A wireless audible indication system comprising a transmitter and a receiver. An embodiment of the transmitter includes a modulator formed by a microprocessor and a radio frequency oscillator. The modulation format employed is selectable by the user using severable jumper wires. A battery status circuit...http://www.google.fr/patents/US5680102?utm_source=gb-gplus-shareBrevet US5680102 - RF data communication link for wireless audible indication system
RF data communication link for wireless audible indication system
