Question

Write a short note on MODEM.

Answer 1

1. Computers store digital data, while telephone lines can only transfer analog data. If a computer is to be connected to the internet through a telephone, then it must convert digital data to analog data before transmitting the computer signals.
2. Converting one signal form to another form is called modulation and reconverting it to original form is called as demodulation.
3. A modem is a modulator/demodulator. A modem is used to connect a computer to the Internet. Modems convert digital data to analog data and vice versa.
4. They have two advantages:
   1. A modem allows a higher speed of transmission on any given analog line.
   2. Modem reduce effect of noise and distortion.
5. The function of a modem is described by the following figure.
   
6. Modems are classified into two categories according to transmission method:
   1. Asynchronous modems
   2. Synchronous modems