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FOA CFOS/L practice questions

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Question 1Fiber optic basics and premises cabling fundamentals

Which fiber component confines the light to the core through total internal reflection?

  1. The aramid yarn
  2. The outer jacket
  3. The cladding Correct answer.
  4. The strength member

Explanation

The cladding has a lower refractive index than the core, so light striking the core-cladding boundary above the critical angle is reflected back into the core. This index step is what makes guided propagation possible.

Question 2Fiber optic basics and premises cabling fundamentals

In a multimode fiber, what does the term 'modal dispersion' describe?

  1. The jacket expands and contracts with temperature
  2. Different ray paths arrive at slightly different times, spreading the pulse Correct answer.
  3. Connector endfaces reflect light back to the source
  4. Wavelengths shift as light travels down the glass

Explanation

Higher-order modes travel longer zigzag paths than the axial mode, so a launched pulse arrives smeared over time. This spreading limits the bandwidth-distance product of multimode fiber.

Question 3Fiber optic basics and premises cabling fundamentals

Which wavelength window is most commonly used for single-mode long-haul transmission because of its low attenuation?

  1. 650 nm
  2. 1550 nm Correct answer.
  3. 850 nm
  4. 1310 nm

Explanation

The 1550 nm window offers the lowest attenuation in silica fiber, roughly 0.2 dB/km, and coincides with erbium-doped amplifier bands. That combination makes it the standard for long-haul and metro single-mode links.

Question 4Fiber optic basics and premises cabling fundamentals

What is the primary function of a loose-tube buffer in an outside-plant cable?

  1. To increase the numerical aperture of the fiber
  2. To carry electrical power to remote nodes
  3. To provide mechanical isolation so fibers float freely and are not strained Correct answer.
  4. To strip the fiber coating during termination

Explanation

In loose-tube construction the fibers sit in a gel or dry water-blocked tube with excess length, so cable strain and thermal expansion do not transfer to the glass. This isolation protects the fiber in harsh outdoor environments.

Question 5Fiber optic basics and premises cabling fundamentals

A technician measures a connector pair with an insertion loss of 0.9 dB. Which statement best describes why this matters?

  1. It changes the wavelength of the source
  2. It increases the core diameter of the fiber
  3. It reduces the optical power reaching the receiver and consumes link budget Correct answer.
  4. It improves the return loss of the connector

Explanation

Each mated pair removes optical power from the link, and the sum of all losses must stay below the budget computed from source power and receiver sensitivity. A 0.9 dB pair is a significant share of a multimode budget.

Question 6Fiber optic basics and premises cabling fundamentals

Which polish geometry is associated with a physical contact connector that has a small radius of curvature and an apex offset within tolerance?

  1. PC
  2. APC
  3. Flat cleave
  4. UPC Correct answer.

Explanation

UPC denotes an ultra-physical-contact ferrule with a domed endface tuned for low backreflection at 1310/1550 nm. PC and APC are also physical contact, but UPC is the standard high-return-loss designation for non-angled SMF connectors.

Question 7Fiber optic basics and premises cabling fundamentals

What is the purpose of a mode conditioning patch cord when launching into installed multimode fiber?

  1. To reduce the cable's bend radius
  2. To convert multimode light into single-mode light
  3. To increase the connector's return loss
  4. To offset the launch so a single-mode source does not excite only the center of the multimode core Correct answer.

Explanation

Legacy 1300 nm single-mode transmitters launched into multimode fiber can excite only low-order modes, causing differential mode delay. A mode conditioning cord offsets the single-mode launch so the power is distributed more like a standard multimode launch.

Question 8Fiber optic basics and premises cabling fundamentals

Which fiber type is specified by ISO/IEC 11801 as OM4?

  1. 850 nm optimized multimode with 4700 MHz-km effective modal bandwidth Correct answer.
  2. Singlemode with 9 micron mode field diameter
  3. Plastic optical fiber for short links
  4. 850 nm optimized multimode with 500 MHz-km overfilled bandwidth

Explanation

OM4 is a laser-optimized 50 micron multimode graded-index fiber with a minimum effective modal bandwidth of 4700 MHz-km at 850 nm. That bandwidth supports 10GBASE-SR to 400 m and higher rates over shorter distances.

Question 9Fiber optic basics and premises cabling fundamentals

In premises cabling, what does the horizontal cabling subsystem connect?

  1. The telecommunications outlet to the horizontal cross-connect Correct answer.
  2. The building entrance to the entrance facility
  3. The equipment room to the service provider demarcation
  4. One building to another across campus

Explanation

Horizontal cabling runs from the work area outlet to the horizontal cross-connect in the telecommunications room. It is the most permanent part of the premises network and is limited by standards to specified media and distances.

Question 10Fiber optic basics and premises cabling fundamentals

What is the maximum recognized horizontal cable length for balanced twisted-pair cabling in the horizontal subsystem?

  1. 300 m
  2. 150 m
  3. 100 m
  4. 90 m Correct answer.

Explanation

Standards allow 90 m of horizontal cable plus up to 10 m of cords and jumpers, giving a 100 m channel. The 90 m figure applies to the permanent horizontal cable itself.

Question 11Fiber optic basics and premises cabling fundamentals

Which characteristic distinguishes single-mode fiber from multimode fiber?

  1. A plastic core with high attenuation
  2. A much smaller core that supports essentially one propagation mode Correct answer.
  3. A graded-index profile with many modes
  4. A larger core that supports many modes

Explanation

Single-mode fiber has a core of roughly 8 to 10 microns, small enough that only the fundamental mode propagates. This eliminates modal dispersion and enables long-distance, high-bandwidth links.

Question 12Fiber optic basics and premises cabling fundamentals

A cable jacket printed 'OFNP' indicates which rating?

  1. Plenum-rated optical fiber cable Correct answer.
  2. Outdoor-rated optical fiber cable
  3. Riser-rated optical fiber cable
  4. General-purpose optical fiber cable

Explanation

The OFNP marking denotes optical fiber, nonconductive, plenum rated, suitable for air-handling spaces. Plenum cables use low-smoke, low-flame-spread materials required by building codes.

Question 13Fiber optic basics and premises cabling fundamentals

What is the main reason to maintain a minimum bend radius during fiber installation?

  1. To preserve the cable's fire rating
  2. To reduce the cable's tensile strength
  3. To keep the connector ferrule clean
  4. To prevent macrobending loss and possible fiber damage Correct answer.

Explanation

Bending below the recommended radius causes light to escape the core, producing macrobending loss, and can crack the glass. Standards specify minimum bend radii for installation and long-term operation.

Question 14Fiber optic basics and premises cabling fundamentals

Which tool is used to verify that a fusion splice has low loss before the splice protector is installed?

  1. A tone generator
  2. An optical time-domain reflectometer or splice loss estimator Correct answer.
  3. A cable jacket stripper
  4. A visual fault locator only

Explanation

An OTDR or the splicer's built-in loss estimator measures splice attenuation by comparing backscatter before and after the joint. A visual fault locator only shows gross faults and cannot quantify splice loss.

Question 15Fiber optic basics and premises cabling fundamentals

Which factor most directly determines the numerical aperture of a step-index fiber?

  1. The cable's tensile rating
  2. The jacket color
  3. The connector polish style
  4. The refractive indices of the core and cladding Correct answer.

Explanation

Numerical aperture is derived from the square root of the difference of the squared core and cladding indices. It describes the cone of light the fiber can accept and is fixed at manufacture.

Question 16Fiber optic basics and premises cabling fundamentals

Which statement describes the purpose of a breakout kit or fan-out on a multifiber cable?

  1. To increase the number of modes in each fiber
  2. To separate and protect individual fibers so each can be connectorized Correct answer.
  3. To provide electrical grounding for the cable
  4. To convert multimode fiber to single-mode

Explanation

Breakout kits transition from the cable's overall jacket and strength members to individual 900 micron buffered fibers. This allows each fiber to be terminated and handled without damaging adjacent fibers.

Question 17Fiber optic basics and premises cabling fundamentals

A link budget for a 10GBASE-SR channel shows 2.6 dB total loss with a 2.6 dB budget. What is the appropriate engineering conclusion?

  1. The link is at the limit and should be redesigned with margin Correct answer.
  2. The link budget has no bearing on the design
  3. The link passes with generous headroom
  4. The link requires a mode conditioning cord

Explanation

Operating exactly at the budget leaves no margin for aging, temperature, or mating variability, so good practice adds headroom or shortens the link. A link that just meets the budget is fragile rather than comfortable.

Question 18Fiber optic basics and premises cabling fundamentals

Which condition causes a macrobend loss that a visual fault locator can reveal as a bright glow?

  1. A cracked ferrule in a patch panel
  2. A misaligned mechanical splice
  3. A tight tie wrap compressing the cable below its bend radius Correct answer.
  4. A contaminated connector endface

Explanation

A tight bend forces light out of the core into the cladding and coating, and a VFL injects visible light that escapes at that point. The glow pinpoints the over-bent section for correction.

Question 19Fiber optic basics and premises cabling fundamentals

What does the term 'return loss' quantify in a fiber link?

  1. The ratio of reflected optical power to incident power at a discontinuity Correct answer.
  2. The total attenuation of the fiber span
  3. The bandwidth-distance product of the fiber
  4. The tensile load the cable can withstand

Explanation

Return loss expresses how much light is reflected back toward the source at connectors, splices, or other discontinuities. Higher return loss values in dB mean less reflection and cleaner transmission.

Question 20Fiber optic basics and premises cabling fundamentals

Which practice best protects a connector endface before mating in a patch panel?

  1. Wipe the ferrule on a shirt sleeve
  2. Inspect and clean both endfaces with appropriate tools Correct answer.
  3. Blow on the endface to remove dust
  4. Leave the dust cap on during mating

Explanation

Contamination is a leading cause of connector failure, so standards require inspection and, when needed, wet-dry cleaning before mating. Proper tools remove particles without scratching the polished surface.

Question 21Fiber optic basics and premises cabling fundamentals

What distinguishes an angled physical contact connector from a flat physical contact connector?

  1. The ferrule endface is polished at an 8-degree angle to reduce backreflection Correct answer.
  2. The connector requires no polish at all
  3. The ferrule is made of ceramic instead of metal
  4. The connector uses a different core diameter

Explanation

APC ferrules are polished at an 8-degree angle so reflected light exits into the cladding rather than traveling back to the source. This yields return loss better than -60 dB, far better than flat PC connectors.

Question 22Fiber optic basics and premises cabling fundamentals

Why are APC and UPC connectors generally not mated to each other?

  1. Their ferrules have incompatible outside diameters
  2. APC connectors carry electrical current
  3. The angled and flat endfaces make poor physical contact and cause high loss and reflection Correct answer.
  4. They use different wavelengths by definition

Explanation

Mating an 8-degree angled endface against a flat one leaves an air gap and poor contact, raising insertion loss and backreflection. Standards therefore pair like polish styles, often with color-coded housings.

Question 23Fiber optic basics and premises cabling fundamentals

Which statement about graded-index multimode fiber is accurate?

  1. The refractive index decreases gradually from the core center outward, equalizing mode transit times Correct answer.
  2. The core has a uniform index across its full diameter
  3. The fiber supports a single propagation mode
  4. Light travels only in the cladding

Explanation

A graded index bends higher-order rays continuously, so longer paths travel through lower-index glass and arrive closer in time to axial rays. This reduces modal dispersion compared with step-index multimode.

Question 24Fiber optic basics and premises cabling fundamentals

What is the purpose of an innerduct in a premises fiber pathway?

  1. To splice fibers together inside the conduit
  2. To terminate the fiber at the outlet
  3. To provide a protective subduct that guides and separates cables within a conduit Correct answer.
  4. To convert optical signals to electrical signals

Explanation

Innerduct creates dedicated, low-friction channels inside a larger conduit so cables can be pulled without abrasion and separated by function or tenant. It also simplifies future adds and changes.

Question 25Fiber optic basics and premises cabling fundamentals

A technician must choose fiber for a 550 m 10GBASE-SR link in a data center. Which choice meets the standard's reach requirement?

  1. OS2 single-mode
  2. OM1 multimode
  3. OM4 multimode Correct answer.
  4. OM3 multimode

Explanation

10GBASE-SR reaches 300 m on OM3 but 400 m on OM4, so 550 m exceeds both standard multimode ratings unless a different PHY is used. Among the listed choices only OM4 offers the greatest multimode reach, though a longer-reach solution such as 10GBASE-LRM or single-mode optics would be needed at 550 m.

Question 26Fiber optic basics and premises cabling fundamentals

Which color code identifies the second fiber in a standard 12-fiber premises cable using the TIA-598 convention?

  1. Orange Correct answer.
  2. Brown
  3. Blue
  4. Green

Explanation

TIA-598 assigns colors in the order blue, orange, green, brown, slate, white, red, black, yellow, violet, rose, aqua for fibers 1 through 12. Fiber position 2 is therefore orange, and the sequence repeats with tracers for higher counts.

Question 27Fiber optic basics and premises cabling fundamentals

In a premises cabling system, which subsystem connects the equipment outlet in the work area to the horizontal cross-connect?

  1. Horizontal cabling Correct answer.
  2. Entrance facility
  3. Work area cabling
  4. Backbone cabling

Explanation

The horizontal cabling subsystem runs from the work area outlet to the horizontal cross-connect in the telecommunications room. It is distinct from the work area cords that plug into the outlet and from backbone cabling that links rooms and floors.

Question 28Fiber optic basics and premises cabling fundamentals

A technician terminates an SC connector on 900 µm buffered fiber inside a rack-mounted enclosure. Which component is required to protect the fiber between the buffer and the connector body?

  1. A strain-relief boot Correct answer.
  2. A mode conditioning adapter
  3. A heat-shrink splice protector
  4. A strength member fan-out

Explanation

A strain-relief boot supports the 900 µm buffer where it meets the connector, limiting bending and pull forces at that transition. Without it, the fiber can kink or the buffer can pull back from the connector.

Question 29Fiber optic basics and premises cabling fundamentals

Which document type typically defines the cable pathways, spaces, and outlet locations for a specific building project?

  1. The project's telecommunications cabling plan Correct answer.
  2. The connector polish datasheet
  3. The ANSI/TIA-568 generic standard
  4. The manufacturer's fiber specification sheet

Explanation

The cabling plan or drawing set for a project records where pathways, spaces, and outlets are to be installed in that building. Generic standards define minimum requirements, while the project plan captures the actual design.

Question 30Fiber optic basics and premises cabling fundamentals

A single-mode link is specified with a 1310 nm source, but the installed cable is labeled 62.5/125 µm multimode. What is the primary consequence?

  1. The connector polish will change from UPC to APC.
  2. The multimode core will not confine the single-mode signal, causing very high loss. Correct answer.
  3. The cable's jacket rating will be exceeded by the source power.
  4. The link will operate normally because the source wavelength is short.

Explanation

Single-mode sources are designed for a core of roughly 8 to 10 µm, so launching into a 62.5 µm core produces a poorly guided, multimode-like launch with large and unstable loss. The correct approach is to match the source type to the installed fiber.

Question 31Fiber optic basics and premises cabling fundamentals

Why is an air-blown fiber installation method attractive for a premises backbone that may need future capacity?

  1. It removes the requirement for bend radius control.
  2. It eliminates the need for any cable jacket.
  3. It permits multimode and single-mode fiber to share one core.
  4. It allows additional fiber units to be blown into empty tubes later. Correct answer.

Explanation

Air-blown systems install microcables or fiber units into pre-installed tubes, so capacity can be added later by blowing more fiber into spare tubes. This defers the cost of fiber until it is actually needed.

Question 32Fiber optic basics and premises cabling fundamentals

A designer must provide a fiber pathway between two buildings on the same campus. Which cabling element is intended for this role?

  1. Horizontal cabling
  2. Backbone cabling Correct answer.
  3. Work area cabling
  4. Patch cord assembly

Explanation

Backbone cabling provides the connection between buildings, floors, and telecommunications spaces. Inter-building campus links are part of the backbone, not the horizontal subsystem that serves individual outlets.

Question 33Fiber optic basics and premises cabling fundamentals

A contractor is pulling a 24-fiber indoor cable through a conduit that already contains several copper cables. Which practice best reduces the risk of damage?

  1. Bend the cable sharply around conduit corners to keep it tight.
  2. Pull at the maximum tension the cable can bear and stop only if the jacket tears.
  3. Attach the pull line directly to the fiber bundle.
  4. Use a pulling lubricant and monitor tension against the cable's rated limit. Correct answer.

Explanation

Lubricant lowers friction in a crowded conduit, and monitoring tension keeps the pull within the cable manufacturer's rating. Exceeding the rated tension can stretch or break fibers even when the jacket looks intact.

Question 34Fiber optic basics and premises cabling fundamentals

Which statement correctly describes the relationship between a telecommunications room and a horizontal cross-connect?

  1. The cross-connect is located only in the entrance facility.
  2. The cross-connect is the point where horizontal cabling terminates and is patched to backbone cabling. Correct answer.
  3. The cross-connect is the outlet plate in the work area.
  4. The cross-connect is a passive splitter that divides optical power.

Explanation

The horizontal cross-connect is the administration point in the telecommunications room where horizontal cables are terminated and connected to backbone and equipment. It is a patching and termination point, not an optical device.

Question 35Fiber optic basics and premises cabling fundamentals

A fiber cable is rated OFNR and is to be installed in a return air plenum above a suspended ceiling. What does the rating indicate about this use?

  1. The cable is suitable if it is installed inside metal conduit.
  2. The cable is not suitable for plenum use because it lacks a plenum rating. Correct answer.
  3. The cable is suitable for plenum use because it is riser rated.
  4. The cable is suitable because all indoor fiber is plenum rated.

Explanation

OFNR indicates a riser-rated cable intended for vertical shafts between floors. Plenum spaces require an OFNP or equivalent plenum-rated cable because of stricter smoke and flame requirements.

Question 36Fiber optic basics and premises cabling fundamentals

Which measurement confirms that a newly installed horizontal fiber link meets its loss allowance before the network equipment is connected?

  1. A continuity check with a copper toner
  2. A visual fault locator check of the connector endface
  3. An optical time-domain reflectometer trace of the entire campus backbone
  4. An insertion loss test of the link with a light source and power meter Correct answer.

Explanation

A light source and power meter measure end-to-end insertion loss, which is compared with the link's loss allowance. This is the standard acceptance test for an installed fiber link.

Question 37Fiber optic basics and premises cabling fundamentals

A 12-fiber cable is to be terminated in a patch panel where only 6 fibers are currently needed. Which practice best supports future growth?

  1. Terminate all 12 fibers on the panel and record the unused ports in the administration records. Correct answer.
  2. Cut the unused fibers back at the sheath entry to reduce clutter.
  3. Terminate only the 6 used fibers and discard the rest of the cable.
  4. Terminate all 12 fibers and leave the unused ones unterminated in the cable sheath.

Explanation

Terminating all fibers and documenting the unused ports preserves capacity and keeps records accurate for future activation. Cutting or discarding unused fibers permanently reduces the cable's capacity.

Question 38Fiber optic basics and premises cabling fundamentals

A link budget calculation for a 1 Gbps multimode channel gives 3.1 dB of available loss, and the installed link measures 2.9 dB. Which conclusion is correct?

  1. The link fails because any loss above 2.0 dB is unacceptable.
  2. The link passes because measured loss is below the available budget. Correct answer.
  3. The link fails because the budget must exceed the loss by 1 dB.
  4. The link passes only if the connectors are APC.

Explanation

A link passes when its measured loss is less than or equal to the calculated available loss budget. Here 2.9 dB is within the 3.1 dB allowance, leaving a small margin.

Question 39Fiber optic basics and premises cabling fundamentals

A technician must route a fiber cable around a 90-degree corner inside a telecommunications room. Which approach best preserves optical performance?

  1. Coil the excess cable into a tight loop and tie it with cable ties.
  2. Route with a large sweeping bend using a bend radius guide or J-hook. Correct answer.
  3. Staple the cable to the wall at the corner.
  4. Route tightly against the corner to save space in the room.

Explanation

A large sweeping bend keeps the cable above its minimum bend radius, avoiding macrobend loss and mechanical stress. Bend radius guides and J-hooks are common aids for maintaining that radius.

Question 40Fiber optic basics and premises cabling fundamentals

A premises design uses an air-blown fiber system with spare tubes installed to each floor. Which statement best explains the lifecycle benefit of this design?

  1. The spare tubes remove the requirement for fire-rated cable.
  2. Additional fiber can be added later without installing new pathway infrastructure. Correct answer.
  3. The spare tubes eliminate the need for link testing after activation.
  4. The spare tubes allow copper and fiber to share the same core.

Explanation

Installing spare tubes during construction means future fiber can be blown in without new conduit or pathway work. This reduces disruption and cost when capacity grows.

Question 41Premises cabling components, cables and connectors

Which premises cable category is specified for 100 m horizontal runs supporting 10GBASE-T up to 100 m and is limited to 500 MHz?

  1. Category 5e
  2. Category 6
  3. Category 6A Correct answer.
  4. Category 7

Explanation

Category 6A (augmented Category 6) is characterized to 500 MHz and is the twisted-pair category designed to carry 10GBASE-T over the full 100 m channel. Category 6 is rated to 250 MHz and reaches 10GBASE-T only at reduced distances.

Question 42Premises cabling components, cables and connectors

What is the nominal characteristic impedance of twisted-pair premises cabling?

  1. 50 ohms
  2. 75 ohms
  3. 120 ohms
  4. 100 ohms Correct answer.

Explanation

Balanced twisted-pair cabling used in premises networks is standardized at a nominal 100 ohm characteristic impedance. Impedance mismatches along the channel cause reflections that degrade return loss.

Question 43Premises cabling components, cables and connectors

A technician must terminate a Category 6A horizontal cable in the field with the most reliable long-term performance. Which termination method is preferred?

  1. Insulation displacement contacts in an outlet or patch panel Correct answer.
  2. Field-installable RJ-45 plugs on both ends
  3. Crimping with a pliers-style tool and no dedicated die
  4. Soldering the conductors to the plug contacts

Explanation

Insulation displacement contacts (IDC) in jacks and panels are the standard field termination for horizontal cable because they maintain category performance and are repeatable. Field-installed plugs are harder to control and generally degrade return loss and near-end crosstalk.

Question 44Premises cabling components, cables and connectors

In an optical fiber link, which component is used to join two fibers permanently with the lowest insertion loss?

  1. A fusion splice Correct answer.
  2. An ST bayonet connector
  3. A fiber distribution panel
  4. A mechanical splice

Explanation

Fusion splicing arc-welds the two glass ends, producing a permanent joint with very low loss, typically well under 0.1 dB. Mechanical splices use an index-matching gel and alignment fixture and generally show higher loss and reflection.

Question 45Premises cabling components, cables and connectors

A single-mode fiber backbone requires a connector with a 2.5 mm ferrule and a spring-loaded bayonet coupling. Which connector type matches?

  1. LC
  2. MPO
  3. SC
  4. ST Correct answer.

Explanation

The ST connector uses a 2.5 mm ceramic ferrule and a bayonet twist-lock coupling. It is common in older single-mode and multimode backbones and in fiber distribution panels.

Question 46Premises cabling components, cables and connectors

Which color code identifies a multimode fiber patch cord terminated with an LC connector intended for 50/125 um OM4 fiber?

  1. Yellow
  2. Blue
  3. Aqua Correct answer.
  4. Green

Explanation

Aqua is the standard jacket color for OM3 and OM4 laser-optimized 50/125 um multimode fiber. Yellow denotes single-mode, and blue denotes standard 50/125 um multimode in some conventions but not OM4.

Question 47Premises cabling components, cables and connectors

Which copper connector is used to terminate a shielded twisted-pair cable where the shield must be bonded to the plug housing?

  1. F-type connector
  2. RJ-11
  3. RJ-45 shielded plug Correct answer.
  4. BNC connector

Explanation

A shielded RJ-45 plug includes a metal housing that bonds the cable shield to the equipment ground through the jack. RJ-11, BNC, and F-type connectors do not terminate four-pair balanced cable.

Question 48Premises cabling components, cables and connectors

What is the minimum bend radius commonly specified for a four-pair horizontal cable during installation, expressed as a multiple of the cable outside diameter?

  1. One times the diameter
  2. Ten times the diameter
  3. Two times the diameter
  4. Four times the diameter Correct answer.

Explanation

Four-pair horizontal cable is typically installed with a bend radius of at least four times the cable outside diameter, and tighter during pulling is often allowed only temporarily. Exceeding this limit can distort pair geometry and raise crosstalk.

Question 49Premises cabling components, cables and connectors

A 100 m horizontal channel is being designed for 10GBASE-T. Which cabling choice meets the standard distance requirement?

  1. Category 5e U/UTP
  2. Category 3 UTP
  3. Category 6A F/UTP Correct answer.
  4. Category 6 U/UTP

Explanation

Category 6A is the twisted-pair category specified to support 10GBASE-T over the full 100 m channel. Category 6 and Category 5e fall short of the 100 m 10GBASE-T objective.

Question 50Premises cabling components, cables and connectors

Which fiber type is required for a 10 km campus backbone using 1310 nm optics?

  1. OM4 multimode
  2. OS2 single-mode Correct answer.
  3. OM1 multimode
  4. OM3 multimode

Explanation

OS2 single-mode fiber has a small core and low attenuation at 1310 nm, allowing links of many kilometers. Multimode grades suffer modal dispersion and are limited to hundreds of meters at best.