85 Questions
What is the format of an ARINC 429 SDI word?
9-10 bits
What is the purpose of the parity bit on an ARINC 429 bus?
To check for corruption during transmission of a word
What is the format of an ARINC 429 word label?
octal
How many LRUs can be connected to an ARINC 429 data bus?
20
What is the characteristic of ARINC 629 terminal transmit interval?
common to each terminal
What type of cable is used in an ARINC 429 bus?
a twisted shielded pair of wires
What type of numbering system is used in ARINC 429 data bus systems?
binary coded decimal
How many bits does an ARINC 429 Binary Coded Decimal word occupy?
11-29
What is a characteristic of an ARINC 629 system?
data can transmit in both directions down the data bus
How do LRUs transmit in ARINC 629?
One transmits and one receives
What limits the number of ARINC 429 receivers on a bus?
the parallel input impedance
What standard should fibre optic cables comply with in aircraft use?
ARINC 636 standard
What is the characteristic of an ARINC 629 databus?
Two cables, bi-directional
What is the primary use of an ARINC 573 data bus?
To input into a Digital Flight Data Recorder
What type of cable is used in an ARINC 429 bus?
A twisted shielded pair of wires
What is the primary function of an ARINC 429 bus?
To transmit data between LRUs
What is the characteristic of an ARINC 636 standard?
It is used for fibre optic cables in aircraft use
What type of data is input into a Digital Flight Data Recorder using an ARINC 573 bus?
Digital data
How are engine indications sent to the FDR?
Via ARINC 573
What system uses base 8?
ARINC 429, in dataword labels only
On an ARINC 629 data bus, what is the maximum amount of current-mode couplers per data bus?
120
What is required to connect an LRU to the data bus?
a current mode coupler, serial interface module and terminal controller
What is the purpose of the E-Core assembly in a current-mode coupler?
to couple the signal to the data bus
What is the low rate of transmission for ARINC 429?
12-14 Kbits/second with high of 100 kBits/second
What is included at both ends of an ARINC 629 bus cable?
a 130 ohm resistor
What type of data does an ARINC 629 stub cable connect?
bi-directional data between the LRU and current mode coupler
What can damage to ARINC 629 cables cause?
corrosion of the conductor
What type of numbering system does ARINC 429 data bus word use?
Binary coded decimal
What system is ARINC 573 related to?
Flight Data Recorder
What type of couplers are used in ARINC 629?
Inductive
What is the characteristic of ARINC 629 databus?
One bus, bi-directional data flow
What is the normal transmission order of ARINC 629 LRUs in periodic mode?
Power up
What do bits 1 to 8 represent in an ARINC 429 word string?
Monitored parameter
What is the characteristic of ARINC 629 terminal transmit interval?
Common to each terminal
What is MIL-STD-1533 a data bus for?
Digital Information Transfer System
What is the purpose of ARINC 629 periodic mode?
Normal operation
How is data coupled to an ARINC 629 data bus?
By an inductive pickup
What is the function of ARINC 629?
Normal flight
How is the word label 206 written in ARINC 429?
Octal 01100001
What is the characteristic of ARINC 629?
Half duplex
What is used in an ARINC 629 system for transmission?
A twisted pair of wires or fibre optics
What is the transmission method used in an in-series ARINC 429 system?
Time division multiplexing
What is the behavior of a terminal controller in an ARINC 429 system?
Will transmit only once during each transmit interval
What is ARINC 561 used for?
Inertial Navigation Systems
What is the characteristic of fibre optic databus links?
Bi-directional
If bits 11-18 are patched in an ARINC data word, what is the LSB bit?
19
Can an option B use both systems, ARINC 629 and ARINC 429?
Yes, via system card files and signal gateways
What determines the number of LRUs that can transmit or receive on ARINC-429?
Parallel input impedance
What format is used in one of the ARINC 429 formats?
BCD
What is a group of bits transmitted at the same time called?
Parallel data
What system is used to transfer data in the ARINC 429 system?
Bi-directional return to zero
Which ARINC is bidirectional?
629
What method is used to transfer data on the MIL-STD-1553B?
Manchester bi-phase
What components make up the general arrangement of ARINC 629?
Databus cable, current mode coupler, stub cable
What is used to terminate ARINC 629 Databus cables?
130 ohms resistor
If bits 11 to 18 had pad bits in ARINC 429, what would be the L.S.B. of the data?
Bit 19
What range of bits contain the BCD data field in ARINC 429?
11-29
In RZ bi-polar modulation, how many states can bits be in?
Three
In the ARINC 429 digital information transfer system, how does data travel?
In one direction only
What is the characteristic of an ARINC 629 data word?
Has only 20 bits
What is the purpose of bit number 32 in an ARINC 429 digital word?
Checking parity
What connects an LRU to the Bus Coupler in an ARINC 629 Data Bus?
Stub Cable
How many states can RZ bi-polar modulation bits be in?
Three
In what direction does data travel in the ARINC 429 digital information transfer system?
One direction only
What type of communication link is required to achieve bi-directional communication within an ARINC 429 system?
Two data buses
What is the characteristic of an ARINC 629 data word in terms of the number of bits?
20 bits
What is the primary advantage of using a serial bus in an aircraft?
It saves weight
How do LRUs transmit in an ARINC 629 system?
When a terminal gap is sensed
What is the characteristic of an ARINC 629 aperiodic mode?
Used for database loads
What is the voltage range of an ARINC 429 signal?
+10v to -10v
What is the occupation of bits 11-29 in an ARINC 429 BCD word?
Filled with padders
How many bits are in an ARINC 629 label word?
12 bits
How many transmitters and receivers are present in a simplex system?
One transmitter and multiple receivers
What is the purpose of the T/R in ARINC 629?
Multiplex/Demultiplex
What is the representation of the heading '320' in bits 1-8 of an ARINC 429 word?
00001011
How does ARINC 629 bus transmit and receive information?
Inductive coupling
In an ARINC 629 system, what determines the order of LRU transmission in aperiodic mode?
Shortest terminal gap to longest terminal gap
What is the purpose of ARINC 561?
To specify Radio Comms data bus
Can an LRU transmit and receive on more than one ARINC 629 bus?
Yes
What type of cable is recommended for use in aircraft avionics?
Fibre optic
What is the characteristic of an ARINC 429 system?
Single Source Multiple Sink System
What is the purpose of intermediate production breaks in ARINC 429 or 629 Data cables?
To allow maintenance personnel to divide the right and left system buses into two parts for easy removal and installation
Where is the parity bit installed in a data word?
Either front or back
What is the function of terminal gap in ARINC 629?
Flexible
What type of coupling is used in ARINC 619?
Inductive coupling
Study Notes
ARINC 429 and ARINC 629 Databus Systems
ARINC 429
- Uses a twisted shielded pair of wires for data transmission
- Data bus word systems use binary coded decimal (BCD)
- Word label format is octal
- Each LRU can transmit and receive on the bus
- Maximum of 20 LRUs can be connected to the bus
- Parity bit is used to check for corruption during transmission of a word
- Data is transmitted in both directions down the data bus
- Limitation on the number of ARINC 429 receivers on a bus is due to the parallel input impedance
- Low rate of transmission is 12-14 Kbits/second with high of 100 kBits/second
- Word label 206 is written in octal as 01100001
- Used for Flight Data Recorders (FDR) and other aircraft systems
ARINC 629
- Uses a twisted pair of wires or fibre optics for data transmission
- Data bus is bi-directional, allowing data to transmit in both directions down the bus
- Each LRU has a unique address and can transmit and receive on the bus
- Maximum of 120 LRUs can be connected to the bus
- Current-mode coupler contains an E-Core assembly to provide effective screening of the signal
- Stub cable connects bi-directional data between the LRU and current mode coupler
- Care must be taken when installing ARINC 629 cables into bus panels to prevent damage and corrosion
- Used for normal flight operations
Other ARINC Systems
- ARINC 573: used for Digital Flight Data Recorders
- ARINC 561: used for Inertial Navigation Systems
- ARINC 636: standard for fibre optic cables in aircraft use
MIL-STD-1553B
-
Data is transferred using Manchester bi-phase
-
Used for Digital Information Transfer System### ARINC 429 and 629 Systems
-
The BCD data field of ARINC 429 is contained within bits 11-29.
-
A binary word in ARINC 429 occupies bits 11-28, while a BCD word occupies bits 11-29.
ARINC 429 Data Transmission
- ARINC 429 is transmitted using a single wire for each transmitter.
- The system sends data to LRUs in series, which saves weight.
- To create a bi-directional communications link within an ARINC 429 system, two data buses are required.
ARINC 629 System
- ARINC 629 is transmitted using fibre optics or twisted pair of wires.
- In an ARINC 629 system, LRUs can transmit and receive on more than one bus.
- LRUs transmit when terminal gap is sensed.
- Aperiodic mode is used for database loads.
ARINC 429 and 629 Data Words
- An ARINC 429 BCD word occupies bits 11-29. If 11-15 are filled with padders, the LSB of the word will be 16.
- An ARINC 629 label word is 12 bits.
- In an ARINC 429 word, the label-representing heading is 320, which is represented in bits 1-8 as 00001011.
Data Transfer and Transmission
- ARINC 429 bi-directional data transfer is achieved using two data buses.
- The output voltage of ARINC 429 signal is +10v to -10v.
- In ARINC 629, LRUs transmit in order of shortest terminal gap to longest terminal gap in aperiodic mode.
ARINC Specifications
- ARINC 561 is used to specify Radio Comms data bus.
- ARINC 429 is a Single Source Multiple Sink System.
- The purpose of the parity bit on an ARINC 429 bus is to indicate to the receiver that the data is valid.
Cables and Installation
- Intermediate production breaks are used in ARINC 429 or 629 data cables to allow maintenance personnel to divide the right and left system buses into two parts for easy removal and installation.
- The parity bit is installed at the end MSB of a data word.
- In a data word, RZ bi-polar modulation consists of three states.
General Information
- ARINC 429 data may travel in one direction only.
- An ARINC 629 data word has only 20 bits.
- In an ARINC 429 digital word, bit number 32 is used for checking parity.
- A stub cable connects an LRU to the Bus Coupler in an ARINC 629 Data Bus.
Test your knowledge of aircraft systems with these multiple-choice questions, covering topics such as ARINC 629 and fibre optic cables.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
