The trunk subsystem should be composed of the trunk cables and optical cables from the equipment room to the telecommunications room.

  Design Points:

Before determining the total number of cables required for the trunk subsystem, the principle of sharing the voice and data signals in the cable must be determined. For the basic type, 2 pairs of twisted lines can be selected in each working area; for enhanced types, 3 pairs of twisted lines can be selected in each working area. For the comprehensive type, each working area can add optical cable systems on the basis of basic or enhanced types.

The shortest, safest and most economical routes should be selected. A closed -type channel with a door with a door should be selected. There are two types of channels for buildings: closed and open types. The closed channel refers to a series of alignment rooms. There is one room on each floor. It uses cable vertical wells, cable holes, pipeline cables, cable bridges, etc. to pass the floor layer of these rooms. There are usually some facilities and fire devices that are convenient for fixed cables. Open channels refer to an open space from the basement of the building to the top of the building. There is no floor separation in the middle. For example, the ventilation channel or elevator channel cannot be laid.

The trunk cable can adopt a point -to -point end connection, or the subtraction of the branch and the direct connection method of the cable can be adopted. The point -to -point end connection is a simple and most direct combination method. Each trunk and cable of the trunk subsystem extends directly to the specified floor and the transfer room. The decreasing end of the branch is to use a large -capacity trunk cable to support the communication capacity of several interlaced rooms or several floors. Several small cables are distributed through the cable joint protection box. Connecting hardware connected to the destination. The direct connection method of the cable is the technology used in special circumstances. One situation is that all the horizontal end of a floor is concentrated in the trunk exchange, and the other is that the secondary transfer room is too small to complete the end connection between the trunk line.

If the device room is at different locations from the computer room, and the phonetic cable needs to be connected to the device room, and the data cable is connected to the computer room, the different parts of the cables or trunk cables should be selected during the design to meet the different different parts, respectively. The need for routes and data. When needed, the optical cable system can also be used to satisfy.