Panasonic KX-TDA50 Programming Manual page 16

1.2 PC Programming
6.
If a system password is forgotten, it can be found by loading a backup of the system data
into a PC, and checking the password using the Maintenance Console software. If you do
not have a backup of the system data, you must reset the PBX to its factory defaults and
reprogram it. Therefore, we strongly recommend maintaining a backup of the system data.
For more information on how to back up the system data, refer to the on-line help of the
Maintenance Console.
However, as system passwords can be extracted from backup copies of the system data file,
do not allow unauthorized access to these files.
16 PC Programming Manual