Fiber Optic Cable and Accessories: Complete Selection Guide

Fiber optic cable is a cable that carries data as pulses of light through a glass core instead of electrical current through copper. A complete cable contains the optical fibers, a protective buffer, one or more strength members, water-blocking materials and an outer jacket. Cable accessories are everything that terminates, protects, joins, identifies or maintains that cable once it is in the ground, on a pole or in a rack.

Quick answer. Choose the construction first, then the fiber. Indoor runs use tight-buffered cable with an LSZH or plenum-rated jacket. Outdoor runs use loose-tube cable with a black polyethylene jacket and a water-blocking fill. Direct-buried runs add steel tape or corrugated armour, aerial runs need a self-supporting or figure-8 design, and every run needs its own accessories: closures where the cable ends, pigtails where it terminates, markers where it must be traceable, and protection hardware wherever it bends.

1. What a fiber optic cable is made of
2. Tight-buffered and loose-tube construction compared
3. Cable types by installation environment
4. Indoor cable constructions
5. Outdoor cable constructions
6. FTTH drop cable and self-supporting aerial cable
7. Jacket, sheath and fire ratings
8. Armour, strength members and rodent protection
9. The optical fibre grades inside the cable
10. Cable marking, metre marking and colour code
11. Fibre count, reel length and packing
12. What counts as a fibre optic accessory
13. Cable protection and routing accessories
14. Closures, joint boxes and terminal boxes
15. Pigtails, patch cords and adapters
16. Markers, labels and identification accessories
17. Tools and consumables for cable work
18. Specification checklist
19. Frequently asked questions
20. Related guides and tutorials

1. What a fiber optic cable is made of

A fiber optic cable is built from the inside out. The light-carrying fiber is drawn from ultra-pure silica glass, then each layer around it takes over a different job: mechanical protection, moisture blocking, tensile strength and flame performance. Understanding the layers is what makes the rest of this guide easy, because every cable type is simply a different arrangement of the same seven elements.

Layer	Typical material	Function
Core	Doped silica glass, 9 µm single-mode or 50/62.5 µm multimode	Carries the light signal. Core diameter and refractive index profile determine the fibre grade and the reach.
Cladding	Pure silica glass, 125 µm	Lower refractive index than the core, so light is confined by total internal reflection.
Primary coating	Soft acrylate, 250 µm	Protects the glass surface from micro-bends and scratches. This is the “250 µm fibre” that loose tubes contain.
Buffer	Tight buffer (900 µm hard plastic) or a loose tube filled with gel or dry water-blocking yarn	The structural fork in cable design. Tight buffer makes each fibre directly connectorizable; a loose tube lets fibres float free of mechanical stress.
Strength member	Aramid yarn (Kevlar), FRP rod, steel wire, or a central steel/FRP element	Absorbs pulling tension and crush load so the glass never carries it. Also sets how stiff the cable is.
Water blocking	Gel fill, swellable tape/powder, or a flooded core	Stops water migrating along the cable if the jacket is damaged. Water that freezes and expands is a common cause of long-term fibre failure.
Outer jacket	PE (outdoor), PVC, LSZH or fluoropolymer (indoor)	UV, abrasion, chemical and flame protection. The jacket material decides which fire rating the cable can claim and where it may legally be installed.

Single-mode and multimode in one sentence

Single-mode cable carries one light path through a 9 µm core and reaches tens of kilometres; multimode cable carries many light paths through a 50 µm core and reaches a few hundred metres, but at a lower transceiver cost. Which one belongs in your cable is decided by distance and by the equipment on each end — see section 9 for the grade tables and the links to our dedicated comparison articles.

Start from the product family. Fiber optic cable overview · Indoor cable · Outdoor cable · FTTH drop cable · Armored cable · Special cable

2. Tight-buffered and loose-tube construction compared

Cross-section diagram comparing tight-buffered 900 um and loose-tube 250 um fiber optic cable construction — Figure 1 — The same fibres, two constructions: tight-buffered fibres are bonded and can be connectorised directly; loose-tube fibres float in a gel-filled tube and are spliced to pigtails.

Almost every cable decision starts here. In a tight-buffered cable each fibre carries its own 900 µm plastic coating bonded directly over the 250 µm primary coating, so the fibre and its buffer move as one unit. In a loose-tube cable, up to twelve 250 µm fibres sit inside an oversized plastic tube filled with gel or dry water-blocking material, and the fibres float free. Everything else — moisture performance, temperature range, termination method, cost per fibre — follows from that one difference.

Attribute	Loose tube (250 µm)	Tight buffered (900 µm)
Fibre mobility	Fibres float inside the tube; mechanical stress and thermal expansion are decoupled from the glass	Fibre is bonded to its buffer; stress on the cable reaches the fibre directly
Temperature range	−40 °C to +70 °C or wider; slack in the tube absorbs expansion	Narrower; best in stable indoor environments
Moisture protection	Gel fill or dry water-blocking — designed for wet, buried and aerial service	No gel; some indoor/outdoor designs use dry water blocking for limited runs
Fibre count range	2 to several hundred (trunk and backbone)	2 to 144 (distribution, breakout, drop, patch)
Termination	Splice to pigtails, or use a breakout/fan-out kit before connectorising	Stripped and connectorised directly — no gel to clean
Typical jacket	Black polyethylene, UV-stabilised	PVC or LSZH, flame-retardant
Typical environment	Duct, direct burial, aerial, long haul	Riser, plenum, equipment room, short outdoor drop
Field workflow	Spliced in closures and panels	Cut, stripped and terminated on site

Where the rule breaks. Indoor/outdoor tight-buffered cable exists for campus links that must cross between buildings without a splice at each entrance. It is more rugged than standard indoor cable and removes one transition, at the cost of a larger diameter for the same fibre count. Where a project needs both — a long duct run that enters a plenum ceiling — the usual answer is loose tube to the entrance, then a splice onto an indoor-rated cable, or a single indoor/outdoor rated cable if the run is short enough to justify it.

3. Cable types by installation environment

The fastest way to specify a cable is to start from where it will be installed, because the environment dictates the construction, the jacket and the fire rating before fibre type is even discussed. The table below maps the seven common installation environments to the cable that belongs in each.

Environment	Construction	Jacket / rating	Notes
Duct / conduit	Central or stranded loose tube, non-armoured or light armour	Black PE, outdoor	The default outdoor build. Pulling tension governs strength member choice; water-blocking is mandatory.
Direct burial	Loose tube with steel tape or corrugated steel armour, double-sheathed	Black PE over armour	Needs crush resistance and rodent resistance. Armour must be bonded and grounded if metallic.
Aerial — lashed or messenger	Loose tube lashed to a messenger wire	Black PE, UV-stabilised	Ice and wind loading act on the messenger, not the cable.
Aerial — self-supporting	Figure-8 with an integral messenger, or all-dielectric self-supporting (ADSS)	Black PE	No separate messenger to install. ADSS keeps the span fully dielectric near power lines.
Vertical riser (indoor)	Tight-buffered distribution or breakout	OFNR / CMR, or LSZH in IEC markets	Must resist floor-to-floor flame spread. Riser shafts, elevator shafts, telecom risers.
Plenum / air-handling	Tight-buffered, low-smoke jacket	OFNP / CMP	Required wherever the cable shares a ceiling void or raised floor with return air.
FTTH drop (last 100 m)	Flat butterfly tight buffer, or self-supporting figure-8 drop	LSZH or PE, often with steel or FRP strength members	Small bend radius, low cost, field-installable connectors.

Two further cases do not fit the grid. Air-blown micro cable is installed by compressed air into pre-installed microduct rather than pulled — useful when the duct is already in place and fibre has to be added later. Our air-blowing micro cable range covers that case, and the microduct system itself is covered separately. OPGW integrates the fibres into the earth wire of a high-voltage transmission line, so it is a specialist transmission product rather than a cabling choice.

4. Indoor cable constructions

Indoor cable is optimised for tight spaces, frequent handling and fire code compliance, not for weather. All of it uses 900 µm tight-buffered fibre so it can be terminated directly on site without a splicing van.

Construction	Fibre count	Where it is used	Why it exists
Simplex	1	Single device link, fibre to a sensor or outlet	Smallest possible cable; 1.6 mm, 2.0 mm or 3.0 mm jacket
Duplex / zipcord / twin flat	2	Equipment cords, workstation outlets, patch leads	Two fibres held together but splittable, so each end can be connectorised separately
Distribution tight buffer	4–48	Riser and horizontal backbone inside a building	Individually buffered fibres around a central strength member — direct termination without a fan-out kit
Breakout	4–24	Equipment room, high-vibration or heavy-handling areas	Each fibre gets its own 2.0–3.0 mm sub-jacket; rugged but bulky
Ribbon / flat indoor	4–24	Aggregation inside a building, mass-fusion splicing	Fibres arranged in a flat ribbon (about 3 mm wide for 12 fibres) for simultaneous splicing
Parallel / multi-core	4–72	Multi-fibre parallel links, short interconnect builds	Fibres side by side in one flat profile, used where each fibre carries its own lane
Indoor/outdoor	4–144	Campus runs that cross outside then continue inside	Rugged enough for duct and UV exposure but still rated for indoor flame performance

The fibre itself is protected from handling but not from moisture, so indoor cable should not be left in a wet duct or buried. Where an indoor run must leave the building, use the indoor/outdoor variant or splice to an outdoor cable at the entry point.

5. Outdoor cable constructions

Outdoor cable must survive water, UV, temperature cycling, rodents and pulling tension for twenty-five years. That is why the jacket is black polyethylene and the fibres live inside gel-filled or dry water-blocked tubes.

Construction	Model family	Strength / protection	Typical route
Central loose tube, non-armoured	GYXTW, GYFXTY	Two parallel steel wires or FRP rods, outside the tube	Duct and aerial where no armour rating is needed
Central loose tube, aluminium tape	GYTA	Aluminium tape moisture barrier	Duct in dry or moderately wet environments
Central loose tube, steel tape armour	GYTS	Corrugated steel tape, bonded to the jacket	Duct and direct burial where rodent and crush protection matters
Non-metallic, non-armoured	GYFTY	FRP rod, all-dielectric	Aerial near power lines, lightning-prone areas; no grounding required
Non-metallic armour	GYFTS	Dielectric armour layer	Rodent-prone duct runs where metallic armour is not acceptable
Double-sheathed armoured	GYTA53, GYTY53, GYFTS	Armour between two jackets	Direct burial, river crossings, high crush load
Stranded loose tube, high count	GYDXTW, GJFXTKY53	Multiple tubes stranded around a central member	Trunk ducts carrying 48–288 fibres
Figure-8 self-supporting	GYTC8S, GYXTC8S, GYXTC8Y	Integral messenger in the second lobe of the figure-8	Aerial spans with no messenger wire to install
All-dielectric self-supporting	ADSS	Aramid and FRP only, no metal	Long aerial spans on transmission corridors
Unitube ribbon	GYDXTW	Ribbon stacks inside one large tube	Mass-splice backbone builds

Model codes are not random — each position in the code describes a property of the cable. Our guide to optical cable naming rules decodes the GYTS / GYTA / GYFTY53 families position by position, and it is the fastest way to check that a quotation matches the cable you actually asked for.

6. FTTH drop cable and self-supporting aerial cable

Cross-sections of three FTTH drop cable profiles: GJXFH flat indoor drop, GJXFCH self-supporting figure-8 drop, and armoured drop cable — Figure 2 — Three drop profiles cover almost every route: flat indoor drop (GJXFH), self-supporting figure-8 (GJXFCH) and armoured drop for rodent or duct exposure.

The drop segment is the last hundred metres to the subscriber, and it has its own design rules: very small bend radius, low cost per home, and a strength member strong enough to survive an aerial span or a wall drop. Three profiles dominate.

Type	Model	Strength member	Use
Flat butterfly indoor drop	GJXFH	Two FRP rods on the sides of the flat profile	Indoor wall and skirting runs; LSZH jacket, flame retardant
Figure-8 self-supporting drop	GJXFCH	Steel-wire or FRP messenger above; fibre unit between two strength members below	Aerial drop between pole and building with no messenger
Armoured drop	—	Round profile: aluminium tape armour over water-blocking tape; strength members inside the central fibre unit, ripcords beside it	Rodent-prone drops, direct-buried drops, duct drops
Vertical riser extract cable	—	Rip cord and extractable fibre bundles	Rising through a building where the cable must be stripped mid-span per floor

Drop cable is normally terminated with field-installable connectors, which means the bend radius and the fibre grade matter more than the fibre count. Use a bend-insensitive grade such as G.657.A2, keep the corner radius generous, and avoid stapling the cable tight enough to deform the flat profile — a crushed FRP rod turns into a permanent bend loss.

7. Jacket, sheath and fire ratings

Decision map of NEC Article 770 optical fibre fire ratings: OFNP plenum, OFNR riser, OFNG general and OFN limited indoor use — Figure 3 — NEC Article 770 assigns the fire rating by where the cable runs: plenum, riser, general horizontal space or limited indoor use.

The jacket is the only part of the cable that building codes actually regulate, and it is the single most common source of a rejected shipment. Two independent properties get confused constantly: fire and smoke performance, which decides where the cable may be installed, and halogen content, which decides what happens when it burns. They are not the same thing, and a cable can satisfy one without the other.

North American ratings (NEC Article 770)

Rating	Test standard	Test method	Where it is required
OFNP / OFCP Plenum	NFPA 262 / UL 910	Steiner tunnel — 88 kW methane, 240 ft/min airflow, 20 minutes; flame spread and smoke optical density measured	Air-handling spaces: ceilings used as HVAC return, raised floors used for air distribution
OFNR / OFCR Riser	UL 1666	Vertical shaft test — 145 kW propane, 12 ft chamber, 30 minutes	Vertical floor-to-floor shafts, elevator shafts, telecom risers
OFNG / OFCG General purpose	UL 1581	Vertical tray flame test	General horizontal spaces with no special code requirement
OFN / OFC	UL 1581 VW-1	Single-cable vertical flame test — lowest tier	Limited indoor use where there is no fire escape path

The suffix letter tells you whether the cable contains metal: C (conductive) means it does and may need bonding and grounding; N (non-conductive) means it does not. This is why an armoured indoor cable has a different rating code from the same construction with an FRP strength member.

Halogen content and the IEC / CPR side

In IEC and EU markets the same question is answered differently. LSZH (low smoke zero halogen) describes the compound: no halogens, so combustion produces little acid gas. It is verified by separate tests — flame spread to IEC 60332, halogen acid gas to IEC 60754, smoke density to IEC 61034. In the EU the CPR framework (EN 50575) then classes the complete cable by heat release and smoke, with sub-ratings for smoke (s1a/s1b/s1/s2/s3), flaming droplets (d0/d1/d2) and acidity (a1/a2/a3). A data-center cable is commonly specified as B2ca-s1a,d0,a1.

A specification trap worth knowing. OFNP is not the same as LSZH. Most OFNP cables achieve their rating with fluoropolymer jackets (FEP/PVDF), which contain fluorine — a halogen. LSZH means zero halogen by definition. If a project needs both, state both and ask for separate test reports: NFPA 262 for the fire rating and IEC 60754 for halogen content.

Jacket compound selection

Compound	Property	Typical use
Polyethylene (PE)	Excellent UV, moisture and abrasion resistance; flammable	All outdoor cable. Black, UV-stabilised.
PVC	Flame-retardant, low cost, contains halogen	General purpose indoor, riser cable
LSZH	Low smoke, zero halogen, lower mechanical toughness than PE	Indoor riser and plenum in IEC markets, tunnels, metro, data centers with strict egress rules
Fluoropolymer (FEP / PVDF)	Highest smoke and flame performance, contains halogen, higher cost	OFNP plenum cable in North America
PU / TPU	Very high abrasion and cut resistance, flexible	Tactical, field-deployable and industrial cable

8. Armour, strength members and rodent protection

Armour and strength members solve different problems and are frequently confused. A strength member (aramid yarn, FRP rod, central steel wire) carries tensile load during installation — it stops the cable stretching. Armour (steel tape, corrugated steel, aluminium tape, dielectric armour) resists crush, impact and rodent attack from outside the cable. A duct cable has a strength member and no armour; a direct-buried cable usually has both.

Protection	Resists	Conductive?	Where it belongs
Aramid yarn	Tensile pulling load	No	Every cable, indoor and outdoor
FRP rod	Tensile load, no metal	No	All-dielectric builds, aerial near power lines
Aluminium tape	Moisture vapour, light rodent bite	Yes	Duct cable in wet environments (GYTA)
Corrugated steel tape	Crush, impact, rodent bite, moisture	Yes	Direct burial and duct (GYTS, GYTA53)
Interlocked / spiral armour	High crush and repeated flexing	Yes	Industrial, mining, heavy-handling routes
Dielectric armour	Rodent bite without metal	No	Rodent-prone ducts where metallic armour is not acceptable (GYFTS)
Glass yarn / nylon jacket	Rodent bite (abrasive to teeth)	No	Anti-rodent cable where armour is not wanted

Two dedicated articles go deeper than this overview. Armored fiber optic cable: types and structure compares the armour constructions in cross-section, and anti-rodent fiber optic cable covers the non-metallic routes to the same outcome. If the route is a transmission corridor rather than a duct bank, ADSS cable explains the all-dielectric aerial option.

9. The optical fibre grades inside the cable

The jacket data sheet rarely tells you what matters most. The fibre grade inside the cable sets the reach, the loss budget and which transceivers will work. Two tables cover almost every project.

Single-mode grades

Grade	Attenuation	Bend performance	Where it is used
G.652.D / OS2	≤0.35 dB/km at 1310 nm, ≤0.25 dB/km at 1550 nm typical	Standard — 10 × cable OD static, 20 × dynamic	Backbone, metro, FTTH feeder and distribution
G.657.A1	Same as G.652.D	≤0.25 dB at 1550 nm on a 15 mm mandrel, 10 turns	Drop cable, tight indoor routing
G.657.A2	Same as G.652.D	≤0.1 dB at 1550 nm on a 10 mm mandrel, 1 turn	FTTH drop at the subscriber end, wall boxes
G.655	Non-zero dispersion shifted	Standard	Long-haul DWDM backbone

Multimode grades

Grade	Core	Bandwidth	Attenuation	Jacket colour
OM1	62.5 µm	200 MHz·km	≤3.5 dB/km at 850 nm, ≤1.5 at 1300 nm	Orange
OM2	50 µm	500 MHz·km	≤3.5 / ≤1.5 dB/km	Orange
OM3	50 µm	2000 MHz·km	≤3.5 / ≤1.5 dB/km	Aqua
OM4	50 µm	4700 MHz·km	≤3.5 / ≤1.5 dB/km	Aqua or violet
OM5	50 µm	4700 MHz·km (wideband)	≤3.5 / ≤1.5 dB/km	Lime green
OS1 / OS2	9 µm	—	See single-mode table above	Yellow

Practical rule. Under 300 m, multimode is usually cheaper once transceiver cost is counted. Over 300 m, or anywhere a future capacity upgrade is likely, single-mode wins. OM1 and OM2 are legacy grades — do not include them in new builds. For a side-by-side comparison of the multimode generations, see Difference between OM1, OM2, OM3 and OM4, and for single-mode grades see Introduction to G651–G657 fiber and OS1 vs OS2.

Recommended products for this stage. Fiber optic cable by construction · Special cable (OPGW, ADSS) · ADSS aerial cable · OPGW overhead ground wire cable

10. Cable marking, metre marking and colour code

TIA-598 twelve-colour fibre sequence with outer jacket colours for OS1/OS2, OM1-OM5 and outdoor cable — Figure 4 — The TIA-598 twelve-colour sequence and the outer jacket colours that identify the fibre class inside.

Cable identification runs on three separate systems that are often mistaken for one. Jacket legend is what is printed along the outside of the cable. Metre marking is the sequential length printed at intervals so a fault distance from an OTDR can be converted into a physical location. Colour code identifies individual fibres and tubes inside the cable. A purchase order that specifies only one of the three will produce arguments on site.

The twelve-colour sequence (TIA-598)

Position	1	2	3	4	5	6	7	8	9	10	11	12
Colour	Blue	Orange	Green	Brown	Slate	White	Red	Black	Yellow	Violet	Rose	Aqua

The same twelve colours repeat for buffer tubes and for ribbons, so tube 1 (blue) holds fibres 1–12, tube 2 (orange) holds fibres 13–24, and so on. Above twelve fibres in a group the colours repeat with a black tracer. Our optical fiber color coding article gives the full mapping including the tracer rules for high-count cables.

What belongs in the jacket legend

Manufacturer and part number — so the cable can be re-ordered exactly
Fibre type and count — for example SM G.652.D 24F
Fire rating — OFNR, OFNP, or the CPR class
Metre mark — sequential length, printed at 1 m or 2 m intervals
Batch / lot number — links the drum back to the factory test report
Customer branding — OEM private label, where the project is supplied under another brand

For large projects, ask for a sample of the print stream and approve it before the drum is run. Re-printing a batch is not possible once the cable is jacketed, and a wrong metre mark is a defect that only shows up during fault-finding.

11. Fibre count, reel length and packing

Fibre count is driven by the splice schedule, not by the current traffic. Sizing a feeder to exactly the equipment on day one guarantees a re-pull later; sizing it two generations ahead costs a fraction of that.

Segment	Typical fibre count	Typical reel / drum	Reason
FTTH drop	1, 2 or 4	1 km, 2 km	One or two fibres per subscriber; spare fibres are cheaper than a second drop
Distribution	12, 24, 48	2 km, 4 km	Feeds a splitter or terminal box serving a cluster of homes
Feeder / backbone	96, 144, 288	2 km, 4 km, wooden drum on request	Once-only installation cost; capacity added by lighting fibres, not by pulling cable
Data center interconnect	8, 12, 24 (multimode or single-mode)	Pre-terminated assemblies, not bulk reels	Pre-terminated avoids field splicing in a live hall

Reel length should be set from the duct section length plus 5–10 % slack for jointing and for the sheave runs. Ordering a single drum that is slightly longer than the longest pull is far cheaper than splicing a mid-span joint into a straight duct run. Standard packing is a wooden drum with an inner end and outer end accessible at both ends of the run.

12. What counts as a fibre optic accessory

Route map showing cable and accessory choices along one FTTH link from feeder cable through closure, distribution, terminal box, drop cable and protection box to the ONT — Figure 5 — One FTTH route, seven transition points: each needs its own cable or accessory, and each is ordered separately.

A fibre optic accessory is anything that completes the cable installation without being cable itself: the hardware that protects it, the enclosure where it terminates, the assembly that connects it, and the tooling that maintains it. Buying these separately from the cable is where most projects lose time, because the accessory specification is usually decided by the installer rather than by the buyer.

Family	What is in it	Where to start
Protection and routing	Spiral wrap, protection sleeves, protection boxes, end caps, trumpet spill-out kits, bend guides, cable locks	Section 13
Closures and terminal boxes	Dome closures, in-line closures, joint closures, access terminal closures, terminal boxes, ODF panels	Section 14
Termination and interconnection	Pigtails, patch cords, adapters, attenuators, loopbacks, splitters	Section 15
Identification	Cable markers, port bezels, labels, colour coding accessories	Section 16
Tools and consumables	Jacket strippers, scribes, cleavers, cutting machines, cleaning products, test equipment	Section 17

Browse the accessory catalogue. Fiber optic accessories · FTTH accessories · Fiber optic tools

13. Cable protection and routing accessories

Most field failures are mechanical, and most mechanical failures happen at the places where the cable changes direction or leaves a duct. These accessories are cheap relative to the cost of a re-pull.

Accessory	What it protects against	Where it is fitted
Cable split protection sleeve	Jacket splitting and abrasion at a riser transition	Where the cable leaves the duct and turns vertically
Drop cable protection box	Impact, UV and tampering at the subscriber entry	Wall entry point of an FTTH drop
Cable end cap kit / port bezel	Water ingress at the end of an un-terminated cable; port identification	Spare ducts and reserved cable ends; panel ports
Trumpet spill-out kit	Bend radius violation where fibres leave the cable or the closure	Closure entry ports and breakout points
Cable connector / junction	Mechanical joint between cable sections	Duct-to-cable transitions
Fibreglass duct rodder	Prevents cable being pushed blind into a blocked duct	Rodding and proving a duct before the pull

Two habits prevent most of this category of damage. First, verify the minimum bend radius at every change of direction — the installed (static) limit is typically 10 × the cable outside diameter for a standard cable and 20 × while it is being pulled. Second, never pull a cable around a corner without a sheave or a bend guide; a bare duct edge acts as a blade under tension.

14. Closures, joint boxes and terminal boxes

Every cable run ends somewhere, and the enclosure it ends in decides whether the splice survives. Closures are selected by splice capacity, by the number and size of cable entry ports, by whether they will be buried, pole-mounted or in a handhole, and by the sealing method — heat-shrink, mechanical or gel.

Enclosure	Mounting	Typical capacity	Where it is used
Dome closure	Pole, manhole, direct burial	Up to 96–144 splices	Trunk and feeder joints, aerial and buried
In-line closure	Duct, direct burial	12–96 splices	Straight-through joints where the cable continues in both directions
Access terminal closure	Pole, wall	1–12 splices	Where a feeder cable drops a service to a subscriber
Splitter dome closure	Pole, manhole	Splitter plus splice trays	Combines a PLC splitter and the splice joints in one enclosure
ODF panel	19″ rack	12–144 ports	Central office and equipment room termination
Splice closure range	All	—	Full catalogue of dome and flat closures

Selection rule. Size the closure for the fibres present plus a 20–30 % spare tray capacity, and count the entry ports you will actually need — including the spare duct you reserved for a future cable. A closure that is full on the day it is installed cannot accept the capacity growth that the feeder cable was sized for.

Recommended products for this stage. Closure AFC-M12AX · Closure AFC-M11AX · Joint closure AFC-06A · Joint closure AFC-M6AX · Access terminal closure AFC-004 · ODF patch panel with door

15. Pigtails, patch cords and adapters

A pigtail ends in a connector at one end and bare fibre at the other, and it is fusion-spliced onto a cable fibre inside a splice tray. A patch cord has connectors at both ends and connects two ports. The distinction matters commercially because the two are ordered in completely different quantities: pigtails scale with splice count, patch cords with port count.

Assembly	Construction	Typical buffer	Ordered by
Pigtail	One connector, one bare fibre end	0.9 mm tight buffer	Splice count — one per splice point
Patch cord	Connectors both ends	2.0 mm or 3.0 mm	Port count — one per cross-connection
Ribbon pigtail	4 / 8 / 12 fibres on one ribbon	Ribbon	Mass-fusion splicing in a ribbon tray
Fan-out / breakout pigtail	One multi-fibre connector to several single-fibre connectors	0.9 mm legs	Connecting a high-density trunk to simplex equipment ports

Colour coding does most of the quality control here. If the pigtail colours match the cable fibre colours, a mistake shows up immediately in the splice tray rather than at the far end of the link. Our FTTH pigtail and patch cord ranges are supplied in single-mode and multimode with LC, SC, FC, ST and E2000 options.

Recommended products for this stage. 12-colour pigtail set · Simplex 2.0 mm pigtail · Multi-core fan-out pigtails · E2000 pigtail · Fiber optic connectors · Fiber optic adapters

16. Markers, labels and identification accessories

Identification is a procurement decision, not an installer preference. The moment a network has more than one cable in a duct or more than one port in a panel, unmarked hardware starts costing money in fault-finding time.

Item	What it identifies	Where it goes
Cable marker	The route, the cable number and the owner	Every manhole, pole and duct entry
Port bezel / label plate	Which panel port is which	Front of every patch panel and ODF
Colour-coded pigtails	Fibre position, matching TIA-598	Splice trays and patch panels
Metre marking on the jacket	Physical distance along the route	Printed by the cable manufacturer

The practical standard is that a technician should be able to stand at any joint, read the marking, and know which cable they are holding without opening anything. Specify the marking scheme in the purchase order alongside the cable itself — retro-fitting markers to a buried route is expensive.

17. Tools and consumables for cable work

The tooling list follows the workflow: strip the jacket, prepare the fibre, splice or terminate it, clean it, then test it. Every one of these steps has a consumable that runs out, and a project that orders tools but not consumables stalls in the first week.

Tool / consumable	Task	Notes
Drop cable jacket stripper	Removing the flat drop jacket without nicking the fibre	Matched to the drop profile, not a generic stripper
Cable stripper	Opening round indoor and outdoor cable	Adjustable blade depth prevents fibre damage
Scribe / cleaver pen	Scribing and cutting bare fibre	For field drops where a bench cleaver is not available
Automatic cable cutting machine	Cutting to length in production	Factory and patch-cord production line use
Cleaning products	Removing gel, dirt and dust from fibres and connectors	Cleanliness is the single largest cause of avoidable loss
Test equipment	OTDR, loss test set, visual fault locator, inspection scope	Acceptance testing needs a launch cable and a documented trace

One test accessory deserves its own mention. An OTDR cannot measure the first and last few hundred metres of a link accurately, because the connector at the instrument is still settling. A launch cable provides that distance, and its length must be longer than the OTDR dead zone. Our guide on how to use the OTDR launch cable properly covers the length calculation and the box options.

18. Specification checklist

Work down this list before sending a cable enquiry. Each line is a decision the factory has to make, and a missing line is what turns into a wrong shipment.

Decision	What to state
Application	Duct / direct burial / aerial / riser / plenum / drop
Construction	Tight buffered or loose tube; central or stranded; armoured or not
Fibre grade	G.652.D, G.657.A1/A2, G.655, OM3, OM4, OM5
Fibre count	Exact count, plus spare capacity if the feeder is being sized for growth
Jacket	PE / PVC / LSZH / fluoropolymer, and the fire rating required by the installing country
Strength and armour	Aramid, FRP, steel tape, corrugated steel, dielectric armour
Water blocking	Gel-filled or dry — dry saves significant splicing time
Marking	Legend content, metre marking interval, OEM branding if required
Reel length and packing	Metres per drum, drum type, whether both ends must be accessible
Test reports	Attenuation and geometry data per fibre, plus fire-rating certificates
Accessories	Closures, pigtails, markers and protection hardware ordered together with the cable

19. Frequently asked questions

What is the difference between indoor and outdoor fiber optic cable?

Indoor cable uses 900 µm tight-buffered fibres with a flame-retardant PVC or LSZH jacket, so it can be terminated directly and passes building fire codes. Outdoor cable uses 250 µm fibres inside gel-filled or dry water-blocked loose tubes with a black polyethylene jacket, so it survives moisture, UV and temperature cycling but is flammable and must not be run inside a building. Indoor/outdoor cable combines both, and is used where a campus run crosses between buildings.

How many fibres should I order for a new build?

Size from the splice schedule two generations ahead, not from current traffic. A typical FTTH drop is 1–4 fibres, a distribution cable 12–48, and a feeder 96–288. The incremental cost of extra fibres in a loose-tube cable is small compared with the cost of re-pulling a duct, and unlit fibres do not need equipment.

Is OFNP the same as LSZH?

No. OFNP describes a North American plenum fire rating tested to NFPA 262. LSZH describes the jacket compound and means it contains no halogens. Many OFNP cables use fluoropolymer jackets that do contain halogens, so a cable can be OFNP and not LSZH. If a specification requires both, state both and ask for NFPA 262 and IEC 60754 test reports separately.

Do I need armoured cable?

Use armour where the cable is at risk of crush, impact or rodent damage: direct burial, rocky duct, industrial sites and rodent-prone routes. Where metal is not acceptable — aerial spans near power lines, or sites where grounding is impractical — a dielectric armour or an anti-rodent jacket gives similar protection without conductivity. Our armored cable types guide compares the options.

Which accessories do I need for a simple FTTH drop?

The drop cable itself, a protection box at the subscriber wall entry, a marker at the pole or duct entry, a terminal or access closure where the drop is spliced to the distribution cable, and a pigtail per splice. In most builds, a field-installable connector removes the splice entirely at the subscriber end.

How do I check that a delivered cable matches the order?

Read the jacket legend against the purchase order: fibre count, fibre grade, fire rating, batch number and metre marking. Then check the factory test report for attenuation and geometry, and confirm the drum count and reel lengths. Our cable inspection criteria article lists the acceptance checks in order.

Why does my cable say GYTA and another says GYTS?

The letters encode the construction. In the GY series, each position describes a property — outdoor use, loose tube, the strength member material, the armour type and the jacket. An aluminium tape barrier (GYTA) and a corrugated steel tape armour (GYTS) are different products for different environments, even at the same fibre count. The naming rules article decodes every position.

About ANFKOM

ANFKOM manufactures fiber optic cable and accessories for FTTH, telecom and data center networks from our own factory in China: indoor and outdoor cable, FTTH drop cable, armoured and specialty cable, splice closures, terminal boxes, pigtails, patch cords and the tooling that goes with them. We supply OEM and private-label orders with factory test reports, and we can produce a specification-matched quote from the checklist in section 18.