Description Patented design provides radio frequency interference (RFI) attenuation up to -57 dB • Eliminates RFI including AM, FM, CB and amateur radio from voiceband DC signal • Passive Device - No ground required • Tip & Ring balanced to 600 ohm telephone line impedance • Reversible in-line single pair connection via modular RJ-11 jack and plug • Compact size, excellent durability, high impact plastic housing • ANSI T1/E1 conforming RJ-11 jack/plug with 50 microns of gold plating • Meets FCC surge protection requirements