ARINC Communications


ARINC Communications

NAI’s latest generation ARINC Communication Modules (AR1 & AR2) are used on our rugged COTS Multifunction Embedded I/O Boards, Single Board Computers (SBCs), and Configurable Systems offered in OpenVPX, cPCI, VME, and PCI/PCIe configurations.

Module AR1 features up to twelve programmable ARINC 429 channels. Module AR2 features two channels with one providing ARINC 568 communication and the other providing ARINC 579 communication.

NAI's Smart Function Modules provide uniquely flexible, mix & match customization options for use with our COTS hardware. Learn More

Module AR1

The AR1 provides an ARINC 429/575 communications interface with 12 channels. This module only provides an interface and data management. Any specific protocol handling must be programmed by the user in the application layer. Each channel is programmable as either Tx or Rx. 

ARINC 429 is a data transfer standard for aircraft avionics. It uses a self-clocking, self-synchronizing data bus protocol (Tx and Rx are on separate ports). The physical connection wires are twisted pairs carrying balanced differential signaling. Data words are 32-bits in length and most messages consist of a single data word. Messages are transmitted at either 12.5 or 100 kbit/s to other system elements that are monitoring the bus messages. The transmitter constantly transmits either 32-bit data words or the Null state. A single wire-pair is limited to one transmitter and no more than 20 receivers. The protocol allows for self-clocking at the receiver end, thus eliminating the need to transmit clocking data. ARINC 429 is an alternative to MIL-STD-1553.

ARINC 575 is an equipment characteristic for a Digital Air Data System (DADS) that provides essential air-data information for displays, autopilots, and other flight controls and instrumentation on commercial and transport-type aircraft. ARINC 575 defined a digital databus for distribution of information to displays and other systems. This databus was later described in ARINC 419 and became what is now known as ARINC 429. There are only minor differences between the digital databus of ARINC 575 and that of ARINC 429. The most significant difference is that ARINC 429 reserves bit 32 for parity, while ARINC 575 could use bit 32 for either parity (when BNR) or data (when BCD).

AR1 Block Diagram

For both the ARINC 429 and ARINC 575 standards, each channel is software-selectable for transmit or receive, and for Hi or Lo speed. The receiver logic converts the serial BRZ data stream to a 32-bit wide parallel data word. If the Label, SDI, and parity bits pass validation, the ARINC data word is sent to the Receive Output FIFO. Message data can be sent immediately or buffered for synchronized transmission. In buffer mode, ARINC words are read from the Txmit buffer and sent out at the Txmit Interval Rate. In repeat mode, ARINC message data is sent continuously. The user interface supports FIFO buffering and interrupts. Txmit data can be sent immediately or scheduled. To schedule a Txmit sequence, the Txmit FIFO can be loaded with a sequence of up to 256 ARINC data words. The transmission interval is programmable. Enabling the channel begins transmission. Tx and Rx data are continuously monitored and verified.

Module AR2

The AR2 module provides an ARINC 568/579 communications interface with 2 channels. Channel 1 is Rx and Tx for ARINC 568 and channel 2 is programmable as either Rx or Tx for ARINC 579. This module only provides an interface and data management. Any specific protocol handling must be programmed by the user in the application layer.

ARINC 568 is an equipment characteristic for Distance Measurement Equipment (DME). DMEs allow aircraft to calculate their position by sending signals to ground based radio beacons and uses the time between the response minus a preset delay to calculate the distance of the aircraft from the beacon. ARINC 568 is a six-wire system involving 3 pairs of wires paired as "clock", "word sync" and "data" respectively. The word length is 32 bits. The first eight bits are the address or label and the last 24 bits are transferred as data.

ARINC 579 is an equipment characteristic for a VHF Omnidirectional Radio range (VOR) short range navigation system. VORs enable an aircraft with a receiving unit to determine its position by receiving radio signals transmitted by a network of ground fixed radio beacons. ARINC 579 is programmable as either a transmitter or a receiver. When programmed as a receiver, the module will wait for 4 null states before processing a message. Once the message is processed, the module will return to waiting for null states.

AR2 Block Diagram

For the AR2 module, the ARINC 568 and 579 standards are implemented on separate channels. Channel 1 is ARINC 568 and channel 2 is ARINC 579. For both ARINC 568 and 579, when messages are received, the FIFO can be programmed to not accept any additional data when full or to overwrite the oldest data when full. These modes are called bounded mode or circular mode (default) respectively. While transmitting, both ARINC standards can either send data immediately or buffer the data while waiting for a trigger. When the transmit FIFO is full, it can be programmed for either bounded mode or circular mode as well. 


Click below for manuals and specifications:

AR112-CH ARINC 429/575 CommunicationsN/AModule Manual - AR1
AR22-CH ARINC 568/579 CommunicationsN/AModule Manual - AR2

Function module(s) featured in products below:

ModelBoard TypeBoard ArchitectureFunction Module SlotsSizeEthernetMaster / SlaveOn Board ReferenceOther
75G53U cPCIARM / Xilinx® Zynq3 2 x GbBoth   
64G5VMEARM / Xilinx® Zynq6 2 x GbBoth YUser application ARM processor capability
68G53U OpenVPXDual Core ARM® Cortex® A9 @ 800 MHz3 2 x GbBoth  Slot profile: SLT3-PER-1U-14.3.3 / Module profile: MOD3-PER-1U-16.3.3-2
79G5PCIe 31/2   N/A 
ModelBoard TypeProcessorFunction Module SlotsMaximum MemoryMaximum StorageVideo OptionsEthernetAvailable O/S
75ARM13U cPCI SBCXilinx® Zynq 7015 with Dual Core ARM® Cortex® A9 @ 800 MHz3512 MB DDR3L SDRAM32 GB SATAII NAND FlashN/A2 x GbWind River® VxWorks®, Xilinx® PetaLinux OS and DDC-I Deos™ support
68ARM13U OpenVPX SBCXlilinx® Zynq 7015 & 7016 w/Dual Core ARM® Cortex®-A9 @800MHz3512 MB DDR3 SDRAM32 GB SATAII NAND FlashN/A2 x GbWind River®, VxWorks® and Xilinx® PetaLinux OS Support
75PPC13U cPCI SBCNXP® QorIQ® P2041 Quad-Core e500mc Processor @ 1.2 GHz28 GB DDR3L SDRAM32 GB SATAII NAND FlashN/A2 x GbWind River® VxWorks®
75INT23U cPCI SBCDual Core Intel® i7 3517UE @ 1.5 GHz28 GB DDR3L SDRAM32 GB SATAII NAND FlashVGA, HDMI, LVDS, or DVI2 x GbCentOS, Red Hat®, Linux®, and Windows® Embedded Standard 7
64ARM16U VME SBCXilinx® Zynq Dual Core ARM® Cortex® A9 @ 800 MHz6 + AC Ref512 MB DDR3L SDRAM32 GB SATAII NAND FlashN/A2 x GbWind River® VxWorks® and Xilinx® PetaLinux OS support
68PPC23U OpenVPX SBCNXP® QorIQ® T2080 Quad Core @1.5 GHz2 8 GB DDR3 SDRAM32 GB SATAII NAND FlashN/A2 x GbWind River® VxWorks®
ModelPhotoBoard TypeDimensions w/Connectors (w x h x d)Volume w/Connectors (in3)Weight / lbs (fully populated)Est. Typ. Power Dissipation (W)# of Board SlotsFunction Module SlotsMax I/O PinsEthernet
NIU1AModule6.8" x 1.5" x 2.5"28.90<1.25 to 15 WN/A1592 x Gb
NIU2AModule7.0" x 3.0" x 2.5"52.5<2.755 to 25 WN/A21322 x Gb
SIU313U4.71" x 2.35" x 8.71"96.41<5.07 to 35 W131322 x Gb
SIU333U4.71" x 4.78" x 8.71"196.10<10.014 to 75 W393222 x Gb
SIU353U7.13" x 4.78" x 8.71"296.85<15.025 to 100 W5155122 x Gb