What is RS485 communication

RS-485 is a telecommunications standard for binary serial communications between devices. It is the protocol or specifications that need to be followed to allow devices that implement this standard to speak to each other. This protocol is an updated version of the original serial protocol known as RS-232. While the original RS-232 standard allowed for the connection of two devices through a serial link, RS-485 allows for serial connections between more than 2 devices on a networked system.
RS-485 is actually a physical layer specification which allows multiple nodes to be connected to a differential 2-wire bus. Unlike RS-232 which can be full duplex (transmit and receive at the same time), RS-485 exchanges must be half duplex. This means there must be rules about who can talk and when. The most straight forward way to start experimenting with this is to connect a UART to a transceiver (LTC1485 and others) and have a go at it. Of course you'll need another node to communicate with, but that is a minor inconvenience.
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