Received our FAB3010 XLR Output Module.  Just to recap, the FAB3010 Module includes a relay-controlled Polarity Reverse. All you need to do is apply Logic “1” to the header pins (located on upper left corner) and it will switch the relays on/off.  A Logic “1” can be anywhere from +3.3V to +5V, or up to your V+ voltage.

I need to make a Revision B board because I want to move the XLR jack farther out, so it won’t have any problems with clearances if you want to mount the XLR jack on a .125″ thick case panel.  But other than that, I think it looks good.

Will try to populate this board in the next day or so, so I can test the Polarity Reverse logic control. I don’t foresee any problems, but the proof is in the pudding as they say.