Ours is integrated into that wonderfully designed (ha-ha) CDSS (I guess that is what Denti is referring to), the SCCM (yes, I have moved on to EASA terminology
) pushes a button that displays 'cabin ready' on the monitor...
I have my own technique though, and that should be fitted to every Boeing - the grab handle above the windshield - if I didnt flip it up before lining up the chief didn't call yet... Same on landing