DDD Translator Card
By Clint Gilliland, ; posted November 26, 2008; hits 2229
| This metal card was used in the early (1950s) DDD Card Translators. The DDD routing for an Area Code was coded by punching selected rectangular slots to a full square. There are 38 tabs on the bottom of the card. These are cut off according to the Area Code. Several hundred cards are held in a tray with 38 bars along the bottom. When a route is to be selected certain bars drop. Only the card with the proper tabs drops. Light beams pass through all rectangular holes. All beams are cutoff except those not blocked by the square holes which becomes the path for the route.
To keep the cards from sticking a magnetic field is turned on about the time the bars are selected. This makes all the metal cards stand up. The selected card is then free to drop.
The cards are 10.5" by 5", probably a magnetic stainless steel. |
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