Lesson 4 Objectives Flashcards
Most LAN networks are based on which ethernet standards?
802.3
The IEEE 802.3 standards are designated how and what does it mean?
X base T
IEEE = Institute of Electrical and Electronics Engineers
x BASE- Y
x = nominal data rate
Y is cable type
100BASE-T=Fast ethernet/copper twisted pair cable. ethernet 100 Mbps
1000BASE-T refers to Gigabet ethernet over copper twisted pair cabling. gigabit ethernet works at 1000 Mbps or 1 Gbps.
What is the mainstream / most popular standard for 802.3 LAN
xBASE-Y
1000BASE-T
Gigabit ethernet over copper twisted pair cabling at 1 Gbps (1000 Mbps)
What are the two main types of ethernet cabling?
Copper and Fiber Optic
How does Copper Cabling communicate data?
Electrical Signaling
How does Fiber Optics communicate data?
Pulses of Light
What does WLAN use to send / receive data?
Wireless Local Area Network
radios and antennas
What standards are most WLAN’s based on?
IEEE Standards / Wireless Local Area Network
802.11
IEEE 802.11 is known by what Brand Name?
Wi-Fi
One example of a WAN is what?
Wide Area Network
The Internet
How are most WAN’s connected?
Wide Area Network
use cabling and equipment leased from an ISP to interconnect two or more LAN sites.
ISP = Internet Service Provider
LAN = Local Area Network
What is the difference between networks supporting SOHO and those supporting larger buisnesses or academic institutions?
SOHO Small office home office
They have the same networking appliances and basic functions but, larger networks must support more clients with a greater degree of reliability.
Each function is performed by a separate network device.
in larger business networks, the internet servics are placed where?
in protected screened subnets, which represent the border between the private LAN and the public internet.
Traffic to / from is strictly monitored and filtered.
Most networks distinguish between two basic roles for the computers
- a server computer–dedicated to running network applications and hosting shared resources
- a client computer allowing end users to access the applications and resources to do work
A SAN is only accessed by what?
Storage Area Network
The servers
it’s completley isolated from the main network.
Who are SAN clients?
Storage Area Network
Servers running databases or applications.
What kind of connectivity technology do SAN’s use?
Storage Area Network
Fibre Channel and Internet SCSI (iSCSI)
Where is the transceiver port located?
In a computer’s NIC.
Network interface card
What kind of adapter do the majority of PC motherboards have built into the NIC?
Network Interface Card
xBASE-Y
1000BASE-T
Compatible adapter
What effect would purchasing cards with multiple NIC ports of the same type such as 1000BASE-T have?
The multiple ports can be bonded to create a higher-speed link.
4 Gigabit Ethernet ports could be bonded to give a link speed of 4 Gbps
What does the NIC need to be able to process the electrical or light signals as digital data?
(2)
Network Interface Card
- Signals (electrical or light) must be divided into regular units with a consistent format.
- Must be a means for each node on the LAN to address communications to other nodes
Local Area Network
Ethernet provides a data link protocol to perform these framing and addressing functions
Each ethernet NIC has a unique what?
Network Interface Card
hardware / physical address
called the MAC media access control address
A MAC address has how many digits and what size?
Media Access Control
Consists of 48 binary digits
6 bytes in size
How is a MAC address usually represented?
Media Access Control
# and format
12 digits of hexadecimal.
What values can a hex digit be represented as and how many are there?
There are 16 values
0-9
A, B, C, D, E, F
What kind of spacing is used to represent MAC addresses?
Media Access Control
written with a colon or hypen separaters or no separaters at all.
How is most cabling connected / run in an office.
connected to a wall port
run via cabling through the walls
to a patch panel.
what kind of ports will you find on the other side of a patch panel?
There are prewired RJ45 ports
How many ports does a hub usually have?
Between 4 and 48
Each computer is cabled to one port
How are transmissions sent through hubs?
the circuitry in the hub repeats an incoming transmission from a computer attached to one port across all the other ports. Essentially, the computers seem attached to the same cable. each attached computer receives all the traffic sent by other connected devices.
How do computers receive the correct transmissions in hubs or collision domains wherein all connected computers receive every transmission?
Each computer ignores any frames that do not match it’s MAC address
Media Access Control
What is one consequence of having too many computers connected to a hub?
Performance is reduced.
All computers receive all transmissions, too many and it would slow down all the computers
On computers connected to a hub, what happens if two or more computers try to send at the same time?
there is a collision and they must wait for a random period before trying again.
What circumstance might you find a hub still used today?
where legacy equipment must be kept in service.
Almost all networks are now based on what instead of hubs?
Ethernet Switching
What kind of configuration does an unmanaged switch support?
An unmanaged switch doesn’t support any kind of configuration.
Ethernet switches are a solution to what problem?
collision domains
Collision domains found within hub networks
What does an ethernet switch have in common with a hub?
They both have one port for each device that connects to the network
What’s different about ethernet switches and hubs?
Ethernet switches can decode each frame and identify source and destination MAC addresses.
Switches can track which MAC source addresses are associated with each port. when it receives an incoming frame, the switch intelligently forwards it to the port that’s a match for it’s destination MAC address.
Media Access Control
With ethernet switches, does each computer have half-duplex or full-duplex connections to the network?
Full-Duplex
Half-Duplex can send and receive but not at the same time
Full-Duplex can send and receive at the same time
What happens if an ethernet switch reads the source address and doesn’t have the MAC address in it’s table of known-addresses yet?
Media Access Control
the switch floods the frame out to all ports to find the associated MAC address
Media Access Control
What is an unmanaged switch?
performs its function wihtout requiring any sort of configuration.
you power it on and connect some hosts to it and it establishes ethernet connectivity between the network interfaces without any more intervention.
How many ports might you find in unmanaged switches?
4-8
where are unmanaged switches often found?
small networks and SOHO router / modems provided by ISP’s to connect to their network
SOHO=Small office home office
ISP = Internet Service Provider
What are managed switches?
ethernet switch that’s configurable via a command-line interface or SDN controller
SDN = Software-Defined Networking
How does a managed switch function out of the box?
like an unmanaged switch
How do you configure a managed switch
The admin connects it over to a managment port, configures security settings, and chooses options for the switches more advanced functionality.
how many access ports does a typical switch come with?
24-48 and have uplink ports allowing them to be connected to other switches
how can you configure a managed switch?
Over the web or a command line interface
How much power can PoE Devices draw?
Power over Ethernet
13 W
or
25 W for PoE+
Name 3 IEEE PoE standards
IEEE= Institute of electrical and electronic engineers
PoE = Power over Ethernet
- 802.3af
- 802.3at
- 802.3bt
802.3af is what kind of standard?
IEEE PoE
IEEE= Institute of electrical and electronic engineers
PoE = Power over Ethernet
How much power does 802.3af use?
PoE standard
13 W–15.4W
Voltage drop over max 100m cable = usable power of around 13 W
802.3af allows how much power?
PoE Standard
25 W with a maximum current of 600 mA
802.3bt is also called what?
PoE++ or 4PPoE
802.3at is also called what?
PoE+
802.3bt (PoE++ / 4PPoE) supplies how much power?
about 51 W (Type 3)
or
73 W (Type 4) Usable Power
a PoE-enabled switch is referred to as
endspan PSE
PSE=Power Sourcing Equipment
How does a PoE-enabled Switch work?
When a device is connected to a port on a PoE switch, the switch goes through a detection phase to determine whether the device is PoE enabled.
If so, it determines the devices power consumption and sets an appropriate supply voltage level.
If not, it does not supply power over the port and, therefore, doesn’t damage non-PoE devices.
What is the most popular type of network cable?
UTP
Unshielded Twisted Pair
What is a UPT made up of?
Unshielded Twisted Pair
4 copper conductor wire pairs
How are the copper wires in UTP twisted?
Unshielded twisted pair
each insulated pair twisted at a different rate from other pairs.
Why are UTP copper wire pairs twisted at different rates from the other pairs?
To reduce interference
The electrical signals in a UTP are balanced which means what?
Unshielded Twisted pair
Each wire carries an equal but opposite signal to its pair.
What is the maximum recommended distance for UTP?
Unshielded twisted pairs.
100 m
When are STP’s most often used?
2
Shielded Twisted Pair
for 10G ethernet and higher within datacenter networks
Also useful in environments with high levels of external interference such as cable run in proximity to flourescent lighting, power lines, motors and generators.
What 3 things is screened cable usually designated as?
ScTP
F/UTP
FTP
Screened Twisted Pair
Foiled / Unshielded Twisted Pair
Foiled Twisted Pair
Fully shielded cabling is referred to as what two things?
S/FTP
F/FTP
Shielded / Foiled Twisted Pair
Foiled (outer shield) / Foiled Twisted Piar
The screening / shielding elements of shielded cable must be bonded to what and for what purpose?
Must be bonded to the connector
To prevent the metal from acting as a large antenna and generating interference.
Which 2 types of twisted pairs facilitate bonding of cable to the connector to prevent interference by incorporating bonding within the design of each element?
F/UTP and S/FTP
Foiled / Unshielded Twisted Pair
Shielded / Foiled Twisted Pair
Higher Cat Specification =
Higher data rates
What would a Cat 5 cable’s Max Transfer rate and distance be?
100 Mbps
100 m
What would a Cat 5e’s Max transfer rate and Max Distance be?
1 Gbps
100m
What would a Cat 6a’s Max transfer rate and distance be?
10 Gbps
100 m
What Category of Twisted Pair Cables would be used for 10BGase-T Ethernet Support?
6A
What Cat Twisted Pair Cables would be used for 100Base-TX (Fast Ethernet) Support use?
5
Where is a Twisted Pair Cable’s Cat specification?
It’s Printed on the cable jacket along with the cable type such as UTP or F/UTP.
What Cat cables would most sites opt to install today?
Cat 6
What kind of connectors would be used to terminate twisted pair cabling for ethernet?
Modular RJ45
What else are RJ45 Connectors referred to as?
8P8C
What does 8P8C stand for?
8 Point 8 Contact
RJ45
in RJ45 Connectors, Ethernet cable is color-coded with each pair assigned a color. What are the colors?
6 (colors and what stripes and solid means)
Orange
Green
Blue
Brown
The first conductor in each pair has a white insulator with stripes of the color.
The second conductor has an insulator with solid color
What are the two methods for terminating Twisted Pairs?
T568A
T568B
What is the difference between T568A and T568B terminations for twisted pairs?
The color of the wires connected to each pin.
in T568A, What color wire is each pin connected to?
Pin 1: Green / White
Pin 2: Green
Pin 3: Orange / White
Pin 4: Blue
Pin 5: Blue / White
Pin: 6 Orange
Pin 7: Red / White
Pin 8: Red
In T568B, What color wire is each pin connected to?
Pin 1: Orange / White
Pin 2: Orange
Pin 3: Green / White
Pin 4: Blue
Pin 5: Blue / White
Pin: 6 Green
Pin 7: Red / White
Pin 8: Red
Twisted Pairs can be used with what type of connection besides RJ-45
RJ-11
What is the difference between RJ-45 and RJ-11 Connectors?
RJ-11 is typically used to terminate two-pair cable
RJ-45 is four-pair cable
RJ-11 is typically used where?
with telephone systems and with broadband DSL modems
In a structured cabling system often used in offices, what connection points are connected between the computer and the Ethernet Switch?
- Wall port using Flexible patch cord
- Behind the wall port, permanent cable run through wall and ceiling to equipment room
- connected to a patch panel.
- Port on the patch pannel is connected to a port on the ethernet switch.
IDC is also known as?
Insulation Displacement Connectors
Punchdown Blocks
Structured cabling systems use what two types of cable termination?
RJ-45 crimped to the end of the cable
Punchdown Blocks terminated to wall ports and patch panels with IDC’s
Insulation Displacement Connectors
What tools does a structured cabling system use?
3
Cable Strippers
Punchdown Tools
Crimpers
To terminate a cable, you must
2
- remove a small section of the outer jacket to expose wire pairs.
- which must be done without damaging the insulation of the wire pairs
How would you use a cable stripper? (4)
- Set the stripper to the correct diameter
- place the cable in the stripper
- rotate the tool once or twice
- the score cut in the insulation should now allow you to remove the section of the jacket
Most cat 6 and all Cat 6A cable has a plastic star filler running through it to keep pairs separated. what tool do you need to use to cut off the end before terminating these cables?
Electricians scissors (snips)
What is a punchdown tool used for?
To fix each conductor to an IDC
Insulation Displacement Connectors
To use a punchdown tool: (3)
- untwist wire pairs
- lay them in color-coded terminals in the IDC in appropriate termination order (T568A / T568B)
- Use punchdown tool to press each wire into the terminal.
When using a punchdown tool, to reduce the risk of interference, no more than how much should be untwisted?
1/2 inch / 13 mm
What is a crimper used for?
To fix a jack to a patch cord
How should you use a crimper?
7
- Orient the RJ-45 plug so the tab latch is underneath.
- Pin 1 is the first pin on the left
- Arrange the wire pairs in the appropriate order (T568A / T568B)
- Push them into the RJ-45 plug
- Place plug in crimper tool
- Close it tightly to pierce the wire insulation at the pins
- seal the jack to the outer cable jacket
Once you terminated a cable, you must test it to ensure what?
That each wire makes good electrical contact and is in the correct pin position.
When is the best time to test / verify wiring installation and termination and why?
Right after you made all the connections
Because you should still have access to the cable runs, making identifying and correcting errors simpler at this point than when trying to set up devices
What can a cable tester be used for?
to test a patch ord or connected via patch cords to a wall port and patch pannel port to test the permanent link.
How does a cable tester work?
2
- you connect it to a patch cord or connected via patch cords to a wall port and patch panel port.
- tester energizes each wire
Using a Cable Tester, what do the LED’s indicate?
LED indicates successful termination
No active LED means the wire isn’t confucting a signal
If a cable tester’s LED’s fail to activate, what does that indicate?
2
- the insulation is damaged
- the wire isn’t properly inserted into the plug or ICD
If a cable testers LED’s do not activate in the same sequence at each end, what does this indicate?
the wires have been terminated to different pins at each end. use the same type of termination at both ends
Many cable testers also incorporate the function of what?
Toner Probe
When might you need to use a Toner Probe?
When cables haven’t been labeled properly.
How does a toner probe work?
3
- conects to a cable using an RJ-45 jack
- applies a continuous audio signal on the cable.
- the probe is used to detect the signal and follow the cable over ceilings and through ducts or identify it from within the rest of the bundle
What should you do before activating the tone generator?
Disconnect the other end of the cable from any network equipment
What is a loopback plug used to test?
NIC or Switch Port
How can you make a basic loopback plug?
from a 6” cable stub where the wires connect
pin 1 to pin 3
and
pin 2 to pin 6
what should you see when you connct a loopback plug to a port?
a solid LED link showing that the port can send and receive
What is a network tap used for?
to intercept the signals passing ovr a cable and send them to a packet or protocol analyzer
Network Taps are
2
Powered
Unpowered
What is a passive TAP
Test Access Point
a box with ports for incoming and outgoing network cabling and an inductor or optical splitter that physically copies the signal from the cabling to a monitor port.
Using a passive TAP, What does the monitor port receive?
Test Access Point
Every frame–corrupt or malformed or not and copying is unaffected by load.
Because no logic decisions are made.
What is an active TAP
Test Access Point
a powered device that performs signal regeneration.
Can an active TAP monitor Gigabit Signaling over copper wire?
no, it’s too complex
Why does an active TAP become a point of failure for links during power loss?
Test Access Point
because it performs an active function.
Why are plenum spaces effective conduits for fires?
because there’s plenty of airflow and no fire breaks and the temperatures may be higher.
General purpose (Non-plenum) cabling uses what?
PVC jackets and insulation
What does plenum-rated cabling use?
treated PVC or fluorinated ethylene polymer FEP
General purpose cables are marked as what?
3
CMG
MMG
for PVC Jackets
Plenum-rated cables are marked as what?
2
CM (communications multipurpose /. CMP plenum)
MP (plenum)
OSP cable types use special coatings to protect against what?
5
Outside Plant
- UV
- Abrasion
- Temperature extremes
- Damp Conditions
- Chewing (by rodents)
OSP Cables are often filled with what?
Outside Plant
gel
Light pulses generated by lasers and LED’s are not suceptible to what?
2
Interference
Suffer less from Attenuation
Optical cabling can support what as opposed to longer cable runs?
Much higher bandwidth links, measured in multiple Gigabits or terabits per second
An optical fiber consists of what?
ultra-fine core of glass to convey light pulses.
core is surrounded by glass or plastic cladding which guides light pulses along the core
the cladding in an optical fiber has a protective coating called what?
the buffer.
What two broad categories do fiber optic cables fall under?
- SMF
- MMF
Single-Mode Fiber
Multi-Mode Fiber
SMF is designed to do what?
2
Single-Mode Fiber
- carry a long wavelength infrared signal
- generated by high-powered, highly coherent laser diode
SMF support data rates of what?
Single-Mode Fiber
10 Gbps or better
How long are SMF cable runs?
Single-Mode Fiber
many kilometers
MMF cables are designed to do what?
Multi-Mode Fiber
- carry a shorter wavelength of infrared light
- using less expensive and coherent LED’s or VCSEL’s
Vertical Cavity Surface Emitting Lasers
Which is cheaper to deploy, SMF or MMF Optic cables
Single-Mode Fiber
Multi-Mode Fiber
MMF
Multi-Mode Fiber
Which supports higher signaling speeds: SMF or MMF
Single-Mode Fiber
Multi-Mode Fiber
SMF
Single-Mode Fiber
Which has longer distance capabilities: SMF or MMF
Single-Mode Fiber
Multi-Mode Fiber
SMF
Single-Mode Fiber
Multi-Mode Fiber
MMF optic cable is most suitable for what kind of networks?
Multi-Mode Fiber
LAN’s
Local Area Network
The core of a fiber optic connector is made of what to ensure continuous reception of light signals?
2
- Ceramic ferrule
- Plastic Ferrule
What connector form factors are available for fiber optics?
3
- ST
- SC
- LC
Straight Tip
Subscriber Connector
Lucent Connector
What is a ST Connector?
Straight Tip
Bayonet-Style connector using push and twist locking mechanism.
Fiber Optic Connector
Fiber Optic Connector
What are ST connectors mostly used for?
Straight Tip
Older Multi-Mode Networks
Fiber Optic Connector
What are SC Connectors?
Subscriber Connector
push/pull design for simpler insertion and removal than FC Connector.
FC Fiber Channel Connector
Fiber Optic Connector
What two types of SC are there?
2
Subscriber Channel
- Simplex
- Duplex: two connectors clipped together can be used for single or multi
Fiber Optic Connector
What is LC?
Lucent connector
Small form factor connector with a tabbed push/pull design.
Similar to SC but smaller size
Subscriber Connector
Do patch cords for fiber optics use the same connector on both sides?
they use either the same connector on each side or different connectors
What kind of signal does coaxial cabling use?
electrical signals
In coaxial cables, the twisted pair uses what to cancel out interference?
balancing, using two conductors that share the same axias.
In Coaxial cables, the core signal conductor is enclosed in what?
plastic insulation
second wire mesh conductor
In coaxial cables, the second wire mesh conductor serves as both what?
shielding from EMI and as a ground.
Coaxial cable is mostly used for what? (3)
- CCTV installations
- patch cable for cable access TV
- Broadband Cable Modems
Coaxial Cables for Cable Access TV installations is typically terminated using what?
Screw-down F-Type Connector
Wi-Fi 802.11
What is infrastructure mode?
every client device is configured to connect to the network via an AP
Access Point
What can an AP do besides establish a wireless-only network?
Access Point
Bridge to forward communications between the wireless stations and a wired network.
A Wired Network is referred to as:
The “Distribution System” DS
How is an AP joined to the network?
Access Point
Much the same way as the host computer is–Via a wall port and cabling to an ethernet switch.
What are the two main frequency bands used by 802.11 standards?
2.4 GHz
5 GHz
Does the 2.4 GHz or 5 GHz frequency band have a longer signal range?
2.4 GHz
Between the 2.4 GHz or 5 GHz frequency band, which supports the most channels?
5 GHz
Does the 2.4 GHz or 5 GHz frequency band support bluetooth?
2.4 GHz
Between the 2.4 GHz or 5 GHz frequency band, which has the highest chance of interference?
2.4 GHz
Does the 2.4 GHz or 5 GHz frequency band support higher data rates?
5 GHz
Is the 2.4 GHz or 5 GHz frequency band better at penetrating solid surfaces?
2.4 GHz is better
What is the normal indoor range for Wi-Fi 2.4 GHz?
45 m
150 ft
What is the normal indoor range for Wi-Fi 5 GHz?
30 m
100 ft
802.11a uses what frequency band?
5 GHz
And it ONLY uses 5 GHz
The 5 GHz frequency band is subdivided into how many non-overlapping channels?
23
The use of channels can be subject to Regulation which can include what?
2
- Limit on power output
- constraining the range of Wi-Fi devices
Devices operating 5 GHz band must use DFS to prevent what?
Dynamic Frequency Selection
To prevent Wi-Fi signals from interfering with nearby radar and satellite installations.
802.11b uses what frequency band?
2.4 GHz
Which has better data rates, 802.11a or 802.11b
802.11a
Using the 5 GHz band with better data rates
How many channels is the 2.4 GHz subdivided into?
14
Do 2.4 GHz channels overlap?
Yes, because they are spaced 5 MHz apart and Wi-Fi needs 20 MHz to channel bandwidth.
In the Americas, Europe, and Japan, which of the 14 channels under 2.4 GHz are permitted to be used?
America: 1-11
Europe: 1-13
Japan: All 14
What does 802.11g offer? (3)
- the same encoding mechanism and Data speed of 802.11a (ie. 5ghz)
- in the 2.4 GHz band used by 802.11b
- with the same channel layout as 802.11b
802.11g offers legacy support for cliens of which version of Wi-Fi?
802.11b
what frequency band does 802.11n use?
2.4 GHz and 5 GHz
Which wireless standard allows channel bonding?
802.11n
Channel Bonding is only practical in which frequency band?
5 GHz
MIMO uses what to increase reliability and bandwidth?
Multiple input multiple output
multiplexes signal streams from 2-3 separate antennas
Using MIMO, what are the antenna configurations?
multiple input multiple output
1X1
2X2
3X3
Indicates the number of transmit and receive antennas available to the radio
Which has a higher data rate, 802.11a or 802.11n
802.11n
72 Mbps
802.11ac is also known as?
Wi-Fi 5
802.11ax is also known as?
Wi-Fi 6
802.11ac (Wi-Fi 5) uses what frequency band?
5 GHz
What frequencies would a tri-band access point have?
3
2.4 GHz
5 GHz
5GHz
802.11ac (Wi-Fi 5) allows how many streams?
(Antenna?) 2 answers
Allows up to 8 streams
Most 802.11ac (Wi-Fi 5) Access Points support 4X4 streams
802.11ac (Wi-Fi 5) Access Points are marketed using AC Values such as AC5300, what 3 numbers are included in the 5300 designation in this example?
- The Mbps over the channel with xXx streams on 2.4 GHz radio
- The Mbps over the bonded channel with xXx streams on the first 5 GHz radio
- The Mbps on the second 5 GHz radio
What Frequency Band does 802.11ax (Wi-Fi 6) use?
2.4 GHz
5 GHz
802.11ax (Wi-Fi 6), Wi-Fi 6e standard adds support for what?
6 new GHz frequency bands
How many clients can 802.11ac and 802.11ax support simultaneously?
802.11ac = 4 clients
803.11ax = 8 clients
Which Wi-Fi standard introduces OFDMA technology?
Orthogonal frequency division multiple access
802.11ax / Wi-Fi 6
OFDMA can work alongside MU-MIMO to improve what?
Orthogonal frequency division multiple access
Multiuser Multiple input multiple output
client density / sustaining high data rates with more stations connected to the same access point
Where is a SSID configured?
Service Set Identifier
on the access point
What length can an SSID be?
Service Set Identifier
Size not characters
32 bytes
How is wireless signal measured?
Unit
dB
Decibel
When measuring signal strength, dBm values closer to 0 represent better or worse performance?
better
When measuring SNR, how is it measured?
Unit
Signal to Noise Ratio
dBm
Decibel milliwatts
When measuring SNR, are dBm values closer to 0 better or worse?
Signal to Noise Ratio
Values closer to 0 are less ideal.
they = higher noise levels
What is a Licensed Frequency Spectrum?
the network operator purchases the exclusive right to use a frequency band within a given geographical area from the regulator.
If any interference sources are discovered, the network operator has the legal right to get them shut down
What is an unlicensed frequency spectrum?
the operator uses a public frequency band such as 900 Mhz, 2.4 GHz, and 5 GHz.
Anyone can use these frequencies meaning interference is a risk.
A wireless signal’s power has 3 main components:
- transmit power = basic strength of radio, measured in dBm
- Antenna gain = amount a signal is boosted by directionality. Measured in dBi
- EIRP = sum of transmit power and gain, expressed in dBm
dBi = decibels isotropic
EIRP = Effective Isotropic Radiated Power
What is measured in dBi
Antenna Gain
What is measured in dBm
EIRP
SNR
Effective isotropic radiated power.
Do lower or higher frequencies have more strict power limitations?
lower frequencies
that propogate farther
What kind of communication medium does bluetooth use?
Radio
BLE is designed for what kind of devices?
Bluetooth Low Energy
Small battery-powered devices
that transmit small amounts of data
infrequently
An unpowered RFID would have what kind of range?
Radio Frequency ID
25m
A powered RFID would have what kind of range?
Radio Frequency ID
100 m
NFC is radio communication over what kind of distances?
Near Field Communications
Within 2 inches
NFC is mostly used for what?
4
Near Field Communication
- Contactless payment readers
- Security ID tags
- shop shelf-edge labels for stock control.
- can be used to configure other types of connections such as bluetooth.
