What is the purpose of a modem?

• A. To connect devices in a local area network
• B. To enable a computer to transmit data over communication lines
• C. To strengthen data signals in long-distance transmission
• D. To eliminate noise in data transmission

Answer: (B)

A modem, short for modulator-demodulator, serves a crucial role in enabling computers and other devices to transmit and receive data over communication lines, such as telephone lines or cable systems. The primary function of a modem is to convert digital signals from a computer into analog signals that can be sent over these lines. Conversely, it also converts incoming analog signals back into digital form for the computer to process. This bidirectional capability is essential for accessing the internet and network resources.

In local area networks (LANs), devices typically communicate using similar digital formats and protocols, negating the need for modulation and demodulation, which is why the capability to transmit data over communication lines is fundamental to the function of modems.