MODEM COMMUNICATION

DEFINITION OF  MODEM

Modem is a device that converts digital signals into analog signals (a process known as modulation) to send over phone lines, a receiving modem at the other end of phone line then converts the analogue signals back to a digital signals (a process known as demodulation).

MODEM COMMUNICATION

Its enables users to transmit data from one computer to another by using standard telephone lines instead of special communication lines such as fiber optic or cable.

TYPES OF MODEMS

In terms of physical size and shape modems can be divide onto following categories:

 EXTERNAL MODEM

External modem is attached to the system unit as an external device by meand of a telephone cable. It is connected to the telephone wall jack by another cable. The modem is a self contained unit which is connected to the PC using a serial cable to the COM1 or COM2  port. Its need an external power supply, and is easy to set up.

 

INTERNAL CARD

An internal modem is a circuit board that can be added to the system unit through an expansion slot. The modem can not be moved easily from one PC to another. It is more difficult to set up than other types of modem.

WIRELESS MODEMS

Wireless modems transmit the data signals through the air instead of by using a cable. They sometimes are called a radio-frequency modem. Wireless modems are not yet perfected, but the technology is rapidly improving.