  For a circle map $f\colon\mathbb{S}\to\mathbb{S}$ with zero topological
entropy, we show that a non-diagonal pair $\langle x,y\rangle\in
\mathbb{S}\times \mathbb{S}$ is non-separable if and only if it is an IN-pair
if and only if it is an IT-pair. We also show that if a circle map is
topological null then the maximal pattern entropy of every open cover is of
polynomial order.
