To: cypherpunks@toad.com
From the L.A. Times Sunday 6/19
Fugitive Relied On And Was Undone By Cellular Phone ... Law enforcement officials subpoenaed the company ( AirTouch Cellular ) for assistance in tracking down O J Simpson. Technicians began monitoring calls made to and from the white Bronco. ... Even if an eyewitness had not spotted the vehicle, such monitoring would have made Simpson's capture inevitable. ... Technicians in the tracking station can, if necessary, track a particular call back to the cell site from which it originates. But the monitoring can not be done unless the phone is in use. [ Is that true? ] * RM 1.4 B0037 *
Technicians in the tracking station can, if necessary, track a particular call back to the cell site from which it originates. But the monitoring can not be done unless the phone is in use. [ Is that true? ]
There is an optional mechanism called "registration" by which the system can keep track of your approximate location even though you're not actually making calls. The intent is not really to track your location, although it could certainly be used for that purpose. It's intended to minimize the amount of "flood paging" that goes on. When somebody calls you on a cell phone and the system doesn't know where you are, it has to broadcast the page (the message announcing the call) on every cell in the system. In large busy systems, this can cause quite a bit of congestion on the paging channels. So the system has the option of asking the users to transmit occasionally so the system can keep track of their location and direct incoming pages to the last known cell, at least as a first try. Think of the system as a large bridged Ethernet and you won't be far off, at least on the concept. On the other hand, the fact that most cell phones see very little use, and the use that they do see is predominantly mobile originated, means that registration actually doesn't buy that much in practice. It can even be counterproductive because of all that non-revenue generating registration traffic that takes up capacity on the access and paging channels. This probably explains why registration isn't often used in practice, as far as I know. The best way to make sure it isn't occurring, of course, is to turn off your phone. Phil
It may be that the phone can be "pinged" unbeknownst to the owner, but I'm fairly confident that if the phone is shut off, you're safe. The truly paranoid might consider stowing the phone inside some sort of RF cage, I guess, or maybe just throw it out the window :-) -- | GOOD TIME FOR MOVIE - GOING ||| Mike McNally <m5@tivoli.com> | | TAKE TWA TO CAIRO. ||| Tivoli Systems, Austin, TX: | | (actual fortune cookie) ||| "Like A Little Bit of Semi-Heaven" |
It may be that the phone can be "pinged" unbeknownst to the owner, but I'm fairly confident that if the phone is shut off, you're safe. The truly paranoid might consider stowing the phone inside some sort of RF cage, I guess, or maybe just throw it out the window :-)
I should have added in my remarks about registration that one very easy way to "ping" a cellular phone is to call it. If the phone is powered on and hears the page, it will automatically acknowledge it on the access channel (the mobile-to-base link that is also used to request a mobile-originated call). This will certainly reveal the mobile's location to the closest cell. Phil
Date: Wed, 22 Jun 1994 01:57:04 -0700 From: Phil Karn <karn@qualcomm.com> I should have added in my remarks about registration that one very easy way to "ping" a cellular phone is to call it. My wife said that some news show last night, maybe it was the Baba Wawa thing, was saying that the current police story on OJ is that someone called the police saying that they thought they saw OJ in the Bronco. Then the police called OJ on the cellular to start pinpointing his location. Presumeably, they'd already figured out who's Bronco it was . . . . Rick
On Sun, 19 Jun 1994, Mike McNally wrote:
It may be that the phone can be "pinged" unbeknownst to the owner, but I'm fairly confident that if the phone is shut off, you're safe. The truly paranoid might consider stowing the phone inside some sort of RF cage, I guess, or maybe just throw it out the window :-)
Maybe something as simple as unplugging/removing bateries? -ck
Mike McNally says:
It may be that the phone can be "pinged" unbeknownst to the owner, but I'm fairly confident that if the phone is shut off, you're safe. The truly paranoid might consider stowing the phone inside some sort of RF cage, I guess, or maybe just throw it out the window :-)
Wouldn't it be much simpler to hit the "power" button? .pm
"Bob MorrisG" wrote:
Technicians in the tracking station can, if necessary, track a particular call back to the cell site from which it originates. But the monitoring can not be done unless the phone is in use. [ Is that true? ]
I wonder about this. A friend had a Motorola handset he was using with our (Telecom) AMPS service. When in stand-by mode, it polls the closest cell to determine link quality and whether any slots are available for use. When we were on holiday a few months ago, we stayed in a little seaside town (ie. a small cell) and I can remember eating and noticing the phone switch to `no service' for a few minutes, presumably as the cell was fully loaded. While travelling through a National Park the following day, in the middle of nowhere effectively, the same thing happened as we went out of network range for a couple of hours. The question is whether this polling includes the handset identifying itself to the cell. Matthew. -- Matthew Gream <M.Gream@uts.edu.au> -- Consent Technologies, (02) 821-2043 Disclaimer: I'm only a student at UTS
-----BEGIN PGP SIGNED MESSAGE----- From the keyboard of: mgream@acacia.itd.uts.edu.au (Matthew Gream)
"Bob MorrisG" wrote:
Technicians in the tracking station can, if necessary, track a particular call back to the cell site from which it originates. But the monitoring can not be done unless the phone is in use. [ Is that true? ]
I wonder about this.
[Description of polling handset deleted]
The question is whether this polling includes the handset identifying itself to the cell.
Yes, it must. If the handset is on standby, it won't receive calls unless the cell can tell which number the handset is using. The only sure way to keep yourself out of the "Position Escrow System" is by keeping the phone turned off, and possibly disconnecting the battery or car power lead. "On Standby" == "In use." Richard -----BEGIN PGP SIGNATURE----- Version: 2.3a-sterno-bait iQCVAgUBLgUGwfobez3wRbTBAQGDWwP/fA5i68L8YGJ0qOQ8nmTVMLRKjpVGWcLj ZGm6kSqXhERJFDuGmoiEzKLsg9KLTkrtHQl6IMKJ/MS921k1an/b13Hzksp6SvRm aFN8zYMoEUUiWcPGdKZC2sf7XjtAkUxnKfYlXXWuDp5qeaGdroPCtQ9MDFsl9ply lORwwdOA7Ls= =15Dp -----END PGP SIGNATURE----- -- Loudyellnet: Richard Johnson | Sneakernet: ECNT1-6, CB 429, CU Boulder Phonenet: +1.303.492.0590 | Internet: Richard.Johnson@Colorado.EDU RIPEM and PGP public keys available by server, finger or request Speaker to avalanche dragons. Do you really think they listen?
participants (9)
-
bmorris＠netcom.com -
Chris Knight -
m5＠vail.tivoli.com -
mgream＠acacia.itd.uts.edu.au -
Perry E. Metzger -
Phil Karn -
pstemari＠bismark.cbis.com -
Richard Johnson -
Rick Busdiecker