Fiber Optic Cables, Components, and Hardware
Cable construction
Know the difference between tight-buffered indoor cable (each fiber has its own buffer, easy to connectorize, used inside buildings) and loose-tube cable (fibers in gel-filled tubes, typical outdoors/OSP, better for temperature and moisture). Indoor/outdoor and armored variants exist for wet locations and rodent protection.
Fire ratings (NEC)
Optical fiber cable is marked OFNP (plenum), OFNR (riser), or OFNG/OFN (general purpose). "C" is inserted (OFCP/OFCR/OFCP?) when the cable contains conductive elements, e.g., OFCR. The classic trap: cable in an air-handling (plenum) space must be plenum-rated; substituting a lower rating because the fiber itself is non-conductive is not acceptable.
Connectors, adapters, and polish
Common field connectors are LC (small form factor, 1.25 mm ferrule), SC (2.5 mm square), and ST (bayonet). End-face geometries are PC, UPC (blue, domed), and APC (green, 8° angled). APC and UPC must never be mated - the angled face leaves an air gap and causes high loss and reflectance. Adapters must match the fiber type: MM adapters usually use phosphor-bronze alignment sleeves, SM adapters ceramic (zirconia) sleeves.
MPO and polarity
MPO/MTP trunk assemblies come in 8, 12, 24+ fiber counts and follow three polarity methods (A, B, C) defined in TIA-568. Mixing polarity types between a cassette and a trunk is a frequent field error found by polarity testing.
Hardware
Splice trays, splice protectors, pigtails, patch panels, innerduct, J-hooks, and cable ties are all "hardware"; respect the manufacturer's bend radius (commonly 10× cable OD installed, 20× during a pull) and never cinch ties tight on fiber.