1. Lift the handset
2. Enter *67*
3. Enter the number to which the calls should be forwarded
4. Enter # after the number
5. Wait for the set-up confirmation and hang up.
This option can be deactivated again by entering #67#.
Please note: If you have activated the “call waiting” function, it is not possible to activate call forwarding. First deactivate “call waiting” with #43#.