After Luis Quiroz suggested UML diagrams to document call flow I checked and discovered that Confluence has the PlantUML add-on installed.
I created a couple examples on the Standards page.
They are very nice with lots of options for color and formatting.
I made a very trivial start to FreeSWITCH call flow on the Life Cycle page, but I don’t have a good enough understanding to make it useful. Feel free to improve the diagram.
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Bote
FreeSWITCH Docs Janitor
http://freeswitch.org/confluence