Specification:
SER2UKB is a pure hardware solution of the CH9328 series serial port to USB keyboard protocol, which supports plug and play, converts
serial port data to USB keyboard values, simulates keyboard input, and displays it at the cursor.
This is a one-way transmission. The direction from serial port to USB cannot be transferred from USB to serial port
Upper pin definition：
VCC 5V voltage output (TTL level default is 3.3V output)
TX- serial port transmitting end, RS485 level B / D- end
RX + serial port receiving end, RS485 level A / D + end GND ground
Lower pin definition:
IO4 No. 4 IO pin
IO3 No. 3 IO pin
IO2 No. 2 IO pin
IO1 No. 1 IO pin
Packaging: TTL / RS232 / RS485 serial port to USB keyboard module
