EXFO VDSL2 - Manual (Page 99)

Multi-meter Tests
Copper, VDSL2, ADSL2+ and IP Triple-Play Test Set 91
Rectified Loop (Corrosion) Detection Test
Rectified Loop (Corrosion) Detection Test
The Rect. L Detection tab displays a
rectified loop state which often
indicates the presence of corrosion on
a circuit. Rectified loops can disrupt
balance and make the circuit
unsuitable for Broadband and other
digital services.
Water Detection Test
The Water Detection Test detects the
presence of water in the circuit. Use
the TDR to locate.