most recent 30 from http://phonehow.com 2010-09-05T01:02:10Z http://phonehow.com/feeds/tag/cdma http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://phonehow.com/questions/178/phone-switched-off-or-out-of-coverage-area Rohit 2010-02-07T04:51:18Z 2010-02-07T10:36:16Z

<p>how does a GSM or CDMA service provider know that a phone is switched off or it is out-of-coverage area?</p> <p>is there a protocol that says that when a phone is switched off it has to tell the tower that it is being switched off or is it a very weak signal that indicates out-of-coverage area while no signal indicates switched off?</p> <p>in case it is the former, then what happens if the phone battery is removed. then is it switched off or out-of-coverage!</p>