Which statement about a modem is true?

A modem serves a crucial role in connecting devices to the internet by performing two essential functions: modulation and demodulation. Modulation involves converting digital data from a computer into an analog signal suitable for transmission over phone lines or cable systems. Conversely, demodulation is the process of taking the analog signals received back into digital data that computers can understand. This dual capability is vital for enabling internet access through various channels, whether via DSL, cable, or other forms of transmission.

The other statements do not accurately describe the functions of a modem. For instance, a modem does not solely transmit signals over Wi-Fi; it typically connects directly to an internet service and can use wired connections as well. Additionally, it is very much related to internet connectivity as it is often the first device that connects a local network to the internet. Lastly, while a modem can be part of a local network, its primary function is to connect this network to the broader internet rather than to manage connections among devices within that local network.