in that when hanging the An auxiliary relay is energized via a line and earth via the hook switch contact that interrupts the official loop and becomes independent via its own contact on the position of the hook switch until the voters have collapsed.

According to the invention, this auxiliary relay has a winding of such high resistance that that the control relay in the group selector, which when hanging the handset in grater with the auxiliary relay is switched to drop out. Since the auxiliary relay on the coin operated remote

*) The patent seeker stated as the inventor:

Hinrich Dohle in Bcrlin-Charlottenburg.

Speaker remains connected to the line leading to the office with the handset hung up, the line is crossed behind the occupancy relay of the first preselector. To this Way is achieved that the auxiliary relay is connected to the battery in the office as long as as long as the voters haven't collapsed.

The embodiment described below relates to a pay phone, which is connected to a self-connecting exchange according to the loop system. In the circuit are only part of a first voter from the self-access exchange and a first group selector are shown as far as this is necessary for an understanding of the invention is required.

In the part of the circuit marked M , the switching devices of the coin operated telephone are shown. VW is the selection and GW is the group selector. In the circuit, all contacts are shown in the rest position. If a connection is to be made from the coin-operated telephone M , the receiver is first removed from the hook. Here the contact HU ^{1 is} closed and the contact HU ^{2 is} opened. The relay R in the preselector picks up and causes a free group selector to be assigned in a known manner. The relay T picks up and closes the exchange loop to the first group selector. The participant must now insert the required fee so that he can set the voters with the help of the number disk, of which the pulse contact nsi and the number ■ disk contact nsa is shown. If the fee is not inserted, the coin feeler lever contact MF is closed when the dial is opened and the selection is prevented. The speaking guest can receive the message from the requested participant with the help of his handset F , but cannot yet speak to him because his microphone is short-circuited. The speaking guest must therefore press the number button through which the inserted coin is conveyed into the coin collecting container and at the same time the contact ZT is turned over, so that the short circuit for the microphone is canceled, while the pulse contact is short-circuited in the. In the case of a connection in which the pay phone is the called station, the caller must also depress the number button in order to clear the short circuit for the microphone. When the receiver is hung up again, the contact ZT returns to its rest position.

Assuming that the subscriber had intended to adjust the voters by briefly moving the receiver hook up and down, the relay H is energized immediately when the receiver hook is pressed down, namely in the following circuit: Earth, H, HU ' ² , t ". Relay A, battery.

Relay H binds itself via its contact W and opens the office loop through contact h " until relay A in the group selector has dropped out and the preselector VW has returned to the zero position, since control relay A of the group selector is over the high resistance of the Relay H. Since the return of the money should be effected by hanging up the receiver if the connection has not been established, the subscriber could try to get the money back by briefly hanging up the receiver in the hope that the existing connection would not be disconnected However, as already described, this is made impossible by the // relay.

Claims (3)

Patent claims: i. Circuit arrangement for connecting the dialing by means of hook switch for coin-operated telephones connected to self-connection offices with loop operation, in which the coin is returned when a connection that has not been established is disconnected and when the receiver is hung up via the hook switch contact, an auxiliary relay which interrupts the exchange loop is influenced, characterized in that via a Line and earth when the receiver is hooked in via the hook switch contact, a relay (H) which interrupts the office loop is excited, which remains independent of the position of the hook switch until the voters collapse via its own contact (Ji ¹ ). 2. Circuit arrangement according to claim i, characterized in that the relay (H) is so high-resistance that the control relay (A) in the group selector (GW) comes to fall. 3. Circuit arrangement. according to claim i, characterized in that the line to the group selector is crossed behind the occupancy relay (R) of the preselector (VW) so that the potentials of the group selector are directed opposite to the potentials of the preselector and line selector. 1 sheet of drawings