angles the latches 44 extend from the short sides the short side 52 has one side edge connected to an end of longer side 53 while the opposite side edge comprises two parallel studs 54 which can be snapped into matching openings 56 in the longer side 53 of the other angled part 51 to form the assembled locking device 36 the two parts 51 are held together by an elastic band 57 the exemplary embodiment of the board connector 2 as shown in the drawings is a transceiver with a top cover 61 with four corners bolted onto a rectangular lower housing section 62 holding an internal transceiver board 63 carrying the opto electronic elements 91 and the feet 72 of the optical coupling device 71 see fig3 a the board connector 2 is mounted into a socket 65 mounted on a substrate 70 such as a printed circuit board see fig1 a the top cover 61 comprises a casing 64 with one side having a receiving opening 66 for receiving the cable connector 3 the top side 67 of the casing 6 slants downwardly from the side with the receiving open 66 to the opposite side of the casing 64 a locking ring 68 with two opposite pinching grips 69 is put over the casing 64 to lock the board connector 2 in the socket 65 the internals of the board connector 2 are shown in fig3 a and 3 b an optical coupling device or optical coupling device 71 is positioned on the.