Requirements

• There shall be no more than two hierarchical levels of cross-connects in the backbone cabling. 
• From the horizontal cross-connect, no more than one cross-connect shall be passed through to reach the main cross-connect. Therefore, connections between any two horizontal cross-connects shall pass through three or fewer cross-connect facilities. 
• Bridged taps shall not be used as part of the backbone cabling.

Recommendations

• Backbone cabling cross-connects may be located in telecommunications rooms, equipment rooms, or at entrance facilities.

NOTES: The limitation of two levels of cross-connects is imposed to limit signal degradation for passive systems and to simplify moves, adds and changes. This may not be suitable for facilities that have a large number of buildings or that cover a large geographical area. In these cases, it may be necessary to divide the entire facility into smaller areas and then connect these areas together.