She scanned the shelf labels: out-of-print conference proceedings, obsolete firmware printouts, a graduate’s thesis that included hand-drawn schematics. Then she noticed the metal box’s lock: a simple tumbler eaten by rust. Inside, beneath a folded cloth, was a battered CD and a spiral-bound photocopy. The photocopy’s header matched the sheet above. Someone had copied the relevant pages, enough to patch software and redesign a connector. The CD’s label read: "Tools for Field Use."
IEC 61869-1 is titled "Instrument transformers - Part 1: General requirements". This part of the standard covers the general requirements for instrument transformers, including their design, construction, testing, and documentation. The standard applies to current transformers and voltage transformers used for measuring and protective purposes in electrical power systems. iec 61869-1 pdf free download
IEC 61869-1 is a protected international standard, and official full versions are not legally available for free download International Electrotechnical Commission (IEC) The photocopy’s header matched the sheet above