The D SERIES-PSP1A is a compact active loudspeaker that delivers rich, detailed sound in Decora-compatible wall or chassis mounts. It is a single-pair audio amplifier module compatible with RDL Format A twisted pair products. The PSP1A receives audio and 24V DC power through a rear-panel RJ45 jack. A rear-panel switch set during installation determines which of the three FORMAT-A pairs is amplified. Amplification is provided by a high-efficiency Class D power stage with audio filtering tailored for crisp, pleasant audio clarity. The high-efficiency Class D output stage produces negligible heat for all levels of expected voice or music modulation. The amplified output level is controlled by a front-panel volume control. The PSP1A includes an analog compressor/limiter that makes higher average sound output levels possible without clipping.