Reply to TO1SITTLER re: tempest TEMPEST is NACSIM 5100A (there are some new numbers which I can't remember), a NSA specification for the emission of compromising EMI from computers and other digital data processing equipment. It is a Faraday cage, except that they divide the system into "black" noise circuits and "red" noise circuits. An example of black emissions would be the constant 50 KHz signal emitted by a switcher power supply, that contains no useful information. You can emit as much black as you want. You cannot emit ANY red information, that is, CRT guns, data busses, data transmission lines, etc. Red information can be reconstructed easily bu passive interception. Your PC, for example, has a monitor that emits enough information to allow unintended interception up to a mile away. If you need more details, write back. Gary trimm@netcom.com --