Q. What is basic working of Modem?

A modem (modulator/demodulator) is an electronic device that takes digital data as a serial stream of bits and produces a modulated carrier signal as an output. That is to say, the digital signals are converted to an analog form with a relatively narrow bandwidth. The carrier signal is then transmitted over the telephone line to a similar modem at the receiving end, where the carrier signal is demodulated back into its original serial stream of bits, as shown in Figure. The serial digital data to be transmitted are modulated, filtered, and amplified for analog transmission; the analog data received at the receiving end are amplified, filtered, and demodulated to produce serial digital signals.