10. Network cables and connectors Flashcards
What does a cable stripper do
It removes the covering over the wires
Which connector is used for 10Base-T network Cables
RJ-45
Which type of port is used to connect a computer to a 100BaseT network
RJ-45
What is an RS-232 connection
a 9-pin serial connection
Which type of port is included on a dial-up modem
RJ-11
What are the three most popular connectors available for fiber-optic cabling
- LC
- ST
- SC
What does a crimper do
It seals the connection of the connector and cable wires
Which device is used for locating faults in unshielded twiser pair (UTP) and coaxial cables
time-domain relectometer (TDR)
Which tool is used to measure the output of a computer’s power supply
multimeter
Which tool is used to measure the component’s current in amperes and volts
multimeter
Which tool should you use to track a cable from the computer to a wiring closet
a tone generator
Which connector is used with the coaxial cable
BNC connector
What is the maximum transmission speed of Category 6 (Cat6) cable
10 Gbps
What is the maximum transmission speed of Categeory 5e cable
1000 Mbps or 1Gbps
What does a cable rated as “plenum” indicate about the cable
it will not produce toxic gas when it burns
Which types of unshielded twisted pair (UTP) cables support data transfer up to 1000Megabits per second (Mbps)
- Cat 5E,
- Cat 6
- Cat 6a
- Cat 7
- Cat 7a
Which unshielded twisted pair (UTP) cables can support Gigabit Ethernet cards)
- Cat 5e
- Cat 6
- Cat 6a
- Cat7
- Cat 7a
Which cable is used with RJ-45 connectors
Unshielded twisted pair (UTP) or shielded twisted pair (STP)
Two main challenges to reading transmission
- Electromagnetic interference (EMI)
- Attenuation
Cable Certifier
A device that performs advanced tests on cable quality and certifies that it meets appropriate performance standards
Coaxial Cable
A cable that has a core wires surrounded by a conducting shield
Ferrule
A rigid cylinder that fits over the end of the cable
Fiber Coupler
A type of splitter where the multiple fibers on one end are fused to join at a single core
Multimeter
A general-purpose electronic tester which measures resistance, current, or voltage between two points
Outer Jacket
The outermost layer of the cable, usually color coded to give technicians information about the type of fiber inside
Patch Panel
A device housing a row of modular jacks in front, and a corresponding punch down block in the rear
Toner Probe
A connectivity-testing tool that can be used to trace and identify a wire along its entire length
EMI
electromagnetic interference
attenuation
means signals weaken over longer lines
Balanced Pair
a circuit made of two identical wires
Twisted-pair cable can be categorized
- wires used in construction
- insulating materials used
- how the paris are bundled
- the twists themselves
- additional electomagnetic shielding
Twisted pair wires can be:
- solid
- each conductor is a single wire
- thinner, less expensive, less prone to corrision
- popular for permanently placed wire
- stranded
- each conductor is several thinner wires wrapped around each other
- more flexible
- less prone to breakage under repeated stress
- popular for patch cables and applications needing frequent movement
Twisted Pair insulators and jackets
-
PVC
- Cheap and flexible plastic
- works well under normal condtions
- can burn and release toxic smoke
-
Plenum Cable
- more expensive
- uses low-smoke fire retardent materials
- safe to run through ventilations sytems and other spaces where a fire might spread
Total conductors in ethernet cables
8 ( four pairs)
total conductors in tradtional analog phone cables
6 ( 3 pairs)
Twisted pair categoris for electromagnetic shielding
- Unshielded twisted par (UTP): No additional shielding (cheaper, lighter, and more flexible)
- Shielded Twisted Pair (STP): Encases the wires in a conducting layer designed to sheild them from electromagnetic interference
UTP
Unshielded Twisted Pair
STP
Shielded Twisted Pair
Two common types of twisted pair shielding
- Foil shielding:
- Braided screening
Foil shielding:
- Uses a grounded foil wrap to provide additional electromagnetic shielding
- The foild can be placed:
- Around each individual pair (U/FTP)
- Around the outer cable (F/UTP)
- Around both (F/FTP)
Braided screening
- Uses a braided copper jacket around the cable to provide shielding
- it can be used
- around otherwise unshielded cable (S/UTP)
- in conjunction with foil shielding (S/FTP and SF/FTP)
- it can be used
Twisted-pair standards
- Cat 1 / Class A
- Cat 2 / Class B
- Cat 3 / Class C
- Cat 4 / (NonStandard)
- Cat 5 / Class D
- Cat 5e / Class D
- Cat 6 / Class E
- Cat 6A / Class EA
- Cat 7 / Class F
- Cat 7A / Class FA
Cat 1
Low sped cable used for older voice telephones. Not used in data networks
Cat 2
Used in older data networks like ARCnet and early Token Ring
Cat 3
Used in early Ethernet, unsuitable for faster networks, but still used for voice telephone cables
Cat 4
Used in early Ethernet and some token ring networks, but was never common
Cat 5
- Widely used for Fast Ethernet and Gigabit Ethernet networks
- Used for telephone and video
- Superseded by Cat5e
Cat5e
- Cat 5 enhanced
- Same overall properties as Cat5, but higher testing standards
Cat 6
- Stronger crosstalk specifications than Cat 5e
- Popular for new Gigabit Ethernet installations
- Popular for short disttance 10Gigabit networks
- Frequently shielded for additional EMI protection (if so the shileding needs a grounded connection)
Cat 6A
- Augmented Category 6
- Shielded
- Allows full distance 10 Gigabit Ethernet operation
*
Cat 7
- Similar to Cat 6A
- Screened and shielded for higher noise resistance
Cat 7A
- Augmented Category 7
- Maybe suitable for emerging 40Gigbit Ethernet
Twisted Pair Ethernet physical Standards
- 10BASE-T
- 100BASE-TX
- 1000BASE-T
- 10GBASE-T
10BASE-T
- The first popular twisted-pair Ethernet Standard
- Used in early 1990s
- Operates at 10Mbps
- uses two wire pairs on a Cat 3 or higher cable
- typically joined with hubs because switches were still expensive in the 1990s, but are compatible with modern switched networks
100BASE-TX
- A 100 Mbps standard
- also known as Fast Ethernet
- Uses two wire pairs on Cat5 or higehr cable
- Somewhat out of date, but still widely available and used in small networks
1000BASE-T
- 1000Mbps
- also know as Gigabit Ethernet
- uses all four wire pairs of a Cat5 or higher cable
- Dominate standard for modern LANs
10GBASE-T
- Operates at 10000Mbps / 10Gbps
- uses all four paris of a Cat 6a cable
- Over short distances, can use Cat 6 cable
- expensive so still limited to high demand apps and network backbones
Modular connector are described by:
the number of positions (P) and contacts (C)
sometimes described by their Registerd Jack Number (RJ)
Telephone cable modular connector description
6P2C
6 positions wide , 1 pair (2) needed for a connection
LAN connection module connector:
8P8C
8 Positions Across, 4 Pairs (8 cables) wired for the connection
RJ45
UTP coupler
used to connect to ethernet cables together
Termination tools
- Snips: Cuts cables to length
- Wire Stripper: Cuts the jacket from the cable
- Crimper: Clamps a moduler jack onto the wire ends of a cable
- Punch Down Tool: Places wires on punch down blocks. It uses a spring-loaded balde to push the wire in place, pierce the insulation, and cut excess length in a single motion
Cable testing tools
- Multimeter: General purpose electronic tester which can measure resistance, current, or voltage between two points
- Toner probe: A connectivity-testing tool that can be used to trace and identify a wire along its entire length
-
Cable tester: A cable testing tool that a the minimum measures conductvity and resistance to detect breaks and shorts. Some are more sophistacted and can measure cable length, noise levels, or what device is active on the other end of the cable
- Also known as a line tester
- Time-domain reflectometer: A more sophistacted cable tester. Measures signal reflections along a cable to find breaks, shorts, or even minor flaws, and estimate their locations
- Cable Certifier: A device that can perform advance tests on cable quality and certify that it meets appropriate performance standards
- Loopback plug: Connects transmit and receive pins on a connector, effectively letting it plug into itself to allow diagnostic tests
RG
Radio Guide
RG types
- RG-59
- RG 6
- RG-11
- RG-8
- RG-58
RG-59
Common for baseband video and older cable TV. Not reliable for broadband network connections
RG-6
Standard for newer digital cable, satellite, and cable modem connections. Essentially a higher grade RG-59
RG-11
Used for same purposes as R6-6
Used for newer cable, satellite, and cable modem commecntions
Usually only used for long distance drops and underground cables
RG-8
Used by 10BAS5 Thicknet Ethernet (first ethernet standard). Now obsolete
RG-58
used by 10BASE2 Thinnet ethernet (cheaper and more limited alternative to Thicknet). Now obsolete
Coaxial Connector
- Called RF connectors (since they are designed to carry radio frequencies on the cable)
-
F connectors
- TV and cable modems
-
BNC connectors (BNC):
- Obsolete thinnet ethernet
- commercial and progessional video applications
Parts of Optical Fibers / Cables
- Core
- Cladding
- Buffer
- Strength Members
- Outer Jacket
Core (Fiber cable)
Transparent fiber that carries the signal.
Usually made out of silica glass
Diameters are under 100microns
Cladding (Fiber cable)
- Second layer, immediately surrounding the core
- Transparent
- Different refractive index than the core
- Light passing down the cable reflects off the boundary with the cladding, keeping it within the core
- Usually 125-140 microns in diameter
*
Buffer (Fiber cable)
- Surrounds the cladding
- strengthens and protects the fiber, but doesn’t affect its optical properties
- innermost part of the buffer is a plastic coating usually 250 microns in diameter
- coating surrounding by further protections
- indoor cables use tight buffer around 900 microns
- outdoor cables use a larger loose tube buffer with gel inserted to protect the fiber from environmental conditions
*
Strength members (fiber)
- Provides tensile strength to support the cable and reduce phyiscal stress on the glass fibers
- usually made of aramid (Kevlar) yarn, fiberglass, or steel cables
- large multifiber cables with often have a central strength member with the fibers themselves places around it
Outer Jacket (fiber)
The outermost layer of the cable
usually color coded to give techs information about the type of fiber inside
Multifiber cables (fiber)
have more than one optical fiber in a single jacket.
each fiber is optically independent from the others, so can be used for separate channels or duplex operation
SMF
Single Mode Fiber
MMF
MultiMode Fiber
Single-mode FIber (SMF)
- very small core (between 8-10 microns)
- light has a wavelength of 1310 nm or 1550 nm.
- Only one possible path, or mode, straigh t down the center of the fiber
- force the light to travel in a single unified stream
- effective range of multiple kilometers
- more expensive
- used for long-distance, high bandwidth MAN or WAN links.
MultiMode Fiber
- thicker core (50-62.5 microns)
- shorter wavelengths (850-1310)
- light has more room, reflects along multiple paths down the fiber
- effective range of 500-2000m
- less expensive to make
- used for LAN backbones
Types of fiber connectors
- ST
- FC
- SC
- LC
- MT-RJ
ST connector
- Straight tip
- Bayonet Coupling
- One of the first popular MMF connectors, but less common for SMF
- Increasing replaced by small form factor (SFF) connectors
FC connector
- Ferrue connector or Fiber Channel
- Screw Coupling
- An early single-mode connector using the same feure type as ST. Very popular in the past, but being replaced by SC and LC connectors
*
SC
- Subscriber connector, or standard connector
- Push/Pull Snapp Coupling
- Suare bodied
- uses same ferrule as ST
- commonly two are clipped together in a duplex SC-DC format
LC
- Lucent connector / Local Connector
- SFF connector
- Similar appearance to SC, but smaller and with a retaining clip
- Available in single and duplex formats
*
MT-RJ
- Mechanical Transfer - Registered Jack
- Snap connector
- A duplex SFF connector
- looks like a RJ-45 connector
- has two fibers in a single rectangular ferrule
