Panasonic KX-TD500 System Reference Manual page 1345

3) Testing the DN button indicators and the DSS button indicators
for lighting in red.
Panasonic
LED
EASA - PHONE
With the PITS model KX-T30830, the DSS
button indicators also light in red.
4) Testing the DN button indicators and the DSS button indicators
for flashing in red.
Panasonic
LED
EASA - PHONE
With the PITS model KX-T30830, the indicators
on the DSS buttons also flash in red.
5) Testing the indicators of the Message Waiting, CONF, FWD/
DND, AUTO/MEMORY, AUTO ANS/MUTE, SP-PHONE
buttons for lighting in red.
Panasonic
LED
EASA - PHONE
CONF button
FWD/DND
button
13-C-33
TEST
DN buttons
TEST
DN buttons
TEST
Message Waiting
button
AUTO/MEMORY button
AUTO ANS/MUTE button
SP-PHONE button