- Press the Off key for a long time to switch off the handset.
- Press and hold down keys 1, 4, 7 and the On key at the same time to switch it on.
- The handset starts operating, and displays its Service menu. You can then enter the key combination 76200.
- Select the Metering Mode menu option and press OK to confirm, then select "Back".
- The handset switches itself off.
- Switch on the handset again. You now see the measurement values at the top of the display.
After using measurement mode, follow the steps above to deactivate it again.