SU1363526A1 - Switching arrangement for electronic dialing device - Google Patents

Abstract

The invention relates to telephony and reduces the level of noise introduced. The device contains diodes 1-4, field-effect transistors (PT) 5 and 6, resistors 7 and 8. During current loading, PT 5 and 6 are open, the telephone set (TA) is bridged . With current supply, terminals 5 and 6 are closed and the TA from the line is disconnected. This ensures that no listening pulses are heard. Resistors 7 and 8 serve for galvanic. isolating the dialer and line voltage control signals. When dialing is terminated, the linear current flows through the TA, ensuring that the conversation is maintained. 1 il. about

Description

The invention relates to telephony in particular to switching devices of telephone sets.

The purpose of the invention is to reduce the level of noise introduced.

The drawing shows a circuit diagram of an electronic dialer switching device.

The switching device of the electronic dialer contains the first, second, third and fourth diodes 1-4, the first and second field-effect transistors 5 and 6, the first and second resistors 7 and 8.

Switch, Ion device of the electronic dialer works as follows.

When the handset of the telephone set connected to the output of the device is laid, the latter is loaded on the call signal receiver. The potential at the gates of the first and second field-effect transistors 5 and 6 is determined by the voltage on the line wires. One of the field-effect transistors depends on the polarity of the line wires. closed and the other open.

Upon receipt of the alternating signal voltage of the call signal, the linear current signal flows from the upper line wire circuit through the third diode 3 receiver of the call signal of the telephone set, the first field effect transistor 5 and the second diode 2 to the lower wire of the line.

When the polarity changes, the linear current passes through the fourth diode 4, the receiver of the call signals of the Go telephone unit, the second field effect transistor 6 and the first module 1. This ensures reception of the: call signals.

When the handset is picked up and the number is dialed, the control pulses from the electronic dialer arrive at the gates of the first and second field-effect transistors 5 and 6 and put their channels into a conducting state. Depending on the polarity of the voltage on the wires of the line 5

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Neynp current flows either through the third and second diodes 3 and 2 and the second fieldbus: nistor 6, or through the fourth and first diodes 4 and 1 and the first field-effect transistor 5.

Since the first and second field-effect transistors 5 and 6 are open at the time of the current send, the telephone apparatus is shunted. In the case of current-free dressing, the first and second field-effect transistors 5 and 6 are closed, due to which the telephone set is disconnected from the line. This ensures that no listening pulses are heard. The first and second resistors 7 and 8 are used for galvanically isolating the control signals of the electronic dialer and line voltage. When dialing is terminated, the line current flows through the telephone, providing listening and conversation.

Claims (1)

Invention Formula  The switching device of the electronic dialer contains the first and second diodes, the anodes of which are interconnected, and the cathodes are connected to the corresponding first and second wires of the line, the first and second field effect transistors, the first and second resistors, and the third and fourth diodes are different in that In order to reduce the interference factor, the anode of the third diode is connected to the cathode of the first diode and the first terminal of the first resistor, the second terminal of which is connected to the gate of the first field-effect transistor, the source of which is The anodes with the anodes of the first and second diodes and the source of the second field-effect transistor, the gate of which through the second resistor is connected to the cathode of the second diode and the anode of the fourth diode, while the cathodes of the third and fourth diodes are connected respectively to the drains of the second and first field-effect transistors and are outputs of the device.