Which device is responsible for linking a computer to the network medium?

• A. Network interface card
• B. Patch panel
• C. Firewall
• D. VPN gateway

Answer: (A)

The device that links a computer to the network medium is the network interface card. It provides the actual connection to the local transmission medium—whether a copper Ethernet cable or a wireless radio—acting as the hardware interface for both sending and receiving data. It handles the physical signaling and data-link functions, including framing and addressing (MAC), so the computer can place frames onto the network and read incoming frames. A patch panel is simply a passive organizing point for cables, not an active link to the network. A firewall sits between networks to filter traffic for security, not to attach a computer to the medium. A VPN gateway establishes secure remote connections, not the direct physical/link layer connection to the network.