In a subscriber’s facility of an announcement broadcasting system utilizing an optical fiber cable TV network, an announcement broadcasting optical receiver receiving an optical transmission signal of audio information and outputting an audio information electric signal for an announcement broadcasting terminal is provided. The first component is disposed to the predetermined component of the robot. A user account is updated with the category and at least a portion of the check data. Water in an amount of 20 to 150 moles is added to 1 mole of the silane mixture, which is subjected to hydrolysis under an acidic condition to obtain an aqueous or alcohol solution of an organosilanol andor the partial hydrolyzed product thereof, and an aqueous alkaline solution is added thereto, mixed and allowed to stand to conduct polycondensation.