Here are the following LED status indicators for the Iridium GO!

Flashing Green = Unit is ON and registered to the Iridium network

Flashing Red = Unit is ON and not registered to the Iridium network

Red = Iridium GO! is powering on

Alternating red and green = Call in progress; ringing, dialing or in a call

Slowly flashing red = SOS has been triggered

Not lit = Device is powered off