FTTx stands for Fiber to the x or Fiber to x. It is not actually a fiber optic technology itself, but a term used to encompass a series of fiber optic deployment topologies or architectures, differentiated according to where the fiber cable terminates.

But when we talk about a fiber optic connection, isn't everything fiber? Well, in most cases no.

Traditionally, a commercial fiber optic connection is actually a mixed solution, using fiber optic cable for the long distance sections of the network and other types of cabling (xDSL copper, HFC coaxial, ethernet…) for the last kilometer ( or mile in English), the closest to the subscriber. This type of architecture allows cost and complexity savings the further the true optical fiber is from the subscriber. Bandwidth and latency remain almost unchanged under the perception of the end user (and if the network is sized well).

Most recognized FTTx variants

The "x" of the term FTTX adopts several letters, the most famous being: Home (home), Building (building), Curb (sidewalk) and Node (node). We are going to know each one of them, ordered by their proximity to the end user, from closest to furthest:

FTTH
Fiber To The Home or fiber to the home, in this variant the fiber reaches the subscriber's home or office. You can read this article to know more details about this connection.

FTTB

Fiber To The Building or Basement or fiber to the building or basement, the fiber reaches a location within the building or block of buildings.

FTTC

Fiber To The Curb or Cabinet or fiber to the sidewalk or cabinet, in this variant the fiber ends in a location close to the building or block of buildings, usually less than 300 meters.

FTTN

Fiber To The Node or Neighborhood or fiber to the node or neighborhood, in this variant the fiber ends in a distribution cabinet of the operator, located at a distance of more than 300 meters from FTTC subscribers.

This image is a good graphic summary of these 4 FTTx variants: