I recently bought a new in box 1.5 Mindstorms kit featuring the RCX. My computer unfortunately does not have a 9-pin connection, and the software does not appear to work on Windows 10. Short of buying an old computer, what can I do to still load programs onto the RCX?

  1. Buy a USB to Serial adapter. There are USB IR Towers, but the drivers are only for older version of Windows. A new USB/Serial adapter, on the other hand, should be compatible with Windows 10 (Windows 10 requires signed drivers, so do your homework before buying).
  2. Use 3rd party software. For example, Brickx Command Center and leJOS are compatible with RCX and have a better chance of running on Windows 10 than the official LEGO software for RCX.

I also found this site, which has the same advice, but with pretty pictures and more details: http://www.instructables.com/id/Making-Mindstorms-RCX-Work-Again/

Note: If you use Linux, there is a built-in driver for the USB IR Tower in the kernel, so just about any Linux desktop system will "just work".

  • Will the 3rd party software work on a 64-bit machine? – Weckar E. Nov 1 '17 at 14:59
  • I suspect most of it will. I've only used BrickxCC myself. – David Lechner Nov 1 '17 at 16:20

Honestly... it was WAY easier for us to find a computer on eBay! We bought an IBM ThinkPad with Windows 2000 installed on it. We won the auction with a bid of $28 and with shipping it was the best $40 I've spent on eBay! The laptop fired right up, we inserted the Lego Mindstorms Robotics Invention System disc, and voila! It installed quickly and easily. The USB tower was recognized right away and my son was programming his RCX 2.0 within 15 minutes of opening the eBay package! We have the Mars expansion set and the RoboSports set also. We are BIG fans of the 20 year old RCX systems!

  • While this doesn't directly answer the question, I think it's a useful idea. Thanks for your contribution! – jncraton Aug 25 '18 at 3:21
  • Not easy to find space for, but nice idea. – Weckar E. Sep 3 '18 at 15:48

There are a few hurdles to jump through.

For the IR tower, you need one of the following:

A 32-bit system to run the software on. If you don't have such a system, one option is to install an old 32-bit version of Windows in a virtual machine, and pass the USB device through to the VM.


The USB RCX Tower only has 32-bit support, which doesn't work on modern Windows versions. It has been reported to work on Linux though (I didn't try that myself).

I own a serial USB RCX Tower which I connected to my computer USB (modern Windows 10) using a (modern) LogiLink AU0002E RS232 adapter which has a Windows 10-compatible 64-bit driver.

I use leJOS and because it is Java I have IntelliJ IDEA community edition as programming environment. This doesn't work with Java 5 and older versions. IntelliJ IDEA does however still support Apache Ant 1.9.14 which in turn supports Java 5 and newer.

Java 5 is the maximum version for leJOS and the minimum version voor Apache Ant 1.9.14 so Java 5 is just right. An Ant build script can compile the java source code and send it directly to the RCX, all from the programming environment.

I started documenting everything here: https://github.com/oversticht/lego-rcx-lejos/blob/master/README.md

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