Tester port: Tester RJ45 master port (M), tester LOOPBACK RJ45 port (L), hunting RJ45 port(SCAN); Remote identifier RJ45 port (R); The extra BNC and RJ11 converters (to measure and check the continuity of coaxial cable and telephone line) Check network cable faults, such as open, short, jumper wire, reverse connection or cross-talk interference Dynamically calibrate cable length and make length measurement as accurate as 95% Single board computer software watchdog design and reliable operation Simple and easy use, big LCD Screen to display test result clear