It was largely an offline reader, downloading both email and new messages from selected forums, and then disconnecting.
Unlike most offline readers, NavCIS also allowed the user to select files for upload and download, and included a system for scripting the session.
These files contained the basic connection information for the modem and the phone number to call, as well as a series of commands that visited different areas in CIS.
The script files were created by clicking on a number of buttons in a settings window, allowing the user to navigate a map of the CIS system, grouped into subject areas.
It then runs through the commands in the session file one by one, completing the tasks and moving any resulting data to the local machine.