Telephone

The telephone is a communication device. You must pay a telephone company a fee per call and per minute to call people.

Description
Telephones are devices used to transmit sounds. The telephone network extends worldwide, so you can reach nearly anyone on the planet.

The very simplest working telephone would look like this inside.

As you can see, it only contains three parts and they are all quite simple:
 * A switch to connect and disconnect the phone from the network - This switch is generally called the hook switch. It connects when you lift the handset.
 * A speaker - This is generally a little 50-cent, 8-ohm speaker of some sort.
 * A microphone - In the past, telephone microphones have been as simple as carbon granules compressed between two thin metal plates. Sound waves from your voice compress and decompress the granules, changing the resistance of the granules and modulating the current flowing through the microphone.