You are in for a major project. There are numerous vendors (Symbol, Intermec, Teklogix) of industrial (you can drop it onto concrete and it still works) RF handhelds which it sounds like you are in the market for. You will also need some industrial (expensive, proprietary) middleware if you plan to connect ‘real-time’ to the “backbone of our business system”, unless RPG has built-in hooks. RF technology has been around for years and is very stable, if you do it right. Do your homework. I would suggest considering a bolt-on solution using near real-time data interfaces, unless money is not a consideration. The difference could be a factor of 10! Did I mention ‘do your homework’?