The Netlinx is basically a bunch of RS232 (and InfraRed) connections that talk to the Lights, Signage, Projector and Extron Matrix etc.
It occurred to me that the AMX panel is basically the same as the iOS/Android/
I started writing the app in the emulator that came with the Android SDK, but this seemed to have a problem with UDP sockets. It emulates a 3G connection, but not WiFi. So I got a shitty 7" Tablet from ebay for £26. I managed to write a small Android app with a few buttons that would trigger certain RS232/IR signals.
I dug my USB-RS232 adpater out. After a lot of pouring over manuals for RS232 codes I managed to get this working. You can test the strings they give you in the manual in a serial terminal - but there is no standard notation in the manuals, you never know if your sending ASCII, Hex etc. The python serial library works a treat though. There is an IR library for Arduino which encapsulates a lot of the codes for common devices - this didn't work for my 1st Gen Arduino, so off to ebay again, and £12 for an Arduino Nano...
It all works like a champ - Java is still a bad language, and I need to find a way to enumerate multiple USB-RS232 devices to make sure I know which one is plugged into which device...