Which device is used to modulate and demodulate signals to enable digital communication over analog channels?

Which device is used to modulate and demodulate signals to enable digital communication over analog channels?

• A. Modem
• B. Router
• C. Switch
• D. Bridge

Answer: (A)

Modulation and demodulation are the processes that let digital data travel over an analog path. A modem does both: it modulates digital bits into an analog signal so it can traverse an analog channel (like a telephone line) and then demodulates the received analog signal back into digital data at the other end. This makes digital communication possible over legacy analog infrastructure. In contrast, routers, switches, and bridges handle data forwarding and network segmentation at various layers but do not convert between digital and analog signals for the transmission channel. So the device whose core function is this modulation and demodulation is the modem.

Modulation and demodulation are the processes that let digital data travel over an analog path. A modem does both: it modulates digital bits into an analog signal so it can traverse an analog channel (like a telephone line) and then demodulates the received analog signal back into digital data at the other end. This makes digital communication possible over legacy analog infrastructure. In contrast, routers, switches, and bridges handle data forwarding and network segmentation at various layers but do not convert between digital and analog signals for the transmission channel. So the device whose core function is this modulation and demodulation is the modem.