Their web site says of this older version:
Free Demo Kit (version 3.8.1.31)
The demo software has all the functionality of the full release (up to 12 stations and no limit on the number of observations).
Current seems to need a 64-bit system:
Columbus 4.6 is a windows based application which will run on 64 bit versions of Windows 7, 8 and 10. It provides all the computational ability of our deprecated Columbus 3.8.X product and more! $525
The free version of Columbus 4.6 allows you to experiment with the embedded sample networks provided in the UI (Data page). Also included is the ability to adjust your own networks from the Adjust File page. You can adjust networks with up to 25,000 stations and unlimited observations using this file driven tool. And, when you are ready to purchase a license, there are no additional installs to perform.
Adjust File:
While the Columbus user interface provides great flexibility and control when adjusting a network, any change to those project settings will affect the adjustment results. For this reason, Columbus supports the concept of adjusting from a file. The Adjust From File page allows you to perform an adjustment based solely on the contents of an input file, bypassing the user interface settings.
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