Signal Types

Question 1

Balanced

Answer 1

TRS (1/4")
XLR
 -- Aditional gain
 -- Noise cancelation
 -- Flipped, equal, and opposite

Question 2

Unbalanced

Answer 2

TS
RCS
NL4
NL8
 -- Anything that carries balanced audio
 -- Short distance (less than 5ft)
Signal level
 -- Mic DB (lowest): -30 - (-60)
 -- Line DB: -10 - (-40)
 -- Speaker DB (highest): +10 and up (usually anything higher than line level)