STB : Subscriber Terminal Box

STB (Subscriber Terminal Box) : Actually STB is a type of box used in the FTTH network. The STB as a box to be used in FTTH network for the connecting, testing capability point for up to 4 & 10 pairs of secondary cable , or buried service wire ( BSW ) or drop wire on the network side and the subscriber`s indoor wire on the customer side . STB to be installed outdoor on the customer's perimeter wall. The STB 10 pair and Aerial / wall DP are the same in shape but when the box is used as Arial DP it must be equipped with pole mounting band and pole mounting plate.

The Aerial / Wall DP shall be used as a connecting, testing capability point for up to 10 pairs of secondary cable and the drop wire on the network side. Aerial / Wall DP's shall be installed outdoor on the customer's perimeter wall or on pole.

STB used in FTTH Network

STB 10 pair and 4 pair

What does STB matter in a FTTH network

STB specification covers the minimum standards and requirements for the construction, properties, testing and packing of the following items-

➤The 4 & 10 pair's Subscriber Terminal Box ( STB ) .
➤The 10 Pair Aerial / Wall Distribution Point ( Aerial / Wall DP ) .
➤The IDC Connection Module & Plug In ( Continuity , Protection ) Module .
➤The Maintenance Testing Unit ( MTU ).

Definition of STB & Aerial / Wall Distribution Point: A box which covers and protects the IDC Connection Module and other hardware contained within the box.

Definition of IDC Connection Module: An interface point between the BSW or secondary cable and the subscriber's indoor wire.

Maintenance Testing Unit ( MTU ): A unit which is used with (STB) IDC Connection Module to determine the faults in the circuit and whether it is in the network side or subscriber side It determines the faults in the network (short) or (open) faults at least, from both sides, by remote control center.

STB General Technical Requirements

STB , Aerial / Wall DP & other item must be compatible with telecom industries installation , operation and maintenance practices. The STB , Aerial / Wall DP shall be designed and constructed to be suitable for flush or surface mounting installation.

All components of the STB & Aerial / Wall DP shall be of high quality design and workmanship. The box shall be free from flaws, pinholes, bubbles, cracks, inclusions , or other defects which are visible with the naked eye. The box shall exhibit a uniform finish both inside and outside.

The STB & Aerial / Wall DP shall be sturdy and impact-resistant against damage during placing or installation operations. The STB & Aerial / Wall DP shall be dust-proof , splash watertight, weather proof , and prevent corrosion to the terminals and other hardware contained within.

The overall appearance of the installed STB & Aerial / Wall DP shall be reasonably aesthetically pleasing. All material used in the STB & Aerial / Wall DP shall be non -toxic and dermatologically safe.

STB Design Requirements

STB design and parameter requirements

STB design and parameter

The STB , Aerial / Wall DP & other item shall be designed and have provision for major components and parts.

STB Base Parameter and requirements
➜ Base material used for STB - Glass fiber reinforced polyester or polycarbonate.
➜ Wall thickness of STB- 2 mm , Minimum , tolerance + 0.2 mm.
➜ Outside dimensions (4 pair box ) - Dimension of BSW or drop wire entry hole-25 mm ( w ) x 18 mm ( H ) and -Dimension of Indoor wire entry hole- 25 mm ( w ) x 18 mm ( H ).
➜ Outside dimensions (10 pair box ) - Dimension of secondary cable entry hole- 25 mm ( W ) x18 mm ( H ). and Dimension of Indoor wire or drop wire entry hole- 49 MM ( W ) x 38 mm ( H ).
➜Mounting - ( 4 pair box ) - Onto wall via four-5 mm diameter screw holes with 10 mm ( max. ) embossed surface protruded at the outer surface of the base.
➜Mounting (10 pair box ) - Onto wall / pole via three- 6 mm x 10 mm screw holes.

STB Cover Parameter and requirements

➜Cover Material used for STB- Glass fiber reinforced polyester or polycarbonate.
➜Wall thickness - 2.5mm, minimum, , tolerance + 0.2 mm.
➜Construction - Hinged on top of the base. Opening angle shall be 95° min. Equipped with a retainer mechanism to secure the cover.
➜Lock type - Male hexagonal type, 12 mm between the flats.

STB Mounting Rail Parameter and requirements

➜Material used- Stainless steel , type 304 ,1 mm thick min. ( a standardized 35 mm wide metal rail with hat-shaped cross section ).

➜Dimension -  4 pair box - 35 mm ( W ) x 111.5 mm ( L ) x 6 mm ( H )
- Other size of 4 pair box- 35 mm ( W ) x 108 mm ( L ) x 6 mm ( H )
10 pair box - 35 mm ( W ) x 246.79 mm ( L ) x 6 mm ( H ), Other size of 10 pair box- 35 mm ( W ) x 232 mm ( L ) x 6 mm ( H ).

STB Connection Module Parameter and requirements

➜Module elements- 

1. Each end where the two wires are connected -Wire Holder Body .
2- Central Body made up of a base and plug-in module.
3- Spring.

➜Material used- Transparent polycarbonate.

➜Construction - The wire holder body are used as a housing for the Secondary cable or BSW or drop wire or Indoor wire. The body material is transparent to facilitate connection by allowing the cable routing to be seen. The side housing body shall be fluid with silicone to make the connection watertight and have membranes which improve this feature and prevent loss of fluid after successive reconnections.

Wire holder screw Shall be made from zamak alloy with direct passivity plus lacquering.The wire holder cover shall be made from polycarbonate.The cleaning membrane shall be made of thermoplastic rubber.

STB Central Body Parameter and requirements

➜Material used- Reinforced polycarbonate with fiberglass.
➜Construction - Shall be contains of 5 contacts two are used for the secondary cable or BSW or drop wire and two for the indoor wire or drop wire .The fifth is a ground connection with contact to the mounting rail and for other special plug-in modules.

The Ground contact shall be of alloy of copper, zinc and nickel. The lower sealant shall be made of epoxy resin.

STB Plug-in Modules Parameter and requirements

➜Material used- The body & cover shall be made of Reinforced polycarbonate with fiberglass. The continuity and protector ground contact shall be made of Tinned hard brass. The “O” ring shall be made of EPDM Ethylene/Propylene/Diene Polymerisate (Terpolymer) Rubber.

➜Construction- Continuity Module Shall be provide the connection between the cable pair and the drop wire pair. It shall be comprise a modular plastic body, 4 contacts and a shorting link between cable and drop connections.

The two test points, sealed with Silicone gel. The module shall be fitted with an “O” ring to provide a watertight seal between the plug-in module and the connection module.

Protection Module :- Shall be used when protection is required. It shall be equipped with gas discharge tubes.

STB Maintenance Testing Unit ( MTU )  Parameter and requirements

➜Main components - A single circuit board with solid state technology. It shall contains a reduced number of components in order to assure its reliability and lifespan. All the components shall be assembled on a small PCB and installed in a plastic housing. The whole assembly shall be filled to provide the excellent environmental protection required.The upper sealant shall be made of epoxy resin.The contact element shall be made of Tinned phosphor bronze.

➜Material used- Housing Shall be made of impact resistant Polycarbonate.

STB Other Requirements

Each STB or Aerial / Wall DP 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. Complete assembly and installation instruction in English shall be provided with each packaged unit.

The individual packages shall be multi-packed to a Max. weight of 25 kg. The shipping cartons shall be of sufficient strength and durability to protect the contents from normal handling , storage and transportation.

Each individual package and multi-packed carton shall be marked in legible color with the following information , in English , on at least two sides of the package / carton-
⏩Telecom Industry name.
⏩Name of Item
⏩Mic. Number
⏩Unit and Package Quantity
⏩Country of Origin
⏩Manufactures Name or Trademark
⏩Month and Year of Manufacture

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