Input / output / Stereo Jack to control the channels. Channels can also be bypasss driver or front panel.
The simplicity of use and effectiveness of rglages and transparency are its strengths.
I used a 3-channel preamp. When I used the clean the GS silent bypass. The crunch channel # 1 of the GS. The lead channel # 2 of GS. Change the channel preamp and Guitar silence were automatically as a pilot with Axess FX1 Elextronics home.
Hush the best rack for guitarists. I Found suprieur same gate at the Dunlop rack. Too bad he is no longer manufactured. I speak in the past because I no longer use two pedals in one amp in the head clean.