What device receives digital data from a computer and converts it to analog for transmission?

The device that receives digital data from a computer and converts it to analog for transmission is a modem. Modems serve a crucial role in enabling communication over traditional telephone lines or cable systems by translating the digital signals produced by computers into analog signals that can be transmitted over these mediums. This conversion process allows for the data to be sent effectively over long distances, connecting the digital world of the computer to the analog world of conventional communication systems.

In the context of networking, the other devices mentioned – routers, switches, and hubs – primarily manage data flow within local networks and do not perform the function of converting digital signals to analog. Routers direct data packets between different networks, switches connect multiple devices within the same local area network to allow communication, and hubs serve as basic connection points in a network that send incoming data to all ports. However, none of these functions involve the conversion of digital data to analog, making the modem essential for connecting digital devices to analog transmission systems.