Features of modem and its different commonly used types of modem. Modem is a device that is used in networking. We use this device for the modulation and demodulation. These two tasks are very important part of networking.Modem contains different features that will be discussing bellow.We also have different types of modem. Modem is related to the conversions of signals. In networking we have two type of signal analog and digital signal. For the transmission of data into the signals the conversion of signals is most important.