Introduction to Data Communications
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v. Handset

The Handset contains transducers for converting mechanical energy into electrical energy. The microphone converts speech into electrical energy. The diaphragm or speaker converts electrical signals into audible signals.

Functions of a Telephone Set:

  1. Request use of network from the CO (Central Office).
  2. Inform you of the network status: Dial-tone, Ringing, Busy, Fast Busy (Talk Mail)
  3. Informs CO of desired number.
  4. Informs you when a call is incoming (phone rings).
  5. Releases use of network when call is complete (hang-up)
  6. Transmit speech on network & receives speech from distant caller.
  7. Adjust power levels and compensates for line length.

24b. Local Loops

The Local Loop is the connection between the Central Office and the home or business. To every home is run 2 wires (1 pair). The pair does not go directly to the Central Office, instead it goes to those big green boxes called "Serving Area Interfaces" (SIA) that you see on the street corners. Then large multi-conductor bundles of wires go from there to the Central Office.

Introduction to Data Communications
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