Panasonic KX-TD500 System Reference Manual page 1067

Description of Assigning Items
DN-(13 to 24)
Type Assigns the use of the DN buttons. The PDN button cannot be assigned.
Number Assigns the number for each DN button which is preset to "PDN", "SDN", "PRV-
CO", "DSS (DN)", "Group CO" or "ONETOUCH".
SDN COS Assigns whether the COS of the SDN button is that of the extension (PDN-Primary
Directory Number) or the COS of the SDN (Secondary Directory Number)
extension.
Day Ring Assigns whether incoming calls have immediate or delayed ringing on PDN, SDN,
SCO or GCO buttons in Day mode. The ringing assignment of the first PDN can
also be changed with this option.
Night Ring Assign similarly as the above item except this applied in Night mode.
Conditions
This screen cannot does not appear if "Extension-Station (1/4)", Telephone Type is
set to "SLT" or "OPX" or the telephone does not have DN key (DN-13~24). Refer to
the section 10-G-1.02 "Station (2/4)".
Function
Same as the "Station (2/4)" screen.
10-G-15