Fiber optic distribution boxes are a key component in fiber optic networks and provide a centralized access point for the administration and distribution of fiber optic cables. The distribution boxes allow large main fiber optic feeder cables to be broken down into individual fibers or smaller groups of fibers for more flexible routing to end users or equipment. Within the protective housing of the box, the fibers are separated, organized, and provisioned for efficient connectivity and splicing as needed.
The main purposes of a fiber distribution box are 1) to provide easily accessible termination points for the main feeder fiber optic cables entering a building or location and 2) allow the network administrator flexibility in directing subsets of fibers to different areas as required. The distribution box serves as an organizational hub and patch panel for crossing connections between feeder fibers and distribution fibers leading to specific areas or devices.
Within a fiber optic distribution box, fiber optic adapters, connectors, splices, splitters and other hardware provide the means to administer the fibers. Fiber adapters allow quick connection and disconnection of fiber patch cords. Fiber connectors such as LC or SC connectors attached to the end of fibers enable mating with adapters. Fiber splices provide permanent joint between two fiber strands. Fiber splitters divide and distribute an incoming fiber to multiple outgoing fibers.
Proper cable entry locations are designated to bring in and break out the main fiber feeder cables and distribution cables that connect to end points. Slack fiber storage and routing hardware such as spools, channels and clips assist in neatly housing and directing the fibers within the box. Ample space and proper cable bend radius is maintained to prevent fiber damage.
Accessibility and ease of cable administration are important aspects of fiber distribution box design. The box allows for neatly managing the intricacies of fiber cross-connections, while providing ready access for any fiber moves, additions or changes. For this reason, distribution boxes are typically located in central communications rooms where fiber technicians can readily get to them. Wall-, pole- or strand-mounted boxes are common options.
Fiber distribution boxes come in a range of sizes and designs to suit the scale and layout of premises. Compact boxes may have capacity for 4-12 fibers while large distribution frames can terminate thousands of fibers. Some key fiber distribution box types include:
- Main distribution box – The centralized box typically located in the communications room of a building, serving as the hub connecting multiple feeder cables to multiple distribution cables out to different areas.
- Secondary distribution box – Provides intermediate connection point, further splitting out fiber distribution cables from the main distribution box to specific zones or floors.
- Customer premises box – A small fiber termination box located at an individual customer site like a business office, providing direct fiber optic cabling into the premises from the distribution cable.
- Fiber terminal boxes – Located outdoors on poles, street cabinets or mounted on strand, these enclose fiber optic cable termination points from the distribution network into drop cables to nearby customer sites.
Proper planning for current and future fiber optic network requirements will determine the appropriate number, size and location of fiber distribution boxes. Overall, fiber distribution boxes provide accessible, organized connection points to optimally cross-connect, configure and protect fiber optic cabling – a critical function enabling the performance and flexibility of high-speed fiber networks.