There are a series of LED indicators on the front panel of a VBOX 3iSL, their functionality is as follows:
GPS:
Flashing Red indicates no satellites in view
Flashing Green sequence indicates the number of GPS Satellites currently being tracked. Each flash indicates a satellite with a short pause between each
sequence.
Flashing Orange sequence indicates the number of GLONASS Satellites currently being tracked. Each flash indicates a satellite with a short pause between