SU949834A1 - Device for switching telegraphy signals - Google Patents

Description

(54) DEVICE FOR TELEGRAPH COMMUTATION

SIGNALS

one

The invention relates to communication technology and can be used in electronic telegraph devices, in data transmission equipment, and also in radio stations having telegraph outputs.

A device for switching telegraph signals is known, which contains an input control unit, the control outputs of which are connected to the inputs of the key block 1.

A disadvantage of this device is the lack of protection against short circuits.

The purpose of the invention is to provide protection against short circuits.

To do this, a device for switching telegraph signals containing an input control unit, the control outputs of which are connected to the inputs of the key block, resistors, a zener diode, an optocoupler, an indicator and a threshold block, the first input of which is connected to the first output of the first resistor and the first output of the block keys, the second output of which is connected to the second output of the first resistor, to the second input of the threshold unit and to the first output of the second resistor, the second output of which is connected to the cathode of the Zener diode and to the first output of the photo optron receiver, the second output of which is connected to the first output of the threshold unit, the second output of which is connected to the first output of the indicator, the second output of which is connected to the anode of the optical diode of the optocoupler, the cathode of which is connected to the third output of the key unit, and the anode of the Zener diode is connected to the corresponding output of the input unit management

The drawing shows the electric

10 is a diagram of an apparatus for switching telegraph signals.

The device contains a block of 1 keys, the keys 2-5 of which are interconnected by a bridge circuit, in one of the diagonals of which a load 6 is included, and in the other - a power source 7 connected in series with a resistor 8 used as a current sensor, an input control block 9 containing the optocouplers 10 and 11, the threshold 2Q block 12, the optocoupler 13, containing the led 14 and the photodetector 15, the zener diode 16 and the resistor 17, the indicator 18.

The threshold unit 12 consists of a Zener diode 19, a transistor 20 and resistors 21 and 22. The LED 14 of the optocoupler 13 is connected

OUTPUT) - threshold unit 12. Optocouplers 10 and 11 contain inputs 23 and 24.

The device works as follows.

In the initial state, in the absence of signals at inputs 23 and 24, all the keys of unit 1 are closed and there is no current in load 6.

When a signal arrives at the device input 23, the photodetector of the optocoupler 10 opens and the input of the key 4 is energized along the circuit plus source 7 - resistor 17 - zener diode 16 - photodetector of optocoupler 10 - key input 4 - minus source 7. Key 4 opens. Thanks to feedback, key 3 is also opened. According to load 6, current flows in the direction as long as: a solid arrow, cesh: plus source 7 - resistor 8 key 3 - load 6 - key 4 - minus source 7. When When the signal arrives at input 24 in the same way, keys 2 and 5 open, and keys 3 and 4 close, and the current in the load changes direction.

When the current in the load 6 does not exceed the set value, the voltage drop across the resistor 8 is insufficient for breaking the Zener diode 19 of the threshold unit

12. The transistor 20 is closed and the LED 14 of the ontron 3 is not excited. With this photoiijjiCM ;; The optocoupler 13 is closed and does not affect the operation of the input control unit 9.

The ripii current increase in load 6 is higher than the value set, the voltage drop across resistor 8 becomes sufficient to break the zener diode 19. A current begins to flow through the base circuit of transistor 20 of the threshold unit, and transistor 20 opens and closes the control circuit of LED 13. LED 14 is energized and opens the photodetector 15 optocoupler

13. At the same time, the power supply circuit of the input unit 9 is bypassed, the optocouplers 10 and 11 are de-energized and the controllers are keyed

4 and 5 of block 1 are not received. The power supply circuit of the load 6 is interrupted, the indicator 18 signals the occurrence of a short circuit. The circuit is in this state until the power is turned on and the cause of the current overload has not been eliminated.

The proposed device, in comparison with the known ones, has protection against short circuits in the load during unipolar and dual transfer.

Claims (1)

Invention Formula A device for switching telegraph signals, comprising an input control unit, the control outputs of which are connected to the inputs of the key block, characterized in that, in order to provide protection against short circuits, resistors, a zener diode, an optocoupler, an indicator and a threshold unit, the first input which is connected to the first output of the first resistor and to the first output of the key block, the second output of which is connected to the second output of the first resistor, to the second input of the threshold unit and to the first output of the second resistor, the second in the waters of which are connected to the cathode of the Zener diode and to the first output of the photo-receiver of the optocoupler, the second output of which is connected to the first Output of the threshold unit, the second output of which is connected to the first output of the indicator, the second output of which is connected to the anode of the LED of the optocoupler, the cathode of the LED The anode of the Zener diode is connected to the corresponding output of the input control unit. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 617842, cl. H 03 K 17/60, 1977 (prototype).