Forwarding using the TK-Portal
The most comfortable option for setting up call forwarding is to do it directly in the TK-Portal.
Head to the following link:
Click on the 'call forwarding' option. This will open a new window.
This window gives the option to set up forwarding under the following conditions:
There are always two target options (Voice box or target number).
Selecting the option 'call not received', you can also select a time limit,
The four second steps for this option are roughly equivalent to one ring of the phone.