This is an optional argument to uCon at startup. If not specified, then uCon will start up with a dialog box that allows you to set up the tool for a specific configuration (COM port, baud rate, etc...). Once the tool is up an running, the established configuration can then be saved to a file for later retrieval by this argument.

This argument can be a file or a directory name...

If a file, then it is assumed to be a configuration file that will be used by uCon for automatic configuration at startup. If it is a directory, then uCon will look for configuration files in that directory and populate a pull-down list of "pre-established configurations", one of which can be selected (in the startup dialog box) as the configuration file.