Here is the path that a Sprint PCS signal takes as it retrieves information from the Internet, or when a call hooks up with a landline system:
1. When a customer turns on a PCS phone, the signal is sent to an antenna and then to the nearest receiving base station, which picks up the phone's transmission.
Then, when a customer dials a phone number, or requests an Internet connection, the base station sends the call through a controller, which controls a group of base stations.
2. The system authenticates the phone and the customer and the phone displays "in service."
3. Base station
4. Base station controller
5. The controller makes the connection to the mobile switching center (often via a fiber-optic line), which decodes and encodes that call and tracks information for billing.
6. If a phone call is being made, the switching center connects the call to the local landline central telephone office (such as Bell Atlantic in this area) to complete the call on the landline system. The same process is used in reverse when receiving a call.
In the case of an Internet query, the request is sent to a server at the switching center, and the Web search begins; when the information is retrieved, it is reformatted to fit on a phone screen, and moves back through the system, using the same process in reverse.
SOURCE: Sprint PCS