What is the function of a modem in communication systems?

A modem plays a crucial role in communication systems by enabling the transmission of data over various types of media, such as telephone lines or cable systems. Its primary function is to convert signals from digital format, which is used by computers and other digital devices, into analog signals that can be transmitted over traditional communication lines. This conversion allows digital devices to communicate with each other over distances where only analog signaling is possible.

In addition to converting digital signals to analog, modems also perform the reverse function, converting incoming analog signals back into digital signals for the receiving device. This bidirectional capability is essential for facilitating internet access and data transmission, making modems a fundamental component of most communication systems.

The other options listed do not accurately describe the primary function of a modem. While data storage, signal filtering, and amplification are important in various contexts in communications, they are not functions performed by a modem specifically.