Which device connects the transmit pin to the receive pin on a port to test NIC functionality without an actual network connection?

Which device connects the transmit pin to the receive pin on a port to test NIC functionality without an actual network connection?

• A. Loopback Adapter
• B. Tone Generator
• C. VRRP
• D. Spectrum Analyzer

Answer: (A)

A loopback adapter is used to test NIC functionality without an actual network by directly connecting the transmit path to the receive path on the port. This creates a local loop so whatever the NIC transmits is immediately received back by its own receiver, letting you verify that the NIC, the port, and the internal transmission/reception paths are working correctly. It’s a self-contained test that can confirm basic connectivity, data framing, and basic hardware operation without any external network. The other options don’t create this internal loopback. A tone generator sends a test signal along cables to help locate faults or verify cable continuity but doesn’t route the NIC’s own transmit data back into its receive path. VRRP is a routing redundancy protocol, not a testing tool. A spectrum analyzer examines the frequency spectrum of signals, which is useful for RF analysis but not for verifying NIC loopback functionality.

A loopback adapter is used to test NIC functionality without an actual network by directly connecting the transmit path to the receive path on the port. This creates a local loop so whatever the NIC transmits is immediately received back by its own receiver, letting you verify that the NIC, the port, and the internal transmission/reception paths are working correctly. It’s a self-contained test that can confirm basic connectivity, data framing, and basic hardware operation without any external network.

The other options don’t create this internal loopback. A tone generator sends a test signal along cables to help locate faults or verify cable continuity but doesn’t route the NIC’s own transmit data back into its receive path. VRRP is a routing redundancy protocol, not a testing tool. A spectrum analyzer examines the frequency spectrum of signals, which is useful for RF analysis but not for verifying NIC loopback functionality.