Fiber optic networks have gained significant popularity in recent years as the demand for increased network speed has been consistently rising across the planet. Due to its high-speed data transmission with low attenuation, particularly for long-distance deployments, fiber optic networks are widely accepted in high-bandwidth applications. This includes mission-critical applications such as surveillance camera systems. Single-mode optical fiber is used extensively for fiber optic communication today as it has virtually unlimited bandwidth capacity.
As the number of connected devices increases worldwide, the management and distribution of fiber cables become more complex. They can get tangled easily if they are not properly maintained. Moreover, they are also quite susceptible to oxidation owing to long-term exposure to the outdoor environment. A Fiber Termination Box (FTB) was essentially developed to address this issue. It helps protect fragile fiber terminals and facilitates a simple system for managing both outgoing and incoming cables.
Fig 1: Fibre Termination Box
Image credit: www.baudcom.com.cn
Fiber Termination Box: A brief overview
A Fiber Termination Box (FTB), also known as Optical Terminal Box (OTB) is a distribution junction, which is specifically built for managing fibre cables in FTTH installations. Its main function is to join the pigtail and core of fibre optic cables. A fibre pigtail is a single, brief optical fibre with a tight buffer that has an optical connector already attached to one end and a certain length of exposed fibre at the opposite end. These ends are stripped, and one of them undergoes fusion splicing to connect to a single fibre. To create an optical data transmission path, the other end links the optical transceiver modules or fibre optic converter. The pigtail is then used for connecting the fiber cable, with the use of couplers or adapters within the box. Hence, it then connects to the fiber patch cord when being used in the termination box.
The fiber termination box is an important aspect of ADSS Cable installation. It provides a budget-friendly means for systematically handling expansive quantities of fiber cables, with higher flexibility and lower expenses. The number of fiber cores in the FTB tends to vary based on distinctive manufacturers. The fiber core may range from 2 to 96 ports, based on real-life applications.
A typical fiber termination box comprises three parts, the fiber connector protection element, internal components, and the housing. Its internal components are typically encapsulated in an IP-rated housing made of impact-resistant and sturdy materials that can protect against damages caused during operation and placement. For long-term outdoor deployments, it becomes important for FTB components to be dustproof and have good resistance to corrosive elements. Its housing should be easy to open and have provisions for a lock to prevent potential tapping.
The internal components of a fiber termination box include fixtures, a fixed fiber tray, as well as a supporting frame. This supporting frame is the main body of the internal structure. To maintain fibers in an organized manner, the fiber tray is used for mounting LC/ST-type fiber adapters. Based on distinctive requirements, the splice tray is sometimes located within the termination box to accommodate fused fibers. The fixtures are subsequently used for fixing fiber pigtails or optical cables for improved organization. The fiber connector is generally shielded by a head-shrinkable clip or tube for improved protection.
Protection and management of fiber optic cables
While fiber optic cables have many advantages, fragility is one of their biggest limitations. Generally made of glass, fiber optic cables are much lighter and thinner than metallic wiring, making them widely susceptible to damage. Radiation or exposure to chemicals can damage a fiber optic network. Its fragile cables can be cut easily during building rewiring or renovations. Fiber cables also have a limited bend radius, thereby complicating the prospect of laying them around corners. Too much bending built into the system may cause breakage or signal attenuation. Hence, extra protection is required to ensure that multicore or single-mode optical fiber works properly. FTB integrates the storage, management, splicing, and termination of fiber optic cables in a single unit. It is designed to be managed, maintained, and installed with ease. With a compact rack or wall mounting design, the Fiber Termination Box is a space-saving solution for fiber optic installation, especially when it is not feasible to have large terminal hubs.
Fig 2: Wall-mounted termination box
Image credit: www.baudcom.com.cn
Fig 3: Rack-mounted termination box
Image credit: www.baudcom.com.cn
Diverse types of FTBs
Wall-mounted and Rack-mounted
Based on the designs, fibre termination boxes can be divided into wall-mounted and rack-mounted boxes. The wall-mounted design features a rear and front opening, along with a side rail attached directly to the server rack. On the other hand, the rack-mounted design is mostly sealed and hung on the wall.
The wall-mounted Fiber Transmission Boxes are typically used to implement direct connections. Certain tasks such as splicing, fusion and termination should be done, before installing the FTBs onto the wall fixture. Such a setup is ideal for building entrances, teleconferencing and other such applications.
In contrast, the rack-mounted Fiber Termination Boxes are preferable mostly for the interconnect or cross-connect architecture. Such fixtures are ideal for building transmission device and external plant cable interfaces. In this fixture, there is enough room for management, distribution, termination and fusion tasks.
This FTB fixture is only recommended for indoor deployments, whereas the wall-mounted FTB fixture can be customized for both indoor and outdoor installations.
Fig 4: Outdoor Termination Box
Image credit: www.baudcom.com.cn
Indoor and Outdoor
FTBs can be categorised as either outdoor termination boxes or indoor termination boxes. The categorization depends on how they are used in various environments. The production materials will be the main factor of distinction between them. In case an FTB is designed for outdoor deployment, the material characteristics must be stable enough with resistance to weather adversities. The melting point of the materials should not be less than 120°C. All of the FTB components must operate in an expansive temperature range of at least -25°C to 45°C. It is to help it survive major temperature fluctuations! The outer casing is often well-sealed to protect all the inner components from wear and tear. These boxes aslo have a very high impact resistance. The indoor FTB, on the other hand, is known to be the transition point between horizontal and upstream cables. They are commonly used as a storage location for fiber distribution and termination in more of a controlled setting and hence do not have any special requirements in terms of the materials.
To select the perfect fiber termination box for your network, you need to assess your requirements competently and opt for the option that effectively aligns with your needs. FTBs can be found in a variety of materials, shapes, and sizes. You need to take into account the number of fibers used and space available, among other things, to identify the one that would work the best for your assembly.
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1. What is a Fiber Termination Box (FTB), and what is its core use?
FTB (Fiber Termination Box) is a distribution junction, specifically designed for managing the fiber optic cables within FTTH applications. The core use of FTB is to ensure protection as well as distribution of the fiber links of FTTH networks. Its direct application is to stop the connection of fiber cables, and then connect its core to pigtail, through splicing.
2. What are the benefits of using a Fiber Termination Box for managing fiber cables?
The benefits of using Fiber Termination Box, includes protection of all fiber optic slices, joining the fiber pigtail and sharing connectivity to respective customers. It enhances the flexibility and reliability of managing the fiber cables and associated connections seamlessly. FTB contains the support structure and all protective elements of fiber cables.
3. What are the internal components of a typical fiber termination box?
Considering the structure, a FTB consists of three parts; a shell, the internal components and the connector protector. To be precise, the internal components of typical Fiber Terminal Boxes include:
- Support Frame
- Fiber Collection Tray
- Fixing Device
4. What are the differences between wall-mounted and rack-mounted FTBs?
Both wall-mounted as well as the rack-mounted FTBs serve different purposes and are beneficial in their own ways. The wall-mounted FTBs are preferable for direct connections. It demands the technicians to get over with termination, splicing and fusion works prior to the installation of wall-mounted FTBs.
In contrast to that, the rack-mounted FTBs are preferable for cross-connect or interconnect optic fiber architectures. With such a setup, building the interfaces between the outdoor plant cable and transmission device is feasible. It is due to the availability of ample space for seamless execution of fusion, termination, distribution and management aspects.
5. What are the differences between indoor and outdoor FTBs, and what materials are used for manufacturing them?
The materials used for the manufacturing of indoor & outdoor FTBs define the potential difference between them. The materials used for making the outdoor FTBs should be resistant to weather adversities and climatic changes. In contrast to that, the indoor FTBs do not need special materials as they are located at safe sites and used for fiber storage and termination.
In general, the FTBs are made up of cold-rolled steel plates and are sprayed with an electrostatic agent. For outdoor FTBs, there’s a need for maintaining a stability of physical and chemical properties, with a properly sealed case on the outside.