Difference between Inter-building, Intra-building and horizontal cabling

We may start with defining the 3 items as follows:

1. Horizontal cabling refers to the cable and pathways between the telecommunications closet and the work area. 
2. Intra-building  backbone  is  the  portion  of  the  cabling  infrastructure  that  includes  all cabling  between  the  telecommunications  closets,  local  distribution  centres,  equipment rooms, and entrance facilities 
3. Inter-building backbone is the portion of the cabling infrastructure that includes cabling between the building entrance facilities. Cable is fiber optic cable. If distance between buildings is greater than 2km, single mode fibre shall be installed, while up to 200m fiber should be 62.5/125  or  50/125  multimode. For  200  to  2 000  m  the  fibres  should  be  a  mix  of multimode  and  singlemode,  e.g.  8  multimode  and  4  singlemode.

Refer to Figure 1 below for detail.

Work area is where the Station Telecom Outlet (STO) located and this is the end user point to connect. The horizontal cable is UTP cable which should have a length not greater than 90 meters.


-End