The manual self explanatory:
When the power switch is turned to ON, the red indicator light will illuminate for 10 seconds. Then, the green indicator light will illuminate for 2 seconds and remain illuminated if the system is functioning properly. The indicator lights indicate the following:
● If the green indicator light illuminates and stays on, the system is enabled.
● If the green indicator light flashes twice per second, an automatic or manual
Emergency Call is being made.
● If no indicator lights illuminate, the system is not enabled.
● If the red indicator light illuminates at any time other than immediately after the power switch is turned to ON, the system may be malfunctioning or the backup battery may be depleted.
● If the red indicator light blinks for approximately 30 seconds during an Emer- gency Call, the call has been disconnected or the cellular network signal is weak.
Therefore if the light is showing green all is working.