On Wed, 10 Apr 2002, Trei, Peter wrote: > So, yes, at the moment they can't scan your wallet very easily. But > this technology is developing as all others are. I don't know about > dealing with many similar tags more or less simultaneously, but some > of the discussed apps for stock tracking require dealing with this > problem.
The tags are passive. All tags (whether inductive or electrostatic) must be energized from the outside. The pumping energy can be shielded, as can the RF emission of the tags itself. The environment is noisy. The tags send simultaneously from the same physical location. I'm not sure whether microwave-pumped digital pulse radio based tags (currently no such technology officially exists) could have a somewhat wider range and less crosstalk, but even then they could be shielded. On this background, the particular technology one uses is not very relevant, as we're talking about limits of physics. Reading secreted banknotes on your body with a magic wand reader is easy (unless wrapped in metal foil), reading them from across the room -- no, sir.
