AET Data Bus Systems and Protocols 3

Question 1

Which avionics data bus standard supports data rates up to 100 Mbps and is used in modern commercial aircraft such as the A380 and Boeing 787?

Accepted Answer

ARINC 664 (AFDX)

Answer

ARINC 429

Answer

MIL-STD-1553B

Answer

RS-422

Question 2

What is the specified characteristic impedance of a MIL-STD-1553 bus cable?

Accepted Answer

70 ohms

Answer

50 ohms

Answer

100 ohms

Answer

120 ohms

Question 3

When troubleshooting an ARINC 429 bus with no output signal, what should a technician check first?

Accepted Answer

Power supply voltage to the transmitter LRU

Answer

Label coding of individual data words

Answer

Number of receivers connected to the bus

Answer

Parity setting of the receiving units

Question 4

In MIL-STD-1553, what is a 'stub'?

Accepted Answer

A short cable connecting a terminal to the main bus

Answer

An unused RT address reserved for future use

Answer

A parity error flagged in a status word

Answer

An unanswered command left pending by the Bus Controller

Question 5

What is the primary purpose of coupling transformers used in a MIL-STD-1553 bus installation?

Accepted Answer

Provide electrical isolation and impedance matching between terminal and bus

Answer

Increase the data transfer speed of the bus

Answer

Filter out RF interference from nearby avionics

Answer

Convert Manchester encoding to NRZ for internal processing

Question 6

What causes a parity error in an ARINC 429 data word?

Accepted Answer

The total count of logic-1 bits in the 32-bit word is not odd

Answer

Data transmitted at incorrect bus speed

Answer

Label field mismatch between transmitter and receiver configuration

Answer

Bus voltage level falling outside the ±10 V specification

Question 7

Which tool is most appropriate for decoding and analyzing traffic on an ARINC 429 bus?

Accepted Answer

ARINC 429 protocol bus analyzer

Answer

Digital multimeter

Answer

Analog oscilloscope only

Answer

Generic Ethernet network protocol analyzer