TrendBox Multifunctional Network Networking Phone Cable Tester USB UTP LAN PC Test Tool RJ11 RJ12 RJ45 CAT5 CAT6 Test correspondingly double-twisted cables 1, 2, 3, 4, 5, 6, 7, 8 and Ground . Capable to judge wrong connection, short circuit and open circuit. Cable Tester for RJ11, RJ12, RJ45, Cat 5e, Cat 5, 10/100 Base-T, AT/T 258 A, TIA-568A/568B .etc It can easily clarify cable, continuity, open and short. Verifying Cable continuity, open, short and cross wire pair up to 1000ft with remote kit.