ARINC 664 Part 7 or A664 is a standard that defines the electrical and protocol specifications for a communications network suitable for use in an avionics environment. This standard is based on earlier work done by Airbus called AFDX (Avionics Full Duplex Switched Ethernet) and used for the A380.
Early History
Many commercial aircraft use the ARINC 429 standard developed in 1977 for safety-critical applications. ARINC 429 utilizes a unidirectional bus with a single transmitter and up to twenty receivers. A data word consists of 32 bits communicated over a twisted pair cable using the Bipolar Return-to-Zero Modulation. There are two speeds of transmission: high speed operates and low speed operates at 12.5 kbit/s.
System Standards
The architecture adopted by A. Westland is centered around the AFDX data network developed for the latest commercial airliners. The AFDX high-speed digital bus has been developed as a specific implementation of A664 Part 7. Another standard, ARINC 629, introduced by Boeing for the 777 provided increased data speeds of up to 2 Mbit/s and allowing a maximum of 120 data terminals.
Other Standards
The ADN operates without the use of a bus controller thereby increasing the reliability of the network architecture. The drawback is that it requires custom hardware which can add significant cost to the aircraft. Because of this, other manufactures did not openly accept the ARINC 629 standard.
AFDX Network
AFDX was designed as the next-generation aircraft data network. Basing on standards from the IEEE 802.3 committee (commonly known as Ethernet) allows commercial off-the-shelf hardware to reduce costs and development time. AFDX is one implementation of deterministic Ethernet defined by ARINC Specification 664 Part 7. AFDX was developed by Airbus Industries for the A380, initially to address real-time issues for flight-by-wire system development.
AFDX Licenses
Building on the experience from the A380, the Airbus A350 also uses an AFDX network, with avionics and systems supplied by Rockwell Collins.[5] Airbus and its EADS parent company have made AFDX licenses available through the EADS Technology Licensing initiative, including agreements with Selex ES. A similar implementation of deterministic Ethernet is used on the Boeing 787 Dreamliner. AFDX bridges the gap on reliability of guaranteed bandwidth from the original ARINC 664 standard.