A baby monitor system incorporated into a receiver of the baby monitor circuitry that can remotely control an electric or electronic device when the output sound level of the receiver reaches a reference level. The control can be by infrared, radio frequency or hardwire transmission of a volume control...http://www.google.com.tw/patents/US6462664?utm_source=gb-gplus-share專利 US6462664 - Baby monitor, system, and method and control of remote devices
