220-1101 Question 202
Single answerSingle-modeA technician is helping connect two buildings on a campus network. The cable run between the network closets is approximately 6 km (3.7 miles), and the link must support high-speed data with minimal signal loss. Which cabling choice is MOST appropriate for this installation?
- A
Single-mode fiber
- B
Multimode fiber
- C
Cat 6 twisted-pair copper
- D
RG-6 coaxial cable
Show answer and explanation
Correct answer: A
Explanation
For long-distance network links between buildings, single-mode fiber is the preferred choice because it supports transmission over much greater distances than multimode fiber or copper cabling. In practical A+ Core 1 scenarios, candidates should recognize that copper Ethernet cabling such as Cat 6 is generally limited to 100 meters, while fiber is used for backbone and interbuilding links. Single-mode fiber specifically minimizes modal dispersion, which is why it is used for long-range, high-bandwidth connections. This aligns with common networking best practices and standard cabling guidance from Ethernet and structured cabling documentation.
- A. Correct.
Correct. Single-mode fiber is designed for long-distance communication and supports high bandwidth over several kilometers by using a very small core that allows light to travel in a single path. This reduces modal dispersion, making it the best choice for a 6 km interbuilding connection.
- B. Incorrect.
Incorrect. Multimode fiber is commonly used for shorter-distance runs within buildings or campuses, but it is not the best choice for a 6 km link. Because light travels along multiple paths in multimode fiber, modal dispersion increases over distance and limits its practical range compared with single-mode fiber.
- C. Incorrect.
Incorrect. Cat 6 twisted-pair copper is typically limited to 100 meters for standard Ethernet runs. A 6 km connection is far beyond copper Ethernet distance limitations, so this option would not meet the requirement without additional active equipment.
- D. Incorrect.
Incorrect. RG-6 coaxial cable is used for applications such as cable television, broadband modem connections, and some video distribution. It is not the standard or appropriate medium for a high-speed 6 km campus backbone network link.