Panasonic KX-TD500 System Reference Manual page 187

3.00 Floating Directory Number
(FDN)
Description
It is possible to assign virtual directory numbers
to resources and make them appear to be
extensions. Those directory numbers are
defined as Floating Directory Numbers (FDNs).
For example, if an operator receives an incoming
CO call for Remote Administration, the operator
can transfer the call to Remote Administration
resource using the FDN, in the same way as if
the operator transfers an incoming CO call to an
extension, that is, if the operator is PITS, by
pressing the TRANSFER button and dialing the
FDN.
FDN can be assigned to the followings:
1. Pilot number for UCD groups 01 to 32
2. General Operator Call (two FDNs can be
programmed)
3. Attendant Console number (ATT1, ATT2)
4. Remote Administration resource
Programming
System Programming
"Special Attended-UCD (1/2)",
FDN
"System-Operation (1/3)",
FDN for General Operator Call
"System-Operation (2/3)",
Remote Directory Number
"Extension-Attendant Console
(1/3)", DN
Reference
VT Dumb
10-I-3.01 11-C-37.00
10-D-1.01 11-C-4.00
10-D-1.02
10-G-4.01 11-C-30.00
3-B-7
Conditions
FDN setting must follow the assignment of
"System-Numbering Plan", 1st Hundred Block
Extension through 16th Hundred Block
Extension, as well as DN setting.