Cell phones are designed to permit people to be moving around while using them. In order for them to be mobile, cell phones interact with cell towers and base stations. The phone coverts a person’s voice into a radio frequency transmission, then sends it over the air to a nearby cell tower. The tower contacts a base station (Mobile Telephone Switching Office, or MTSO), which sends the radio transmission to the receiving phone. The receiving phone then converts the electrical radio transmission back into an audio voice transmission. As the phone moves around, the voice transmission is passed from one MTSO to another MTSO and a tower within closer range of the phone. Technical Process When a call is initiated, the cell phone searches for a System Identification Code (SID) on a MTSO’s control channel. The control channel enables the cell phone and MTSO to communicate with each other so a call can be set-up and allow for channel changing as the phone moves around. After the phone gets the SID, it compares that SID to the one the phone has already been assigned by the mobile phone carrier. If the two SIDs match, the phones establish a connection. The [...]
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