Directory Numbers Classification

The Cisco HCS dial plan enables the creation of directory numbers (Cisco Unified Communications Manager Internal DNs) with these choices of characteristics:

Dial Plan Classification

Dial Plan Configuration Type	Site Location Code (SLC)	IDP (Inter Site Prefix (ISP))	IDP in DN	Extension Dialing Prefix (EDP)	Extension Format
1	Yes	Yes	No	Unnecessary with ISP	SLC + Ext, No ISP in SLC
2	Yes	Yes	Yes	Unnecessary with ISP	ISP+SLC+Ext (ISP is part of SLC)
3	Yes	No	No	Yes/No	SLC+Ext and no ISP, can be with or without EDP
4	No	No	No	Not Applicable	Ext (Flat Dial Plan/ no SLC)