Parameter in order to know if it's up or down

[Sergio]

Hello!

I wanted to know if there's anything to know if a device is on or off. 
Maybe a parameter or some internal way to do it.

I ask this because we have tried to query a device while connected and 
while disconnected, answering GenieACS the same for some parameters of 
the CPE's status.

It's obvious that querying how much time since the last inform will 
work, but that's our last option.

Thank you!