I'm trying to open some circuit schematics for some equipment I have in my lab. However, they were designed some time ago (2013) by an unknown technician with an unknown program. There are two folders, one called SCH (with file types .SCH, .NET, .ERC, .CMP, .CLN) and one called PCB (file types .PCB, .NET, .LIB, .CMP, .LST, .CNF, .ERR). If i try to open the .SCH file it's a binary, apart from a "Schematic FILE" header.

Does anybody have any clue about what program might have been used to make these? I've tried to open them with the Allegro viewer, but with no success.


  • \$\begingroup\$ Have you looked up the file extension? It's not a binary, that's for sure :) \$\endgroup\$
    – user103380
    Feb 18, 2020 at 16:49
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    \$\begingroup\$ @KingDuken: I think OP meant "binary" as opposed to ASCII, not binary as in "executable". \$\endgroup\$
    – Transistor
    Feb 18, 2020 at 16:51
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    \$\begingroup\$ I'm pretty sure the .sch files I've got from nearly 20 years ago that start with Schematic FILE were created with OrCAD. \$\endgroup\$
    – Finbarr
    Feb 18, 2020 at 17:23
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    \$\begingroup\$ Upon further research I agree with Finbarr, I think those are OrCAD design files. \$\endgroup\$
    – DerStrom8
    Feb 18, 2020 at 20:40
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    \$\begingroup\$ pcengines.ch/orcadff.htm \$\endgroup\$ Feb 18, 2020 at 22:27

1 Answer 1


Sometimes it can be helpful to open the files in a hex viewer utility that shows the binary file contents in hexadecimal and ascii format side by side. Some software packages may embed a vendor specific header or text string that can can help to identify the source tool set.

  • \$\begingroup\$ notepad++ can also open binary files and allows you to see any text within the binary \$\endgroup\$
    – jsotola
    Feb 18, 2020 at 17:32

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