Today, lectures and presentations are mostly held with audio and visual media support. Connecting laptop computers to the mixing consoles of PA systems, however, can be a major problem due to incompatible connector formats. The Palmer Line Level Convertor PLI06 is a dedicated interface to feed the unbalanced stereo signal typically provided by a laptop to the balanced (mono) microphone inputs of professional mixing desks. It mixes the stereo output to mono while impedance matching and signal balancing are achieved by a high quality audio transformer especially designed for the unit. Moreover, it also prevents ground loops and the annoying hum they result in. The PLI06 is entirely passive and does not require mains power or batteries.