Lego RCX 1.0 brick relationship to Robotics Invention System (RIS) & RCX firmware versions

Question

What is the relationship between a Lego RCX 1.0 brick and these:

Robotics Invention System (RIS) versions

• 1.0
• 1.5
• 2.0

RCX firmware:

• firm0309.lgo: RCX firmware version 3.09
• firm0328.lgo: RCX firmware version 3.28
• firm0332.lgo: RCX firmware version 3.32

Answer 1

The main differences between the versions were:

1. Firmware - although later versions of the firmware were backwards compatible with the earlier bricks
2. Power Adaptors:
   1. RIS/RCX 1.0 had a power socket on the brick as well as battery options
   2. RIS/RCX 1.5 removed the power socket from the brick
   3. RIS/RCX 2.0 Functionally equivalent to RCX 1.5
3. IR Tower connections:
   1. RIS 1.0 and 1.5 had a serial connection for the IR Tower
   2. RIS 2.0 had a USB connection for the IR Tower, which doesn't operate nicely with 64bit Operating Systems (ironically* the serial connection does work with a serial-USB adaptor apparently)
4. Manuals - I believe the Constructopedia was more comprehensive in 1.0 than in 2.0.

* I say ironically as I originally returned my 1.0 or 1.5 set as I was unable to get the serial connection to work on my PC at the time and later bought a 2.0 which worked fine then, but not any more on my more modern hardware.

Answer 2

There is no significant hardware difference (*) affecting software between the RCX bricks, so 1.0 brick is compatible with all firmware and RIS versions.

(*) Known hardware differences:

• RCX 1.0 sold with RIS 1.0 had a power adapter plug.
• RCX 1.0 sold with RIS 1.5 no longer had this plug.
• RCX 2.0 had a 76 kHz IR interface instead of 38 kHz. It remains compatible with old versions (harmonic 2) albeit with a slightly reduced range. New frequency allows to communicate with Spybots bricks.