miércoles, 24 de febrero de 2010
Mdern Telephones
There are very different kinds of telephones which are used to do different things. For example, there are computer modems. The computer modems are what people use a lot today for sending written messages. E-mailing and instant messages are written messages sent back and forth to one another using the telephone line and a computer modem.
The Fax Machine is another different use of the telephone network. The fax is like a copy machine except you can send a document to someone else using telephone lines.
Videophones are a very different use of the telephone network because instead of talking through a phone and not seeing the person, you get to see who you are talking to through a camera that sends a visual image through the network to a television.
The telephone network allows immediate voice, print and visual contact between people separated by thousands of miles. Our world seems a lot smaller after Alexander Graham Bell`s invention because now instead of taking 10 days to talk to someone on a different continent it only takes about ten seconds.
History of the Telephone
In the 1870s, two inventors Elisha Gray and Alexander Graham Bell both independently designed devices that could transmit speech electrically (the telephone). Both men rushed their respective designs to the patent office within hours of each other, Alexander Graham Bell patented his telephone first. Elisha Gray and Alexander Graham Bell entered into a famous legal battle over the invention of the telephone, which Bell won.
The telephone (from the Greek: τῆλε, tēle, "far" and φωνή, phōnē, "voice") is a telecommunications device that transmits and receives sound, most commonly the human voice. It is one of the most common household appliances in the developed world, and has long been considered indispensable to business, industry and government. The word "telephone" has been adapted to many languages and is widely recognized around the world.
The device operates principally by converting sound waves into electrical signals, and electrical signals into sound waves. Such signals when conveyed through telephone networks — and often converted to electronic and/or optical signals — enable nearly every telephone user to communicate with nearly every other worldwide. Graphic symbols used to designate telephone service or phone-related information in print, signage, and other media include ℡(U+2121), ☎(U+260E), ☏(U+260F), and ✆(U+2706).
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