A system and method for an adaptive time-division multiplexing communications protocol for collecting data from remote sensors equipped with RF transceivers using an RF transceiver equipped mobile data collection unit. RF transceivers interfaced to remote sensors actively monitor a predetermined...http://www.google.co.uk/patents/US5687175?utm_source=gb-gplus-sharePatent US5687175 - Adaptive time-division multiplexing communications protocol method and system 
