I see RS232 as more of a programming interface or tool. Crestorn and AMX weren't really developed for the home AV market originally. They were developed for the pro industry (convention sytems, etc.) Most people that use a Crestron system in a residential sytsem use wireless models, and other than programming the hardware. It's all RF and IR . In a hardwired scenario such as a large convention centre or a venue that has a dedicated complex hardwired multi-zone AV system, it's totally interactive with feedback, and yes was developed for the PC platform well before most of the hardawere that has followed. you will see RS232 in industrial situations such as ice arena's where temperature and other parameters are provided in real time via RS232, or HVAC systems , etc.