This Adapter allows you the freedom to keep using your existing home phones when your service moves to Digital Voice or Digital Home Phone. If your current home phone is a DECT Cordless phone, with or without additional handsets, you will only need 1 Adapter. Suitable for residential lines only. If you only use Corded phones in your home, you will need an Adapter per phone. (You can have up to 5 Digital Voice products registered to the Smart Hub, this includes the Digital Voice Adapter) You require an adapter if: You want your DECT phone in a different location to your Smart Hub. You'll only need 1 Adapter You use Corded phones around your house. You'll need an Adapter per Corded phone You do not need an adapter if: It's convenient for you to plug either your Corded or Cordless phone directly into the green port at the back of your Smart Hub.