: A modem is a special process by which the digital signal of the transmitting computer (in the modulation process) is converted to analog signal and the analog signal (in the process of demodulation) is converted to digital signal. A modem is a data communication device that transmits data from one computer to another by means of a medium. The term modem is an acronym for Modulator - Demodulator . The modulator converts digital signals to analog signals and the D-modulator converts analog signals to digital signals. The modem has a modulator and a demodulator. Modulation acts as a modulator connected to the sender computer. Demodulation acts as a modem de-modulator on the receiving computer. The signal is sent from the sender device in a modulating manner. The receiver uses the computer to separate the signals from the demodulating method. Two types of modems are commonly used in computers depending on the connection method. The internal modem is inserted into the motherboard's expansion slot. The external modem computer has to be connected to the communication port on the back of the motherboard. This type of modem is usually attached to a USB port