Which of the following is both an input and output device? 

The correct answer is Modem.

Key Points

• A modem, which stands for Modulator-Demodulator, is a hardware device that converts data between analog and digital formats.
• It serves as both an input and output device by receiving data from the internet (input) and sending data to the internet (output).
• Modems are essential for connecting computers to the internet via telephone lines, cable systems, or satellite links.
• They facilitate communication between different networks, enabling the transmission of data over long distances.

Additional Information

• Modem Types
  • Dial-up Modem: Uses telephone lines to connect to the internet; provides slow data transfer speeds.
  • DSL Modem: Digital Subscriber Line modems use telephone lines but offer higher speeds than dial-up.
  • Cable Modem: Connects to the internet through cable television lines and offers high-speed data transfer.
  • Fiber Optic Modem: Uses fiber optic cables for extremely high-speed internet connections.
• Modulation and Demodulation
  • Modulation: The process of converting digital signals into analog signals for transmission over telephone or cable lines.
  • Demodulation: The process of converting received analog signals back into digital signals.
• Router vs Modem
  • Modem: Connects directly to the internet and translates data between the internet and a local network.
  • Router: Distributes the internet connection from the modem to multiple devices in a local network.
  • Modem-Router Combo: A single device that performs the functions of both a modem and a router.
• Network Standards
  • ITU-T: International Telecommunication Union Telecommunication Standardization Sector, responsible for standardizing modem technology.
  • IEEE: Institute of Electrical and Electronics Engineers, responsible for network standards such as Ethernet and Wi-Fi.