UARTRS232RS485

UARTRS232RS485 refers to a hardware interface or module that implements a UART (universal asynchronous receiver-transmitter) with support for both RS-232 and RS-485 electrical standards. Such devices provide the standard UART data framing while offering two different signaling layers that suit different environments and distances.

UART is an asynchronous serial protocol that transmits data one bit at a time using a start bit, data bits, optional parity, and a stop bit. RS-232 is a single-ended, point-to-point standard that uses voltage levels relative to ground, typically producing negative voltages for one logic state and positive voltages for the other. RS-232 commonly uses DB9 or DB25 connectors and is suitable for short to moderate distances at modest baud rates. RS-485, by contrast, uses differential signaling over twisted pair, enabling longer distances and multi-point networks. RS-485 devices share a bus and may require line termination and biasing resistors to define a known idle state; network direction control is needed for multi-drop configurations.

Devices supporting both interfaces usually incorporate level shifters and transceivers, and may include features such as automatic or controlled direction switching for RS-485 (DE/RE control). Some designs allow selectable operation between RS-232 and RS-485 or provide an integrated USB-to-UART core with separate RS-232/RS-485 transceivers.

Common applications include microcontroller to PC communication, industrial automation sensors and controllers, and embedded systems that must interface with legacy RS-232 devices or robust RS-485 networks. When selecting such a device, considerations include voltage levels, baud rate support, cable length, impedance, termination, and whether automatic direction control is available.