A handpiece can treat biological tissue using electromagnetic radiation, which can be substantially fluorescent light. In one embodiment, the authentication is performed using an identical authentication process a video sink device would authenticate itself to the video source device. A top magnetic pole is provided as two layers with the first layer including front and back tips with spaced apart walls positioned adjacent the trench bottom defining trench sides. Another aspect of the present invention provides a combined static and dynamic dictionary or binary code tree to perform communication protocol compression. The at least one sensing device interogates a bone location for one or more variables of the bone location as the device is moved over the bone location.