FOA CFOS/H cheat sheet

Single-mode fiber (SMF) carries one propagation mode at 1310/1550 nm with a core near 8-10 µm; multimode fiber (MMF) carries many modes with a 50 or 62.5 µm core and is used with 850 nm VCSELs.

Standard SMF attenuation is about 0.35 dB/km at 1310 nm and 0.20-0.25 dB/km at 1550 nm; MMF OM3/OM4 is roughly 3.0-3.5 dB/km at 850 nm.

Bend-insensitive SMF (ITU-T G.657) tolerates a 5-10 mm bend radius versus 30 mm for standard G.652.D, which is decisive for in-wall and corner routing.

Home architectures: point-to-point (one fiber per subscriber) versus PON (GPON 2.5/1.25 Gbit/s, XGS-PON 10/10 Gbit/s) sharing a single feeder via splitters, typically 1:32 or 1:64.

FTTH reference points: OLT at the central office, ODN with splitters and closures, ONT/ONU at the home; the drop cable runs from the nearest splitter or access terminal to the subscriber.

Loss budget formula: link loss = sum of connector pairs × connector loss + splice count × splice loss + fiber length × attenuation + splitter insertion loss + margin (typically 3 dB).

Splitters are bidirectional and loss is fixed by ratio: a 1:2 splitter loses about 3.5 dB, 1:4 about 7.2 dB, 1:8 about 10.5 dB, 1:32 about 17 dB (per splitter stage).

Wavelength plan: 1310 nm upstream / 1490 nm downstream for GPON, 1270 nm upstream / 1577 nm downstream for XGS-PON, with 1550 nm reserved for RF video overlay.

Reflectance matters: APC ferrules (8° angled) return about -60 dB and mate only with APC; UPC returns about -50 dB; mixing APC and UPC causes high loss and permanent damage.

Indoor drop cable types: 2.0 mm or 3.0 mm simplex/duplex riser-rated cable, flat drop with FRP strength members, and LSZH jacket for low smoke and halogen in dwellings.

Connector families: SC (2.5 mm ferrule, square push-pull), LC (1.25 mm ferrule, small form factor, common at ONT), plus field-installable and fusion-splice-on connectors.

Polish codes: UPC (blue) for most home links; APC (green) for PON drops and RF video; PC (black/beige) is legacy. Endface geometry is defined by IEC 61755-3-1/3-2.

Typical mated-pair insertion loss: 0.3 dB for good factory connectors, 0.5 dB maximum per TIA-568; field-installable connectors often 0.5-0.75 dB.

Hardware: fiber outlet/faceplate with SC or LC adapter, splice-on pigtail inside a wall box, small wall-mount enclosure (ONT box) or slack storage cassette for 1-2 m of spare fiber.

Minimum bend radius rule: 10× cable outer diameter under load, 20× unloaded for standard cable; G.657 drop cable permits tighter radii but never below manufacturer's stated minimum.

Tight-buffered indoor cable uses 900 µm buffer over 250 µm coating; loose-tube and flat drop use 250 µm fiber with aramid or FRP strength members for tensile load.

Maximum tensile rating is typically 50-100 N short-term and 25-50 N long-term for indoor drop cable; the strength member, not the fiber, carries the load.

Media converters, SFP/SFP+ transceivers and ONTs must match fiber type and wavelength; a 1310 nm SMF SFP will not work over MMF, and 850 nm MMF optics will not work over SMF.

Never exceed the cable's minimum bend radius: a kink creates macrobend loss that is visible at 1310/1550 nm and can permanently damage the fiber.

Pull tension must stay below the short-term rating; use a swivel and pull grip on the jacket/strength members, never on bare fiber, and avoid jerking.

Route away from electrical power cables and keep separation per local code; do not staple fiber cable, and use cable clips or conduits sized for future additions.

Firestopping: seal penetrations between floors and fire-rated walls with listed materials; use plenum-rated (OFNP) cable in air-handling spaces and riser-rated (OFNR) in vertical shafts.

Leave slack: 1-3 m at the ONT/outlet and a service loop at the entry point or enclosure to allow re-termination and future splicing.

Prepare the fiber by stripping the jacket and buffer, cleaning with lint-free wipes and 99% isopropyl alcohol, then cleaving with a good cleaver; a bad cleave angle causes high splice or connector loss.

Fusion splicing a field connector or pigtail: align cleaved ends, arc-fuse, then protect with a splice protector sleeve in the splice tray; typical splice loss 0.1 dB or less.

Label both ends of every fiber with the destination and port; record cable routes and lengths in an as-built drawing for later troubleshooting.

Test after installation and before closing walls: verify continuity, loss and polarity (A-to-B, B-to-A for duplex) and store the results with the as-built documentation.

Visual fault locator (VFL): a red laser that shows breaks, tight bends and bad connectors as a glowing point; it does not measure loss.

Optical loss test set (OLTS): a light source and power meter at the link's actual wavelength; result in dB compared with the calculated loss budget.

Reference method matters: one-cord reference for a link with one connector at each end; two-cord or three-cord reference when testing patch cords or mated pairs.

OTDR locates events by distance using backscatter; set the correct IOR, wavelength and pulse width; a launch cable (100-300 m) is needed to see the near-end connector.

Inspection: use a video inspection probe; IEC 61300-3-35 defines endface acceptance zones (core, cladding, contact, ferrule) and pass/fail criteria for scratches, pits and contamination.

Clean before every mating: dry one-click cleaners or lint-free wipes with alcohol; a dirty endface is the most common cause of high loss and permanent damage.

Symptom rules: high loss with good continuity suggests contamination, macrobend or a bad splice; no light at all suggests a break, wrong port or reversed polarity.

Total internal reflection failures from tight bends show up as loss that disappears when the cable is straightened; test at 1550 nm for sensitivity to bends.

Record results per TIA-568 or IEC 61280 style reports: wavelength, direction, reference method, measured loss and pass/fail against the link budget.

Define the service: GPON/XGS-PON FTTH, point-to-point active Ethernet or in-home fiber backbone; the choice sets fiber count, splitter loss and ONT placement.

Capacity planning: reserve at least one spare fiber or conduit per drop; duplex LC for a single link, plus one spare strand for future 10G or a second service.

Loss budget example: 1:32 splitter (17 dB) + 20 dB fiber/connector/splice loss leaves little margin against a typical 28 dB GPON Class B+ budget, so keep connector count low.

ONT placement rules: near the entry point, on a power outlet, within Wi-Fi coverage needs, with ventilation and access for testing; avoid basements and metal enclosures.

Project phases: site survey, design and bill of materials, permits and landlord approval, installation, testing and acceptance, as-built handover.

Bill of materials must include cable length with 10% waste, connectors, adapters, enclosures, splice protectors, fasteners, labels and test equipment.

Schedule and risk: lead times for ONT/transceivers, access to walls and risers, and coordination with the ISP's activation window are the usual critical path items.

Acceptance criteria: measured loss within the calculated budget, correct polarity, labeled ports, documented test results and a signed handover with warranty terms.

Standards to cite: TIA-568 for premises cabling, IEC 61755 for connector interfaces, ITU-T G.652/G.657 for fiber, and local electrical and fire codes for routing.

Treat the home fiber plant as a project with a single owner: one document set covering topology, cable schedule, loss budget, test results and as-built drawings.

Topology decision rule: star from a central enclosure to each outlet is easier to test and upgrade than daisy-chained or spliced-through outlets.

Budget the loss before buying: sum splitter, connector, splice and fiber loss plus 3 dB margin; if the result exceeds the equipment budget, reduce splitter ratio or connector count.

Procurement rule: order connectors, adapters and pigtails from the same polish family (all UPC or all APC) to avoid incompatible mating.

Change control: any added splice, extra adapter or longer route requires a re-check of the loss budget and an updated test record.

Handover package: as-built topology, cable and port labels, test reports per link, equipment list with serial numbers, and contact for the ISP activation.

Risk register items: hidden existing cabling, fire-rated penetration approval, power availability at the ONT, and tenant/landlord permission for wall penetrations.

Quality gate before closing walls: continuity, polarity, loss test and endface inspection passed and recorded; otherwise rework cost rises sharply after finishing.

Choose connector polish by system: APC for PON drops and RF video where reflectance matters; UPC for general data links; never mate APC to UPC.

Choose fiber type by distance and optics: SMF for any run over a few hundred meters or for PON; MMF OM3/OM4 only for short in-home backbone with matching 850 nm optics.

Cable jacket rating follows the space: OFNP plenum for air-handling ceilings, OFNR riser for vertical shafts, LSZH for general indoor low-smoke requirements.

Field-installable connectors trade speed for loss (often 0.5-0.75 dB) versus factory pigtails fusion-spliced (about 0.1-0.3 dB) but need a splicer and tray space.

Enclosure sizing rule: allow space for at least 1 m of slack per fiber, splice trays, adapters and the ONT, with a removable cover for testing access.

Adapter and faceplate choices: SC or LC keystone adapters must match the connector family; hybrid adapters exist but add a mating point and loss.

Transceiver matching: check wavelength, fiber type, reach and connector; a 1550 nm SMF SFP+ will not run over OM3 MMF beyond short distances.

Hardware fasteners and clips must not compress the cable; use radius-controlled clips and conduit bends that respect the cable's minimum bend radius.

Sequence: survey, route and pull cable, leave slack, terminate or splice, clean and inspect endfaces, test loss and polarity, then close and label.

Pull with the strength members, keep tension under the short-term rating, and never exceed the bend radius at corners, entries and enclosure loops.

Cleave quality drives results: a cleaver in good condition and a clean fiber give splice loss near 0.1 dB; a chipped cleave causes high loss or a failed splice.

Inspection before mating: IEC 61300-3-35 zones; reject endfaces with contamination in the core zone and re-clean or re-terminate.

Test with an OLTS at the system wavelength using a documented reference method; compare measured loss with the calculated budget plus margin.

Use a VFL for quick fault finding on breaks and macrobends; use an OTDR with a launch cable when the fault location matters.

Record every link: identifier, wavelength, direction, reference method, loss and pass/fail; store with the as-built drawing for acceptance.

Common failures: dirty endface, APC/UPC mismatch, tight bend, reversed duplex polarity, wrong transceiver wavelength, and exceeded splitter budget.

Scope definition: number of outlets, services (internet, TV, voice), ONT location, backbone type and whether fiber reaches each room or only a central point.

Design deliverables: topology drawing, cable schedule with lengths, loss budget per link, bill of materials, test plan and acceptance criteria.

Scheduling rule: order long-lead items (ONT, transceivers, enclosures) first and align the ISP activation with the tested and labeled plant.

Cost drivers: cable length and jacket rating, connector type and count, splice labor, enclosure size, and wall/riser access work.

Permits and approvals: landlord or building management consent for penetrations, firestopping approval, and electrical code compliance for power at the ONT.

Acceptance gate: all links pass the loss budget, polarity is correct, labels match the as-built, and test reports are signed off before handover.

Handover contents: as-built drawings, cable and port labels, test reports, equipment serials, warranty and the ISP activation contact.

Post-handover: keep spare connectors, adapters and a cleaner on site, and record any change to splices or routes in the as-built document.

No signal: check transceiver wavelength and fiber type match, port assignment, polarity of duplex pairs, and whether the ONT is powered and registered.

High loss with continuity: suspect dirty or damaged endface, macrobend, poor splice, or an extra adapter; inspect and clean first, then re-test.

Intermittent link: look for a tight bend, a loose connector latch, a damaged patch cord, or a splice protector not seated in the tray.

VFL shows a bright glow at a tight bend or break; straighten or replace the cable and re-test the link loss.

OTDR event at a known distance: compare with the cable schedule to find the closure, splice or connector; a reflective spike is a connector, a non-reflective step is a splice or bend.

Loss budget check: if measured loss is near the calculated maximum, reduce connector count or splitter ratio before adding services.

Document the fault, the action and the new test result; repeat failures at the same point indicate a routing or hardware problem, not a cleaning problem.

Safety: never look into a fiber or connector; use a VFL only as intended and treat laser sources as hazardous even when invisible.

TIA-568 covers premises cabling: cable performance, connector loss limits, polarity and test procedures for customer-owned fiber.

IEC 61300-3-35 defines endface inspection zones and pass/fail criteria used with a video inspection probe.

IEC 61755 defines connector interface geometry including APC 8° angle and UPC physical contact.

ITU-T G.652.D is standard SMF; G.657.A1/A2 covers bend-insensitive fiber for tight indoor routing.

GPON and XGS-PON wavelength and splitter ratios are defined by ITU-T G.984 and G.9807 families; the loss budget class (B+, C+) sets the allowed ODN loss.

Fire codes require plenum (OFNP) or riser (OFNR) rated cable in the relevant spaces; LSZH jackets reduce smoke and halogen in dwellings.

Local electrical codes govern separation from power and grounding; fiber is non-conductive but metallic strength members must be bonded where required.

Acceptance documentation should cite the standard used for each test so the result is reproducible.

Reserve one spare fiber or conduit per drop; adding fiber after finishing walls is far more expensive than the spare strand.

Duplex LC is the common home backbone interface; a spare duplex pair supports a future 10G or a second service without re-cabling.

Splitter ratio trade-off: 1:32 saves feeder fiber but adds about 17 dB loss; 1:8 or 1:16 gives margin for longer drops and future upgrades.

Wavelength reuse: GPON uses 1310/1490 nm, XGS-PON uses 1270/1577 nm, and 1550 nm is reserved for RF video; plan filters and splitters accordingly.

Loss margin: keep at least 3 dB headroom in the design so aging, added connectors and repairs do not push the link out of budget.

Upgrade path: SMF with UPC/APC connectors and G.657 cable supports 10G and beyond without re-cabling; MMF limits future reach and speed.

Document capacity: record spare strands, unused splitter ports and conduit space in the as-built so future work starts from known data.

Test the spare strands at installation so they are proven ready for future activation.

Never look into a fiber end or an unmated connector; invisible infrared light at 1310/1550 nm can damage the retina.

Treat fiber scraps as sharps: use a labeled waste container, never leave cleaved ends on floors or in clothing.

Wear safety glasses when cleaving and splicing; a cleaved fiber can penetrate skin and break off.

Handle bare fiber with lint-free wipes and alcohol; skin oils and dust cause loss and permanent endface damage.

Do not exceed bend radius or pull tension; mechanical damage may not show immediately but degrades loss over time.

Use the correct jacket rating and firestopping; burning cable in a dwelling releases smoke and halogen unless LSZH is specified.

Keep laser sources and test equipment away from children and untrained occupants; label active fibers.

Dispose of alcohol wipes and fiber scraps per local rules; do not mix fiber waste with general refuse.

As-built drawing: topology, cable routes, enclosure and ONT locations, splitter positions and port assignments.

Cable schedule: cable ID, from/to, type, length, connector polish and number of splices per link.

Test report: link ID, wavelength, direction, reference method, measured loss, budget and pass/fail.

Labeling rule: both ends of every fiber and every adapter port labeled with destination and port number.

Equipment list: ONT, transceivers, enclosures, splitters and serial numbers for warranty and support.

Handover sign-off: owner acceptance, warranty terms, and the ISP activation contact and circuit ID.

Change log: any added splice, connector or route change recorded with a new test result.

Spares and consumables left on site: cleaners, adapters, patch cords and a spare connector kit.

Link loss = fiber attenuation × length + connector pairs × connector loss + splices × splice loss + splitter loss + margin.

Example: 500 m SMF at 0.35 dB/km = 0.18 dB; 2 connector pairs at 0.3 dB = 0.6 dB; 1 splice at 0.1 dB; 1:32 splitter 17 dB; margin 3 dB → about 20.9 dB.

GPON Class B+ allows 28 dB ODN loss; Class C+ allows 32 dB; check the splitter and fiber loss against the class before design.

Connector loss allowance per TIA-568 is 0.75 dB maximum per mated pair for field-terminated, 0.5 dB for factory.

Splice loss allowance is typically 0.1-0.3 dB per fusion splice; mechanical splices are higher and less reliable.

Bend loss becomes significant below the minimum bend radius and is worse at 1550 nm than at 1310 nm; test at 1550 nm for bend sensitivity.

Margin of 3 dB covers aging, repairs, temperature and added connectors; do not design to the exact budget.

Reduce loss by lowering splitter ratio, reducing connector count, or using factory pigtails instead of field-installable connectors.

OLTS: light source plus power meter; measure at the system wavelength and both directions for a full report.

Reference methods: one-cord for a simple link, two-cord for patch cords, three-cord when both ends need a reference connector; record which method was used.

VFL: red laser for breaks, macrobends and connector faults; shows a glow but gives no dB value.

OTDR: backscatter trace with distance; set IOR, wavelength and pulse width; use a launch cable to see the near-end connector.

Video inspection probe: endface image graded by IEC 61300-3-35 zones; clean and re-inspect before every mating.

Cleaning: dry one-click cleaner or lint-free wipe with 99% isopropyl alcohol; let dry before mating.

Continuity and polarity test: verify A-to-B and B-to-A for duplex links with a source and meter or a VFL pair.

Record results in a report with link ID, wavelength, direction, reference method, loss and pass/fail against the budget.

SMF G.652.D for standard runs; G.657.A1/A2 for tight indoor bends and in-wall routing.

MMF OM3/OM4 only for short backbone with 850 nm optics; check reach and transceiver compatibility.

Jacket rating: OFNP plenum for air-handling spaces, OFNR riser for vertical shafts, LSZH for low-smoke indoor use.

Connector: SC for robustness and legacy ONTs, LC for small form factor and high port density; match the ONT and patch panel.

Polish: UPC (blue) for data, APC (green) for PON and RF video; never mate APC to UPC.

Field-installable connectors for speed, fusion-spliced pigtails for lower loss and reliability.

Enclosure: wall box or ONT box with slack storage, splice tray and adapter panel; size for at least 1 m slack per fiber.

Adapters and faceplates must match the connector family; hybrid adapters add a mating point and loss.

Survey first: route, penetration points, power at the ONT, and existing cabling to avoid.

Pull cable with strength members, respect bend radius and tension, and leave 1-3 m slack at each end.

Terminate or splice, then clean and inspect every endface before mating.

Test continuity, polarity and loss at the system wavelength; compare with the calculated budget.

Fix faults before closing walls; rework after finishing is far more costly.

Label both ends and update the as-built drawing with routes and lengths.

Firestop penetrations and use the correct jacket rating for the space.

Handover with test reports, labels, equipment list and warranty terms.

No light: break, wrong port, reversed polarity, unpowered ONT or wrong transceiver wavelength.

High loss with continuity: dirty endface, macrobend, poor splice or extra adapter.

Intermittent link: loose connector latch, damaged patch cord, tight bend or unseated splice protector.

VFL glow at a point: break or tight bend; straighten or replace and re-test.

OTDR reflective spike: connector; non-reflective step: splice or bend; compare distance with the cable schedule.

Loss that changes when the cable is moved: macrobend or mechanical damage.

Loss at 1550 nm much higher than at 1310 nm: bend sensitivity; check routing.

Repeat failure at the same point: routing or hardware problem, not cleaning.

Single owner for the document set: topology, cable schedule, loss budget, test results and as-built.

Order long-lead items first: ONT, transceivers, enclosures, splitters.

Align ISP activation with a tested and labeled plant.

Cost drivers: cable length and jacket rating, connector count and type, splice labor, enclosure size, wall access.

Approvals: landlord consent, firestopping approval, electrical code compliance for ONT power.

Quality gate before closing walls: continuity, polarity, loss and endface inspection passed and recorded.

Acceptance: measured loss within budget, correct polarity, labels match as-built, signed test reports.

Handover: as-built, labels, test reports, equipment serials, warranty and ISP contact.

TIA-568: premises cabling performance, connector loss limits, polarity and test procedures.

IEC 61300-3-35: endface inspection zones and pass/fail criteria.

IEC 61755: connector interface geometry including APC 8° and UPC physical contact.

ITU-T G.652.D: standard SMF; G.657.A1/A2: bend-insensitive fiber.

ITU-T G.984 (GPON) and G.9807 (XGS-PON): wavelengths, splitter ratios and loss budget classes.

Fire codes: OFNP plenum, OFNR riser, LSZH for low smoke and halogen.

Local electrical codes: separation from power and bonding of metallic strength members.

Record the standard used for each test so results are reproducible.

Reserve one spare fiber or conduit per drop for future services.

Duplex LC backbone with a spare pair supports a future 10G or second service.

Splitter ratio trade-off: 1:32 saves feeder fiber but adds about 17 dB loss; 1:8 or 1:16 gives margin.

Wavelength plan: GPON 1310/1490 nm, XGS-PON 1270/1577 nm, 1550 nm for RF video.

Keep at least 3 dB design margin for aging, repairs and added connectors.

SMF with UPC/APC and G.657 cable supports 10G and beyond without re-cabling.

Record spare strands, unused splitter ports and conduit space in the as-built.

Test spare strands at installation so they are proven ready.

Never look into a fiber end or unmated connector; infrared light is invisible and hazardous.

Treat fiber scraps as sharps; use a labeled waste container.

Wear safety glasses when cleaving and splicing.

Handle bare fiber with lint-free wipes and alcohol; skin oils cause loss.

Do not exceed bend radius or pull tension; damage may appear later as loss.

Use the correct jacket rating and firestopping to avoid smoke and halogen release.

Label active fibers and keep test equipment away from untrained occupants.

Dispose of wipes and fiber scraps per local rules.

As-built drawing: topology, routes, enclosure and ONT locations, splitter positions, port assignments.

Cable schedule: ID, from/to, type, length, polish and splice count per link.

Test report: link ID, wavelength, direction, reference method, loss, budget and pass/fail.

Label both ends of every fiber and every adapter port.

Equipment list with serial numbers for warranty and support.

Handover sign-off: owner acceptance, warranty terms, ISP activation contact and circuit ID.

Change log for any added splice, connector or route change with a new test result.

Leave spares and consumables on site: cleaners, adapters, patch cords, connector kit.

Link loss = fiber attenuation × length + connector pairs × connector loss + splices × splice loss + splitter loss + margin.

Example: 500 m SMF at 0.35 dB/km = 0.18 dB; 2 connector pairs at 0.3 dB = 0.6 dB; 1 splice 0.1 dB; 1:32 splitter 17 dB; margin 3 dB → about 20.9 dB.

GPON Class B+ allows 28 dB ODN loss; Class C+ allows 32 dB.

Connector allowance: 0.75 dB maximum per mated pair field-terminated, 0.5 dB factory.

Splice allowance: 0.1-0.3 dB per fusion splice; mechanical splices are higher.

Bend loss is worse at 1550 nm than at 1310 nm; test at 1550 nm for bend sensitivity.

Keep 3 dB margin for aging, repairs, temperature and added connectors.

Reduce loss by lowering splitter ratio, reducing connector count or using factory pigtails.

OLTS: source plus power meter at the system wavelength, both directions for a full report.

Reference methods: one-cord, two-cord, three-cord; record which was used.

VFL: red laser for breaks and macrobends; no dB value.

OTDR: set IOR, wavelength and pulse width; use a launch cable to see the near-end connector.

Video inspection probe: grade endface by IEC 61300-3-35 zones; clean and re-inspect before mating.

Cleaning: dry one-click cleaner or lint-free wipe with 99% isopropyl alcohol; let dry.

Continuity and polarity: verify A-to-B and B-to-A for duplex links.

Report: link ID, wavelength, direction, reference method, loss and pass/fail against the budget.

SMF G.652.D for standard runs; G.657.A1/A2 for tight indoor bends.

MMF OM3/OM4 only for short backbone with 850 nm optics.

Jacket: OFNP plenum, OFNR riser, LSZH for low smoke and halogen.

Connector: SC for robustness, LC for small form factor and density; match the ONT.

Polish: UPC (blue) for data, APC (green) for PON and RF video; never mix.

Field-installable connectors for speed; fusion-spliced pigtails for lower loss.

Enclosure with slack storage, splice tray and adapter panel; size for 1 m slack per fiber.

Adapters and faceplates must match the connector family; hybrid adapters add loss.

Survey route, penetrations, power at the ONT and existing cabling first.

Pull with strength members, respect bend radius and tension, leave 1-3 m slack.

Terminate or splice, then clean and inspect every endface before mating.

Test continuity, polarity and loss at the system wavelength against the budget.

Fix faults before closing walls; rework after finishing is costly.

Label both ends and update the as-built drawing.

Firestop penetrations and use the correct jacket rating.

Handover with test reports, labels, equipment list and warranty.

No light: break, wrong port, reversed polarity, unpowered ONT or wrong transceiver wavelength.

High loss with continuity: dirty endface, macrobend, poor splice or extra adapter.

Intermittent link: loose latch, damaged patch cord, tight bend or unseated splice protector.

VFL glow: break or tight bend; straighten or replace and re-test.

OTDR reflective spike: connector; non-reflective step: splice or bend; compare distance with the cable schedule.

Loss that changes when the cable moves: macrobend or mechanical damage.

Loss worse at 1550 nm than 1310 nm: bend sensitivity; check routing.

Repeat failure at the same point: routing or hardware problem, not cleaning.

Single owner for topology, cable schedule, loss budget, test results and as-built.

Order long-lead items first: ONT, transceivers, enclosures, splitters.

Align ISP activation with a tested and labeled plant.

Cost drivers: cable length and jacket rating, connector count and type, splice labor, enclosure size, wall access.

Approvals: landlord consent, firestopping, electrical code for ONT power.

Quality gate before closing walls: continuity, polarity, loss and endface inspection recorded.

Acceptance: loss within budget, correct polarity, labels match as-built, signed test reports.

Handover: as-built, labels, test reports, equipment serials, warranty and ISP contact.

TIA-568: premises cabling performance, connector loss limits, polarity and test procedures.

IEC 61300-3-35: endface inspection zones and pass/fail criteria.

IEC 61755: connector interface geometry including APC 8° and UPC physical contact.

ITU-T G.652.D: standard SMF; G.657.A1/A2: bend-insensitive fiber.

ITU-T G.984 (GPON) and G.9807 (XGS-PON): wavelengths, splitter ratios and loss budget classes.

Fire codes: OFNP plenum, OFNR riser, LSZH for low smoke and halogen.

Local electrical codes: separation from power and bonding of metallic strength members.

Record the standard used for each test so results are reproducible.

Reserve one spare fiber or conduit per drop for future services.

Duplex LC backbone with a spare pair supports a future 10G or second service.

Splitter ratio trade-off: 1:32 saves feeder fiber but adds about 17 dB loss; 1:8 or 1:16 gives margin.

Wavelength plan: GPON 1310/1490 nm, XGS-PON 1270/1577 nm, 1550 nm for RF video.

Keep at least 3 dB design margin for aging, repairs and added connectors.

SMF with UPC/APC and G.657 cable supports 10G and beyond without re-cabling.

Record spare strands, unused splitter ports and conduit space in the as-built.

Test spare strands at installation so they are proven ready.