This is just one of over 75 professional audio mixers covered in The Mixer Output Guide, which describes direct outs, inserts, hidden mods and more. To see the rest, and for definitions, visit The Guide.
Direct Out:
depends on card configuration, outputs are multi-use as direct outs, aux, main, group, matrix, switchable pre/post fader
Insert:
depends on card configuration, outputs are multi-use as direct outs, aux, main, group, matrix, switchable pre/post fader
Gain Control of Direct Output: