See also:

Activating HDC
Press the button; the LED above the button lights up. ...

Replacing the batteries
No rechargeable batteries Do not use rechargeable batteries, as damage may result from the substances in the batteries. 1. Remove the cover. Press on the cover, arrow 1, and push forward, ...

Deleting the button assignments
1. Press buttons 1 and 8 simultaneously for approx. five seconds. 2. "OK" ...