Mobile phones ( Activity 1 )

A mobile phone allows calls into the public switched telephone system over a radio link. Early mobile phones were usually bulky and permanently installed in vehicles; they provided limited service because only a few frequencies were available for a geographic area. Modern cellular "cell" phones or hand phones make use of the cellular network concept, where frequencies are re-used repeatedly within a city area, allowing many more users to share access to the radio bandwidth. A mobile phone allows calls to be placed over a wide geographic area; generally the user is a subscriber to the phone service and does not own the base station. By contrast, a cordless telephone is used only within the range of a single, private base station.

Advantages: 
- you can carry a mobile phone with you so you don't miss important calls
- if you are lost, you can call for directions.
- if you are in an accident, you can call the police or ambulance - and if the phone has a camera, you can take pictures of the accident.
- you can listen to music, text, play games when you're bored.

Disadvantages:
- mobile phones can be expensive .
- they can damage your ear .
- sometimes the reception is poor in some areas, limiting your connectivity (you can't talk underground or on planes).
- people use the phone while they are driving, and this can cause problems.