http://original.jamesthornton.com/fun/blinkenlights.html The 220 was a 10 digit plus sign BCD machine. Each register was displayed on the console as an 11 x 4 matrix of neon bulbs. The bulbs were in a plastic "eggrate" matrix. The kicker, and the reason for the sign, was that the bottom divider under each bulb was actually a contact switch that, when pushed, inserted a bit into the register, even if the machine was running
These guys have a poster for sale, the original Blinkenlichts text set in a gothic font. Very cute.