FT232RL chip;

FT232RL chip lead all the signal port, TTL / CMOS level;

RXD / TXD transceiver communication indicator light;

USB powered, optional 5V or 3.3V Interface level (if need other levels,  can supply voltage at VCC and GND)

easily applied to a variety of human-computer interface design

Built-in large common 3V button battery, use a long time, easy to replace