Role of Fiber Termination Box (FTB) in FTTH Network

Role of Fiber Termination Box (FTB) in FTTH Network: The FTB shall be used to provide a fiber termination point with test facilities between drop cables and inside wiring for customer’s building. The FTB shall be installed in the customer building's outside wall or designated communication room. FTB generally installed on the wall of the customer's house, from which easy to be provided FTTH services  to the customer.

The FTB must be compatible with telecom operator for the installation standards and operation and maintenance practices.The FTB must be suitable for the outer environment and constructed for outdoor installations, it is suitable either flush mounted, surface-mounted on concrete walls or pole mounted. The Installation of the FTB shall require only simple hand tools.

Working on FTB

Fiber Termination Box (FTB)

Use of Fiber Termination Box (FTB)

FTB use for the termination of optical fiber up to the customer premises.The FTB allow termination, splicing, storage and management of optical fibers contain within. The FTB shall employ a fiber management system such that all fibers are properly routed and secured. All points in the fiber path shall maintain a minimum bending radius of 30 mm.

The FTB shall be sturdy and impact-resistant against damage during placing or installation operations. The FTB shall be dust-proof, splash watertight, weather proof, and prevent corrosion to the hardware contained within.The overall appearance of the installed FTB shall be reasonably aesthetically pleasing. All material used in the FTB shall be non-toxic and dermatological safe.

Looking at the customer's requirement or the size of the building, the type of FTB is decided. Generally the FTB available in four choices of built-in fiber termination capacities as the followings:

➥FTB with 2 fiber capacity in box type 1.
➥FTB with 4 fiber capacity in box type 1.
➥FTB with 12 fiber capacity in box type 2.
➥ FTB with 24 fiber capacity in box type 2.

According to fiber capability, the name of the box can be different in different countries.I think it is advisable to write box type-1 and box type-2 here, that's why I have written but you can call the box's name as per your country's telecom industry.

Design Structure of Fiber Termination Box (FTB)

Material used for the FTB is Glass fiber reinforced polyester or poly-carbonate. Generally wall thickness 32mm minimum. Outside dimensions (mm), is approximately as mentioned below-

Outside Dimension of FTB box

FTB box type and dimension

Or other suitably sized, corresponding to the number of fiber terminations or splices, to allow efficient fiber management and easy access to all components.

FTB have proper entry and exit holes for the cables. Entry holes for cables have sufficient number of grommeted entry holes or knockout inserts shall be provided at top and bottom panels for the full complement of incoming cables.

Exit holes for distribution fiber cords have sufficient number of grommeted entry holes or knockout inserts shall be provided at top and bottom panels for the full complement of fiber cords. It has minimum of 4 mounting bolts for wall mounting.

Patch Panel (Plate) used in FTB

Patch panel (Plate) used in FTB is LC panel for mounting LC-type adapters. Termination capacity used for the Box Type-1; 4 adapter patch panel for fiber terminations and Box Type 2; 24 adapter patch panel for fiber terminations.

Shall be mounted separately and with sufficient space from the splice trays.It allow front or side patching. Shall be equipped with panel-specific guide rings or routing clips for proper management of fiber cords.

Splice Tray in FTB

Splice tray in FTB is high quality plastic. It has Snap-on type for heat-shrink splice protectors or mechanical connectors. Splice holder capacity in FTB is for Type 1; 1 splice tray or build-in splice holders into the base of the box with 8 holders for incoming and outgoing fibers splicing to pigtails and  for Type 2; 2 splice trays, each with 24 holders for incoming and outgoing fibers splicing to pigtails. Fiber bend radius acceptable inside the tray is 38 mm, minimum.

Adapter (Thru-Connector) in FTB

Type of adapter used in FTB is LC through-adapter (4 units of adapters for type 1 and 24 unit of adapters for type 2). It has Insertion loss approx 0.1 dB (typical). LC shall be mounted by snap in latch type or fixed by means of 2 screws on square flange.Number labels, of minimum 8x8 mm, shall be provided for each connector/adapter position.

FTB Accessories

Pigtails: Pigtails with LC/APC connectors shall be provided as the followings to terminate the incoming drop cable:

➥2 units for FTB 2F.
➥4units for FTB 4F.
➥12 units for FTB 12F.
➥24 units for FTB 24F.

Splice protection sleeve: Heat-shrinkable sleeve, for fusion splice.

Protective tube set: Spiral tube, white, 1m long, 15-17 mm inside diameter.

Material Properties of FTB

The FTB shall meet all the material properties as per below mentioned table-

Material Properties

Material Properties of FTB

Some other points about Fiber Termination Box (FTB)

➤Each FTB and its accessories shall be packed such that all components for a complete unit meet the installation requirements.
➤All the components/parts for the FTB as described in this specification shall be provided as a complete assembly and as one packaged unit.
➤The individual FTB packages may be multi-packed in strong, weather resistant carton boxes suitable for shipping, handling and storage. The weight of each multi-packed carton shall not exceed 25 kg.
➤The FTB shall be completely assembled (Ready to install) with the following components:

➥Housing equipped with base and cover and Patch panel (Plate).
➥Cable clamp hardware and fiber guide rings or clips.
➥No. of required Splice trays, equipped with splice holders.
➥No of required LC Adapters (4 for box Type 1 and 24 for box Type 2) and Numbering labels.
➥2 Pigtails, with LC/APC connector for 2 Fiber FTB.
➥4 Pigtails, with LC/APC connector for 4 Fiber FTB.
➥12 Pigtails, with LC/APC connector for 12 Fiber FTB.
➥24 Pigtails, with LC/APC connector for 24 Fiber FTB.
➥No. of required fusion splice protection sleeve for each type.
➥Protective tube set and adapter cap for stand by adapter.

➤The FTB and its accessories shall be covered with a protective material to prevent scratching or damage during shipping or storage, prior to placing the items into the packing carton.

➤Each unit of FTB shall be supplied with complete installation instructions, in English  for the assembly of parts.