Installation
Equipment and installation routes

How Fibre Enters Your Home: Boundary Box, Drop Cable and ONT

UrbanX Installations & Field Operations
26 Aug 2026
9 min read
Quick Answer

Fibre reaches a home from an FNO distribution point in the street, chamber, cabinet, pole, estate or building. A final drop cable runs to the property, may terminate in a boundary or wall box, then continues to an indoor termination and ONT. The ONT converts the optical service to an Ethernet handoff for the ISP router. Names and box arrangements differ between FNOs. Focus on the function of each part rather than expecting every installation to look identical.

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Last reviewed: 26 August 2026 · 9 min read

The complete path at a glance

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FNO distribution network → property drop → termination point → internal fibre → ONT → Ethernet → ISP router → home devices

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This is a functional sequence, not an instruction to open, move or reconnect the equipment.

1. FNO distribution network

The local access network brings fibre close enough to serve a group of properties. Depending on the design, distribution can occur through:

  • underground chambers and ducts;
  • street cabinets;
  • pole-mounted enclosures;
  • estate distribution points;
  • building communications rooms, risers or floor boxes.

The customer does not normally interact directly with this infrastructure. It is part of the FNO network and should be opened only by authorised personnel.

2. The final drop

The drop is the connection between the distribution network and the individual premises or unit. It may:

  • pass through underground duct;
  • cross private property in protected conduit;
  • run overhead from a pole;
  • travel through an estate duct;
  • use a building riser before entering an apartment.

The drop route is agreed during installation and should be protected from sharp bends, crushing, vehicles, doors, gardening and building work.

3. Boundary or external termination

Some networks use a box at the boundary or exterior wall to separate the street-side and premises-side route. Names include boundary box, termination box, access box or other FNO-specific terms.

Its function can include:

  • protecting a join or connector;
  • providing an identifiable transition point;
  • allowing maintenance without disturbing the full internal route;
  • associating the property with a network distribution path.

Not every design uses a separate visible boundary box.

4. Internal fibre route

From the property entry or termination, a smaller protected fibre cable reaches the indoor equipment position. It may run through approved conduit or surface-mounted protection.

The route should be:

  • agreed before drilling;
  • secured rather than loose;
  • protected at wall entries and corners;
  • kept away from crush points and moving furniture;
  • accessible enough for future maintenance;
  • within owner and building permissions.

This is optical fibre, not the Ethernet cabling covered by the Home Network Infrastructure pillar.

5. Fibre termination box

Some installations use a small wall-mounted termination or access box near the ONT. The drop or internal fibre is safely terminated or joined inside it, and a short fibre lead connects onward.

Do not open the box, pull the lead or inspect the connector. Contamination and physical damage can interrupt the service.

6. Optical network terminal

The ONT is powered electronic equipment registered on the FNO network. It receives the optical signal and provides the service handoff used by the ISP.

Depending on product and network, the device may have:

  • optical input;
  • one or more Ethernet ports;
  • power connection;
  • identifying serial or line information;
  • status lights;
  • voice or other product-specific ports.

The existence of unused ports does not mean the customer may connect services to them. Use only the port and method supplied for the order.

For equipment placement, read Choosing the Best ONT Location.

7. Ethernet handoff

The ONT provides an Ethernet connection to the ISP router. This point marks an important responsibility boundary:

  • the FNO delivers the access connection to the termination equipment;
  • the ISP provisions internet access and usually supplies or supports the router;
  • the home network distributes the connection to devices.

ISPA’s consumer-education guidance distinguishes the FNO service at the fibre termination from performance on the customer’s internal Wi-Fi or devices.

8. ISP router

The router creates the household network and directs traffic between the home and ISP service. It may connect by DHCP, PPPoE or another provider-specific method. Follow the supplied instructions.

This article stops at the handoff. Router CPU, Wi-Fi, access points, mesh and Ethernet design already have a canonical home-network pillar.

What may look different in an apartment or estate

Shared distribution can add:

  • estate or building fibre entry;
  • main distribution frame or communications room;
  • vertical riser;
  • block, floor or passage distribution point;
  • shorter final unit drop.

The unit still normally ends in a termination/ONT arrangement and router handoff, but equipment and naming vary.

Who owns each part?

Ownership is determined by operator and service terms. As a safe operational rule:

  • treat street, pole, building-distribution, drop, wall-box and ONT equipment as FNO infrastructure unless documents say otherwise;
  • treat the router according to the ISP equipment terms;
  • treat customer-installed Ethernet and home-network devices as separate from the FNO fibre route.

Do not remove the ONT when moving house or changing ISP without explicit instruction.

What to record at handover

  • location and photographs of the property route;
  • visible termination and ONT position;
  • ONT serial or service identifier;
  • designated Ethernet port;
  • FNO and ISP names;
  • installation and activation references;
  • ownership or damage-liability terms;
  • any outstanding physical work.

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