What does an OTDR tester do?

An OTDR tester (Optical Time Domain Reflectometer) sends a pulse of light down a fiber and measures what returns — mapping the entire fiber run in a single graph that shows splice loss, connector reflections, fault locations, and fiber length from one end without a technician at the far end.

An OTDR tester works by timing how long reflected and backscattered light takes to return, then converting that into distance. The result is a trace — a visual plot of the fiber run where every event shows up as a change in the line. A good splice appears as a small step down; a broken fiber shows up as a hard reflection followed by a flat line. The D YEDEMC Mini-Pro OTDR produces this trace across a 5m–60km test range, covering FTTx drops, access network builds, and enterprise campus fiber in a single handheld unit.

• D YEDEMC Mini-Pro OTDR test range: 5 meters to 60 kilometers on single-mode fiber.
• Mini-Pro OTDR dynamic range: 24 dB at 1310nm and 22 dB at 1550nm.
• Mini-Pro OTDR event dead zone: 3 meters — short enough to resolve events in dense FTTH splice enclosures.
• Mini-Pro OTDR attenuation dead zone: 8 meters, meaning loss at closely spaced events is measurable within 8 meters of a reflection.
• Any splice reading above 0.2 dB on an OTDR trace is a flag to re-splice; acceptable core-alignment fusion loss is ≤ 0.05 dB.