SM Pro Audio M-Patch 5.1, 5.1 surround controller, No power has to be connected to the MPatch 5.1 in order for the unit to opearate, the power is only needed for LED indication, it is a totally passive surround controler. 5.1 Surround Controller, Balanced inputs (D-SUB), Unbalanced RCA surround inputs, Balanced TRS stereo inputs, Unbalanced RCA stereo inputs, Dual Balanced XLR L/R outputs, Balanced TRS surround outputs, Balanced slave output (D-SUB), Rotary analog stereo volume controls, 8 output selector switches with mutes, -20dB pad switch, Stereo/Mono switch, Master Mute Switch, incl. Rackmount-Kit