Panasonic KX-TD500 System Reference Manual page 182

In addition to the feature numbers which can be
set in "System-Numbering Plan", fixed feature
numbers are provided and these are shown in
the following table.
Fixed Feature Numbers
Function
While busy tone is heard
Call-back (for extensions only)
Busy Override
OHCA
BSS
While Do Not Disturb tone is heard
DND Override
When handset is on-hook (PITS only)
Time display/date display switching
Background music on/off
Day/Night mode display
While talking to doorphone
Open the door
While calling with the Voice
Calling feature
Changing to the ringing mode
Others
Account code delimiter
Account code delimiter (for dial pulse type
SLT only)
Account code re-input
• The feature numbers which are set in the
"System-Numbering Plan" are listed on the
following pages.
Number
6
1
2
3
1
*
1
#
5
*
#
99
*
3-B-2