Since: Apr 08, 2004
Well most manufacturers use pin 2 hot:
Pin 1 = Shield ground
Pin 2 = Positive balanced signal
Pin 3 = Negative balanced signal
So I'd say, earth to pin 1, white to pin 2, blue to pin 3.
Do this on both ends, so they're straight through.
If the other end is already terminated, use a meter to see where pin1 is going, then copy that on other end.
This is necessary for a 'balanced' signal, instead of an unbalanced. Balanced lines reject any noise introduced on the line itself (like RF, electrical, etc).
Here's what WIKI has to say about it: