To some people, telephones are the greatest invention that they
heard of, most of these people are teenagers! These people find
Alexander Graham Bell their hero because he was the inventor of
This simple device contains three parts. One is a hook switch which
connects and disconnects the telephone from the network. This happens
when you pick up and put down the handset. The next part is the
speaker. This part lets you hear the other person speak, which is
quite helpful. The last piece is the microphone. This is made up
of carbon granules put in between two extremely thin metal plates.
The sound waves from your voice would decompress and compress the
granules by changing the resistance and modulating the current flow.
This is all just with your voice. Any phone you come across will
still have the switch recognizing pulse dialing which is when you
hit where the reciever is held as many times as you want.
A remarkable part of the telephone and its system is its network.
A pair of copper wires, one red and one green, run from a road to
a box at your home and connect to each phone at the house. If the
house has two lines, two pairs of copper wires come. The second
pair will have different colors that are ordinarily colored yellow
and black. All these copper wires are buried under ground. The lines
run either right to the phone company or a box the size of a refrigerator.
This acts like a digital concentrator in your neighborhood. The
network, though seeming complicated, doesn't take much to figure