Which device converts digital signals into analog signals to enable transmission over telephone lines?

Which device converts digital signals into analog signals to enable transmission over telephone lines?

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

Answer: (A)

Modulation for telephone-line transmission is what this item is about. A modem takes digital data from a computer and encodes it into analog electrical signals that can ride over traditional telephone lines. At the far end, another modem decodes those analog signals back into digital data for the receiving computer. This up-and-down conversion is needed because telephone networks carry analog signals, while computers produce digital data. Routers move data between networks, switches forward frames within a local network, and a NIC provides the hardware interface to a network but does not convert digital data for telephone-line transmission.

Modulation for telephone-line transmission is what this item is about. A modem takes digital data from a computer and encodes it into analog electrical signals that can ride over traditional telephone lines. At the far end, another modem decodes those analog signals back into digital data for the receiving computer. This up-and-down conversion is needed because telephone networks carry analog signals, while computers produce digital data.

Routers move data between networks, switches forward frames within a local network, and a NIC provides the hardware interface to a network but does not convert digital data for telephone-line transmission.