Thanks Tido, but I'm writing to the forum because CEC has proven too slow to return the status information mailny because it has to setup a CEC connection first that takes a few seconds.
I am looking for a faster way to get the status of the monitor and was hoping for a non-cec method similar to the method availble to raspberry pi where one can query /sys/class/amhdmitx/amhdmitx0/hpd_state which equals 0 when the TV is off.
Is there something similar that can be queried on a H3 device?