A fiber optic cable is coupled with an electro-optic transducer through a ferrule which terminates the cable that is inserted in a passageway of a housing which is mounted on a planar surface so that the passageway is transverse thereto. A cover placed over the housing and latched thereto isolates the ferrule from dust and external light and insures its proper alignment with the electro-optic element, which is inserted in the passageway from the opposite end via an opening in the planar surface, by exerting a spring force on a flange of the ferrule which is a greater distance from the end of the ferrule than the distance between the passageway entrance to the ferrule and the electro-optic transducer when positioned in the passageway so that the fiber optic cable and transducer abut one another upon placement in the passageway to effect an efficacious coupling.