  A $2\pi$ phase shift across a Josephson junction in a topological
superconductor injects vortices into the chiral edge modes at opposite ends of
the junction. When two vortices are fused they transfer charge into a metal
contact. We calculate the time dependent current profile for the fusion
process, which consists of $\pm e/2$ charge pulses that flip sign if the world
lines of the vortices are braided prior to the fusion. This is an electrical
signature of the non-Abelian exchange of Majorana zero-modes.
