DAPHNE can use a real scoreboard from a Dragon's Lair cabinet. The scoreboard plugs into the Parallel Port of your PC.
On an x86-based machine, the parallel port is sometimes known as LPT1. It has 25-pins.
Daphne for Windows XP/2000/NT/98/95 can access the parallel port directly, although you may need to have admin privileges.
In linux, you must run DAPHNE as 'root' to access the parallel port.
As of the time of this writing, only parallel ports on x86-based machines are supported.
To use a real scoreboard, you will need to make your own cable because Robert DiNapoli chose the pin-outs for this cable arbitrarily so you won't find any compatible cables out there.
On one end of the cable, you need a 16-pin Symbex connector that plugs into the back of your Dragon's Lair scoreboard. It looks like this:
On the other end of the cable you will need a 25-pin connector that plugs into your Parallel Port on your computer. Here is the one Rob made for me:
NOTICE that two of the wires are not connected to anything! These wires are for +5 volts and ground. I have been using my PC's power supply to provide the +5 volts and ground. Of course you can use any +5 V source. The red wire of my PC's power supply is +5 and the black one next to it is ground. DON'T TAKE MY WORD FOR IT! IF YOU DO THIS WRONG YOU WILL RUIN YOUR SCOREBOARD SO DOUBLE CHECK BEFORE YOU DO SOMETHING FOOLISH. I OF COURSE WILL NOT BE HELD RESPONSIBLE FOR ANY DAMAGE THAT OCCURS TO YOUR HARDWARE BY ATTEMPTING THIS VERY OPTIONAL HACK.
Finally you will need to know the pin-outs to construct the cable.