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:
1/4" (+4?), post-EQ, post-fader, impedence balanced, only on ch 1-8. "First click" (-10) insert for ch 9-16 DO.
Insert:
1/4" unbal, pre-EQ, pre-fader, TS/RR
Gain Control of Direct Output: