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:
XLR, post-EQ, pre-fader. PRE switch makes DO pre-insert, pre-EQ AND pre-mute.
Insert:
TRS, separate send and return jacks, post-EQ. PRE switch makes insert pre-EQ. INS switch engages return.
Gain Control of Direct Output: