Path: utzoo!utgpu!water!watmath!clyde!att!pacbell!ames!killer!vector!nobody From: westmark!dave@rutgers.edu (Dave Levenson) Newsgroups: comp.dcom.telecom Subject: Re: Cellular Phone Question Message-ID: Date: 1 Oct 88 01:21:25 GMT Sender: chip@vector.UUCP Lines: 31 Approved: telecom-request@vector.uucp (USENET Telecom Moderator) X-TELECOM-Digest: volume 8, issue 149, message 4 X-Submissions-To: telecom@xx.lcs.mit.edu (Mailing List Coordinator) X-Administrivia-To: telecom-request@vector.uucp (USENET Telecom Moderator) In article , weinstoc@SEI.CMU.EDU (Chuck Weinstock) writes: > If I call a number associated with a cellular phone, how does the > cellular phone operator know which phone to ring and where it is... When you dial a number assigned to a cellular mobile telephone, all of the cell-sites in the mobile phone user's home region broadcast the incoming call alert. The mobile unit periodically scans the page channels upon which such a message can be broadcast, and locks on the one with the strongest signal. Thus the mobile, while not busy, locates itself wrt the cellular network, and decides which cell-site to monitor for incoming calls. When it hear's its own number in the data-stream it receives on the page channel, it transmits an acknowlegement on the access channel specified in the page channel's message. When a mobile phone user originates a call, the mobile phone transmits a service request on this same access channel, and expects to receive a channel-assignment in reply. Once a call is in-progress, the mobile telephone switching office (MTSO) decides which channel on which cell-site station will handle the call, and directs the appropriate hand-offs. In summary, idle cellular telephones locate themselves. Busy cellular telephones are located by the MTSO. -- Dave Levenson Westmark, Inc. The Man in the Mooney Warren, NJ USA {rutgers | att}!westmark!dave