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Cyberspace and society lecture notes 9

Walkie talkie one channel o cb radio 40 channels o

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Walkie talkie – one channel o CB radio – 40 channels o Cell phones – at least 1,664 channels Range o Walkie talkie – about 1 mile o CB radio – about 5 miles o Cell phones – virtually unlimited due to cell switching technology MTSO – Mobile Telephone Switching Office o Handles phone connections to land lines o Controls the base stations o Keeps track of the cell you are located in
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o Hand-off calls from one cell to another Cell phone codes o Identify the phone, phone’s owner and the service provider ESN (Electronic Serial Number) programmed into the phone when manufactured permanent code MIN (Mobile Identification Number) – a 10-digit number derived from your phone’s number programmed in when you activate the phone SID (System Identification Code): unique number assigned to each carrier Cellular technologies o GSM: most popular worldwide Europe, Asia, Africa Better international service Dominate the world market Only on digital networks GSM phone SIM card; in theory more flexible In US – EDGE national network AT&T, T-Mobile o CDMA: most prevalent in the US and competes equally with GSM Power on o Power is turned on, phone listens for a unique identifier-called SID (identifies the carrier) on a special channel that the base station and cell phone use to communication o Phone transmit a registration request which the MTSO keeps track of in a database to identify the cell you are in when it wants to ring the phone Sending a call o Sound is converted into radio waves o Travel thru the air until they reach a base station o Base station sends your call thru the telephone network Receiving a call o MTOS determines the cell you are in o Picks and communicates the frequency o Phone and base station switch on those frequencies o As you move to the edge of the cell, base station notes your signal is diminishing as next base station sees your signal increasing
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Walkie talkie one channel o CB radio 40 channels o Cell...

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