This paper reports on experimental measurements performed on a human cadaver and equivalent phantom models to characterize the body as an electrical transmission medium. Since the human body supports current flow through various pathways established by intra-cellular and cellular membranes, an effective communication channel can be established between electrodes in direct contact with the skin and internal electrodes of an implant system. It is shown that the signal attenuation over the frequency range of 1-20MHz varies between -10dB to -40dB, and that, unlike inductive links or far-field coupling, direct line- of-site between coupling electrodes is not required. This general property of the human body as a conductive medium can be used to effectively power and communicate with ultra small in vivo low power devices using body worn electronics.