Passive Optical Network, a design in which one optical line terminal port feeds a single fiber that passive splitters divide among 32 to 64 or more subscriber ONTs. GPON sends downstream at 1490 nm and upstream at 1310 nm; XGS-PON uses 1577 nm down and 1270 nm up, so both can share the same fiber. Because the splitters cost a large share of the loss budget, PON is sensitive to every extra connector and dirty APC end face.
That PON port has 28 ONTs on it, two more and we're splitting the feeder to a new card.
Related terms
Splitter
A passive optical device that divides the light from one fiber among several output fibers.
FTTH
Fiber to the Home: access networks that run fiber all the way into each residence.
APC
Angled Physical Contact: a singlemode connector polish with an 8 degree angle that sends reflections into the cladding.
WDM
Wavelength Division Multiplexing: sending several signals on different wavelengths over the same fiber.
Drop
The final fiber cable run from a distribution terminal on the street to a single customer building.