Mobile telephones are two-way radios. When you talk into a mobile telephone, it picks up your voice and converts the sound to radiofrequency energy (or radio waves). The radio waves travel through the air until they reach a receiver at a nearby base station. The base station then sends your call through the telephone network until it reaches the person you are calling, when you receive a call on your mobile phone, the message travels through the telephone network until it reaches a base station close to your phone. The base station then sends out radio waves that are detected by a receiver in your telephone, where the signals are changed back into voice or data.........