Which of the following is NOT listed as a visual sign of a failing line?

• A. Frayed cable
• B. Corroded connectors
• C. Moisture on connectors
• D. A carbon microphone

Answer: (D)

Visual signs to look for reflect problems with the line itself and its connections, not just any component connected to the line. A frayed cable shows insulation wear that can lead to conductor damage or intermittent contact. Corroded connectors indicate poor electrical contact and potential open or high-resistance paths. Moisture on connectors can cause corrosion and shorting, especially in damp environments. The carbon microphone, while an important part of the system, is a separate device from the line. Its condition doesn’t reveal the line’s integrity, so it isn’t listed as a visual sign of a failing line.