What is A²B?
A²B (Automotive Audio Bus) is a digital audio bus technology developed by Analog Devices for use in vehicles. It enables low-latency, high bandwidth (up to 50 Mbit/s) audio transmission over a single, cost-effective cabling system. This technology is used in the automotive industry to transmit audio signals, and considerably reduces cabling requirements. A²B is constantly being developed to enable higher data rates, optimized latency times and improved integration into vehicle systems.
What is the operating principle of A²B?
A²B is based on a master-slave architecture where a single master node can control up to 16 slave nodes in a daisy-chain topology. Data is transmitted bidirectionally over a single, unshielded twisted pair cable that transmits both audio data and control signals while also carrying 50 W of power for the connected devices. The maximum total length of a network can be up to 15 m via single nodes and up to 40 m in a daisy-chain topology.
Which application areas is A²B used in?
In the automotive industry, A²B plays a key role in distributing audio signals in vehicles, and is particularly used in:
Active Noise Cancellation (ANC):
Effectively reduces street-based noise to create a more pleasant driving experience.
Road Noise Cancellation (RNC):
Minimizes road-based noise through targeted counter frequencies.
In-Car Communication (ICC):
Enables improved voice communication between vehicle passengers and supports several microphone arrays1 in the vehicle.
Telematics systems:
Enables clear voice transmission for emergency call systems and other communication services.
A²B is also used in other areas of the automotive sector such as in passenger transport services and the transport sector. One example of this is its integration into bus stop button systems.
In addition to the automotive sector, A²B is also used in Unified Communications2, aerospace technology, professional audio technology and home cinema systems.
What are the advantages of A²B?
Reduced cabling:
Saves up to 75% in cabling requirements, thereby reducing weight and costs.
High audio quality:
Supports high-resolution audio signals with minimum latency.
Robust:
Ensures the reliable transmission of audio signals, including in demanding, electromagnetic environments (EMC).
Easy integration:
Does not require any additional software overheads, thus reducing development time and costs.
Flexibility:
Scalable and can be used in different sectors and applications.
Through the combination of high bandwidth, low latency and reduced cabling requirements, A²B makes a decisive contribution to the optimization of audio transmission in vehicles and other applications.
1 Microphone arrays are arrangements of several microphones which capture and process audio signals, enabling the accurate localization and suppression of sources of noise.
2 Unified Communications (UC) is the term used to describe the integration of different communication services, such as voice calling, video conferencing and instant messaging, into a single platform to improve collaboration and efficiency in companies.
Tobias Hartl
Tobias Hartl has been involved in technical product management in the area of multi core cables at MD since 2019. He began his career as an application engineer for international customers. Before joining MD, he gained 6 years’ valuable experience in the area of mobile media head units, which he applies successfully in his every day work. What Tobias finds particularly motivating is the contact with global customers and implementing new technologies in collaboration with an international team.
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