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What is FTTH drop cable
The sheathed FTTH drop optical cable is mostly single-core or double-core structure, and can also be made into a four-core structure. The cross section is in a figure-8 shape. The reinforcement is located in the center of the two circles. Metal or non-metallic structure can be used. . The optical fiber in the leather cable adopts G.657 small bending radius optical fiber, which can be laid with a bending radius of 20mm.
Introduction of FTTH drop cable
FTTH drop cable is commonly known as indoor hanging wiring cable. Under the circumstance that the optical fiber access market shows a good development momentum, optical fiber access has become a hot spot in the field of optical communication. In the optical fiber access project, the indoor wiring close to the user is the most complicated link. The bending performance and tensile performance of conventional indoor optical cables can no longer meet the needs of FTTH (fiber-to-the-home) indoor wiring.
The dish-shaped drop cable for access network (for indoor wiring) is to place the optical communication unit (optical fiber) in the center, and place two parallel non-metallic reinforcing members (FRP) or metal reinforcing members on both sides. Finally, extrude black or color poly It is sheathed with vinyl chloride (PVC) or low smoke halogen free material (LSZH, low smoke, halogen free, flame retardant).
FTTH drop cable Features
Special bend-resistant optical fiber provides greater bandwidth and enhances network transmission performance;
Two parallel FRP or metal strength members make the optical cable have good compression performance and protect the optical fiber;
The optical cable has simple structure, light weight and strong practicability;
Unique groove design, easy to peel off, easy to connect, simplify installation and maintenance;
Low-smoke halogen-free flame-retardant polyethylene sheath or flame-retardant PVC sheath, environmentally friendly.
Can be matched with a variety of field connectors and can be field terminated.
Because of its softness and lightness, the leather cable is widely used in the access network; the scientific name of the leather cable: butterfly-shaped lead-in cable for access network; because of its butterfly shape, it is also called butterfly cable, Figure 8 cable.
Cable Structure
Ordinary FTTH drop cable is a standard 8-shaped structure; two parallel strengthening cores, with an optical fiber in the middle;
The self-supporting optical fiber cable adds a thick steel wire hanging wire to the structure of the ordinary optical fiber cable; in general, the self-supporting optical fiber cable just has one more steel wire, and nothing else has been changed;
The structure of this kind of optical cable is different for each manufacturer. But they are generally not metal reinforced cores, such as butterfly-shaped ftth drop cable. The shape of the cross section is like a butterfly, so it is called. The two sides are the leather wire and the inner part is the reinforcement, and the middle part is the optical fiber.
- Butterfly optical cable is divided into indoor and indoor (indoor) and outdoor. The price of the two is quite different. The price of the outdoor type is about twice the price of the indoor type. The price factor should be considered when making a specific design plan. The ordinary optical cable (GYTA-G 652D) is still used outdoors, and the indoor butterfly optical cable is used indoors, and the two are transitioned through a fiber distribution box or a splice box.
- The butterfly optical cable has the characteristics of small curvature radius, light weight, relatively good bending resistance, easy to fix, and easy to be terminated in the terminal box.
- Butterfly-shaped home optical cable has two forms: non-metallic reinforcing member and metal reinforcing member. Considering the factors of lightning protection and strong electric interference protection, non-metallic reinforcing member butterfly optical cable should be used indoors.
- Indoor butterfly optical cable has 1 core, 2 core, 3 core, 4 core and other specifications. Residential users should use single-core cable for access to butterfly optical cable; business users can access butterfly optical cable according to 2--4 Core cable design.
Applications
It is used for indoor wiring, and the end user directly uses the cable;
Used for building drop cables;
It is used for indoor wiring of users in FTTH.
Structural parameters
| CSM type central strength member | Size（mm） | Tensile(N) long/short | Crush(N/100mm) long/short |
| non-metallic CSM | 3.0×2.0 | 40/80 | 500/1000 |
| metallic CSM | 3.0×2.0 | 100/200 | 1000/2000 |
Installation method
The large-scale use of leather cable in the FTTX project mainly adopts two connection methods: one is the cold splicing technology (physical splicing) of the optical cable based on the cold splicing, and the other is the hot-melting technology using the fusion splicer as a tool.
Cold splicing technology
Cold splicing technology: The optical fiber cold splicer is used when two pigtails are butted. The main component inside is a precise V-shaped groove. After the two pigtails are pulled out, the cold splicer is used to realize the butt of the two pigtails. It is simpler and faster to operate and saves time than welding with a welding machine.
On the surface, the cold splicing operation is simple and fast, which saves time compared with the fusion splicer, but the cold splicing technology is mainly used in emergency applications after the optical cable communication is interrupted.
There are obvious disadvantages of cold splicing technology:
(1) The cold connection loss is large. Due to the physical connection, the two optical fibers are connected completely by the V-groove and matching liquid, and the loss is obviously greater than that of the hot-melt connection point. In the FTTX project, although the loss requirements of the line are not as strict as those of the trunk line, the large loss point is a potential fault point.
(2) Short service life and high maintenance cost. In cold splicing technology, the role of matching fluid is very important. Referring to the statistics of the operator's customers, the imported matching fluid generally has a lifespan of about 3 years, while the domestically produced matching fluid has a lifespan of only 1.5 to 2 years. This increases the cost of maintenance. And the cost of a cold joint is generally about 30 to 50 yuan (removable and reused, but the accuracy of disassembly and reuse is greatly reduced, so the cold joint is nominally repeatable, but it is actually in the construction process. Only used once), the actual use and maintenance costs are high.
Hot melt technology
- The welding loss is small. The two optical fibers are spliced by hot-melt technology and are spliced according to the trunk line standard, which greatly reduces the splicing loss.
- Long service life and low maintenance cost. Since the hot-melt standard is required in accordance with the construction of the trunk line, the service life of the general fusion point will be similar to that of the ordinary optical cable, and there is no problem of the service life of a single point.
Fiber To The Home method
User indoor wiring
In the FTTH project, the user's indoor wiring is the most complicated link, and many factors are considered. It is necessary to ensure the safety of the line, take into account the beauty of the interior, and at the same time facilitate the construction. The traditional single-core indoor optical cable can no longer meet the indoor wiring requirements of the current FTTH project. As a substitute for traditional indoor optical cables, Vipson leather cable can adapt to most indoor wiring conditions. For example, it can turn with a bending radius of 20mm, can bear the lateral pressure of people stepping on the optical cable, and the drag caused by engineering construction. pull. At the same time, with a variety of on-site connectors, on-site termination and docking can be realized in the shortest time. Therefore, Wipuxun leather cable is the best choice for FTTH indoor wiring.
In-building vertical and horizontal wiring
Like the user's indoor wiring, the Wipsun leather cable is also suitable for vertical and horizontal wiring in the building. The horizontal wiring is not very demanding on the optical cable, but the vertical wiring must require the optical cable to have a certain tensile strength. Wipuxun leather cable can withstand the short-term 200N and long-term 100N tensile force, so it can ensure the construction safety and stable performance of vertical wiring of the leather cable within a certain height range.
Self-supporting overhead access wiring
Since the self-supporting "8" wiring optical cable has a metal hanging wire unit, it has stronger tensile performance and can withstand a span of 50 meters. The optical cable is laid outdoors in an overhead manner. Before entering the house, the metal suspension wire unit is cut off and fixed on a special fixture. The remaining optical cable is stripped of the metal suspension wire and introduced into the room with a leather cable.
Pipeline wiring
Compared with the leather cable, the pipeline mapping optical cable is harder and has a higher tensile strength. At the same time, the optical cable contains water-blocking materials, which can reduce outdoor rain erosion, so it is more suitable for long-distance outdoor pipeline laying. Vipson's pipeline mapping optical cable adopts an all-non-metal structure, thus avoiding the introduction of lightning into the room. After the optical cable enters the house, strip its outer sheath, water blocking material and reinforcements, and directly use the middle leather cable for indoor wiring, which inherits all the advantages of indoor wiring of the leather cable, and reduces the connection of outdoor and indoor optical cables.
