They are the perfect bugging tool for spies: cellphones that answer calls silently. Eavesdroppers can hide a digital cellphone in an office or bedroom, then call it to listen to conversations.
"The cellphone takes care of the hardest part of bugging or tracking, which is setting up a reliable communications link," says Lauren Weinstein, who runs Vortex, a technology consultancy in Woodland Hills, California.
Many modern digital cellphones and pagers allow users to disable audible ringing, so they can quietly pick up calls in public places or have the phone take messages. And some newer phones can be set to automatically answer incoming calls, allowing people driving cars or wearing headsets to respond without having to fumble for their phones. Each capability seems innocuous, but a hidden cellphone with both features can silently and automatically answer calls, establishing a radio link for bugging a room.
Barry Smith, a technology specialist at the FBI in Washington DC, would not confirm that cellphone bugging is possible, but he warned: "It is illegal under federal law to listen to or record any conversation you aren't a party of." This would cover hidden cellphones. In Britain, intrusive surveillance that does not use phone-tapping equipment remains legal. But the government is bringing legislation into line with the European Convention on Human Rights, so this may soon change.
The idea of cellphones as bugs was new to the proprietors of Counterspy, a New York store which sells surveillance equipment. It was also new to the office of Heather Wilson, a New Mexico Congresswoman whose proposal to ban radio scanners that can eavesdrop on cell-phone calls has just been passed by the House of Representatives.
But as Weinstein points out, "private investigators and law enforcement officers have apparently been using cellphones like this for quite some time".
A standard cellphone alone cannot be used as a bug because users must speak directly into it. It takes an external microphone, such as those used with a hands-free set, to turn the device into an effective eavesdropper: it can pick up sound across a room. The act of plugging in the head-set jack switches on the auto-answer function in many phones, so the hands-free user does not have to fiddle around with the phone when it rings. Standard batteries can power digital cellphones for several hours of transmission or days of standby operation.
Other covert radio transmitters available from security equipment dealers have serious drawbacks. Tiny microphones hooked up to concealable antennas generate weak signals, so receivers must be hidden nearby. Higher-power transmitters can be used over greater distances, but are larger, more expensive and easier to detect. Cellphones are cheap by comparison, and the industry's multibillion infrastructure puts electronic surveillance within the reach of amateur spies, business competitors or suspicious husbands with minimal technical skill. "Anybody could do this," says Weinstein.
Author: Jeff Hecht, Boston
New Scientist issue 21 August 1999
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