If like me you have several mobile phones and a couple of landlines, but often want to forward all of those devices to one single number then usually the following sequence should work.

To forward your telefonica  land line to a mobile number:

1) Pick up the handset until you hear a dial tone
2) On the phone keypad type *21* the mobile number #
3) You will hear a voice on the phone confirming the forwarding request
4) Hang up the phone. All calls to that landline number will be forwarded to the mobile number

To reverse the above action and cancel the redirect:

1) Pick up the handset until you hear a dial tone
2) On the phone keypad type #21#
3) You will hear a voice on the phone confirming the cancellation request
4) Hang up the phone. The call forwarding will now be cancelled.

The above codes will also work on a mobile phone, but on a mobile phone, instead of picking up and waiting for a dial tone, you simply type the codes into the phone and click the “make call” button (or whatever other button you use to initiate a call)  on your phone and you will see in the screen of the phone whether the request was successful.