TP: use a bus designed for KNX
A TP installation needs suitable KNX cable, a correctly sized bus supply with choke and a topology designed within the applicable length/current limits. Follow the actual supply and device manuals for polarity, connections and segregation. Do not add Ethernet components or generic DMX/RS485 terminators to a KNX TP bus.
The bus carries communications and device power where specified; actuators and lighting loads can have separate mains supplies. SELV bus operation is not permission to work inside an energised distribution board. Australian mains work still belongs to an appropriately licensed electrician.
RF and IP
KNX RF can extend control where cable is difficult, using compatible devices and TP/RF couplers where required. Check the regional radio version, local approval, building materials and actual coverage. The presence of a generic sub-GHz receiver does not make it a KNX RF interface.
KNXnet/IP interfaces provide commissioning/tunnelling access, while suitable routers can route KNX telegrams over an IP backbone. An IP interface is not automatically a full lighting logic controller. Newer KNX IoT uses IPv6-capable media and its own defined interfaces; do not assume it is identical to classic KNXnet/IP.
A first look at the protocol
Individual addresses identify devices for management; group addresses connect application functions. The datapoint type supplies meaning: an on/off value, dimming command and temperature are not interchangeable just because they fit into a message. Use explicit status objects where available instead of assuming the last sent command is physical confirmation.
Specification access
The official KNX Specifications page links the public specification set and describes its volumes, including system communication and application descriptions. It also explains that members receive the fuller/current member material and updates. Public access does not remove certification, trademark or ETS licensing requirements. Separately published national/international standards may have their own purchase conditions.
Start with the technology overview, then the relevant specification volumes and exact product application manuals. Commissioning training and a backed-up ETS project are more useful to an owner than random packet examples without the project's group-address plan.
Official reading
Official TP, RF, KNXnet/IP and KNX IoT overview
Public KNX specifications and member-access explanation
Bus versus auxiliary power output example