It's not possible for a host to know how to scale
a port from just the unit
labeling. Unit labeling and input value scaling are independent, in fact
are completely orthogonal except in certain conventional cases like
IEC for some (not all!) dB ranges.
++. there definitely needs to be a 'logarithmic' hint. maybe even log(10) vs
log(2). im sure this RDF/JSON/YAML thing can make a case for it