Hello,
courtesy of Norman Brandinger, there is now a new tutorial describing the tables in OpenSER Database.
http://openser.org/docs/OpenSER_Database_Structure.html
The dokuwiki page which was create to collect users' contributions in this respect will point to this tutorial.
If anyone wants to contribute with more description, please sent email to devel@openser.org or add the text in the dokiwiki page. http://openser.org/dokuwiki/doku.php?id=database_description
Cheers, Daniel