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Old November 16th 05, 11:58 PM posted to uk.railway,uk.transport.london,uk.telecom.mobile
Chris! Chris! is offline
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First recorded activity at LondonBanter: Apr 2005
Posts: 140
Default Plan for dealing with obnoxious phone calls on trains?

Gavin Hamilton wrote:
A friend of mine suggested a small device that transmitted the sound
of a low flying aircraft on bluetooth frequencies - it would be
exceedingly amusing to watch those with bluetootehed mobile phones
diving for cover - in the office :-)

One day we'll work out how to make one..........

G


I'm pretty sure this isn't possible because:
1. The signal received by the earpiece from the "small device" would
have to be stronger than the signal received from the phone
2. The "low flying aircraft" data frames would have to be aligned with
genuine data frames
3. Any encryption would have to be mimicked
4. The frequency hopping pattern would need to be known
5. The computer misuse act would need to change

The best you could hope for is to provide hostile interference which
could jam the signals between phone and headset. Problem with this is
that bluetooth uses frequency hopping because it is intended for use in
a congested frequency spectrum (the unlicensed band)

On the topic of mobile phone jammers... The UK government charges
mobile phone companies a lot of money to license the frequencies hence
I doubt they are going to legalise any form of unrestricted broadcast
over them