The Magical DMX Distribution (MDD) system consists of a card edge system in to which up to seven cards may be inserted. The rackmount card support unit distributes power and data to the cards.
There were two types of card available - MDD (Magical DMX Distribution) and MDR (Magical DMX Receiver) cards.
Connections were made at the rear of the unit on a 5 pin header.
1 = DMX common
2 = DMX -
3 = DMX +
The MDD card was an opto-isolating DMX splitter card. It took one DMX input and gave a DMX thru (unbuffered) plus six buffered DMX outputs. Each output is individually fused with a 0.25A 1/2" type F Fuse.
The MDR card is a DMX prioritizer. It takes up to 5 ports of DMX and outputs the lowest port number which is recieving a valid DMX data stream. It was used to prioritize between architectural systems and consoles and in similar situations.