Acquisition method for phase recovery in a direct sequence code division multiple access communications system, in which a first phase alignment is made at the end of a first symbol period, subsequently a new mean phase shift is detected at the end of a second symbol period and a second phase correction is applied, either integrally at 100%, or preferentially enhanced at 150%. A conveyor system is also provided onto which parcels are placed by the robotic arm system. By virtue of the plurality of domes, the optoelectronic device achieves high performance. A first safety shutter which can be opened or closed in arranged at the USB port on the socket cover, or a second safety shutter which can be opened or closed is arranged at the conventional power connector.