INF - Instructions
The system time shall be synchronized with the KNX precision clock.
One can also write in the data point Time or TimeUTC of the System port, given that a W-flag is set for the address. Simply connect the NominalValue of the system data point with the ActualValue of the KNX-data point and you’re done!
Attention: Changing of the system time requires special rights, therefore it might just work with Win7/8 if the Elvis Server is running.
Besides, the Elvis Server is just accepting time differences of the computer from -5 to +10 minutes, if you are trying to change the time further, the server might not work anymore.