DSN File

What are DSN files and how to open them

Are you having problems opening a DSN file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your DSN files.

What is a DSN file?

DSN files have multiple uses, and ISIS Schematic is one of them. Read more about the other uses further down the page.

ISIS Schematic File

The ISIS Schematic File (.DSN) is the native circuit design file used by the ISIS module of the Proteus Design Suite from Labcenter Electronics. This format stores a complete electronic schematic design - both graphical appearance (component placement, wires, annotation, sheet layout) and electrical connectivity (which pins connect, net names, etc.). These are not just diagrams: the .DSN file holds everything needed to simulate circuits via Proteus VSM, generate netlists, produce bills of materials, and carry designs forward into PCB layout tools.

Proteus ISIS (Intelligent Schematic Input System) is the program that writes .DSN files. The workflow typically is: you design the schematic in ISIS, save it as a .DSN, then optionally simulate within ISIS / Proteus VSM; next you export netlist information or pass the design to the ARES layout module if you're making a printed circuit board. The schematic .DSN file can also embed the visual template settings used for the design's appearance so that when someone else opens it, it looks as intended.

Technically each .DSN file begins with a fixed signature: the ASCII header "ISISSCHEMATICFILE" starting at byte offset zero. This header string identifies the file as this specific ISIS schematic format.

How to open DSN files

We have identified one DSN opener that is compatible with this specific type of DSN file.

Programs that open ISIS Schematic files

Last updated: August 6, 2026

All known file formats using extension .DSN

While ISIS Schematic File is a popular type of DSN-file, we know of 4 different uses of the .DSN file extension. Different software may use files with the same extension for different types of data.

Microsoft ODBC Data Source

A variety of different database applications use files that contain the .dsn file extension. The DSN files contain the information that is required to connect to a database remotely, such as the server address, the user ID, the password, the data source name and the database directory. These DSN files are normally stored in plain text format.

While we have not verified the apps ourselves yet, our users have suggested ten different DSN openers which you will find listed below.

OrCAD Schematic Capture Schematic

OrCAD Schematic Capture Schematic (.DSN) is a proprietary, binary file format used by OrCAD Capture to store the design of an electrical circuit in schematic form. It includes all details needed to represent circuit diagrams: components (symbols), their connections (nets/wires), schematic pages or hierarchical folders when the design is organized in multiple pages or modules. Each DSN file corresponds to one design within a project, and serves as the central file for capturing how parts are laid out and interconnected.

This file is generated and edited using OrCAD Capture. It acts as the core schematic component of an OrCAD Capture project (usually paired with a .OPJ project file which tracks libraries, netlist outputs, settings, hierarchy, and external files). DSN files are used when creating, modifying, reviewing, or printing schematic diagrams. They do not contain simulations or netlist analyses themselves - those are derived later using external processes or tools.

Internally, the .DSN file is encoded in OrCAD's proprietary format (often using Microsoft's compound document structure). The file contains metadata such as creation and modification dates, title blocks, names, parts, symbols, libraries, pages and page size. It includes recognizable strings such as "ORCAD WINDOWS DESIGN", "GRAPHICS", "LIBRARY", "SYMBOLS", "PART REFERENCE", and "PAGE COUNT". Byte-level signatures are present: at offset 0 the compound file signature begins with bytes D0 CF 11 E0 A1 B11 AE10 0; at offset 1024 there is text representing "Root Entry".

DSN opener for Windows

We have identified one DSN opener that is compatible with this specific type of DSN file.

SPECCTRA Design

We know that one DSN format is SPECCTRA Design. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Various apps that use files with this extension

These apps are known to open certain types of DSN files. Remember, different programs may use DSN files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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