190302 dB Flashcards
What is loop or ring topology?
Early networks used a loop or ring topology in which all modules are wired in series.
One major disadvantage of the loop topology is that if one module on the bus loses power or ground the whole network could lose communication
What is star topology?
In the star topology master module controls the data bus and the remaining modules are dependent on slave modules
This configuration allows the network to continue to communicate even when power or ground is lost to a module
What is linear topology?
Linear topology in which there is a main backbone with stops running to each module there is no master module all modules receive all broadcast would speed up the rate of data communication
What is MID?
Message identifier
- is one byte long and indicates the source address of the transmitting node
What is PID?
Parameter identifier
- is usually one bite long and indicates to what parameter the following data correspondence
What must follow a PID?
All PIDs must be followed by at least one data value. The length varies depending on the amount of data transmitted but cannot exceed 18 bites
What is “topology”?
Topology describes a logic structure of the control modules on the data bus
The checksum comes before the final byte of data T/F?
False, it comes after the final byte of data
What is one of the first tests you need to conduct with all multiplexed systems?
Determine if the system is receiving power.
When testing multiplexed systems, we can use any multi meter. T/F
False; Failure to use a high impedance meter will result in damage to the electronic components.
SAE J1939-11 multiplexed systems run at what speeds?
250 kb/s
Difference between shielded and unsheilded j1939 is?
Shielded twisted pair has a drain wire
Terminating resisters are used at each end to prevent?
Standing waves
Signal corruption occurs when?
An electromagnetic force is induced in the data link. Example. Run across a data link , twisted pair looses integrity or anything with any magnetic properties
Which of the following best describes multiplexing?
a) the ability to communicate analog signals between communication devices
b) the ability to send and receive digital electronic signals over a pair of wires
c) the ability to increase the amount of wires necessary to connect inputs and
outputs
d) the ability to control devices wirelessly
the ability to send and receive digital electronic signals over a pair of wires