A modem (modulator-demodulator) is a device that modulates signals to encode digital information and demodulates signals to decode the transmitted information. It is a device that transmits and receives data using a modulated carrier wave. Modems are used to establish network and internet connections. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. The most common use for modems is for both sending and receiving of the digital information between personal computers. It attached to a computer converts digital data to an analog signal that it uses to modulate a carrier frequency.
Modern is a network device that both modulates and demodulates analog carrier signals for encoding and decoding digital information for processing. Moderns can be used with any means of transmitting analog signals, from light emitting diodes to radio. A common type of modern is one that turns the digital data of a computer into a modulated electrical signal for transmission over telephone lines and demodulated by another modem at the receiver side to recover the digital data.