The professional balanced/XLR pin arrangement in the U.S.A. adheres to AES File 48:
Pin 1: Ground
Pin 2: Non-inverted signal
Pin 3: Inverted signal
That is how all pro equipment is wired (as well as consumer electronics designed by engineers who wish to conform to that standard, such as Atma-Sphere's Ralph Karsten, Music Reference's Roger Modjeski, and EAR-Yoshino's Tim de Paravicini), and how all pro audio cables are terminated.
In Europe, pins 2 & 3 are reversed.