well, the D'B'K models output raw Bayer data and the deBayeing is done on the host computer, the D'F'K models (german Farbe=color) transfer the image data as RGB to the host, hence the DFK models require 3x bus bandwidth compared to the DBK (and DMK) models.
My review of the 21AF04.AS and some basic thoughts on the ImagingSource camereas can be found on my website (direct link).