The IO4/4 panel features power, signal input and loudspeaker output connections: Power: one (1) three-phase 16Amp CEE-form connector (red) that leads to a 3-way Schucko socket block (one phase per socket), so up to three (3) ALC’s can be powered, each with their own power supply / phase. Signal: one (1) 3-pin XLR female input connector that leads to one (1) cable with 3-pin XLR male connector, to be connected to the ALC signal input. From there, the signal can be linked from one ALC to the other by short XLR-XLR link cables. One (1) 3-pin XLR male output connector. To be used as signal distribution to other ALC racks. Loudspeaker: four (4) NL4 output connectors that lead to four (4) NL4 cables/connectors, to be connected to the NL4 loudspeaker outputs of the ALC. This is used to connect Alcons passive-filtered cabinets or subwoofers.