How to open a .SOR file

The quick answer

Open the free OTDR Trace Viewer, drag your .sor file onto the page, and the trace opens instantly. No sign-up, no install, and the file never leaves your computer. It also reads .msor, .trc, .trcx, and OTDR .json exports.

What is a .sor file?

A .sor file is an OTDR trace saved in the Bellcore / Telcordia SR-4731 standard (the "Standard OTDR Record" format, also called GR-196). When a fiber tech shoots a span with an OTDR, the instrument saves the result as a .sor: the waveform, the events it detected (connectors, splices, the fiber end), the loss and reflectance numbers, and the test settings like wavelength and pulse width.

Because it is a binary instrument format, not a document, your computer has nothing to open it with by default. That is why a .sor file looks like a dead file until you load it into something that understands the SR-4731 format.

Why won't my .sor file just open?

Three common situations:

• No software installed. The OTDR makers (EXFO, Viavi, Anritsu, and others) ship desktop viewers, but they are Windows-only, need downloading and installing, and each mostly reads its own format. On a locked-down work laptop you often can't install them at all.
• Wrong vendor's software. A viewer from one maker may refuse another maker's .sor, even though SR-4731 is a shared standard.
• You're on a phone or a borrowed machine. No fiber software is installed and you just need to glance at the trace.

A browser-based viewer solves all three: it reads the standard SR-4731 format from any manufacturer, runs on any device, and installs nothing.

How to open a .sor file online (step by step)

1. Go to the OTDR Trace Viewer.
2. Drag your .sor file onto the page, or click the drop area to browse and pick it.
3. The trace draws immediately. You'll see the waveform, span length, total loss, worst reflectance, and a full event table.
4. Drag the A and B markers to measure loss across any section, use the wheel to zoom, and switch wavelengths if the file has more than one.

Nothing uploads. The file is read locally in your browser, so a customer's trace never leaves your device.

What you'll see when it opens

• The trace waveform with the launch, events, and fiber end marked.
• Span length and total loss for the fiber.
• An event table listing each connector and splice with its distance, loss, and reflectance.
• Test metadata: wavelength, pulse width, and the OTDR make and model that recorded it.

That's the whole span at a glance. For the full event-by-event breakdown (splices, connectors, the fiber end), see how to read an OTDR trace.

What about .trc, .msor, and .json files?

Same tool, same steps. It also opens:

• .trc and .trcx — EXFO's OTDR trace formats. If you searched for how to open a .trc file or a .trc file viewer, this is the same answer.
• .msor — Viavi's multi-wavelength container (several SR-4731 traces in one file).
• OTDR .json exports from EXFO and Viavi.

Analyzing a whole job, not just one trace

If you have a folder full of traces from a whole build (both directions, multiple wavelengths, dozens of spans) and want one pass/fail verdict per fiber instead of opening them one at a time, drop the entire job into Fiber Analysis. It groups the files by fiber, reads OTDR, OLTS, and OPM results together, and gives you a per-fiber acceptance table.

Related

• OTDR Trace Viewer & Analyzer, the free tool that opens .sor / .msor / .trc files
• Fiber Analysis, for a whole job of traces at once
• Trace Editor, to fix identifiers on a .sor without the native software
• Fiber Testing Field Guide
• All field guides