Yes, you are able to receive Public Switched Telephone Network (PSTN) without USB connection.

Insert the plug of the power cord into the socket on the bottom of the base unit then plug the power supply unit into your power outlet.

Connect the telephone line cord to the phone socket on the back of the base unit and to the plug (optional and country dependent) then to the wall phone socket.

Note : You may find the box contains the line adaptor, delivered separately from the line cord. In this case, please plug this line adaptor into the line cord first before connecting it to the line socket.

 USB plug is only mandatory for SKYPE internet calls.