To connect an external effects unit to the UB1202, follow these steps: 1.) Use a cable to connect from the FX SEND port to the input of the effect processor. 2.) Then connect a cable from the output of the effects device to one of the LINE ports. If the device has stereo outputs, you can use both stereo line inputs (5/6, 7/8, etc.) 3.) Adjust the the effects processor to 100% wet. 4.) Turn the FX knob on the channel you are plugged into all the way down (to avoid a feedback loop).