Unitrol Omega 90 +12 or gnd for trigger

[Leonardo1947]

I have a Federal Signal Unitrol Omega 90 Amp and using it with a FS MC100 Speaker. Works great. I only want to use the airhorn and am using the BROWN wire for the air horn control. I have noticed that either +12VDC or GROUND will trigger the airhorn. Which should I be using or does it matter? It will be used on my motor home. AIR HORN ONLY. Thanks in advance

 

[shues]

This is by design. You can use either +12vDC or ground as your trigger.