Abstract: A home automation module having an externally powered communications port. The module includes an automation microprocessor for controlling the module, a communications port for enabling the module to draw power in limited quantities from an external source, a receiver/transmitter section, a power line carrier (PLC) coupler for enabling the transfer of signals between the module and a main while electrically isolating the module from the main, a zero-crossing detector for monitoring the phase of the power on the main while maintaining substantial electrical isolation of the module from the main, and a boost regulator for enabling the module to derive sufficient power from the communications port to drive the PLC coupler during signal transmissions from the module to the main. The detector maintains substantial electrical isolation through an opto-isolator. The boost regulator stores up power over time so that sufficient power will be available when the demand is made.

Abstract: A system comprised of a parent and child unit perform multiple position-dependent functions. The parent and child unit each comprises a directional antenna, power source, transceiver, processor and memory. The processor is coupled to the transceiver to control transmission and reception in each unit according to a predetermined stored protocol. The parent unit has a directional antenna and the child unit has an omnidirectional antenna. The transceivers in the units bidirectionally communicate to automatically perform one or more of the multiple position-dependent functions including electronic leash, finder, and proximity functions. Typically, a plurality of child units bidirectionally communicate with the parent unit to automatically perform the multiple position-dependent functions over a plurality of frequencies, by means of a plurality of different digital codes or both. The invention also comprises a method comprised of the steps necessary for performing the functions.