Rendering can be based on attribute fields containing non-numeric information as well. For instance:
RENDER=( Sex = 'MALE' )
RENDER = ( Street Type = 'Main' )
RENDER = ( Street Type = 'Secondary' )
Be sure to use ' ' marks and not " " to connote a non-numeric item.
Or you might find it easier to use the desktop TatukGIS Viewer (free product) or Editor or to set up the rendering and save to a TatukGIS project file for use with the DK.