Download and install the latest version of Filestar.
Right click on one or more Cals file(s) on your desktop and select Convert with Filestar.
Type convert to otb in the search box.
Press Convert.
Or let an AI agent do it: filestarcli -i photo.cals -c "convert to otb" (how).
Documents - File Explorer─☐✕
This PC › Documents
Home
Desktop
Downloads
Documents
Pictures
Music
.calsContract.cals
.xlsxBudget.xlsx
.pdfReport.pdf
.pngLogo.png
Filestar*Help✕
Drop files here to get started
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Let your AI agent convert CALS to OTB
Claude Code, Codex, Cursor and other agents can do this on your computer with Filestar. Your files stay on your machine.
Install Filestar and add it to your agents:
npm install -g filestar
filestarcli agent install
Then ask your agent:
“Convert the CALS files in my Downloads folder to OTB”
Or run it yourself:
filestarcli -i photo.cals -c "convert to otb"
Runs on your computer, so your files stay on it. Works on Windows, macOS and Linux. 50 free conversions with the npm install, no account needed.
Can my AI agent convert CALS to OTB?
Yes. Install the Filestar CLI with npm install -g filestar and your agent can run filestarcli -i photo.cals -c "convert to otb" on your computer, so your files stay on it.
The CALS Raster Graphic File, having the extension .cals, is a type of image file format primarily used for the storage and exchange of digital images, especially in the context of technical and engineering documents. Developed in the mid-1980s by the United States Department of Defense, the CALS format was part of an initiative to standardize electronic document management and interchange, particularly for military and government applications.
The OTB (Nokia Over The Air Bitmap Image) file format is a type of image file developed for use on Nokia mobile devices. These files are specifically optimized for efficient transmission and display on Nokia phones, particularly older models. The OTB format is designed to be compact to facilitate over-the-air (OTA) transmission, which was an essential feature in the era of limited bandwidth and data transfer capabilities. The format supports monochrome graphics, making it suitable for simple images like icons and logos.
