KR100194460B1 - Door phone power control circuit in key phone system - Google Patents

Abstract

A circuit for controlling the door phone power after the door phone call ID is input through the voice signal transmission transformer T1 and the CPU reads the input signal, wherein the door phone is busy and after the call is terminated. It is configured to control the power on or off.

Description

Door phone power control circuit in key phone system

1 is a circuit diagram according to the present invention.

The present invention relates to a door phone power supply control circuit in a key phone system.

In the conventional door phone call, the function is completed when only the cross (X) point of the network is connected to the door phone and the station to which the user wants to talk. However, conventionally, even after the call with the door phone is completed, there is a problem in that howling is continuously supplied to the door phone.

Accordingly, an object of the present invention is to provide a circuit for supplying power to the door phone only in order to eliminate the howling problem and removing the howling by turning off the power in the idle state in which the communication path is not formed.

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

FIG. 1 is a circuit diagram according to an embodiment of the present invention, which is input through the voice transformer T1 and the voice transformer T1 for transmitting the state of the 1-2 door phone voice signals DV1 to DV2. A CPU that checks whether there is an abnormal signal and generates a control signal for controlling the door phone power, and a transistor that controls the door phone power supply when there is an abnormality in the door voice call in the CPU. TR1, TR2).

Therefore, a specific example of the present invention will be described in detail with reference to FIG.

In FIG. 1, when the signal transmitted through the voice transformer T1 is changed from high to low, the central processing unit (CPU) reads the above value and converts the data value from the low to high to the door phone power supply control terminal (D). To print. When the door phone control terminal D of the CPU is high, the transistor TR2 is turned on to turn on the transistor TR1, and the + 12V voltage is caused by the collector current of the transistor TR1. To drive. That is, the collector current Ic amplified by the base current Ib of the transistor TR1 arrives at the door phone circuit along the line of the door phone circuit. At this time, +12 V is supplied to the power input to the output transistor TR1. The poly switch PS applied to the track is applied to protect the circuit due to the sorting between the tracks when the door phone is installed or by mistake. And when all calls to the door phone is finished and idle state, the central processing unit (CPU) changes the value of the data stage (D) from high to low. At this time, since the operation of the mode circuit is disabled, the operation of the door phone is stopped. The circuit description in the dormant state is performed in the reverse order of the operating state, and thus description is omitted.

As described in the above circuit description, the present invention can completely eliminate the howling problem in the door phone call pause state by adopting a simple method, and there is a unique address and data for each system in door phone control, and thus the description is omitted. The resistors R1 and R2 applied to the respective circuits are adjusted to control the base current 1b of the transistor TR1, and are set to a value suitable for the hfe of the transistor TR1. The reason is applied to control the + 12V power supply and can also enlarge the hfe.

As described above, after reading the call ID of the door phone, it is checked whether the command of connecting the corresponding port of the cross point and the power supply of the door phone are performed, and the H / W until the above command is delivered. The operating state of the active devices to be controlled can be verified, and since the power supply is provided only during a call and the power supply is cut off in the idle state, there is an advantage in that the howling problem can be solved.

Claims (1)

In the door phone power supply control circuit of the key phone system, an abnormality of the signal inputted through the voice transformer T1 and the voice transformer T1, which transmits the state of the 1-2 door phone voice signals DV1 to DV2, is present. Checks whether the central processing unit (CPU) generates a control signal for the door phone power air, and checks whether there is an abnormality of a signal input through the voice transformer (T1) and generates a control signal for door phone power control to generate a door phone voice. It consists of transistors TR1 and TR2 that control the door phone power supply to be cut off when there is an error, and polyswitch PS for circuit protection due to short circuit on the track of the transistor TR1. Door phone power control circuit in the key phone system, characterized in that.