A powerline data transmission system for smart shelves provides AC power and network data propagated over a single cable. In disclosed embodiments, a starter unit encodes an ethernet signal onto an alternating current power source with a driver unit decoding the ethernet signal from the power source to provide separate power and data at a location such as a shelving unit bay. The separated power and data signals are provided to a technology box which communicates power and data to sensors positioned on the shelves of the unit. A support structure for the smart shelf system provided mounting of the driver unit and technology box along the top of the shelving unit or in a lower tray of the unit.