FOA CFOS/O flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Outside plant definition

All cable, enclosures, and hardware installed outdoors between the central office or headend and subscriber premises, exposed to weather, moisture, and physical hazards.

Direct-buried cover depth

Typical minimum cover for optical cable is about 24 inches under ordinary soil, deeper under roads and cultivated fields; always confirm against the governing local code.

Installation bend radius rule

Keep bends at or above 10 times the cable outside diameter while pulling and 20 times the OD after installation; tighter bends cause macrobend loss and possible fiber damage.

Trench backfill cushion

Place smooth sand or select backfill around the cable and a warning tape above it, so rocks do not crush the cable and future excavators can locate the route.

Duct proofing

Before pulling cable, run a mandrel or brush through the duct to confirm it is clear, round, and continuous; remove debris and verify pull points and drainage.

Loose-tube OSP cable

Cable with fibers inside gel-filled or dry water-blocked buffer tubes stranded around a central strength member; the standard construction for high-count outside plant runs.

Ribbon fiber cable

Cable containing bonded fiber ribbons that are mass fusion spliced as a unit; a 12-fiber ribbon spliced at once greatly reduces time in high-count plants.

Armored OSP cable

Cable with a corrugated steel or aluminum tape layer for rodent, crush, and moisture protection; common in direct-buried and duct installations needing mechanical protection.

Splice closure requirements

Closures must be watertight, re-enterable, and matched to the cable sheath and strength-member type; metallic armor or members require bonding and grounding at the closure.

12-fiber color code

The standard buffer tube and fiber sequence is blue, orange, green, brown, slate, white, red, black, yellow, violet, rose, aqua; memorize it for identification and splicing.

Hardened outdoor connector

A sealed, weatherproof connector and adapter pair used at FTTx drop terminals and ONT connections, protecting the ferrule end face from moisture and contamination.

Pull tension monitoring

Continuously measure tension during a pull and keep it below the manufacturer's rated maximum; a breakaway link or tension meter physically enforces the limit.

Pulling swivel purpose

A swivel attaches the pull rope to the cable eye so the cable does not twist as tension is applied, preventing jacket damage and fiber stress.

Cable pulling lubricant

A lubricant compatible with the cable jacket and duct, applied along the run rather than only at the entry, to lower friction and pulling tension.

Air-blowing installation

Jetting cable into duct with compressed air and a feed unit; it suits long duct and microduct runs and requires clean, continuous duct with gentle offsets.

Duct fill ratio

The ratio of cable cross-section to duct inside diameter; jetting commonly targets roughly 50 to 70 percent fill, with exact limits from cable and duct data.

Sidewall pressure limit

Force concentrated on the jacket at a bend; sharp corners can exceed limits even when total tension is within spec, so use large-radius bend shoes.

Slack coil purpose

Extra cable coiled at handholes, closures, and building entrances so future re-splicing or re-termination can be done without pulling new cable.

Fusion splice sequence

Strip, clean with lint-free wipe and alcohol, cleave to under about 0.5 degree, align in the splicer, arc-fuse, proof-test, and protect with a splice sleeve.

Cleave angle importance

A poor cleave angle or chipped end raises splice loss and reflection; the splicer's estimated loss will show it, so re-cleave before fusing.

Typical fusion splice loss

A good single-mode fusion splice is typically below 0.1 dB; field acceptance commonly allows 0.1 to 0.3 dB per splice depending on the standard.

End-face inspection

Scope and inspect every connector end face for scratches, pits, cracks, and contamination before mating; a dirty face can permanently damage the mating connector.

Connector cleaning rule

Dry clean first with a lint-free wipe or cassette cleaner; if contamination remains, use isopropyl alcohol on a lint-free wipe and dry fully. Never use compressed air.

UPC versus APC

UPC is a flat polish with low reflectance; APC is an angled polish with the best reflectance. APC and UPC must never be mated because the end faces do not match.

Link loss budget

Total loss equals fiber attenuation times length plus splice losses plus connector losses plus splitter losses; compare the measured value against the budget, not a generic number.

Single-mode attenuation values

Typical single-mode fiber attenuation is about 0.35 dB per km at 1310 nm and about 0.20 to 0.25 dB per km at 1550 nm.

OTDR distance formula

Distance equals the speed of light times time divided by twice the group index; if the IOR setting is wrong, every reported distance is wrong.

OTDR dead zones

The event dead zone limits resolving closely spaced reflective events; the longer attenuation dead zone limits loss measurement right after a reflective event. Shorter pulses improve resolution.

Bidirectional OTDR testing

Splice loss measured from one direction is biased by backscatter differences; test both directions and average the two readings for accurate splice loss.

Visual fault locator use

A red laser VFL finds breaks, tight bends, and bad connectors within a short range by making the fault glow through the jacket or connector.

Laser eye safety

Never look into a fiber or connector; treat every fiber as live, verify with a power meter, and cap unused ports, because laser eye damage is instant and painless.

Fiber shard handling

Broken fiber shards cut skin and threaten eyes; work on a dark mat, pick shards up with tape or a damp wipe, and never blow debris with compressed air.

Confined space entry

Handholes and vaults may be permit-required confined spaces; test oxygen, flammable gas, and toxic gas before entry and keep a standby attendant outside.