1. Outer skin: Indoor optical cables are usually made of polyvinyl chloride or flame retardant polyvinyl chloride. They should be smooth, bright, flexible and easy to peel off. Fiber optic cables with poor quality have poor surface finish and are easy to adhere to the inner sleeves and aramid fibers.
Outdoor cable PE sheath should use high-quality black polyethylene, cable after the formation of smooth, bright, uniform thickness, no small bubble. The outer skin of inferior optical cable is generally produced with recycled materials, so can save a lot of cost, such optical cable skin is not smooth, because there are a lot of impurities in the raw material, make the optical cable outer skin has a lot of very small pit wow, a long time on the cracking, water.
2. regular cable production enterprise generally USES metal grade A fiber core, some cheap inferior cable typically use C, D fiber and unknown smuggling fiber, the fiber source is complicated, the factory for A long time, often feel has damp discoloration, and multimode optical fiber is often mixed with single mode fiber, and the lack of necessary testing equipment of general small plant, not to judge the quality of optical fiber. Due to the naked eye can not identify such fiber, construction often encountered problems are: bandwidth is very narrow, short transmission distance; Uneven thickness, not able to butt with the tail fiber; Fiber lacks flexibility, and when it is twisted, it breaks.
3. strengthen steel wire: regular manufacturers of outdoor cable steel wire is after the phosphating treatment, the surface is gray, such steel wire cable does not increase hydrogen loss, not rust, high strength. Inferior fiber optic cable is commonly used in place of thin iron wire or aluminum wire, identification method is very easy -- the appearance is white, can be bent at will in the hand. The production of fiber optic cable with such steel wire hydrogen damage, a long time, the end of the fiber optic box will rust fracture.
4. steel armor: regular production enterprises use double-sided brush anti-rust coating longitudinal wrapped steel belt, poor cable is the ordinary iron sheet, usually only one side of the rustproof treatment.
5. loose casing: fiber optic cable in the loose casing should be PBT material, such a high strength casing, no deformation, anti-aging. Inferior cable generally use PVC to do casing, such a casing outside diameter is very thin, with a pinch on the flat, a bit like the straw we drink.
6. ointment: ointment mainly fiber paste and cable paste, under normal circumstances fiber paste should be full of the whole loose sleeve, cable paste should be full of the cable core under pressure every gap. Fiber paste is filled with half full or less practice, cable paste is some only in the cable core with a layer, some is filled in the middle of the cable. This will make the optical fiber can not be good protection, affect the optical fiber attenuation and other transmission performance, poor waterproof performance can not meet the national standard, once the cable accidental seepage will lead to the whole link water scrapped. Under normal circumstances, even if the accidental seepage of water only need to repair the seepage of a paragraph, do not need to start over. (national standards require water resistance: three meters of cable, one meter of water column pressure, 24 hours without water seepage.) If poor ointment will also appear above problems, and may be because of the ointment thixotropy is poor, will cause fiber micro-bending loss, the transmission characteristics of the whole link is not qualified; If the ointment belt acid will also occur with the cable metal materials in H reaction precipitation hydrogen molecules, and optical fiber with H attenuation will rapidly increase, resulting in the entire link interrupt transmission.
7. aramid fiber: also known as kevlar, is a high strength chemical fiber, currently in the military industry with the most, military helmet, bulletproof vest is the production of this material. By 2013, only dupont and aksu in the Netherlands could produce it, and the price was about 300,000 tons. Indoor optical cable and power aerial optical cable (ADSS) is to use aramid fiber yarn as a strengthening piece, because aramid fiber cost is higher, poor quality indoor optical cable generally make the outside diameter very thin, so you can use a few aramid fiber to save costs. Such cables are easily broken when they are threaded through a tube. ADSS cable because it is based on span, wind speed per second to determine the use of aramid fiber cable, generally dare not cut corners.
8. water resistance belt: cable with water resistance belt or water resistance yarn through the product internal distribution of uniform super absorbent resin has a strong water absorption performance, in the infiltration pressure, affinity, rubber elastic joint action, super absorbent resin can quickly inhaled several times the weight of water. Moreover, once the water-resistant powder meets water, it will immediately expand the gel, and no matter how much pressure is applied to it, the water will not be squeezed out. Therefore, the water resistance with absorbent resin coated cable core, in case of cable wall damage, wound part of the super absorbent resin due to expansion and play a sealing effect, can prevent the water into the minimum. Inferior fiber optic cable usually use non-woven cloth or paper tape, once the fiber optic cable skin damage, the consequences will be very serious.
