To use all inputs and outputs the AC power adapter must be connected before the Fast Track Ultra is powered on. If the AC power adapter is connected after the Fast Track Ultra is connected and powered on, it will be limited to 4 inputs and 4 outputs (Analog ins/outs 1/2, and the SPDIF I/O). If the AC power adapter was connected after the device was powered on, simply power the device off, then back on, and you will be able to use all inputs and outputs.