It looks like your NetBSD question is in the OpenBSD section. It may make a difference as to where you look for documentation.
I have not modified the console output other than the text display options. My understanding is that it emulates a VT100 terminal. There an extensive NetBSD guide with a section on the console drivers which I think addresses your question
http://www.netbsd.org/docs/guide/en/chap-cons.html
If you are using OpenBSD