Panasonic KX-TD500 User Manual page 216

Problem
I hear a warning tone from the telephone. •
The MESSAGE button light lit.
A Power Failure occurred.
Appendix
Table 5
The handset was off-hook in an idle status for an
extended period of time.
Replace the handset.
• Another extension left you a message waiting indication
during you were on the phone or left your desk.
When a power failure occurs...
The system and Panasonic proprietary telephones stop
all functions. Specific extensions are automatically
connected straight to specific CO lines. This provides CO
line conversations between the pre-assigned extensions
and CO lines:
Consult your dealer for detailed information.
All intercom calls and features do not function.
When turning the power back on...
Your system restarts with the stored data automatically.
Memory is protected by a pre-installed lithium battery.
There is no memory loss except for Automatic Callback
Busy (Reserving a busy line) and Held calls.
5.1 Troubleshooting
Remedy
215