Intelligent fire alarm telephone alarm circuit - finger circuit

  
Automatic alarm circuit includes a DTMF Automatic dialing, password control circuit, voice detection and alarm circuit, telephone interface circuit, power supply circuit and th
Intelligent fire alarm telephone alarm circuit - finger circuit - schematic

e keyboard display circuit. (1) automatic dial-up alarm is not only part of the MT8888 chip DTMF signal transceiver function, and having a telephone tone detection function can, it can be easily and MCS51 series microcontroller interface. In this system, MT8 and external circuit shown in Figure 13-41, its reception section points using a single-ended input by Rz0 1, R2U2 and C20i composition, its transmission portion Rs, R206, G shad, Ck and XTAL2 composition, its control system composed of a portion R2c3, Goi. Since the IRQ and CP output terminal is open source, so use the pull-up resistor R204. C203 decoupling capacitors. DTMF and DTMF OUT IN connected to the telephone interface circuit.




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