KR970004822B1 - Auto-selecting circuit of a telephone - Google Patents

Abstract

An automatic selecting circuit of general and keyphone telephones of keyphone system used for together with is disclosed. The circuit comprises: a general telephone feeding means(1) for generating a feeding current; a photocoupler means(U1) connected to the feeding means; a first transformer(T1) being one connected to parallel of the feeding means and other connected to a microprocessor; a second transformer(T3) for transforming data from the microprocessor; and a third transformer(T2) being one connected to a connecting terminal(DR) of the keyphone and a ground and other connected to the output terminal of the photocoupler means(U1).

Description

General telephone / key phone telephone automatic selection circuit

1 is a block diagram of a automatic telephone / telephone telephone automatic selection circuit according to the present invention.

* Explanation of symbols for main parts of the drawings

1: General telephone feeding unit U1: Photo coupler

T1, T2, T3: transistors R1 to R6: resistors

D1 to D4: Diodes C1 to C3: Condenser

TR1: Transistor PS: Parity Switch

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a general telephone / keyphone telephone automatic selection circuit in which a telephone is automatically selected and connected to any telephone without a distinction between a general telephone and a telephone telephone.

Conventionally, there is a separate connection circuit for using a general telephone or a key phone, the general telephone is used to connect to the general telephone connection terminal and the key phone is connected to the key phone telephone connection terminal.

Therefore, due to the addition of unnecessary circuits for the use of ordinary telephones and key phones, the price increases, the volume of the key phone system increases, and there is a problem that compatibility is lost due to the division of circuits.

The present invention devised to improve the above problems is to provide a general telephone / key phone telephone automatic selection circuit that can be connected without distinction between a general telephone or a key phone telephone.

In order to achieve the above object, the present invention provides a general telephone / key phone telephone automatic selection circuit of a key phone system that can be connected and used without distinction between a general telephone and a key phone telephone, wherein the general telephone is connected to the key phone system. When connected, a general telephone feeding means for generating a feeding current, a photocoupler means connected to the general telephone feeding means, and operated when the feeding current is generated, one side is connected to a key phone system in parallel with the general telephone feeding means and the other side is a micro A first transformer connected to a processor to perform voice transmission, one side of the general telephone feeding means and a key telephone telephone connection terminal, and the other side of the microprocessor to a data output terminal and a power supply to transfer data from the microprocessor. 2 Transformers and Awards One key phone is connected to the telephone connection terminal and the ground and the other end is connected to an output of the light receiving element and the ground of the photocoupler means is characterized in that it consists of a third transformer for transmitting the data from the phone system.

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

1 is a block diagram of the automatic telephone / telephone telephone automatic selection circuit according to the present invention, 1 is a general telephone feeding unit, A, B, C, VA is a terminal connected to the microprocessor, U1 is a photo coupler, T1, T2 and T3 represent a transformer, R1 to R6 represent a resistor, D1 to D4 represent a diode, C1 to C3 represent a capacitor, TR1 represents a transistor, and PS represents a parity switch.

In the general telephone / key phone telephone automatic selection circuit according to the present invention, as shown in FIG. 1, the general telephone feeding unit 1 is connected in parallel to the terminals VT and VR of the key phone system to which the general telephone is connected. The input terminal of the photocoupler U1 is connected to the general telephone feeding unit 1, the output terminal is connected to the terminal C of the microprocessor, and the terminal VT, VR of the key phone system to which the general telephone is connected. One side of the voice transmission transformer T1 is connected in parallel with the telephone feeding unit 1, and the other side is connected to terminals A and VA of a microprocessor (not shown), and the voice transmission transformer ( T1) Connect the diode D1 that removes the limit voltage between one end connected to the terminal A and the power supply (+ 7.5V) on the other side, and the one end connected to the terminal A and the power supply (+ 2.5V). Connect a diode (D2) to remove the total voltage in between.

In addition, one end of one side of the transformer (3) is connected to the terminal (DT) of the key phone system to which the key phone is connected, and the other end is connected to one end of the parity switch (PS) and the general telephone feeding part (1). Ground via (C2). The other end of the transformer T3 is connected to the microprocessor terminal B through the npn transistor TR1 and grounded through the capacitor C3, and the other end is connected to the power supply (+ 5V) through the resistor R5. do.

One end of the transformer (T2) is connected to the terminal (DR) of the keyphone system to which the keyphone telephone is connected, the other end is grounded, a resistor (R3) is connected between the other end and one end, and the other end is one end of the resistor (R4). The other end of the resistor R4 is connected to the microprocessor terminal C, and the other end of the transformer T2 is grounded.

In addition, the other end is connected to the power supply (+ 5V) through the limit voltage removal diode (D3) to the ground through the limit voltage removal diode (D4).

Referring to the operation of the automatic selection circuit of the general telephone / key telephone telephone configured as described above are as follows.

First, when a general telephone is connected to a key phone system, the door photo coupler U1 operates so that a feeding current flows from the general telephone feeding unit 1, and thus, a terminal C connected to a light receiving element which is an output terminal of the photo coupler U1. ) Will change state from Low to High. The microprocessor then detects this and performs the work related to the general telephone.

In addition, when the key-phone telephone is connected to the key-phone system, data is transmitted to the terminal C of the microprocessor through the terminals DT and DR connected to the key-phone system and through the transformers T2 and T3. In C), data with a certain period is transmitted. The microprocessor then detects this and performs the work associated with the key phone.

Port B of the microprocessor transmits data output from the microprocessor to the key phone telephone. In the figure, capacitors C1, C2, and C3 function as noise cancellation, the resistors R1 to R4 protect the system, and the resistors R5 and R6 function as voltage dropping diodes. D1 to D4) serve to remove the limit voltage, and the parity switch PS serves to protect against overvoltage.

The present invention is configured and operated as described above to remove the circuit for the connection of the general phone and the key phone phone to the key phone system and to connect without any distinction between the ordinary phone and the key phone phone to lower the volume and price and to have a compatible line on the circuit It works.

Claims (1)

An automatic selection circuit for a general telephone / keyphone telephone of a key phone system that can be used in connection with a common telephone and a key telephone telephone without distinction; A photocoupler connected to the key phone system and connected to the telephone phone system to generate a feeding current when the telephone is connected to the telephone system. The photocoupler is connected to the telephone phone feeding means (1) and operates when the feeding current is generated. Means (U1), a first transformer (T1) is connected to a key phone system in parallel with the general telephone feeding means (1) and the other side is connected to a microprocessor to perform the function of voice transmission, the general telephone feeding means ( 1) and a second transformer T3 having one side connected to the key phone telephone connection terminal DT and the other side connected to the data output terminal B of the microprocessor and a power source, and transferring data from the microprocessor, and the key phone telephone. One side is connected to the connection terminal DR and the ground, and the other end is connected to the light receiving element, which is an output terminal of the photocoupler means U1, and the ground to a key phone system. A general telephone / key phone telephone automatic selection circuit comprising a third transformer (T2) for transferring data from.