Passive Optical Networking (PON) enables a single optical fiber to be shared by many customers, so there is no need to install or manage separate fibers from each customer to the hub. A splitter is not a filter like a wavelength division multiplexer (WDM). Rarely, there can be two inputs to provide potential redundancy of route. Light power goes in and light power coming out of the various legs is reduced in. Some ISP's use ONT's that have integrated routers - its easier for THEM but it gives them more control over your network. Each architecture has tradeoffs in terms of upfront costs, engineering, inventory, maintenance, restoration, and future. There is really no way to generalize on the design process for fiber to the home (FTTH) networks - or any fiber optic network for that matter - since every system is unique. If you are familiar with FOA's other design materials, you know we don't give you formulas or outlines to follow.
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