FX ON-OFF [CH1 / CH2 / MIC, LINE 3] -These backlit buttons control the signal flow of the effects module. Press any of the buttons separately to turn the effects on or off for Ch.1, Ch.2, or Mic/Line 3. The corresponding button will light up to show the effect is on. When turned on individually, there can only be one channel effected. Assigning the effect to a different channel will turn off the effect on the previous channel. When Ch.1 and Ch.2 are pressed simultaneously, the effect signal is sent to the master output, and both (Ch.1 & Ch.2) button will be lit. When connecting a foot pedal to the remote output, the FX ON/OFF buttons become assign switches and the foot pedal becomes the actual ON/OFF switch. The selected button will flash to show it is selected, and it will light up once the foot pedal is pressed to show the effect has been turned on.