In a RFI, an ICT distribution designer instructs the contractor to test all the fibers In a PON Installation. Which of the following testing requirements does the designer include?

Question

Options

• AUni-directional 850 nm and 1300 nm
• BBi-directional 850 nm and 1300 nm
• CUni-directional 1310 nm and 1550 nm
• DBi-directional 1310 nm and 1550 nm

• B
  7% (1)
• C
  13% (2)
• D
  80% (12)

Explanation

PON (Passive Optical Network) installations use single-mode fiber, which operates at 1310 nm and 1550 nm - these are the wavelengths that match real PON traffic (upstream and downstream respectively), making bi-directional testing at those wavelengths the correct requirement. Options A and B are wrong because 850 nm and 1300 nm are multimode fiber test wavelengths; PON does not use multimode fiber, so testing at those wavelengths would be meaningless for a PON installation. Option C uses the correct wavelengths but specifies uni-directional testing, which is insufficient - since PON carries traffic in both directions on the same fiber strand, a fault in either direction would affect service, so the designer must require testing in both directions to fully qualify each fiber. Option D captures both requirements correctly: the right wavelengths for single-mode fiber and the right test direction to verify the complete optical path.

Memory tip: PON = single-mode = 1310/1550 nm, and because PON is a two-way system (upstream and downstream share one fiber), testing must also go two ways - bi-directional.

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