  We present a new typology for classifying signals from robots when they
communicate with humans. For inspiration, we use ethology, the study of animal
behaviour and previous efforts from literature as guides in defining the
typology. The typology is based on communicative signals that consist of five
properties: the origin where the signal comes from, the deliberateness of the
signal, the signal's reference, the genuineness of the signal, and its clarity
(i.e., how implicit or explicit it is). Using the accompanying worksheet, the
typology is straightforward to use to examine communicative signals from
previous human-robot interactions and provides guidance for designers to use
the typology when designing new robot behaviours.
