4.5V PC Interface
The first programmable Lego product (1989). It came with a dedicated IBM-PC-compatible ISA interface card, a ribbon cable, and a control panel. The control panel included six non-reversible 4.5V output ports, three reversible 4.5V output ports (each using the power lines from their two adjacent non-reservible ports), two 4.5V input ports, and one continuous 4.5V output port. It also features a manual-override stop-button. Using programs running on the host computer, the user could create stationary programmable robotic Lego inventions using the older 4.5V system. The 4.5V PC Interface was superseded by the 9V-based Dacta Control Lab in 1995.
Read more about this topic: Lego Mindstorms