The u::Lux Switch RJ45 is connected to the control system via Ethernet. All eight wires of the network cable are used — four for data and four for power supply (48 V DC). This allows several u::Lux Switches to be operated in a daisy-chain configuration, with up to 10 devices per line. For power, the system does not use the official PoE standard, but an open 48 V supply system that enables flexible cascading of devices.

Power supply options

u::Lux power components – supply for up to 20 u::Lux Switches:

• u::Lux NetCon Power – 4-port switch, two ports with 48 V power output
• u::Lux NetInj Power – dual injector for power feed-in without switch function

Both devices are powered with 24 V DC (standard control cabinet voltage) and internally generate 48 V DC. Each powered port can supply up to 10 u::Lux Switch RJ45 units, meaning up to 20 devices per unit in total.Alternative: Passive PoE injectorsSo-called passive PoE injectors with a fixed 48 V output can also be used (recommended mainly for testing or single setups). Many inexpensive injectors marketed as “PoE injectors” do not follow the official PoE standard (IEEE 802.3af) but simply apply 48 V DC to the four unused wires of the network cable. The u::Lux Switch RJ45 uses exactly this principle and can therefore be operated with such injectors.Wiring detailsCabling is done using CAT 5e or higher. The RJ45 plug connection makes installation extremely simple and is ideal for line wiring. The u::Lux NetLink RJ45 (the base unit of the u::Lux Switch) contains a genuine 3-port Ethernet switch – two ports for the RJ45 sockets and one internal connection to the display. The system is not PoE in the official sense, since PoE supports only a single powered device and does not allow cascading. In the PoE standard, the power supply is ramped up gradually at startup, and the device reports its power class back to the injector. In contrast, the u::Lux RJ45 system applies 48 V permanently to the four power wires – allowing multiple devices to be operated in series.

u::Lux Switch RJ45 - Manual

The u::Lux Switch LSA/IDC  is connected to the control system via Ethernet and powered by a standard PoE switch (minimum Class 1). The connection uses LSA/IDC insulation displacement technology in a star wiring topology. “LSA/IDC” stands for solderless, screwless, and insulation-displacement – a proven technique from network installation in which the wires are simply pressed into color-coded terminals. Termination is done using an LSA/IDC punch-down tool – fast, clean, and permanently reliable. The wiring uses Category 6 (CAT6) or higher installation cables. Each u::Lux Switch LSA has its own dedicated cable directly connected to the PoE switch or PoE injector. This makes the LSA version ideal for classic star-wiring installations in modern buildings.

Power and data transmission

The u::Lux NetLink LSA/IDC (the base unit of the u::Lux Switch) transmits both data and power according to the PoE standard IEEE 802.3af (Class 1). Depending on the PoE equipment used, power can be supplied in two ways:

• Mode A: Data and power are transmitted together over the same four wires.
  
• Mode B: Data and power are transmitted separately – four wires for data and four for power.

The u::Lux Switch LSA supports both modes, ensuring full compatibility with all standard PoE switches and injectors. The connected PoE device automatically detects the u::Lux Switch and provides the required power. During startup, the voltage is ramped up in a controlled manner while the device reports its power requirements (device class) back to the PoE switch.

Additional sensor connections
In addition, the u::Lux NetLink LSA (base module of the u::Lux Switch) features four extra insulation-displacement terminals for the u::Lux AddOn cable, which allows optional u::Lux sensor modules – e.g. for temperature, humidity, or CO2 – to be connected.

u::Lux Switch LSA - Manual

UDP-communication
The u::Lux Switch sends and receives UMP messages via UDP port 0x88AC. No TCP handshake, no drivers – communication takes place directly over Ethernet (UDP/IP). 

Open data model 
Each message contains a header (descriptor) with length, address, and version information, followed by one or more message IDs that carry data or commands. Byte order: Little Endian.

Bidirectional communication 
The u::Lux Switch sends events (button presses, sensor values, status changes). The control system sends commands, e.g. to display text or values, change LED colors, or switch pages.

Integration into automation systems
Supported control systems include any platform with UDP capability - already integrated for example alonco, Beckhoff, Comexio, Domiq, evonHOME or Phoenix Contact Emalytics/Niagara. Custom solutions or middleware (e.g. Node-RED, MQTT bridges, JavaScript servers) can also communicate directly with the u::Lux Switch.

The full protocol specification is documented in the u::Lux Message Protocol (UMP). Here’s an example of a typical sequence: 

Device startup: The u::Lux Switch sends an InitRequest message. The controller responds with InitResponse and optionally TimeUpdate.

Normal operation:
ID-EditValue / ID-RealValue – Display of values
ID-LED / ID-PageIndex – Display and control functions
ID-Event – Button events
ID-I2C-Temperature – Sensor data

Status reporting: The u::Lux Switch continuously transmits its internal states, which can be processed by the control system.

Status
Status information is transmitted via StateFlags, e.g.:

> Display active/inactive
> Proximity detected
> Sensor values valid
> Error or communication state

These flags allow the control system to respond immediately to status changes.