Theben Training Case KNX Manual page 14

The FDSK is saved in the project and can be viewed in the project overview. All
keys for this project can also be exported (backup).
During configuration, it can be defined subsequently which functions/objects
are to communicate securely. All objects with encrypted communication are
identified by the "Secure" icon in the ETS

Keep the FDSK key safe, because if it is lost, it is impossible or difficult to
reproduce.
4.6.2 Start-up without KNX Data-Secure
Alternatively, the device can also be put into operation without KNX Data
Secure. In this case, the device is unsecured and behaves like any other KNX
device without KNX Data Secure function.
To start up the device without KNX Data Secure, select the device in the
'Topology' or 'Devices' section and set the 'Secure start up' option in the
'Properties' area of the 'Settings' tab to 'Disabled'.
Manual for the training case KNX
The KNX bus system
:
14