Leo,
Pin #3 connects to the 1/4-inch plug's tip.
Pin #1 connects to the 1/4-inch plug's sleeve.
Pin #2 connects to pin #1.
Both pins #1 and #2 are grounded. This is the same configuragion in three adapters that I have and use regularly.
If you were using a floating system with an XLR to TSR hook-up, Pin #3 connects to the 1/4-inch plug's tip.
Pin #1 connects to the 1/4-inch plug's sleeve.
Pin #2 connects to the 1/4-inch plug's ring. I only have one of these adapter cables, and I've never used it, but that's how the circuit rings out with the Ohm meter.
Good Luck,
Gary
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PSR-S950, TC Helicon Harmony-M, Digitech VR, Samson Q7, Sennheiser E855, Custom Console, and lots of other silly stuff!
K+E=W (Knowledge Plus Experience = Wisdom.)