The backbone of the entire system will be the ability to connect the various node, in the need of identify the best way to do so, i have selected five alternatives:
> KNX
> CAN
> DALI
> WIFI/RF
> Developing a proprietary protocol based on DALI and CAN

(+) Pro
(-) Cons

KNX (TP)
- requires complex power supply
- little choice of transceiver ICs (more expensive)
+ only 2 wires for bus and power supply
+ multimaster
+ line/bus, tree and star topology are allowed

CAN
- requires 4 wires, two for power and two for the bus
- only line/bus topology
- requires termination resistance
+ multimaster
+ cheaper transceivers

DALI
- Manchester encoding
- master/slave (dali 1)
+ only 2 wires for bus and power supply
+ simple power supply
+ the interface is realizable with passive components
+ line/bus and star topology are allowed

WIFI/RF
- requires power supply (mains)
- not good if is inserted inside the wall
+ simple to implement + tree, star and mesh topology are allowed

Developing a proprietary protocol based on DALI and CAN
(HW interface based on DALI protocol based on CAN)
- everything needs to be developed (HW & SW)
+ only 2 wires for bus and power supply (DALI)
+ simple power supply (DALI)
+ the interface is realizable with passive components (DALI)
+ line/bus and star topology are allowed (DALI)
+ mltimaster (CAN)