KR890003425Y1 - Telephone off-hook display circuit - Google Patents

Abstract

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Description

Indicator drive circuit of telephone

1 is a block diagram of the present invention.

2 is a detailed circuit diagram of FIG. 1.

3 is a waveform diagram at each part of FIG. 2;

* Explanation of symbols for main parts of the drawings

1: key input 2: driver

3: Display unit 4: Initialization unit

R1-R9: Resistor C1-C4: Capacitor

D1-D3: Diode TR: Transistor

G1-G3: Logic Gate FF1-FF4: Flip-Flop

SW: Memory function switch of key input unit

The present invention relates to an indicator driving circuit of a telephone, and more particularly to a circuit for displaying a data writing operation state in a memory of a telephone capable of storing a telephone number.

Conventionally, in a phone equipped with a microcomputer, there is a display function, but there are disadvantages in that the components of the circuit are not universal and the production cost is high.

Therefore, the object of the present invention is to indicate whether the telephone number is written in the memory of the telephone, thereby preventing the malfunction caused by the user's misoperation in advance, and by attaching it to another telephone equipped with the memory by using a general circuit element. To provide a circuit that can be used.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a block diagram of the present invention, the key input unit 1 is composed of a keyboard (Key Board) installed in the phone is a circuit consisting of function switches, such as numbers 0-9 and memory functions, the driver 2 Denotes a circuit for driving the display unit 3 by the key input signal of the key input unit 1 described above.

The display unit 3 is a circuit which is turned on when data is written to the memory by the output signal of the driver 2, and the initialization unit 4 is initially driven when the power is supplied and the operation of writing data is completed. (2) A circuit for initializing.

Detailed circuit diagram of the present invention configured as described above is shown in FIG.

When the initial power is supplied to the circuit, the input power is initialized by applying to the clear terminal CK of the flip-flops FF1-FF4 through the grounded resistor R8, the capacitor C4, and the grounded resistor R9. When the memory switch SW of the key input unit 1 is pressed, the " 1 " (high signal) supplied from the power source is applied to the input terminals J1 and K1 of the flip-flop FF1.

Output terminal Q1- of the flip-flop FF1 Q1) is applied to the input terminals J2 and K2 of the flip-flop FF2 and the input terminal J3 of the flip-flop FF3 to which the input terminal K3 is grounded, respectively, and the output terminal Q2 of the flip-flops FF2 and FF3. Signal Q3 is applied to the input terminal J4 of the flip-flop FF4 and one input terminal of the AND gate G1, and the memory switch SW of the key input unit 1 is pressed and the telephone number (0-9) is pressed. The signal TD generated at the input is passed through the diode D1 and the resistor R1 and filtered through the grounded capacitor C1 and the grounded resistor R2 to the other of the gate G1. Connect to the input terminal.

The output terminal signal of the AND gate G1 is applied to the input terminal K4 of the flip-flop FF4, and the output terminal signal Q4 of the flip-flop FF4 is applied to the base of the transistor TR through the resistor R3. Power is applied to the light emitting diode D2 via an emitter through the resistor R1 connected to the collector, and the other output terminal Q4 signal of the flip-flop FF4 is inverted at the inversion gate G2. Through the resistor R5 and the grounded capacitor C2, it is applied to the inverted gate G3 and inverted again, and the inverted signal is grounded resistor R6, the capacitor C3, the grounded resistor R7, and the diode. Via (D3) it is applied to the clear terminal (CK) of each flip-flop (FF1-FF4) of the drive unit 2 is connected to be initialized.

Next, in the display driving circuit of the telephone of the present invention having the above-described configuration, a circuit operation indicating a writing operation state when writing telephone number data into a memory will be described based on the waveform diagram shown in FIG. .

When power is supplied to the circuit, the differential signal is initialized by clearing each flip-flop (FF1-FF4) by the capacitor C4 and the resistor R9, which are differential circuits, and the memory switch on the keyboard of the key input unit 1 ( When SW is pressed, the signal " 1 " "1" and "0" (low signal) are respectively output to 1).

At this time, "1" is applied to the input terminals J2 and K2 of the flip-flop FF2, so that "1" is output to the output terminal Q2 and applied to the input terminal J4 of the flip-flop FF4.

At the same time, the transistor TR is turned on by the signal "1" of the output terminal Q4 of the flip-flop FF4, the light emitting diode D2 is turned on, and the operating state is stored in the memory.

Next, when telephone number data is keyed in the key input unit 1, a square wave tone data (TD) generated when only numeric (0-9) data is input is generated and filtered. The same waveform as "A" is applied as a "1" signal to one input terminal of the AND gate G1, but the "0" signal of the output terminal Q3 of the flip-flop FF3 is applied to the other input terminal, so that the output terminal of the AND gate G1 is applied. Is output to the input terminal K4 of the flip-flop FF4.

In the above operation, all the numbers to be stored are keyed in and stored in the memory, and then the memory switch SW of the key input unit 1 is pressed again. 1) The signal is inverted to output "0" and "1", respectively.

At this time, the output terminal Q3 of the flip-flop FF3 becomes "1", and "1" is continuously applied to only one input terminal of the AND gate G1 to output "0".

When the function switch other than the telephone number of the key input unit 1 is pressed, the tone data TD is not output from the key input unit 1, so that the output of the AND gate G1 continues to be " 0 " Light-emitting diode D2 is continuously lit.

In addition, even if the memory switch SW of the key input unit 1 is repeatedly pressed, the light emitting diode D2 is continuously turned on because the output terminal Q2 and Q3 signals of the flip-flops FF2 and FF3 continue to be "1". do.

In this way, when all the phone numbers are written in the memory and the memory switch SW is pressed and the memory number is pressed in the key input unit 1, the tone data TD is generated to output the " 1 " signal of the output terminal Q3 of the flip-flop FF3. Together with the " 1 " signal to the end gate G1.

Therefore, "1" is output to the output terminal of the AND gate G1, and "0" is thrust to the output terminal Q4 at the moment of being applied to the input terminal K4 of the flip-flop FF4, so that the light emitting diode D2 is flickered.

And the output terminal of the flip-flop FF4 ( 4) When the signal "1" is output and inverted at the inversion gate G2, the power charged in the capacitor C2 is discharged through the resistor R5, and the voltage level of the capacitor C2 is critical. When the voltage is lowered, the thrust end signal of the inverting gate G3 becomes "1", and the differential signal generated through the capacitor C3 and the resistor R7, which is the differential circuit, is transmitted to all the flip-flops FF1-FF4 of the driving unit 2. Clear to initialize.

As described above, according to the present invention, even if the telephone circuit is replaced with another type of circuit, the circuit of the present invention does not need to be changed, and can be simply designed using a general-purpose circuit element.

Claims (1)

In the telephone which stores the telephone number in the memory by the key input unit 1 composed of switches such as numbers and memory functions, and automatically calls the telephone number with a simple operation, the memory switch SW of the key input unit 1 is turned off. When pressed, the driver 2 outputs a driving signal for the display unit 3 through the output terminal Q of the flip-flop FF4 until the memory number is pressed, and the output signal of the driver 2 until the memory number is input. According to the light emitting diode D2, the display unit 3 indicates that telephone number data is being written to the memory, and a pulse is generated by the differential signals C4 and R9 at the initial power supply. An initialization unit for clearing (FF1-FF4) and initializing the drive unit 2 by clearing the flip-flop (FF1-FF4) by generating pulses by the differential circuits C3 and R7 upon completion of writing phone number data into the memory. Made including 4 That a display drive circuit of the telephone set is characterized.