What Is a Fiber Distribution Terminal (FDT)?
A fiber distribution terminal (FDT) is the enclosure where distribution fiber is split and routed to individual customer drops in an FTTx network.
A fiber distribution terminal (FDT) is an outdoor enclosure, mounted on a pole, in a pedestal, or inside a cabinet, where distribution-level fiber optic cable is split, spliced, or connectorized and broken out into individual drop cables that run to each customer's home or business. It marks the transition point between shared network fiber and dedicated last-mile service.
Where an FDT Fits in the Network
In an FTTx network, fiber runs from the central office or hub through feeder cable to a distribution point, then out to individual customers as drop cable. The FDT sits at that middle handoff. Distribution fiber arrives from one direction, and drop cables leave in the other, one per subscriber or small group of subscribers. Inside the enclosure, technicians splice or connectorize each fiber so it can be tracked, tested, and serviced without disturbing the rest of the distribution network. Because an FDT concentrates dozens of live connections in one box, correct labeling and slack management inside it directly affect how fast a crew can troubleshoot an outage or turn up new service.
What's Inside an FDT
Most FDTs hold one of two things: fused splices joining distribution fiber to drop fiber, or optical splitters that divide a single PON feed into multiple output legs for a GPON or XGS-PON deployment. Splice trays store and protect the fragile fusion points; splitter modules snap into the same footprint on networks using passive splitting. Ports are typically factory-terminated with connectors so a technician can patch in a new drop cable at turn-up without a splice trace back at the hub. Slack loops of fiber are coiled and secured inside the housing so the enclosure can be reopened for repairs or reconfiguration without pulling new cable from the distribution route.
FDT Types and Placement
FDTs come in a few physical forms depending on the build. Pole-mounted and strand-mounted units serve aerial routes, pedestals sit at grade over buried cable, and larger wall-mount or rack cabinets serve dense multi-dwelling or commercial builds. The right form factor depends on plant type, expected port count, and how easily a technician needs to access it later for splicing, testing, or a service call. Placement gets decided during the design phase alongside splice point spacing and drop cable routing, since moving an FDT after construction means re-splicing distribution fiber.
Fiber Distribution Terminal (FDT), answered
What Is a Fiber Distribution Terminal (FDT)?
A fiber distribution terminal (FDT) is an outdoor enclosure, mounted on a pole, in a pedestal, or inside a cabinet, where distribution-level fiber optic cable is split, spliced, or connectorized and broken out into individual drop cables that run to each customer's home or business. It marks the transition point between shared network fiber and dedicated last-mile service.
What's the difference between an FDT and a splice closure?
A splice closure protects fusion splices inline along the fiber route, with no intent to break out drop cable there. An FDT is built specifically as a service access point, giving each customer drop its own port so it can be connected or disconnected without disturbing the rest of the distribution network.
How many customers does one FDT typically serve?
It depends on port count and splitter ratio, but a common range is 8 to 32 subscribers per FDT. Pedestal and cabinet units generally run higher counts than small pole-mounted terminals.
Is an FDT the same as a NID?
No. A NID (network interface device) sits at the customer's home or business and marks the property line between the network and the customer's own wiring. An FDT sits upstream in the distribution plant and serves multiple customers from one enclosure.