Telephone RJ11 Line ADSL Modem Filter/Splitter with surge protector‎.‎ This adapter separates voice signal and ADSL digital signal from telephone signal‎.‎ Built‎-in Noise filter‎,‎ and surge protector‎.‎ Protect the voice signal and ADSL digital signal from the interference of a telephone and a fax machine and surge in the line‎.‎ One RJ11 at one end for line‎.‎ Two RJ11 at the other end for phone and modem‎.‎