Requirements: Usually the notebook is not a serial port, so the serial data to be sent to the notebook, usually through the USB to the string of small board to turn the serial data into USB data, and then the computer to receive. Similarly, the computer through the USB string to the data into serial data, so that the next function to receive.
USB to string Small board connection method:
Lower machine serial port RX-->USB to string Small board TX
The lower machine serial port TX-->USB turns the string small board Rx
The lower machine serial port GND-->USB turns the string board GND
RS-232 serial Port The biggest advantage is simple, Although he is using the connector is 9-pin, single-actual communication with only 3 wire machine can be ( send, accept, signal ground), if you only send not accept, then two lines on line, However, the USB interface can be a minimum of three lines (d+, D-, signal ground), the remaining wire is the Power 5V, the device itself has the power can not
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USB String Connection