Panasonic KX-TD500 Features Manual page 351

extension (with DN) or virtual extension (with FDN) directly after translation of the MDN
number.
MDN (Multiple Directory Number) Configuration
ISDN
Features Guide
MDN line
MDN 1000 1001
TD500 MDN
1002 (Ext.2000)
1003 (Ext.2001)
1004 (Ext.2002)
1005 (Ext.2003)
ISDN Features
351