Safety precaution system is the most important part of building intelligent system. Good security system is self-evident for safety. And a good security system, its cable transmission system, is also playing an important role in the whole security system, and security system, the application of fiber is a very large part. Today, let's talk about some notices of fiber in reality.

光纤的选用除了根据光纤芯数和光纤种类，还要根据光纤的使用来选择光纤的外护套，在选用时要注意以下几点：

The selection of optical fiber is based on the number of optical fiber cores and types of optical fiber, and the outer sheath of optical fiber should be selected according to the use of optical fiber.

1. 户外用光纤直埋时，宜选铠装光纤，架空时，可选用两根或多根加强筋的黑色塑料外护套的光纤。

1. when outdoors are directly buried with optical fiber, the armored optical fiber should be selected. When it is overhead, two or more reinforced plastic black plastic sheathed optical fibers can be selected.

2. 建筑物内用的光纤在选用时应该注意其阻燃，毒和烟的特性，一般在管道中和强制通风处，可选用阻燃和有烟的类型，暴露的环境中应选用阻井盖钢模具 U型槽模具 天津水处理设备 检查井钢模具 保定公司注册 u型槽模具 流水槽模具 燃、无烟和无毒的类型。

2. the fiber in the building should pay attention to its flame retardancy, poison and smoke, generally in the pipe and forced ventilation, the type of flame retardant and smoke can be selected, and the type of flame retardant, smokeless and non-toxic should be selected in the exposed environment.

3. 楼内垂直布线时，可选用层绞式光纤;水平布线式，可选用分支光纤。

3., when the vertical wiring is used in the building, the layer twisted fiber can be selected, and the branch optical fiber can be used for horizontal wiring.

4. 传输距离在2km以内的可选用多模光纤;超过2km可选用中继或单模光纤。

4., multimode fiber can be selected within 2km distance, and relay or single mode optical fiber can be used over 2km.