  We present the implementation of a programmable atom-photon quantum
interface, employing a single trapped $^{40}$Ca$^+$ ion and single photons.
Depending on its mode of operation, the interface serves as a bi-directional
atom-photon quantum-state converter, as a source of entangled atom-photon
states, or as a quantum frequency converter of single photons. The interface
lends itself particularly to interfacing ions with single or entangled photons
in hybrid quantum networks.
