WHAT IS MODEM
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A Modem is a network device that both modulates and demodulates analog carrier signals for encoding and decoding digital information for processing. Modem allows computer to send and receive data from another computer or Digital Subscriber Line (DSL) network.
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A modem or modulator-demodulator is a piece of computer hardware. It is used to communicate between distant computers. Two modems, one on each computer, are required to make a connection, and each modem can send and receive data to and from the other modem.
Modulation • is changing the digital data from a computer to analog data to be sent over telephone lines.
Demodulation • is changing the analog data which is received over the telephone lines to digital data to be used by the PC.
A modem is a device that modulates signals to encode digital information and demodulates signals to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. Modems can be used with any means of transmitting analog signals, from light emitting diodes to radio. A common type of modem is one that turns the digital data of a computer into modulated electrical signal for transmission over telephone lines or cable television lines and demodulated by another modem at the receiver side to recover the digital data.
Modem links your home network to the Internet through your Internet Service Provider (ISP). The Internet services that are outside your home or business which are supplied by your ISP are either DSL, cable, dial-up, or satellite. Your ISP gives you a modem that works with their system.
Modems are classified by the amount of data they can send in a given time, normally measured in Bits Per Second (BPS). They are also classified by their connection method. Dial-up modems were the usual kind in the 20th century, and DSL modems and Cable TV modems are now more used.
Modems that connect to the computer by a cable are called external modems. Modems that go inside the computer are internal modems. Some internal modems are part of the motherboard; others are inserted into the computer on a PC card. Most DSL and cable modems are external.
Many modems are used to connect to the Internet through telephone service or cable television service. Slow telephone service is called dial-up. Faster telephone service is called DSL and is usually more than ten times faster. Cable modems connect through cable television, and are similarly fast.
