RS232 to RS485 Converter, RTS controlled

This project demonstrates how we produce an electronic project using one particular PCB CAD package. Our business is about producing finished custom electronics, and the PCB design process is an important part of that. This page might be of interest to new designers wanting to learn principles, or to potential clients wanting to understand our processes more thoroughly.

The project we have chosen as our example is an RS232 to RS485 converter. This is a often needed device which can demonstrate a lot of principles of circuit design, and hopefully the finished project will be useful to some people, just as it stands. If you just need the RS485 converter without the tutorial, click here.

We start with a specification - to do things "by the book" - we should define our goals and set limits.

RS232 to RS485 Converter specification DB9 RS232 connector compatible with PC TxD and RxD translated from RS232 to RS485 Direction of transmission controlled by PC RTS line Handshake loop the PC connection so it works with all software RS485 signals output on 6 way modular jack Indicator LED(s) to show communications traffic Power supplied by external unregulated 9v plugpack ... and a few extra features, not essential, but desirable RS485 Termination resistor, jumper selectable Pullup/Pulldown resistors on RS485 to establish line-idle condition

Click the Continue arrow below to go to the RS485 converter or the tutorial.

Overview Tutorial RS485 converter without the tutorial