They provide assurance that analog audio, digital audio, or video signals are present and meet established quality standards before being broadcast, recorded, or otherwise distributed. The various models differ primarily in the types and number of signals they can monitor, though all are housed in compact, single space chassis that occupy minimal rack real estate.
All models share many basic features and capabilities.
A pair of highly compact yet full range shielded stereo speakers are built in, along with a Speaker Mute switch. An amply powered TRS output is provided for headphone listening. The speakers and headphone amplifiers share a Volume slide control. A Phase indicator displays the phase relationship of the left and right channels of the source being monitored. The indicator will glow green to amber under normal conditions, and red during conditions of total phase reversal, aiding in determining mono-compatibility.