how can i use just use the lcd from my gateway profile4 all in one?
I'm doing the same and this was helpful as it confirmed that the gateway one has no input video port. What I did was used Remote Desktop from my Gateway one to my laptop (small display) and life is great. Good luck!
You can't. Profile 4 does not have video in capability.
Where to use it?
Advertising player Applications
Advertising player is a kind of multimedia advertising and public information distribution system, because of its demonstrated ability to express the content, and therefore it's suitable for almost all public places:
Building multimedia information broadcasting system.
Residential elevator hall, the elevator box, residential building entrance; Business Building lobby, etc.