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ETA · Last updated November 2026

ETA Broadband Fiber Installer (BFI): free practice test

BFI is ETA's stand-alone certification for technicians installing FTTx networks at the physical layer, with a working knowledge of passive optical networks and OTDR use. The written exam has 75 questions in 2 hours with a 75% pass mark, across 15 competency areas from single-mode fiber and cables to splitters, splicing and testing. A hands-on course at an ETA-approved school is required first; this prep covers only the written exam.

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About the ETA BFI exam

BFI is ETA's stand-alone certification for technicians installing FTTx networks at the physical layer, with a working knowledge of passive optical networks and OTDR use. The written exam has 75 questions in 2 hours with a 75% pass mark, across 15 competency areas from single-mode fiber and cables to splitters, splicing and testing. A hands-on course at an ETA-approved school is required first; this prep covers only the written exam.

What's on the exam

ETA BFI
Light, Wavelengths and Active Devices
7 key facts
Single-Mode Fiber Types and FTTx Terms
7 key facts
FTTx Cables and Installation
8 key facts
Connectors and Endface Care
7 key facts
Splicing, Closures and Hardware
7 key facts
PON Architecture, Splitters and Power Budgets
7 key facts
OTDR and Field Testing
8 key facts
Safety for Broadband Fiber Work
6 key facts

Each branch is a topic in the official outline. Members see every key fact on the full mind map. Read the free study guide →

How to pass the ETA BFI exam

  • PON numbers carry many marks: 1490 nm down, 1310 nm up and 1550 nm video for GPON, and theoretical splitter losses of 3, 6, 9, 12 and 15 dB for 1:2 to 1:32.
  • ETA's BFI list names many standards: ITU-T G.652, G.655, G.657, G.671 and L.301, Telcordia GR-20 and GR-765, TIA-568, TIA-598 and TIA-758. Know what each covers rather than memorizing clause text.
  • Practise OTDR trace reading: reflective versus non-reflective events, gainers, ghosts, dead zones and splitter steps, and why you test both directions and two wavelengths.
  • 75 questions in 2 hours is 96 seconds each and you need 75%. BFI is the prerequisite for BFT, so build the foundations properly now.

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Create a free account after the test: your score by topic, a mistakes bank, the complete study notes for the first topic, flashcards and the RCDD Numbers & Formulas Sheet.

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What's in the premium ETA BFI prep

Premium ETA BFI prep is studied one topic at a time. Each step starts with that topic's key notes and flashcard deck, then its own question sets of 25, so you master one topic before you move to the next. When every topic is strong, the 6 full mock exams show you're ready.

3,000practice questions, every answer explained
6full-length mock exams, 75 questions each, timed
800flashcards with spaced repetition, sorted by topic
60comprehensive key notes across 8 topics

Your step-by-step study path

  1. 1
    Light, Wavelengths and Active Devices8 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Notes free with an account
  2. 2
    Single-Mode Fiber Types and FTTx Terms8 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  3. 3
    FTTx Cables and Installation8 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  4. 4
    Connectors and Endface Care8 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  5. 5
    Splicing, Closures and Hardware7 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  6. 6
    PON Architecture, Splitters and Power Budgets7 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  7. 7
    OTDR and Field Testing7 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  8. 8
    Safety for Broadband Fiber Work7 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  9. Final step: 6 full mock exams75 questions each, timed like test day. Pass them, then book your exam.
    Premium
Free with an account

Read the complete ETA BFI study notes for “Light, Wavelengths and Active Devices”

Our first full set of comprehensive notes, about 12 minutes of reading: Wavelengths in FTTx · Light sources and safety classes · dB and dBm · Reflections and receivers, a worked exam example, the traps examiners use and a one-minute recap. Create a free account to read it and see how premium notes work before you decide.

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Study tools included

3,000 practice questions

3,000 exam-style questions per exam, organized topic by topic in sets of 25. Every answer explained, with the rule it comes from.

6 full mock exams

6 full-length timed mock exams per exam, with real question counts and time limits, so test day feels like practice day.

Exam Readiness Score

One 0 to 100 number that tells you when you're ready to book. Reach 80 and you're covered by our Pass Guarantee.

800 flashcards + spaced repetition

800 flashcards per exam, in a deck for each topic, that come back right before you'd forget them. Five minutes a day keeps every number fresh.

60 comprehensive key notes

60 key notes per exam, split across its topics and each explained in full: the concepts, worked exam examples, the traps examiners use and a quick recap. Your first set is free with an account.

Mind maps

See the whole exam on one screen: every topic and the facts under it.

Sample questions with answers

These are the questions in the free test above, with answers. Try the test first. You'll learn more by getting some wrong.

1. A GPON drop also carries an RF video overlay. Which wavelengths carry downstream data, upstream data and the video signal?
Answer: 1490 nm down, 1310 nm up, 1550 nm video. In GPON (ITU-T G.984) the OLT sends data downstream at 1490 nm, ONTs send upstream at 1310 nm, and an RF video overlay uses 1550 nm. All three share one fiber through WDM filters. EPON uses the same 1490/1310 nm pair.
2. An MDU riser and hallway install will route drop fiber around tight corners and staples. Which fiber type is the best match?
Answer: ITU-T G.657 bend-insensitive single-mode fiber. G.657 fibers are designed for small bend radii (about 10 mm for A1, 7.5 mm for A2 and 5 mm for B3) and are compatible with G.652.D for splicing. G.652.D needs larger bends, G.655 is a long-haul DWDM fiber, and multimode is not used in PON.
3. A high-count microduct cable uses fibers with 200 µm coating instead of 250 µm. What does the smaller coating change?
Answer: Cable size shrinks while the 125 µm glass stays splice-compatible. Reduced-coating fiber keeps the standard 125 µm cladding and the same optical properties, so it splices to 250 µm fiber, but more fibers fit in a smaller cable for microducts. Coating is outside the cladding and plays no part in guiding light.
4. A crew will winch a drop cable rated 1335 N (300 lbf) through conduit using a winch set up for 2670 N (600 lbf) feeder cable. What should they add?
Answer: A breakaway swivel or tension limit set below the drop cable's rating. The pull must never exceed the drop cable's rated tension, so use a breakaway swivel or set the winch's tension limit below 300 lbf. Lubricant reduces friction but doesn't protect against overload, and pulling on the fibers instead of the strength members breaks them.
5. Sheath marks show 5,000 ft of stranded loose tube cable between two splice closures, but the OTDR measures about 5,090 ft of fiber between the same splices. What is the most likely explanation?
Answer: Helical lay makes each fiber longer than the sheath, plus slack. In stranded loose tube cable the tubes spiral around the central member and fibers sit loosely in the tubes, so fiber length exceeds sheath length; slack loops in closures add more. An index setting error can also shift distance, so allow for both when locating faults from OTDR readings.
6. Why do FTTx networks normally use APC connectors at the OLT, splitters and ONTs?
Answer: The 8° angle gives very low reflectance, which PON lasers and RF video need. Angled physical contact sends reflected light out of the core, giving reflectance around -65 dB or better. Reflections degrade lasers and especially analog RF video at 1550 nm. Insertion loss is similar to UPC, and APC endfaces still need inspection and cleaning.
7. Two clean, well-polished connectors mate perfectly, yet the pair shows slightly higher loss than expected. One fiber's MFD is noticeably larger than the other's. What kind of loss is this?
Answer: Intrinsic loss from the fibers themselves; cleaning won't fix it. Intrinsic losses come from differences in the fibers, such as mode field diameter, core size or concentricity, and cleaning or re-seating can't remove them. Extrinsic losses come from the connection: dirt, gaps, offset or angle. Bidirectional OTDR testing averages out the apparent gain or loss MFD mismatch causes.
8. A fusion splicer reports a cleave angle of 2.8° on one fiber. What should the technician do?
Answer: Re-cleave, checking the cleaver blade and that the fiber is clean. A poor cleave angle causes high splice loss and weak splices; splicers flag angles above their set limit, commonly around 1°. Strip, clean and re-cleave, and rotate or replace the blade if bad cleaves repeat. Index matching gel is for mechanical splices, not fusion splices.
9. In a centralized-split GPON design, where are the 1:32 splitters usually housed?
Answer: In a fiber distribution hub (FDH) between the feeder and distribution cables. A centralized design places splitters in an FDH cabinet in the field: one feeder fiber in, 32 distribution fibers out toward the homes. MSTs and fiber access terminals connect drops nearer the homes, and distributed (cascaded) designs may put a second stage there. The OLT and ONT are active ends, not splitter locations.
10. A distributed-split design uses a 1:4 splitter in the hub, then 1:8 splitters in terminals. What is the total theoretical splitting loss to one home?
Answer: About 15 dB, the same as a single 1:32. Theoretical split loss is 10 log N: 1:4 is 6 dB and 1:8 is 9 dB, about 15 dB in total, the same as 1:32. Real splitters add some excess loss and each extra stage adds connectors or splices, so measured loss is a little higher, but there is no saving from cascading.
11. An OLT launches +3 dBm at 1490 nm. Measured losses are 7.2 dB (1:4 splitter) and 10.5 dB (1:8 splitter), with 12 km of fiber at 0.25 dB/km and 4 connectors at 0.5 dB each. What power reaches the ONT?
Answer: -19.7 dBm. Total loss = 7.2 + 10.5 + (12 x 0.25 = 3.0) + (4 x 0.5 = 2.0) = 22.7 dB, so the ONT receives +3 - 22.7 = -19.7 dBm. Forgetting the launch power gives -22.7 dBm, and skipping the fiber or connectors gives the higher readings. Compare the result with the ONT's sensitivity and overload.
12. A fusion splice reads -0.10 dB (a gainer) from end A and 0.36 dB from end B. What is the true splice loss?
Answer: 0.13 dB. Average the two directions: (-0.10 + 0.36) / 2 = 0.13 dB. A gainer appears when the fiber after the splice backscatters more light, for example because of a smaller MFD; the opposite direction overstates loss by the same amount. That is why acceptance tests are bidirectional.
13. A technician needs to OTDR-test a drop fiber on a PON that is carrying live customer traffic. Which approach does ITU-T L.301 (formerly L.41) support?
Answer: Test at 1650 nm in the U-band through a filtered OTDR port. L.301 sets aside the 1625 to 1675 nm U-band for in-service maintenance, so a 1650 nm OTDR with filters can test without disturbing 1310, 1490 and 1550 nm traffic, and filters at the ONT block the test light. Testing at a traffic wavelength would corrupt service.
14. A 3.5 km drop has a strong reflection at a patch panel at 1.05 km. The trace also shows a reflective spike at exactly 2.10 km, with no loss across it and no hardware there. What is it?
Answer: A ghost caused by the strong reflection at 1.05 km. A ghost appears at a multiple of the distance to a strong reflection and shows no loss across it, because no real event is there. Clean or replace the reflective connector, or use index matching at the launch end, and the ghost shrinks. A real break would show the trace dropping to noise.
15. A splicing crew must work in an underground vault after heavy rain. What is required before anyone enters?
Answer: Test the air for oxygen, flammable and toxic gases, and ventilate as needed. Vaults can be permit-required confined spaces, so test the atmosphere for oxygen, flammable gases and toxic gases from outside before entry and keep monitoring while people are inside, with ventilation and an attendant as required. Waiting doesn't prove the air is safe, and engine exhaust adds carbon monoxide.

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ETA BFI exam FAQ

How many questions are on the ETA BFI exam?

75 multiple-choice questions, with a time limit of 2 hours. Format: closed book; scratch paper and a non-programmable calculator are allowed. eta requires a broadband fiber installer course with hands-on training at an eta-approved school before the exam, so this prep covers only the written knowledge exam.

What is the passing score for ETA BFI?

75%.

How much does the ETA BFI exam cost?

US$155 for the exam, with one free retake within one year of the first sitting; course fees are set by the school. Certification term 4 years, with maintenance required. BICSI fees can change without notice, so confirm on bicsi.org before you apply.

Which languages is the ETA BFI exam offered in?

English. ETA does not list other languages for BFI; confirm with ETA or your school.

Where do I take the ETA BFI exam?

ETA-approved fiber training schools with an ETA Course Approval, which run the required BFI course and hands-on training; the written exam is proctored by an ETA Certification Administrator online (Trapeza) or on paper.

Is this ETA BFI practice test free?

Yes. The 15-question practice test on this page is free, with an explanation for every answer and no signup. A free account also unlocks the complete study notes for the first topic. The full ETA BFI prep is Premium at $147 a month for this exam.

What's in the premium ETA BFI prep?

3,000 practice questions organized topic by topic (Light, Wavelengths and Active Devices: 375; Single-Mode Fiber Types and FTTx Terms: 375; FTTx Cables and Installation: 375; Connectors and Endface Care: 375; Splicing, Closures and Hardware: 375; PON Architecture, Splitters and Power Budgets: 375; OTDR and Field Testing: 375; Safety for Broadband Fiber Work: 375), 6 full-length timed mock exams of 75 questions, 800 flashcards and 60 comprehensive key notes split across all 8 topics, plus a mistakes bank and the Readiness Score.

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Exam details are summarized from the official candidate information available in October 2026. BICSI changes formats and fees, so confirm with ETA International (Electronics Technicians Association), accredited by ICAC under ISO/IEC 17024 before you book. RCDDQuizBank is not affiliated with BICSI or Pearson VUE.

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