US Patent:
20030030568, Feb 13, 2003
Inventors:
Roc Lastinger - Mesa AZ, US
James Rodgers - Mesa AZ, US
William Fowler - Phoenix AZ, US
Dean Freiwald - Mesa AZ, US
International Classification:
G08B005/22
Abstract:
Monitoring systems and protocols are disclosed that are flexible in mode operation and format depending on the environment in which they are used. Such monitoring systems and protocols are able to change their utilization automatically, or by received instruction to do so. A location detection system includes one or more low frequency transmitters, one or more radio frequency monitoring tags and one or more receiving devices. The low frequency transmitter transmits location identification information, such as the transmitter ID, to a tag in the vicinity of the transmission. The tag relays the transmitter ID using a higher frequency transmission sent from the tag to the receiver. Communication protocols are disclosed that enable deciphering of multiple tag transmissions starting simultaneously.