rs prefer lavaliere microphones, which are worn on lapels or collars, or looped around the neck with an attached cord. The lavaliere can be wired or wireless. Both types uniformly capture a speaker's voice but wireless versions can be susceptible to radio frequency interference. If a lapel microphone is used, it important to keep the speaker away from the loudspeakers to avert feedback problems. If a wireless microphone is used, it is important to remind speakers to remove it before leaving the facility. Many organizations start out with wireless microphones only to revert to wired varieties after replacement costs mount. As an organization develops its audio conferencing strategy, it should ensure ample auxiliary inputs for video or audio capture, external audio bridges for multipoint audio, and voice-activated cameras. Finally, the audio component of any conferencing system should provide privacy and security. Implementing Group-Oriented Systems LIGHTING To render a natural scene, a videoconferencing facility must offer light of the right level, angle, and color temperature. There must be enough light to provide a noise-free picture with adequate depth of focus, and it must emit from the proper direction to avoid undesirable facial shadows. Lighting should also enhance image depth and contours by intentionally creating desirable shadows and highlights. Light intensity is measured in foot-candles. One foot-candle offers illumination equal to the amount of direct light thrown by one candle on a square foot of surface. High light levels (125 foot-candles and above) support improved camera performance and depth of field, and thereby make it easier to focus. High light levels also reduce noise in the video signal, which appears as fine-grained static in the displayed image. Unfortunately, high light levels produce heat, which, in turn, can make the room harder to cool and can necessitate noisy HVAC equipment. A minimum illumination level of 75 foot-candles is necessary for acceptable results. While low-light environ