Is after connection when switched on a soft, high-frequency whistles of itself. Even if it is not loud, it is still annoying when you want to work near this equipment (especially when all other technical appliances and sockets not whistle). I am sending this product (replacement against) on Amazon back, and will update my recession when the part arrives. The programming functionality I have not tested because the whistle is a knock-out criterion for me. I do not want more noise than necessary, and especially not from an outlet.
Update:
I got from Amazon a replacement unit, and since more than 11 months in operation - this no longer whistles. Seems only with some devices to appear. So I increase the star rating as well. The socket can be easily controlled from the Raspberry Pi, as well as of the Synology DiskStation.
