An interface circuit including a galvanic isolation barrier between a transmission line and a user equipment, and a detector for detecting, independently from a transmission, the idle or busy state of the line. The system comprises a power generator, a buoy floating the power generator on the surface of the water, and a fixing apparatus restricting movement of the buoy and the power generator. The first feedback control circuit detects voltage signals of the voltage-increasing circuit and the load and controls output voltage of the voltage-increasing circuit. With an O-ring attached to the metallic member and with the resin case pressed from above, the pressure sensor cell is secured to an enclosure, such as an oil enclosing block. The sealing member includes polyamide having an equilibrium moisture content at a relative humidity of 50% of 0. Similar processes deposit molybdenum nitride, which is suitable for layers alternating with silicon in X-ray mirrors.