The optional intermediate distribution area is used to support intermediate cross-connections (IC), which is common in large data centers that occupy multiple buildings, multiple floors, or multiple computer rooms. Each room, each floor or even each building can have one or more intermediate distribution areas, serving one or more horizontal distribution areas and equipment distribution areas and one or more telecommunications rooms outside the computer room. As the second-level backbone, the crossed distribution equipment is located between the main distribution area and the horizontal distribution area. The middle distribution area can contain active devices.

The horizontal distribution area is used to serve HC equipment that is not directly connected to the main distribution area. It mainly includes horizontal distribution equipment, local area network switches for terminal equipment, storage area network switches and KVM switches. Small data centers may not have horizontal distribution areas, but are supported by main distribution areas. A data center can be equipped with computer rooms on each floor, and each floor contains at least one horizontal distribution area. If the horizontal wiring distance of the equipment in the equipment distribution area exceeds the requirements of the horizontal cable length limit, multiple horizontal distributions can be installed. The horizontal distribution area provides network connections for the terminal equipment located in the equipment distribution area. The number of connections depends on the number of connected equipment ports and the space capacity of the cable duct, and space should be reserved for future development.

In a large computer room, in order to obtain higher configuration flexibility between the horizontal distribution area and the terminal equipment, the horizontal wiring system can include an optional docking point called the zone distribution area. The zone distribution area is located in an area where the equipment frequently moves or changes. The cable connection can be completed by the wiring facility through the assembly point (CP), or the regional socket can be set to connect the equipment in multiple adjacent areas. There must be no cross-connections in the zone distribution area, and no more than one zone distribution area shall be allowed in the same horizontal cable routing. Active devices cannot be used in the zone distribution area.

The equipment distribution area is the space allocated for terminal equipment installation. Terminal equipment includes all kinds of servers, storage devices, small, medium and large computers and related peripheral equipment, etc. The horizontal cables in the equipment distribution area are terminated on the connecting hardware fixed to the cabinet or rack. A sufficient number of power sockets and connecting hardware should be installed in the cabinet or rack of each equipment distribution area to shorten the length of equipment cables and power cords to the shortest distance.