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Arise, you have nothing to lose but your barbed wire fences!

1993-08-13 - Beepers can also be used to track you down!

Header Data

From: karn@qualcomm.com (Phil Karn)
To: rarachel@ishara.poly.edu
Message Hash: a9951d3fbf56120c20dd7939030cee5d7eff3d27c26787bcf358f19f7e376bd6
Message ID: <9308131744.AA21446@servo>
Reply To: <9308131050.AA28463@ishara.poly.edu>
UTC Datetime: 1993-08-13 17:48:27 UTC
Raw Date: Fri, 13 Aug 93 10:48:27 PDT

Raw message

From: karn@qualcomm.com (Phil Karn)
Date: Fri, 13 Aug 93 10:48:27 PDT
To: rarachel@ishara.poly.edu
Subject: Beepers can also be used to track you down!
In-Reply-To: <9308131050.AA28463@ishara.poly.edu>
Message-ID: <9308131744.AA21446@servo>
MIME-Version: 1.0
Content-Type: text/plain


Eh? Conventional pocket pagers are receive only. This is well known. Oh,
they probably do emit tiny amounts of RF from their local oscillators,
but I doubt much could be done with that.

Cell phones, on the other hand, *do* tell the system which cell you
are in, and they can do this even when you're not in a call. It's
called "registration".  The usual purpose is benign: directing pages
(land-to-mobile call requests) only to the cell you're in, instead of
having to "flood" them all over the system. But it *could* be used to
keep track of your location.

I carry both a pager and a cell phone.  Normally I keep the cell phone
turned off to save its batteries. When I get a page, I can turn the
phone on and return the call.  The pager/cellphone combination is very
nice, as I effectively get "caller ID" functionality.  Even better,
*I* get to choose when, how or even if to answer a particular page.
And since pagers are unidirectional (no acks) I can always lie about
not having gotten a page from somebody I don't want to talk to!  :-)

Phil

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