AsteriskRealtime

Anybody Help on ?asteriskrealtime?
I?m currently configuring corporate PBX. I have encountered a number of issues. There are fields in a table that are not described.
Can someone guide me where can I find meaning of:
— IAX_BUDDIES Table fields:
dbsecret, notransfer, inkeys, outkey, auth, accountcode, amaflags, qualify

—SIP_BUDDIES Table fields:
fromuser, fromdomain, fullcontact, insecure, restrictcid, rtptimeout, rtpholdtimeout

In both tables you have regseconds field. What event triggers this field and why it?s counted up and down?
Many thanks for helping with this issue