Monitor installation system engineering fiber use instructions

Type of fiber

Optical fibers are classified into indoor optical fibers, outdoor optical fibers, branched optical fibers, and wiring optical fibers depending on the application.

According to the laying method: self-supporting overhead fiber, pipe fiber, armored buried fiber and submarine fiber.

According to the fiber structure: beam tube fiber, layer twisted fiber, skeleton fiber, tight fiber, ribbon fiber, non-metal fiber and branch fiber.

According to the purpose: fiber for long-distance communication, short-distance outdoor fiber, hybrid fiber and fiber for building;

Optical fibers can be divided into single mode and multimode according to transmission mode, and single mode fiber is generally used for monitoring.

Single-mode fiber: An optical fiber that transmits only one mode optical signal. Conventionally, G.652, G.653, G.654, and G.655 are classified into transmission classes. Single-mode optical fiber transmits hundreds of megabits of signals up to several tens of kilometers. Single-mode fiber, only the main mode is transmitted, that is, the light is transmitted only along the inner core of the fiber. Since the mode dispersion is completely avoided, the transmission band of the single-mode fiber is wide, so it is suitable for large-capacity, long-distance fiber-optic communication. The single mode fiber uses a light wavelength of 1310 nm or 1550 nm.

Multimode fiber: A fiber that can transmit multiple modes of optical signals. It is G.651 grade. It is divided into OM1, OM2, and OM3 according to the optical mode. The maximum transmission distance of multi-mode fiber transmission is 100 kilometers. Multimode fiber, in a certain working wavelength, there are multiple modes of transmission in the fiber. This fiber is called multimode fiber. Due to dispersion or aberration, this fiber has poor transmission performance and narrow transmission band. Smaller and shorter.

Fiber laying methods and requirements

Conventional outdoor optical fibers are containers with loose tubes as the core, which is the most common fiber core laying method; indoor optical fibers are usually tightly laid; the cores of large core fibers are also combined in the form of strips. core.

The laying requirements of the optical fiber: the bending radius of the optical fiber should be at least 15 times of the outer diameter of the optical fiber, and should be at least 20 times during the construction process; when the optical fiber is laid, the rotation of the optical fiber disk should be synchronized with the deployment speed, and the speed of the optical fiber index is generally 15 meters per minute; when laying out the fiber, the fiber should be kept at a loose arc, and the buffering margin should be kept, and it should not be too much to avoid the back buckle of the fiber; the fiber has a reserved length of 5-10 meters at both ends. When laying the fiber, label the line and fill in the line record; all fibers should not be exposed.

Light core selection

The number of cores is the number of glass fibers contained in each fiber. The following small series introduces some methods to determine the number of cores.

First, know the number of routing points in the layer, calculate the number of switches, and whether the connections between the switches are stacked or not. If the core switch is dual-system hot standby redundancy, the 6-core is sufficient (2 cores each use 2 cores and 2 cores redundant).

If you do not stack a switch to 4 cores, multiply the number of switches by 4 plus 4 core redundancy, you can. (Note: Redundancy: as long as it is used more, the extra is called redundant active and standby: one used, the other one is the same as the standby; hot backup: at the same time in the working state; cold backup: the backup device is in standby mode.)

Experience: Each floor wiring closet (horizontal wiring cabinet), set up an optical fiber, generally six cores: two core use, two core spare, two core redundancy; also use eight core fiber. The minimum configuration of the specification is 2 cores per 48 points. Of course, 48 points can be selected as 4 cores, because the 2 core is the smallest unit of the fiber, and it is more appropriate to leave 2 cores as the backup.

The above is the introduction of the method for determining the number of cores of the fiber. You can find out. Backup can be selected for people, so the number of fiber cores that come out is quite different. According to the specification, only one minimum selection and one backup core number can be guaranteed.

be careful

In addition to the number of fibers and the type of fiber, the choice of fiber should be based on the use of the fiber to select the outer sheath of the fiber. Pay attention to the following points when selecting:

1. When the outdoor fiber is directly buried, the armored fiber should be selected. When the frame is empty, the fiber with black plastic outer sheath of two or more reinforcing ribs can be selected.

2. The fiber used in the building should be selected for its flame retardant, poison and smoke characteristics. Generally, it should be in the pipeline and forced ventilation. Flame retardant and smoked types should be used. Flame retardant should be used in the exposed environment. , smokeless and non-toxic types.

3. When the vertical wiring in the building is used, the layered fiber can be selected; for the horizontal wiring type, the branch fiber can be selected.

4. Optional multimode fiber with a transmission distance of less than 2km; relay or single mode fiber for more than 2km.

The above are a few issues that are considered from the application side, and they need to be flexible when implemented. In fact, the wiring environment is complex and diverse, and various problems may occur at any time. This requires us to strictly follow the wiring standards during planning and construction. If problems are encountered and flexible analysis is performed, it will be satisfactorily resolved.