USB RS232 to RS485 Converter Dongle



This USB dongle will convert RS232 to RS485 for use with the lighting system. It's generic enough that anyone doing an RS485 project should benefit from it.


I borrowed from Sparkfun's design for their USB-to-UART FTDI FT232RL breakout board as well as the examples on the FT232RL datasheet. Then, I added a SN75176B (a MAX485 clone), configured for data output mode and two RJ-45 jacks. A 120Ω resistor is needed if you are terminating the lines.

There's a few status LEDs showing power, TX, and RX status too.

Schematics and Layout

These files contain the full plans for the board. I use Kicad for schematic capture and board design.

I found all the parts I need on Digikey, but it's possible to get some of them cheaper on Avnet.