In this article, you will learn the technical details of using serial on Edge IO.

Edge IO supports serial connections over USB, RS-232, or RS-485. This article will cover the hardware connections and software identifiers for each connection.

To learn how to communicate this serial data to Tulip, please see our other support articles:

Guide on Generic Serial Driver

Guide on Node-RED setup with Serial

Connect using USB

To use serial over USB, you will need a serial device that connects over USB, or a serial-to-USB adapter (for example, a RS232-to-USB adapter cable, or RS485-to-USB adapter).

The Edge IO has six USB ports; you can plug your USB cable into any USB port.

While plugging into USB, the identifiers will be assigned in order of being plugged in:

  • 1st USB port plugged in: /dev/ttyUSB0

  • 2nd USB port plugged in: /dev/ttyUSB1

  • 3rd USB port plugged in: /dev/ttyUSB2


Connect using RS-232/RS-485

The Edge IO also has RS-232 and RS-485 ports.

The identifier for the serial device:

  • RS-232: /dev/ttyS1

  • RS-485: /dev/ttyS2

Note: RS-232 uses a standard DB9 connector, and supports RTS/CTS, but not DCD/DTR/DSR. RS-485 is half-duplex.

Edge IO Port Diagram:

See above the RS-232 and RS-485 pinouts.

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