A Cordless Phone That Can Thwart Eavesdroppers
To industrial spies and other snoops, the millions of cordless phones in use are gold mines of information. Conversations can be plucked from the air by means of a police-type scanner, and with increasing ease. The latest no-cord technology offers clearer sound and longer ranges--up to half a mile. That's because the new phones broadcast signals at 900 megahertz, or 20 times the frequency of current models.
Cincinnati Microwave Inc. figures executives and consumers will pay a small premium for cordless privacy. The company has developed a phone, to be marketed in October by its Escort division for about $300, that thwarts eavesdroppers with "spread-spectrum" technology, which is similar to the encryption method the military uses in secure radios. The signals between the handset and the base unit are digitized, making them unintelligible to humans, and the transmission randomly hops among various frequencies within the 900-Mhz spectrum. To bring the cost down to the range of other 900-Mhz models, Cincinnati Microwave has developed special microchips that keep the handset and base in sync.