If you no longer have the Digital Voice (RJ11) adaptor that came with your Fritz!Box router and you need one for Digital Voice to work with your landline phone, you can request one below and we will send you a replacement free of charge.
Most phones won't require the adaptor but some older ones will. You can check if you will need an adaptor by removing the wire connecting your phone to the BT socket and checking if it fits in the FON port at the back of your Fritz!Box router. | 
