Are you referring to the Status Feedback on the 6023 or the “Learned RF” LED on the M1XRFTWM? The ELK Two-way Sensors (6000 Series) include a Status Feedback LED and when the sensor trips it sends a signal to the M1XRFTWM. The M1XRFTWM processes the signal and sends an Acknowledgement back to the sensor and the LED on the sensor will turn Green. If the LED on the Sensor turns RED the signal was not acknowledged which could mean out of range or not learned into the system.
On the M1XRFTWM the “Learned RF” LED will flash when the M1XRFTWM hears a Two-way transmission signal which could be a sensors tripping or the supervision signal.