General Mindstorms questions and compatibility. Use the ev3, nxt or rcx tag to mark questions depending on the system used.
History
In 1984 the LEGO Group partnered with the Media Laboratory at Massachusetts Institute of Technology, which among others led to the development and release of the technic Computer Control system in 1986 and Mindstorms in 1998.
Mindstorms Robotics Invention System
Mindstorms 1.0, 1.1 and 2.0 came with an rcx brick that had ports to connect 3 motors and 3 sensors using the 9V connector cables and a 2x2x2/3 brick with metal in the studs.
Communication with the RCX brick is via infrared, either a Serial/USB "Tower" or a remote control.

Mindstorms NXT
Mindstorms NXT was released in 2006 and can be enhanced with microphones, cameras, and other sensors. The nxt brick has 4 sensor ports and 3 motor ports, and uses RJ12 connectors.
Communication with the NXT brick is via either a direct USB connection or Bluetooth.

Mindstorms EV3
In January 2013 the LEGO Group announced Mindstorms EV3, the latest incarnation of the Mindstorms which comes with the upgraded "ev3 Intelligent Brick". Enhancements include:
- New Linux-based firmware
- A USB port
- SD expansion slot
- iOS and Android support out of the box
- 3D Building instruction app
