pchris@ucbarpa.Berkeley.EDU (Chris Perleberg) (10/22/88)
Here at UC Berkeley, a common security device is the "Detex" Card, otherwise known as the "Card Key" or "FACSCARD". It is a credit card sized card made of three pieces of plastic laminated together. By the door you wish to enter is a 6 by 6 inch panel with a red LED in the center to indicate the panel is on. You press your card against the panel (either side of the card, any angular orientation, anywhere on the panel), and the door unlocks. The card usually requires a $20 to $25 dollar deposit to obtain. A friend seperated the laminated plastic of the card. Inside are traces of copper arranged in spiral patterns (there were several individual spirals). It looks like some type of microwave resonator. The cards are uniquely identified by the security system (i.e. the security system knows whose card was used to enter) so each card probably has a unique set of copper foil patterns that resonate at distinct frequencies. The following address is on the cards: Glen Industrial Communications, Inc. FACSCARD P.O. Box 9032 Rockville, MD 20856 If someone knows more details of how these cards work, could you post to the net? Thanks, Chris Perleberg pchris@sim.berkeley.edu