"John R. Covert 10-Aug-1990 1055" <covert@covert.enet.dec.com> (08/10/90)
John Gilmore writes: > The US cellular telephone standard defines a way to "ping" a cellular > phone without making it ring. > If I ever get a cellular phone, this 'ping' will be one of the first > things I reprogram... No you won't. It's not a programmable feature on most phones. You see, the way incoming calls work is as follows: 1. All cell sites send "NPA NXX-XXXX, please report". This is what you called a 'ping'. 2. Your phone responds. It does not ring. 3. The cell site which hears your response sets up the call. If the call can't be set up (for any number of reasons, the most obvious being that the cell site which heard your response is out of channels), your phone never rings. Obviously, if "they" want to track your whereabouts, they just do step one, wait for your phone to respond, and do nothing else. You could only disable this feature by disabling all incoming calls. Dave Levenson writes: >If you re-program this feature, you will probably be unable to receive >incoming calls when you're roaming. Dave, you're talking about a different feature: autologin. This is the feature that causes your phone to identify itself when it travels into a new service area (new system ID). It, too, is done on request, but the request is constantly being sent along with the system id information, not as a specific request to a specific phone. If "they" are out to get you, "they" would certainly not rely on this feature to track you, since you only log in each time you cross a system ID boundary. "They" would arrange for your phone to receive incoming 'pings' but never go to the final step of starting ringing. If you don't want your location tracked, don't turn on your phone. john
nagle@uunet.uu.net> (08/12/90)
>followed by call setups, you could determine if any user location >activity is taking place. It's not clear if you're entitled to monitor the cellular control cqhannel under the ECPA. Monitoring the voice channels is prohibited, but the control channel may be OK. An opinion here would be useful. Actually, it would be useful if someone monitored the control channel in major cities and produced independent statistics on usage. This would help in valuing cellular telephone properties and in evaluating the validity of cellular operators requests for more bandwidth. John Nagle