What is a Modem
For those who do not know the modem is an electronic device that makes it possible to communicate more computer systems (eg computers) using a communication channel typically composed from a data or twisted pair line.
This device allows the modulation and demodulation of signals containing the information: the name of these two main functions of the device takes the name of MODEM. In other words, sequences of bits are recoded as electrical signals. In practice, the Modem (DCE Data Circuit Equipment), associated with a network terminal or a PC (DTE Data Terminal Equipment) implements all those conversion procedures and coding of the electrical information signal from analog to digital (demodulation numerical) at the inlet to PC (which is in fact a digital system) and digital to analog (digital modulation) output from the PC along the transmission channel, namely the twisted pair, to other destinations of the Network.