Green
Single flash every 3 seconds: It has good connection
Double flash every three seconds: It is searching for signal. However, because of the multi network SIM, the device will always be searching for a better signal, even when it has signal
Continuous flash: Wifi connected
Blue
Single flash every 3 seconds: Searching for gps
Double flash every 3 seconds: GPS is connected
No light: No gps connection at all
Red
In dock
Light on (solid): Device is fully charged
Flashing steadily: Device is charging
Out of dock
Single flash once every few seconds: Battery lower than 20%
Double flash every three seconds: Connected to the dock via bluetooth