its an ISDN voice box/answering machine package for linux

I think if you take a look at those 2 entries, (one for michael, and one for nicole right?) you will notice the # at the start of the line, meaning they are commented out, and are there mainly for example purposes.

Generally if I don't know what a file is, I first check to see if there is a man page about it (there is in fact a man page for vboxd.conf) or do a search on the net for the file name, it will usually come up with something. I generally have best results with google.

google is your friend