(Multi-select) You use an OTDR to locate an abnormally attenuated point on the optical path.

Standard OTDR operation allows you to configure multiple acquisition parameters:

Measurement range (distance range): sets the maximum span to be traced; best practice is typically 1.5–2× the fiber length under test.

Wavelength: select test wavelength(s), e.g., 1310/1550 nm for SM fiber, to observe different loss characteristics.

Mode: vendors provide real-time/average (or similar) acquisition modes to stabilize traces.

Pulse width: controls dynamic range vs. event resolution; longer pulses see farther but increase dead zones, while shorter pulses improve resolution at the cost of range.

These are documented in foundational OTDR references and application notes.