SU780221A1 - Communication line state monitoring device - Google Patents

Description

i4) DEVICE FOR MONITORING Line Conditions

The invention relates to communication technology and can be used in devices for monitoring the states of two wired communication lines. A device for monitoring line conditions is known, comprising a series-connected key block whose input through a first and second resistor connected in series is connected to the output of a power source and an actuator, a block, a transistor with a collector and emitter resistor, a diode and a stabilizer of l. However, the known device for monitoring line conditions does not allow to determine the line occupation during a telephone conversation and does not determine the nature of the line fault. The purpose of the invention is to improve the accuracy of the control. To do this, a line-connected key block, whose input is connected via a series of first and second resistors to the power supply output, and an executive unit with a collector and emitter resistors, a diode and a zener diode, are introduced into the device for monitoring line states. a zener diode and an additional resistor, which are connected in series, a thyristor and a switching button, while the cathode of an additional zener diode is connected to a common point of the first and second D to the anode of the Zener diode, the cathode of which is connected to the base of the transistor, the collector of which is connected to another output of the additional resistor and the control electrode of the thyristor, in which the cathode is connected to the power source and to another output of the collector resistor, and the anode through the switching button to another input the executive unit and the cathode of the diode, the anode of which is connected to the input of the key unit. The drawing shows the principle electrical circuit of the device for monitoring line conditions. The device for controlling line conditions contains a key block 1, resistors 2 and 3, a power source 4, an executive block 5, a transistor 6, an emitter and a collector resistors 7 and 8, respectively, a diode 9, a Zener diode 10, an additional Zener diode 11, an additional resistor 12, thyristor 13, switching

button 14, controlled line 15. The add-on unit 5 contains a relay 16, a line fault indication lamp 17, a transistor 18 and a line occupation lamp 19.

The device for monitoring line conditions operates as follows.

In the initial state, when the controlled line 15 is connected to the device, the resistance of which

located within the specified limits / at the common point between the second resistor 3 and the controlled line 15, setting such a voltage at which the thyristor 13, the transistor 6 and the key unit 1 are in the closed state. As a result, there is no indication signal at both inputs of the execution unit 5 and the device does not consume / 1 current. If the resistance of the controlled line 15 is above the specified limits, but does not correspond to the value of the line break, then the thyristor 13, the transistor 6 and the key block 1 do not change their closed state. If the resistance of the monitored line 15 decreases, for example, by conducting a telephone conversation between the subscriber and the operator (line occupancy), then under the action of the reduced voltage between the second resistor 3 and the resistance of the monitored line 15, the key unit 1 is triggered. the voltage from the output of the key block-1, to the other input of the execution unit 5, opens the transistor 18, the load of which is the line indication lamp 19, which in this case lights up and burns during the whole time Meni conducting telephone conversation between abonentomi central station operator. If the resistance of the controlled line is 15

becomes below the permissible limits, which corresponds to its malfunction (short closing), then the voltage

on the additional stabilizer 11 and, consequently, on the control electr; ohristor 13, becomes less than the allowable voltage value relative to the cathode of the thyristor 13. This triggers the thyristor 13 and the negative voltage of the power source 4 through the open thyristor 13 and the switching voltage

button 14 enters another input

The control unit 5 causes the relay 16 to fire and the ignition lamp 17 to illuminate the fault: line equality. The negative voltage of the power source through the diode 9 is also fed to the input of the key block, 1, prohibiting its operation. It does not interrupt the state of the monitored line 15 by the thyristor 13 to block the state of the line fault monitoring until the technical conditions until the switching button 14 is pressed. Unlocking will occur only if the resistance of the monitored line 15 is again established within the tolerance . If the resistance of the monitored line 15 becomes greater than the maximum allowable value, which may be, for example, if the line is broken, by increasing the voltage, the Zener diode 10 will break, open the transistor b and the thyristor 13, after which the device will operate in the same way as previously described. To determine the nature of the malfunction, line 15 presses the switching button 14. If the lamp comes on while the switching button 14 is pressed. indication of 17 line faults, it means there was a break in the line. If the malfunction indication lamp 17 goes out and the line indication lamp 19 lights up, the line is closed.

Claims (1)

1. USSR author's certificate 515310, cl, H 04 M 3/32, 1975 (prototype).