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Universal powerline bus (UPB) is a protocol for communication between devices used for home automation. It uses power line wiring for signaling and control. UPB was developed by PCS Powerline Systems of Northridge, California, and released in 1999. Based on the concept of the ubiquitous X10 standard, UPB has an improved transmission rate and higher reliability. While X10 without specialty firewalls has a reported reliability of 70-80%, UPB reportedly has a reliability of more than 99%. ==Power-line carrier control overview== Household electrical wiring, such as Romex or BX cable, is used to send digital data between UPB devices. While in the X10 protocol the digital information is encoded onto a 120 kHz carrier, transmitted as bursts during the relatively quiet zero crossings of the 50 or 60 Hz AC sine wave, the UPB protocol works differently. The UPB communication method consists of a series of precisely timed electrical pulses — called UPB Pulses — that are superimposed on the normal AC power sine wave. Receiving UPB devices can easily detect and analyze the UPB Pulses and extract the encoded digital information from them. UPB Pulses are generated by charging a capacitor to a high voltage and then discharging that capacitor into the power line at a precise time. This quick discharging of the capacitor creates a large “spike” (or pulse) on the power line that is easily detectable by receiving UPB devices wired large distances away on the same line. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Universal powerline bus」の詳細全文を読む スポンサード リンク
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