What is the primary function of a modem in a network?

The primary function of a modem in a network is to modulate and demodulate signals for data transmission. This process involves converting digital data from a computer into analog signals that can travel over telephone lines or other communication media (modulation) and then converting incoming analog signals back into digital data that the computer can understand (demodulation).

This capability is crucial for enabling digital devices to communicate over traditional communication mediums, which are often analog in nature. For example, in a typical home internet setup, the modem connects to a service provider’s lines and allows the household's digital devices to access the internet.

The other options do not accurately define the primary role of a modem. While encryption relates to data security, it is not a function of modems. Connecting multiple networks typically involves routers rather than modems. Additionally, distributing network traffic across servers is a function managed by load balancers or switches, not modems.