Which device is used for modulation and demodulation of binary data into analog signals?

The device that is designed for modulation and demodulation of binary data into analog signals is the modem. Modems perform the critical function of converting digital data from a computer or network into analog signals that can be transmitted over traditional telephone lines or other types of analog media. This process, known as modulation, allows binary data (which consists of 0s and 1s) to be sent over these media, as they are inherently analog.

When the signal reaches its destination, the modem at the receiving end performs the inverse operation, known as demodulation, converting the analog signal back into digital data for the receiving device. The essential role played by modems in facilitating communication over long distances, particularly in environments where only analog infrastructure exists, underscores their importance in network security and configuration.

In contrast, routers are primarily used for directing data packets between networks, switches connect devices within a local area network and facilitate data forwarding, while bridges serve to connect and filter traffic between network segments. These devices do not modulate or demodulate signals, which is why they are not suitable answers for this specific function.