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Chapter 12
End of Chapter Review Questions Answer Key
1. What is used to rate the speed of transmission on a data bus?
2. Which of the following terms is used to rate the data volume that can be transmitted
on a data bus?
3. When observing a scoped view of a J1939 message packet, what is the usual voltage
differential spread of content data if the bus is functioning normally?
4. Which of the fields in a data packet contains the priority rating of the message?
5. Which field in a data packet is used by receiver stations to indicate that they have
received an uncorrupted message?
6. What is used to indicate the end of a data packet message?
7. What current SAE J-standard is used as the backbone of a multiplex data bus in
current medium- and heavy-duty highway trucks?
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8. Which of the following best describes the role of an FET in a smart switch
transaction?
9. What will result if a smart switch is disconnected at the connector?
10. How many cavity pins are used in the J1939 Deutsch DLC?
11. Technician A says that power line carrier (PLC) technology allows trailer ABS
electronics to communicate with the tractor data bus. Technician B says that PLC
signals are superimposed over the blue auxiliary power line in a standard 7-pin trailer
connector. Who is correct?
12. Which of the following colors would be associated with a J1939 twisted-wire pair?
13. Which of the following is true of a post-2014 J1939 DLC?
14. Which OEM uses a 16-pin J1962 DLC to access its post-2014 J1939 data bus?
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15. Technician A says that the F-cavity in a green J1939 9-pin receptacle is smaller than
in the black pre-2014 equivalent. Technician B says that a green 9-pin J1939 DLC
cannot connect to a black 9-pin receptacle. Who is correct?
16. What is the usual source address (SA) on a J1939 bus for an electronic transmission
controller?
17. How many cavity pins are in a J1962 DLC?
18. Technician A says that a ladder switch is type of smart switch that uses internal
resistors to signal switch status. Technician B says that some smart switches have
processing capability. Who is right?
19. When a global PGN is broadcast on a J1939 bus, which controller receives the data?
20. Which cavity pin on a standard J1939 controller is used for the J1939 dominant low
( ) transmission?