Red LED: Indicates presence of an FXO/GSM port.
Orange LED: Indicates presence of a BRI port.
Green LED: Indicates presence of an FXS port.
LED Blinking- Red blinking: No connection between FXO port and
PSTN
LED Alternating - Red and Green (slow blink): FXO port is receiving
an incoming call.
LED Alternating - Red and Green (fast blink): FXO port is in use
LED Dual - Green and Red (slow blink): FXS port is ringing
LED Dual - Green and Red (fast blink): FXS port is in use