Immediately
If "Call forwarding immediately" is configured on the phone, the phone does not ring when there is an incoming call. The call is forwarded to the entered call forwarding destination. The call can be taken there.
Configuration
Web interface: 
Telephony > Call forwarding > Immediately
*Details about the settings are in Call forwarding
Function keys > Choose a key > Function: Call forwarding immediately
*Details about the settings are in Function keys
Phone: 
Settings > Telephony > Call forwarding > Immediately
*Details about the settings are in Telephony
Settings > Function keys > Choose a key > Function: Call forwarding immediately
*Details about the settings are in Function keys
Provisioning: 
*Details about provisioning this function in the Auerswald DokuWiki at Setting and Key