A system comprising a cable (12,14), a casing and a strain relief and cable retention apparatus for retaining the cable to the casing, wherein: the strain relief and cable retention apparatus comprises: an anchor made of a flexible material and comprising a tube section and an oblong planar section at one end of the tube section, the anchor having an internal bore along an axis of the tube and ending in a hole in the planar section, the bore sized to fit an outer jacket of the cable, and the planar section comprising first and second tabs extending away from the tube section along second and third axes perpendicular to the axis of the tube, the tabs occupying a plane perpendicular to the axis of the tube; and a plate made of a stiff material and generally matching the shape of the planar section of the anchor and extending along the two tabs of the planar section of the anchor; the plate rests flat against the planar section of the anchor; the cable comprises a plurality of conductors and a reinforcing layer contained within an outer jacket; the casing contains electronics electrically or optically coupled to the conductors of the cable, the casing receiving the cable through a hole in a face of the casing; the oblong planar section of the anchor being located inside the casing, the cable passing through the internal bore, and the plane occupied by the tabs of the planar section being parallel to the face of the casing; the plate rests flat against the planar section of the anchor between the planar section of the anchor and the face of the casing; characterized in that the tube section of the anchor passing through a central hole in the plate; the tube section of the anchor passing through the hole in the face of the casing; and the reinforcing layer of the cable comprises fibers, the fibers being split into at least two bundles inside the casing, each of the two bundles being tied in knots around one or the other of the tabs of the planar section of the anchor and the plate, such that external strain applied to the cable is transferred to the plate via the reinforcing fibers. the strain relief and cable retention apparatus comprises: an anchor made of a flexible material and comprising a tube section and an oblong planar section at one end of the tube section, the anchor having an internal bore along an axis of the tube and ending in a hole in the planar section, the bore sized to fit an outer jacket of the cable, and the planar section comprising first and second tabs extending away from the tube section along second and third axes perpendicular to the axis of the tube, the tabs occupying a plane perpendicular to the axis of the tube; and a plate made of a stiff material and generally matching the shape of the planar section of the anchor and extending along the two tabs of the planar section of the anchor; the plate rests flat against the planar section of the anchor; an anchor made of a flexible material and comprising a tube section and an oblong planar section at one end of the tube section, the anchor having an internal bore along an axis of the tube and ending in a hole in the planar section, the bore sized to fit an outer jacket of the cable, and the planar section comprising first and second tabs extending away from the tube section along second and third axes perpendicular to the axis of the tube, the tabs occupying a plane perpendicular to the axis of the tube; and the anchor having an internal bore along an axis of the tube and ending in a hole in the planar section, the bore sized to fit an outer jacket of the cable, and the planar section comprising first and second tabs extending away from the tube section along second and third axes perpendicular to the axis of the tube, the tabs occupying a plane perpendicular to the axis of the tube; and a plate made of a stiff material and generally matching the shape of the planar section of the anchor and extending along the two tabs of the planar section of the anchor; the plate rests flat against the planar section of the anchor; the cable comprises a plurality of conductors and a reinforcing layer contained within an outer jacket; the casing contains electronics electrically or optically coupled to the conductors of the cable, the casing receiving the cable through a hole in a face of the casing; the oblong planar section of the anchor being located inside the casing, the cable passing through the internal bore, and the plane occupied by the tabs of the planar section being parallel to the face of the casing; the oblong planar section of the anchor being located inside the casing, the cable passing through the internal bore, and the plane occupied by the tabs of the planar section being parallel to the face of the casing; the plate rests flat against the planar section of the anchor between the planar section of the anchor and the face of the casing;