Which device is used to test and verify the physical and data link layers of a network?

• A. A spectrum analyzer.
• B. A power quality meter.
• C. A protocol analyzer.
• D. A network multimeter.

Answer: (D)

Testing the physical and data link layers means checking both the actual cabling and electrical signals (layer 1) and how frames and MAC-level operations behave on the network (layer 2). A network multimeter is built to cover both areas: it can verify cable continuity, impedance, length, and signal quality on the physical links, as well as provide diagnostics related to link status and basic frame/packet handling at the data link level. This dual capability makes it the best fit for confirming that both the wiring and the immediate network operations are working correctly.

Other tools don’t fit as well. A spectrum analyzer looks at RF frequencies and is aimed at wireless or RF signals, not wired Ethernet signaling. A power quality meter monitors electrical power characteristics, not networking signals. A protocol analyzer focuses on inspecting frames and protocol-level details, which is great for diagnosing data link behavior, but it doesn’t test the physical cabling and electrical integrity that a network multimeter can assess.