An ICT distribution designer installed a 50/125 mm/1300 nm fiber optic cable from Building A to identical Building B with a distance of 600 m (1968 ft). At Building B, the designer fusion splices…

Question

Options

• A2.95 dB
• B3.40dB
• C3.90 dB
• D4.35 dB

• A
  8% (5)
• B
  14% (9)
• C
  73% (46)
• D
  5% (3)

Explanation

Option C (3.90 dB) is correct because it accurately applies the standard TIA/EIA-568 loss values for each component: the 1400 m of total fiber (600 m + 800 m) at 1.5 dB/km for 50/125 µm at 1300 nm yields 2.10 dB; one fusion splice adds 0.30 dB; and two SC connectors (one at each building endpoint) at 0.75 dB each add 1.50 dB - summing to exactly 3.90 dB.

Why the distractors are wrong:

• A (2.95 dB) - uses understated component values, likely applying too-low connector or splice losses
• B (3.40 dB) - swaps the correct SC connector value (0.75 dB) for 0.50 dB, which applies to LC connectors, not SC
• D (4.35 dB) - inflates the fusion splice loss (using ~0.75 dB instead of 0.30 dB), confusing fusion splice loss with mechanical splice loss

Memory tip: Think "SC = ¾" - SC connectors cost 0.75 dB each. Fusion splices are fast and clean at 0.30 dB, while 50/125 µm fiber at 1300 nm runs at 1.5 dB/km. Identify every component (fiber, splices, connectors), plug in the right standard value, and sum - that's all a loss budget is.

No community discussion yet for this question.