Automatic offhook device for telephone communication

Abstract

An automatic off-hook device for telephone communication belongs to the field of telephone remote control. The problem of high cost, large volume and poor safety performance of the existing on-hook control device for telephone communication is solved. The invention includes a directional circuit composed of diodes D1-D4, a composite tube circuit composed of resistors R6, triodes T2 and T1, a varistor ZNR, an equivalent resistance composed of resistors R4 and R5, and the DC resistance of an audio transformer. processor. Its structural feature is that the telephone line CJ2 is connected to the directional circuit, the varistor ZNR is connected to the directional circuit in parallel, the negative end of the directional circuit is grounded, and the positive end is connected to the emitter of the triode T1 in the composite tube circuit. The collector is connected with the equivalent resistance, and the microprocessor connects the base of the triode T2 in the composite tube circuit through the optocoupler U7-2. The present invention is mainly applied to a telephone device for home network communication.

Description

technical field [0001] The invention relates to an automatic off-hook device for telephone communication, which belongs to the field of telephone remote control. Background technique [0002] The existing automatic off-hook technology for telephone communication usually uses a dual-tone transformer to adjust the resistance value of the smart phone connected to the telephone network, so that its impedance and loop current meet the requirements of the national standard telephone network. However, the dual-audio transformer is large in size, and there is no mass production in China, so it needs to be customized or ordered from abroad. Therefore, the existing off-hook control device for smart phones has the problems of high cost, large volume, or poor safety performance, which may damage the equipment of the telephone office and adversely affect the telephone network. Contents of the invention [0003] Aiming at the above-mentioned problems in the prior art, the present inven...

AI Technical Summary

Problems solved by technology

However, the dual-audio transformer is large in size, and there is no mass production in China, so it needs to be customized or ordered from abroad.

Therefore, the existing off-hook control device for smart phones has the problems of high cost, large volume, or poor safety performance, which may damage the equipment of the telephone office and adversely affect the telephone network.

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