  Let $C$ be a smooth curve in $\PP^2$ given by an equation F=0 of degree $d$.
In this paper we parametrise all linear pfaffian representations of $F$ by an
open subset in the moduli space $M_C(2,K_C)$. We construct an explicit
correspondence between pfaffian representations of $C$ and rank 2 vector
bundles on $C$ with canonical determinant and no sections.
