What do you mean by a modem ? Why is it used ?

A modem is a computer peripheral that allows us to connect and communicate with other computers via telephone lines. Modem stands for 'Modulator Demodulator'. The modem at the sender’s end acts as a modulator that converts the digital data into analog signals. The modem at the receiver’s end acts as a demodulator that converts the analog signals into digital data that the destination node can understand.