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ETA · Last updated November 2026

Fiber Optics Designer (FOD): free practice test

The FOD is ETA's design-level fiber certification, tied to a 40-hour course on optical LAN design: protocols, network layouts, cable and hardware selection, TIA-568 and TIA-942 compliance, NEC rules, fiber counts, testing and documentation. The 80-question, 2-hour knowledge exam needs 75% and follows ETA's 19-category competency list. ETA suggests FOI or FOT knowledge first but does not require it; this prep covers only the written exam.

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About the ETA Fiber Optics Designer (FOD) exam

The FOD is ETA's design-level fiber certification, tied to a 40-hour course on optical LAN design: protocols, network layouts, cable and hardware selection, TIA-568 and TIA-942 compliance, NEC rules, fiber counts, testing and documentation. The 80-question, 2-hour knowledge exam needs 75% and follows ETA's 19-category competency list. ETA suggests FOI or FOT knowledge first but does not require it; this prep covers only the written exam.

What's on the exam

ETA Fiber Optics Designer (FOD)
Fiber Theory, Sources and Fiber Types
7 key facts
Cable Selection and the NEC
7 key facts
Termination, Splicing and Hardware
7 key facts
Cross-Connects and TIA-568 Structured Cabling
7 key facts
Networks: Ethernet, Fibre Channel, Voice and Video
6 key facts
Data Center Cabling Design
7 key facts
Fiber Types, Counts and Routes
7 key facts
Testing and Loss Budgets
7 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 Fiber Optics Designer (FOD) exam

  • The FOD exam is broad: 19 competency categories reach from fiber physics to Ethernet, Fibre Channel, voice and security video. Don't over-study theory; protocol and design categories make up most of the list.
  • Practise design arithmetic: fiber counts with spares, panel and housing capacity, link loss budgets and margins. Write each step on scratch paper with a scientific calculator.
  • Learn the standards by role: TIA-568.0 generic, 568.1 commercial buildings, 568.3 fiber components, TIA-942 data centers, TIA-606 labeling, TIA-607 bonding, NEC Articles 770 and 800 for cable listing.
  • Know IEEE 802.3 multimode reach by fiber grade, and when a mode conditioning patch cord is needed. Distance limits drive many design answers.

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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 Fiber Optics Designer (FOD) prep

Premium ETA Fiber Optics Designer (FOD) 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, 80 questions each, timed
800flashcards with spaced repetition, sorted by topic
60comprehensive key notes across 8 topics

Your step-by-step study path

  1. 1
    Fiber Theory, Sources and Fiber Types8 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Notes free with an account
  2. 2
    Cable Selection and the NEC8 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  3. 3
    Termination, Splicing and Hardware8 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  4. 4
    Cross-Connects and TIA-568 Structured Cabling8 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  5. 5
    Networks: Ethernet, Fibre Channel, Voice and Video7 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  6. 6
    Data Center Cabling Design7 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  7. 7
    Fiber Types, Counts and Routes7 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  8. 8
    Testing and Loss Budgets7 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25
    Premium
  9. Final step: 6 full mock exams80 questions each, timed like test day. Pass them, then book your exam.
    Premium
Free with an account

Read the complete ETA Fiber Optics Designer (FOD) study notes for “Fiber Theory, Sources and Fiber Types”

Our first full set of comprehensive notes, about 15 minutes of reading: Theory a designer uses · Dispersion · Sources and modulation · Fiber types and launch conditions, 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 campus plans to run 1000BASE-LX switches over an existing 50/125 µm multimode backbone. What must the design include so the links work reliably?
Answer: Mode conditioning patch cords at the switch ports. A 1310 nm laser launched into the center of multimode fiber excites only a few modes and suffers differential mode delay, which closes the eye. A mode conditioning patch cord offsets the launch into the multimode core so many modes are filled evenly. Attenuators fix overload, not DMD.
2. A designer specifies a long single-mode link at a high bit rate. Chromatic dispersion from the directly modulated laser's chirp is limiting reach. Which source design addresses this?
Answer: A continuous laser with an external modulator. Directly modulating a laser shifts its wavelength slightly on each pulse (chirp), which broadens the spectrum and worsens dispersion. Running the laser continuously and modulating it externally, for example with a Mach-Zehnder modulator, keeps the linewidth narrow. LEDs and 850 nm VCSELs have far wider spectra or suit only short multimode links.
3. An unlisted outside plant fiber cable enters a building. The equipment room is 30 m (100 ft) from the point of entrance, and the cable is not in a raceway. Which design meets the NEC?
Answer: Splice it to listed cable in an enclosure within 15 m (50 ft). The NEC allows unlisted outside plant cable to run no more than 15 m (50 ft) inside a building from the point of entrance, ending in an enclosure, unless it runs in a permitted raceway such as rigid metal conduit. Being nonconductive does not remove the limit, because the concern is fire spread along the jacket.
4. A designer needs 432 fibers in one cable through a congested duct, with mass fusion splicing planned at both ends to save time. Which cable type fits best?
Answer: Ribbon cable (flat or rollable ribbon). Ribbon cables pack fibers densely and let 12 fibers be mass fusion spliced in one step, which saves hours on high fiber counts. Rollable ribbon fits even smaller ducts. Tight-buffered and breakout cables are far larger per fiber and must be spliced one fiber at a time.
5. A 144-fiber loose tube cable from outside enters an equipment room, where every fiber must end on LC connectors. Which termination method gives the lowest loss and the fastest field work?
Answer: Fusion splicing factory-terminated LC pigtails. Pigtail splicing joins each bare fiber to a factory-polished pigtail with a fusion splice, giving low loss, low reflectance and consistent endfaces, and it is quick for high fiber counts. Fanout kits with field-polished connectors work but are slower and more variable. Mechanical splices add reflective joints.
6. A campus design will carry analog RF video over single-mode fiber alongside data. Which connector finish should the designer specify for the video links?
Answer: APC, for the lowest back reflection. Analog RF video is very sensitive to back reflection, which adds noise and distortion. APC connectors use an 8° angle that sends reflected light into the cladding, giving the lowest reflectance. UPC is fine for most digital links, but insertion loss is not the deciding factor here.
7. A main cross-connect needs 288 fibers terminated now plus 50% growth. Each housing holds 12 adapter panels of 12 fibers. How many housings are needed?
Answer: 3. Total fibers = 288 × 1.5 = 432. Each housing holds 12 × 12 = 144 fibers. 432 ÷ 144 = 3 housings. Sizing only for today's 288 fibers gives 2, which leaves no room for the growth the design calls for.
8. In a centralized optical fiber cabling design, a work area outlet is 260 m from the centralized cross-connect, counting horizontal and backbone cabling. The fibers are spliced in the telecommunications room. Does this meet TIA-568.1?
Answer: Yes; splice or interconnect designs may run up to 300 m. TIA-568.1 allows centralized optical fiber cabling to reach 300 m from the work area to the centralized cross-connect when a splice or interconnect is used in the telecommunications room. The 90 m figure applies to pull-through cables, which run continuously with no splice.
9. A university is designing security video for 200 cameras spread across six large buildings and wants to keep backbone fiber counts low. Which design fits best?
Answer: Distributed backbone with video electronics in each building. A distributed backbone places multiplexers or switches in each building, so a few backbone fibers carry many cameras: lower fiber count, more electronics, well suited to large networks. Centralized cabling raises fiber count and lowers electronics, which suits small networks. Copper home runs cannot reach across a campus.
10. A storage network must let any server reach any storage array at full port bandwidth, with room to scale beyond a hundred devices. Which Fibre Channel topology fits?
Answer: Switched fabric (FC-SW). A switched fabric connects every device through Fibre Channel switches, giving any-to-any connections at full bandwidth and the largest scale. An arbitrated loop shares bandwidth among up to 127 ports, and point-to-point links only two devices. Token-passing rings are not a Fibre Channel topology.
11. A data center designer wants a consolidation point under the raised floor between the horizontal distribution area and equipment cabinets, to make moves easier. Under TIA-942, which space is this, and what may it not contain?
Answer: Zone distribution area; no cross-connects or active equipment. The zone distribution area is an optional interconnect or consolidation point in the horizontal cabling between the HDA and the EDA. TIA-942 bars cross-connects and active equipment there. The MDA holds the main cross-connect, and the entrance room is where carrier circuits arrive.
12. After a data center duplex fiber link is installed, the switches show no link. Swapping the two LCs in the duplex clip at one end brings the link up. What did the design or installation get wrong?
Answer: Polarity: transmit was not mapped to receive. Each fiber must connect a transmitter at one end to a receiver at the other. When both fibers land transmit-to-transmit, swapping the pair at one end corrects it, which proves polarity was wrong. A consistent polarity method (A, B or C in TIA-568.3) across trunks, cassettes and patch cords avoids this.
13. A backbone design serves 8 telecommunications rooms. Each needs 6 fibers for current applications, and the design adds 100% spare. How many backbone fibers are needed in total?
Answer: 96. Each room needs 6 fibers plus 100% spare, so 12 fibers, which matches a standard 12-fiber buffer tube or subunit. 8 rooms × 12 = 96 fibers. 48 leaves out the spare, and 72 adds only 50%.
14. A 2.5 km single-mode backbone at 1310 nm has 4 mated connector pairs and 2 splices. Using 0.5 dB/km, 0.75 dB per pair and 0.3 dB per splice, what margin remains if the transceiver power budget is 6.2 dB?
Answer: 1.35 dB. Link loss = 2.5 × 0.5 + 4 × 0.75 + 2 × 0.3 = 1.25 + 3.00 + 0.60 = 4.85 dB. Margin = 6.2 − 4.85 = 1.35 dB. Leaving out the splices gives 1.95 dB, and counting only the two end connector pairs gives 2.85 dB.
15. Two contractors measured the same multimode link with different light sources and got results 0.6 dB apart. What should the designer specify so loss results are consistent?
Answer: A launch meeting Encircled Flux requirements. Multimode loss depends on how the source fills the modes; an overfilled launch reads higher than a lightly filled one. Encircled Flux (IEC 61280-4-1, adopted in TIA-526-14-B) tightly defines the launch, so different testers agree within a small tolerance. A 1550 nm OTDR doesn't test multimode links.

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ETA Fiber Optics Designer (FOD) exam FAQ

How many questions are on the ETA Fiber Optics Designer (FOD) exam?

80 questions on the knowledge exam, with a time limit of 2 hours. Format: closed book. eta allows scratch paper and a non-programmable scientific calculator. eta publishes only the question count, not the item types; our practice uses 4-option single-best-answer questions. eta lists the fod as hands-on required: the course, its case-study work and a skills exam from an eta-approved school come first, so this prep covers only the written knowledge exam.

What is the passing score for ETA Fiber Optics Designer (FOD)?

75% (60 of 80 questions).

How much does the ETA Fiber Optics Designer (FOD) exam cost?

US$155 exam fee (ETA list price); the 40-hour course is priced separately by the school. One free retake within one year of the first attempt. 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 Fiber Optics Designer (FOD) exam offered in?

English. ETA does not list other language versions for this exam; confirm with ETA or your school.

Where do I take the ETA Fiber Optics Designer (FOD) exam?

An ETA-approved school with an ETA Course Approval, after the 40-hour ETA Fiber Optics Designer course and its skills exam; the knowledge exam is proctored by an ETA Certification Administrator, online in ETA's Trapeza system or on paper.

Is this ETA Fiber Optics Designer (FOD) 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 Fiber Optics Designer (FOD) prep is Premium at $147 a month for this exam.

What's in the premium ETA Fiber Optics Designer (FOD) prep?

3,000 practice questions organized topic by topic (Fiber Theory, Sources and Fiber Types: 375; Cable Selection and the NEC: 375; Termination, Splicing and Hardware: 375; Cross-Connects and TIA-568 Structured Cabling: 375; Networks: Ethernet, Fibre Channel, Voice and Video: 375; Data Center Cabling Design: 375; Fiber Types, Counts and Routes: 375; Testing and Loss Budgets: 375), 6 full-length timed mock exams of 80 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); certification programs accredited by ICAC to ISO/IEC 17024 before you book. RCDDQuizBank is not affiliated with BICSI or Pearson VUE.

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