Primary cabling, also referred to as site cabling, is company-wide site cabling used to connect the individual buildings on a campus. In this process, the building distributors are connected to the site distributor via the primary cable.
According to the specifications of the cabling standards ISO/IEC 11801 and EN 50173 for universal cabling, the maximum extension of the primary area can be 3 km. This results from the maximum distance between the site distributor and the building distributor, which is limited to 1,500 m. In the primary area, optical fib res in single-mode and multi-mode fibres are generally used; SC connectors are recommended as connection elements for new installations, existing ST connectors are also provided.faults in the central concentrator and also to link failure, it is recommended to set up a double or a combined topology. Interesting alternatives to the single star topology are the double star, the double ring or a combination of ring and star topology. priority buildings are connected to each other via a ring, while those with low priority are connected to a high priority building in a star topology. With this combined topology, the entire primary area can continue to be operated via redundancy paths even if a star connection fails or if the ring is interrupted.