Abstract: A system for providing wire-free and contact free electric power and communication connection in a security installation between a door and a frame. The cores, windings, and control circuits of first and second portions of a split core transformer are disposed in the frame and the door, respectively. Power applied to the first portion induces a voltage and current in the second portion when the door is in a closed position. Modulation of the voltage amplitude in either the first or second portion defines a communication signal between the door and the frame. Status and data are transmitted at data rates that are essentially twice the frequency of the voltage applied to the split core transformer. In a second embodiment, voltage transfer occurs at 20 KHz and data transfer is in the range of 100K baud.