The chain you will work in
FTTH plant runs: central office (OLT) → feeder cables → FDH cabinet with splitters → distribution cables → drop terminals → drop cables → customer ONT. Point-to-point active Ethernet serves business links; PON shares one OLT port among 32–64 homes through passive splitters. Knowing which segment you are standing in decides which fibers are shared (touch = many customers down) and which are dedicated.
Splitter placement
Centralized splitting (all splitters at the FDH) gives clean test access and efficient OLT port fill. Cascaded splitting (e.g., 1:4 then 1:8 in terminals) saves distribution fiber but complicates testing. Both appear in the field; the design documents, not habit, tell you the splitter ratio behind any port.
The drop and the home
Drops use G.657 bend-insensitive fiber, pre-connectorized where possible; the ONT side is almost always SC/APC. Wall-box slack, staple-free routing and radius discipline at the last 30 meters decide most residential service quality.
Working live plants
Every touch in a shared segment follows method-of-procedure: identify the correct fiber (records + filtered identifier), notify, use 1625/1650 test wavelengths, and never open a splitter tray without a change window. One wrong tube in an FDH is a neighborhood outage with your name on it.