Press the button to transmit a signal, the corresponding data bit will output high. Leg 9 bits,respectively, VT,18,17,16,15,14,13,12,11,10,9, 8, 7, 6, 5, 4,3, 2, 1, the +5 V and GND. VT is a valid signal high output pin Upon receiving a valid signal, the pin output high, may also drive the relay.
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