The IOC-4 audio input/output center acts as a networked intermediate link between a D-75N digital audio console and the central NET router. It is a 2RU chassis with base I/O, expansion I/O slots and internal power supply. Note: Photo shows the IOC16. The IOC-4 includes 4 AES Digital Inputs with Sample Rate Converters, 4 AES Digital Outputs; 4 Stereo Analog Inputs, 4 Stereo Analog Outputs, Network Interface.