Abstract: A coupling apparatus for separably connecting cable controls to the storage unit of a radiographic system, having a coupler component fixed to the storage unit and a separable component fitted to the control cable. The latter fits into an aperture in the fixed component, where it can be locked against removal. The fixed component locks the radioactive material leader for safe storage when the control cable is disconnected. Connection of the control cable permits the operator to release the lock on the leader. The act of releasing that lock establishes an interlock which prevents removal of the separable component from the fixed component.