Terms of use

The terms this service runs on.

This is a courtesy translation. The binding text is the Russian one at /eula; if the two ever diverge, the Russian text prevails.

OTDR Master is a service for viewing fiber-optic OTDR trace files. Short and first: the files you open are processed and stored with us — the trace is computed on our servers, and the same files are how the service learns to read more formats — and you send them at your own risk: we do not guarantee correct reading. We do not pass your files to third parties, do not publish them and do not sell them.

In force since August 21, 2026. By opening a file in OTDR Master you accept these terms. If they don't suit you — don't open files; nothing else is required.

1. What we do with your files

The file is processed entirely on our servers. By opening a trace you send the file to us: it is parsed there, the curve is computed there and events are searched there, while the browser shows the finished result. There is no separate on-device parsing, and the service does not work offline.

The file is stored on our servers and serves the service's development: there are more instruments and formats out there than the program can read today.

What we never do, under any circumstances:

• we do not pass your files to third parties;
• we do not publish them and do not show them in examples, demos or advertising;
• we do not sell or trade them;
• we do not use the information they contain about sites, customers and contractors for anything beyond the purposes above.

The accepted file size is limited to 1 MB. That is plenty — the largest OTDR trace we have ever met weighs 300 KB.

The service's pages carry no visitor counters, no third-party scripts and no ad systems: the page's security policy forbids requests to any outside address, and you can verify that in your browser's developer tools rather than take our word for it.

What we do guarantee:

• The file is never damaged. If you changed nothing, the exported .sor is byte-for-byte identical to the opened one. The property is verified by a run over 287 real files from roughly twenty vendors.
• We do not draw traces. There is no synthetic trace generator and there never will be one, in any form.

2. What you confirm by opening a file

That you have the right to hand us this file: it is yours, or you have permission for this.

Do not open in the service what you are forbidden to show. Measurements are sometimes part of work closed by an NDA or an access regime. We cannot check that for you and rely on your word.

3. Deleting your files

Write to ilya@cheredin.ru and say what to delete: file names, a site or a period. We will delete them on our side and reply when it is done. No reason needs to be given.

Traces opened in the browser also live in its local storage — you remove those yourself, with the cross in the file list; no request to us is needed.

4. What the service does not promise

By sending a file you act at your own risk. We do not guarantee that a file will be read, read correctly, or displayed completely: there are more measurement formats and dialects than any program can read, ours included. Verify the numbers that matter against the instrument and its vendor software.

OTDR Master is a tool, not a verdict. Below is what we do not promise, named directly and with numbers.

• We supply no norms. Not a single threshold value ships with the product: what is acceptable on your site is known by your project and your customer, and a plausible number sitting in a field would read as normative.
• Automatic event detection is help, not a verdict. Over our corpus of 270 traces it finds 39 % of the events instruments marked, and 34 % of the events of the VeEX vendor analyzer. It also shows noticeably more of its own: about 60 % of what we find, the instrument did not mark. You see both — a divergence is a reason to look closer, not a conclusion. It does not replace an engineer.
• We do not certify a measurement's authenticity. The service shows the file's contents — and says nothing about how the measurement was taken.
• Reading other vendors' formats is reading only. An imported trace can be neither edited nor exported as .sor: that would produce a file that reads as an original instrument recording.

Found a bug, or something reads wrong — write to ilya@cheredin.ru. Especially if we misread an instrument or a format: attach the file if it can be shown, or at least the instrument model and what you expected to see. The build version is visible on the app screen — include it.

The service is provided as is. We are not liable for decisions made on its readings, nor for losses caused by interruptions in its operation.

5. Changes to these terms

If the terms change, we will change the date at the top of this page and say what exactly changed. A change that widens what we do with files gets named directly on the service's pages, not only here — that is exactly what we did on August 19, 2026, when we withdrew the former promise that a file stays only on your computer.

On August 21, 2026 file processing moved entirely to our servers, and the separate "What we guarantee" and "Honest comparison" pages were taken down: everything they said moved here — the guarantees into section 1, the limits and numbers into section 4. Nothing said there was dropped silently.

6. Contact

All questions about these terms — ilya@cheredin.ru. A person answers.