CONFIGURE BAUD RATE, FLOW CONTROL, PARITY FOR YOUR BOARD: The default baud rate for Raspberry Pi is 115200. Flow control is not supported by the Raspberry Pi 3 so it should be disabled. 8N1 mode must be selected so that there are 8 data bits, no parity, and 1 stop bit.PLUG AND PLAY WITH WINDOWS MAC LINUX: Fire up putty for Windows, Minicom or Screen or Mac and Linux to get direct access when you don't have video or network.CONNECTING TO 40 PIN HEADER: Three pins need to be connected for UART to work, the black ground (GND) wire, the white RX wire, and the green TX wire. Black should be connected to pin 6, white should be connected to pin 8, and green should be connected to pin 10.RASPBERRY PI 3/4 GUIDE: You must open /boot/config.txt or edit config.txt on your MicroSD card and add "enable_uart=1" without quotes in order for this to work for Raspberry Pi 3/4 Model B and Model B+. Otherwise UART is not enabled and will not display anything.DEBUG SERIAL UART CABLE FOR RASPBERRY PI AND OTHER 3.3V SYSTEMS: Instead of guessing problems through a black screen, find out exactly what is going on with your board. Issue commands, grab logs, and debug problems quickly with his convenient USB cable.