PCC-170SWO is a surface-mounted supercardioid of professional quality. This handsomely styled unit is appropriate for use on the most elegant boardroom table or lectern. Other applications include churches, courtrooms and council chambers. Because of its highly directional pickup pattern, the PCC®-170 SWO minimizes background noise and feedback. The microphone reproduces voice with a clean, clear and natural sound. The user can turn the mic on and off by pressing a membrane switch on the mic. A pair of extra leads in the mic cable allow isolated remote sensing of the microphone switch closure. In a typical distance-learning application, a video camera would track to the person who switched on the microphone. Mic can be set to be always on. In this mode, the switch only activates the remote sensing and LED. This is useful when using an external gated mixer (automatic mixer). Remote sensing is done by a patented opto-coupled MOS switching circuit. At the remote-sensing leads, the resistance goes low when the mic is on. The microphone is attenuated 70 dB when the switch is off. Since the microphone capsule is placed on a boundary or surface, direct and reflected sounds arrive at the diaphragm in-phase. This coherent addition of direct and reflected waves increases sensitivity 6dB and prevents phase cancellations. The mic capsule is small enough to ensure phase coherency up to the highest frequencies in the audible spectrum, resulting in a wide, smooth frequency response free of phase interference. Clarity and reach are also enhanced.