The classic Passenger Service Unit (PSU) receives a digital upgrade: with touch displays, intelligent control, and efficient networking via 10BASE-T1S, the Smart Connected PSU makes the flight experience more comfortable for passengers and simplifies cabin operations for the crew. Developed as part of Eduard Lomtadze’s bachelor thesis at HAW Hamburg and ZAL, it is now on the shortlist for the Crystal Cabin Award 2026.

The Passenger Service Unit – known in the aircraft as the PSU – is something everyone has seen and used. It provides functions such as reading lights, ventilation, or summoning the cabin crew. Anyone who has flown ten, twenty, or even thirty years ago will have noticed one thing: the PSU has remained surprisingly unchanged. Since the early days of modern aviation, its functionality has hardly evolved.

At the same time, our everyday lives have changed dramatically: touchscreens, digital services, and personalized content are now commonplace – yet onboard reality often looks very different.

This could soon change, as digitalization and networking are gradually making their way into the aircraft cabin. One building block of the cabin of the future is a modernized, intelligent PSU. It offers great potential to enhance the passenger experience and support the crew in coordinating cabin operations.

Within the framework of the research consortium DaKliF* (Data Platform for Climate-Neutral Flying), the Smart Connected PSU was developed at ZAL. It extends the classic aircraft component with numerous new functions provided via touch displays and internal intelligence. This enables an improved flight experience for passengers, easier communication for the crew, and new revenue opportunities for airlines – all in a single, compact device.

What the new PSU offers

• Touchscreens for every passenger
  → Intuitive control of lighting, crew call, and other functions

• New information and service offerings
  → Remaining flight time, altitude, connecting flight information, exchange rates, weather forecasts, and more

• Direct connection to the crew
  → Passengers can more easily submit messages or communicate their needs

• Enhanced safety
  → Individual alerts such as “Please fasten your seatbelt”
  → Support in emergencies, e.g., by displaying the nearest emergency exit

• Maintenance
  → Passengers can report defects directly from their seat
  → Thanks to internal intelligence, the PSU can perform self-diagnosis and detect faulty components

Lean network, low energy consumption

Additional devices mean more data traffic in the cabin network, more cables, and higher power consumption. Cabin networks are already complex today: they consist of many different, often proprietary communication standards. Every piece of information – from movies to temperature sensors – must be translated into different “network languages” via so-called protocol converters. These interfaces can create data bottlenecks, slowing down the network and making the implementation of new functions more labor-intensive.

Within the DaKliF project, a continuous, standardized Ethernet cabin network is being developed. The Smart Connected PSU uses 10BASE-T1S, a single-pair Ethernet technology with a multidrop topology. It allows multiple devices to be connected via a single line, reducing cabling effort and system complexity.

Advantages of 10BASE-T1S at a glance:

• Multidrop topology: Multiple end devices (e.g., Smart PSU) can be connected to a single line like a string of lights

• Low energy consumption

• Efficient bandwidth usage

• Deterministic communication with low latency

• Seamless integration into a continuous Ethernet network

Meaning of the designation 10BASE-T1S:

• 10 → Data rate of 10 Mbit/s

• BASE → Baseband transmission (no frequency multiplexing)

• T → Twisted pair copper wires

• 1 → One pair of wires (Single Pair Ethernet)

• S → Short Reach

Energy-efficient intelligence

The PSU is controlled via the ZAL Endpoint ECO, an energy-efficient microcontroller from the ZAL Endpoint family. It was specifically developed for use in Ethernet-based cabin networks and enables low-power operation in a compact form factor.

The Smart Connected PSU demonstrates how existing cabin components can be digitally expanded step by step and integrated into future network concepts: digital, connected, modular, and efficient.

*DaKliF is supported by the Federal Ministry for Economic Affairs and Energy.