The default keynoting data provided in Revit is based on the 1995 Construction Specification Institute (CSI) Master format system, which uses 16 divisions to organize construction process and materials. This system is widely used in the United States. A more recent version of this system is based upon 50 divisions and was introduced in 2004. Revit supports both versions of the CSI system.
This system is most effective when objects that are used throughout a project are already assigned their respective keynote values. When these values are not supplied, you can assign a value as you place a keynote tag. Materials, system and component families, and detail components can have keynote parameters entered in advance.
To specify the keynote file to use, see Keynoting Settings.