Hello friends! Today we will learn what a serial port is, how it transfers information and how to connect serial devices without confusing their electrical interfaces. We will begin with bits and bytes, then examine UART framing, the familiar nine-pin RS-232 connector and the settings needed for a useful conversation between two devices. You may encounter a serial port as a connector on an instrument, a small header on a microcontroller board or a COM port that appears when a USB adapter is plugged into a computer. These can provide similar software interfaces while using very different voltages and wiring. Understanding that distinction is the first step toward a reliable connection. The original article introduced the connector and its applications. This revised tutorial keeps that progr ...