Digital Comms Flashcards
(41 cards)
1
Q
- What function does the MSTR block perform in a modicon controller with modbus?
a. It does and instructed by the CPU
b. It is the secondary command structure and completes transaction via ack signals from the slave units.
c. The MSTR command controls the communications between two devices on a modbus system. It is the master in reads or writes to the slaves.
d. The MSTR command sets the LSB to zero on all secondary routines.
A
c. The MSTR command controls the communications between two devices on a modbus system. It is the master in reads or writes to the slaves.
2
Q
- Explain the difference between an A null modem cable and straight through cable?
a. There is no difference
b. A straight through cable connects DCE to DTE A one to one connection on all lines, while a null modem cable connect DTE to DTE crossing lines TX and RX
c. a straight through cable connects DTE to DTE has a one to one connection in all lines, while a null modem cable connect DCE to DCE crossing lines TX and RX
d. a straight through cable connects DCE to DCE has a one to one connection in all lines, while a null modem cable connect DTE to DTE crossing lines TX and RX
A
b. A straight through cable connects DCE to DTE A one to one connection on all lines, while a null modem cable connect DTE to DTE crossing lines TX and RX
3
Q
- What type of address is the following? AA-1C-27-FE-1E-00
a. It is the Mac address for the Nic card factory programmed.
b. Serial number for nic card
c. The address of the 27th segment of the 256K memory chip
d. Microsoft address for the CPU chipset
A
a. It is the Mac address for the Nic card factory programmed.
4
Q
- How many layers is the ISO/OSI model for network communications
a. There are 7 defined layers
b. Layers are not defined
c. There are 12 layers
d. There are four layers
A
a. There are 7 defined layers
5
Q
- What layer of the TCP/IP protocol would the program TELENET be in
a. Access to the Internet
b. Layer number 3
c. The middle layer
d. The upper or application layer
A
d. The upper or application layer
6
Q
- What does the Domain Name System provide?
a. Access to the Internet
b. DNS serves as the Internet phone book by translating host names example www.example.com into IP address e.g. 208.77.188.166
c. DNS activates the web browser
d. DNS accesses direct name search
A
b. DNS serves as the Internet phone book by translating host names example www.example.com into IP address e.g. 208.77.188.166
7
Q
- What does the TX line of a DTE device connect to add another DT device in RS232 cable?
a. The TX line connects to the TX line of the other device
b. The TX line connects to the RX line of the other device
c. The TX line connects the ready to send line of the other device
d. The TX line connects to the write enable line of the other device
A
b. The TX line connects to the RX line of the other device
8
Q
- What does SMTP stand for and what layer it is implemented in?
A
Simple mail transfer/transport protocol
9
Q
- In serial communications what does the baud rate referred to?
a. The rate of transfer in bits per second
b. Laredo transfer in bytes per second
c. Pipeline data transfer protocol
d. The maximum rate of data transfer between the CPU and SDRAM
A
a. The rate of transfer in bits per second
10
Q
- What occurs after a collision in an Ethernet system?
a. Retry after 10 seconds
b. Nothing
c. The host will send another available signal
d. After a collision the signal will travel back to the sending device, then the device detects the collision it will send a jam signal and wait a random time to resend.
A
d. After a collision the signal will travel back to the sending device, then the device detects the collision it will send a jam signal and wait a random time to resend.
11
Q
- What is the difference between 10baseT and 100baseT?
a. The speed of 10 megabytes per second versus 100 megabytes per second
b. 10 baseT is faster
c. Megabytes versus megabits
d. There is none
A
a. The speed of 10 megabytes per second versus 100 megabytes per second
12
Q
- What is the major drawback of HART communication?
a. There is none
b. Distance between instruments
c. The slow speed 1200/2200 Hertz
d. Low impedance in line feeds
A
c. The slow speed 1200/2200 Hertz
13
Q
- Why is the modbus frame embedded in the modbus+ frame?
a. To commodate CANBUS.
b. For speed
c. No reason
d. To provide compatibility with modbus device on a mod bus+ network
A
d. To provide compatibility with modbus device on a mod bus+ network
14
Q
- What is the proper resistance for the Terminator in a 10base2 cable?
a. 25 ohms
b. 70 ohms
c. 50 ohms
d. 90 ohms
A
c. 50 ohms
15
Q
- How many network layers are used in foundation field bus?
a. 2
b. 5
c. 3
d. 8
A
c. 3
16
Q
- What is the maximum number of devices that can be on a modbus+?
a. 32
b. 16
c. 54
d. 80
A
a. 32
17
Q
- How is the Communication controlled in a modbus + system?
a. TCP/IP
b. Token passing
c. By varying bitrate
d. In packets
A
b. Token passing
18
Q
- Where can a HART calibrator be connected to HART loop?
a. Only at the Terminator
b. Only at the DCS input card terminals
c. At any point that the wires are accessible
d. The only way to connect it directly to the heart output terminals in the transmitter
A
c. At any point that the wires are accessible
19
Q
- List the three layers of the seven layer model that are present in every network
a. Application, datalink and physical
b. Application, session, physical
c. Physical, detailing, session
d. Application, transport, data link
A
a. Application, datalink and physical
20
Q
- Explain frequency shift keying.
a. Each key has its own frequency
b. FSK uses multiple carriers
c. The carrier has two different frequencies, one representing a 0 on the other representing a 1.
d. FSC sets tone burst sequencing for each key
A
c. The carrier has two different frequencies, one representing a 0 on the other representing a 1.
21
Q
- Provide physical description, Max frequency, Max length and impedance for 10baseT cable.
a. Coax, 10Mhz, 1000 meters, 65 ohms
b. Twisted pair, 10Mhz operation, 100 meters Max, 100 ohms
c. Shielded 2 core stranded, 25 megahertz, 100 meters, 75 ohms
d. Twisted pair, 100 MHz operation, 100 meters max, 100 ohms
A
b. Twisted pair, 10Mhz operation, 100 meters Max, 100 ohms
22
Q
- What does the signal designation RTS stand for?
A
Request to send
23
Q
- How many ISO layers are implemented in the modbus protocol and what are they?
A. 2, application at transport layers
b. 4, application, detailing, session and network layers
c. 3, application, data link and physical layers
d. 1, physical layer
A
c. 3, application, data link and physical layers
24
Q
- What network device provides the greatest amount of network traffic isolation?
a. A DSL modem
b. A router or routing switch
c. 56K modem
d. The ethernet card used in a computer
A
b. A router or routing switch
25
26. Following TCP IP class B address 172.18.154.32/16. What indicates the network portion?
a. 154.32
b. 154.32/16
c. 172.18
d. 18.154
c. 172.18
26
27. What is the function of a gateway in a network system?
a. A gateway connects two different networks together and performs A protocol translation between them.
b. It has no useful function
c. Give me opens in closest to allow data to and from a computer
d. Gateway controls DSL modem.
a. A gateway connects two different networks together and performs A protocol translation between them.
27
28. What is bit transfer rate for foundation field bus H1?
a. 128 mb/sec
b. 31.25 mb/sec
c. 16.3 mb/sec
d. 43.5 mb/sec
b. 31.25 mb/sec
28
29. What is the impedance of RG-6U cable?
a. 64 ohms
b. 50 ohms
c. 75 ohms
d. 80 ohms
c. 75 ohms
29
30. What's end or does the 802.11 standard refered to?
a. The standard for DSL modems
b. The standard for 56K modems
c. Standards for wireless Ethernet
d. The standards for Nic cards
c. Standards for wireless Ethernet
30
31. Describe the first layer in any network system?
a. This is the physical layer which determines the topology ,cable, signal strength, voltage levels, encoding, and any other factors that pertain to the actual transmission of the signal
31
32. What is the difference between a half duplex and full duplex system?
a. Full duplex is slower than half duplex
b. There is no difference
c. Both transmit in both directions, half duplex being in One Direction at a time, full duplex being both directions simultaneously
d. Half duplex can only receive
c. Both transmit in both directions, half duplex being in One Direction at a time, full duplex being both directions simultaneously
32
33. What does the term dipole refer to?
a. This is the distance the wave travels in 1/2 cycle
b. The distance the wave travels in four cycles
c. The amplitude of the wave
d. The direction of the electric field
a. This is the distance the wave travels in 1/2 cycle
33
34. Describe the use of compel data (CD) foundation fieldbus.
a. The compel data is used on startup only
b. The compel data is issued by the link active scheduler to a device for that device to publish data to the network. This is a cyclic occurrence.
c. Compel data allows multiple devices to access the network simultaneously.
d. Compel data controls the link active schedulers functionality.
b. The compel data is issued by the link active scheduler to a device for that device to publish data to the network. This is a cyclic occurrence.
34
35. Which are the OS I network layers execute the checksum calculation and a token passing?
a. The session layer
b. The application layer
c. The physical layer
d. The data link layer
d. The data link layer
35
36. What is a AS-1 bus designed for?
a. Multiple bit communications
b. Serial nibble communications
c. Discreet bit communications
d. Serial Byte communications
c. Discreet bit communications
36
37. Where is token passing used in foundation field bus?
a. Token passing is used for scheduled data transmission, noncyclic
b. Token passing is used for unscheduled data transmission, cyclic
c. Token passing is used for scheduled data transmission, cyclic
d. Token passing is used for unscheduled data transmission, non cyclic
d. Token passing is used for unscheduled data transmission, non cyclic
37
38. What does the term HMI stand for?
a. Human machine interface.
38
39. What are the three benefits of using fiber optics for data communication?
a. Longer distance, immunity to electric noise, security
b. Longer distance, lower cost, ease of installation
c. Low cost, ease of installation, immunity to electrical interference
d. Longer distance, immunity to electrical noise, low cost
a. Longer distance, immunity to electric noise, security
39
40. Your company has been assigned to following Class C network 196.151. 132. 0/24 what is the broadcast address for the total network?
a. 196. 151. 132. 124
b. 196. 151. 132. 0/24
c. 196. 151. 132. 24
d. 196. 151. 132. 255
d. 196. 151. 132. 255
40
41. In HART protocol why can the digital signal be superimposed on the 4-20 ma signal without affecting it?
a. The signal is FSK which has a 0 Volt DC component, so it does not affect the DC signal that is superimposed on
b. It is high impedance so has a very small influence in the signal
c. The signal is FLT which has a 1 Volt DC component, so it does not affect the signal that is superimposed on.
d. The signal is now balanced FM frequency modulation and piggybacks on the 420 milliamps signal.
a. The signal is FSK which has a 0 Volt DC component, so it does not affect the DC signal that is superimposed on
41
42. In the designation TCP/IP what do the letters TCP stand for?
Transmission control protocol or transport control protocol.
