Chapter 3: Networking Connectors and Wiring Standards

Why are wires twisted together in twisted pair cables?

Because when electromagnetic signals are conducted on copper wires in close proximity-like inside a cable-it causes interference called crosstalk. Twisting two wires together as a pair minimizes interference and even protects against interference from outside sources.

Category 7 (cat 7) cable

Has the strictest specifications for crosstalk and noise of the Cat cables. allows 10 GB ethernet over 100 meters of copper cabling.

What are two advantages of fiber-optic cabling?

It is completely immune to EMI and RFI and can transmit up to 40 kilometers (about 25 miles).

if youre trying to match the straight-through and crossover cables with the T568A and T568B standard, here is how it would look:

T568A + T568A = Straight-Through T568B + T568B = Straight-Through T568A + T568B = cross over

RS-232

The recommended standard (RS) upon which all serial communication takes place on a PC. -connects to computers serial port to an external modem. -replaced by USB

Crossover Cable

- Can be used to connect the following devices: Switch to switch Hub to hub Host to host Hub to switch Router direct to host Router to router - The same four wires used in the straight-through cable are used in this cable, just connect different pins together - Instead of connecting 1 to 1, 2 to 2, and so on, connect pins 1 to 3 and 2 to 6 on each side of the cable

UTP Gigabit Wiring (1000Base-T)

- Requires four wire pairs and uses more advance delectronics so that each and every pair in the cable can transmit simultaneously - Almost identical to 10/100 cabling, except that it uses the other two pairs in the cable - For a gigabit straight-through cable it's still 1 to 1, 2 to 2, and so on up to pin 8 - For a gigabit crossover cable, still cross 1 to 3 and 2 to 6, but add 4 to 7 and 5 to 8

RJ-48c

- used with shielded twisted pair - used with T1, which is long distance wide area network (WAN). - wired differently that RJ-45

What are the three types of popular cables used in modern networking designs?

-Coaxial -Twisted-pair -Fiber Optic

List the common media converters

-Single-Mode Fiber to Ethernet -Multimode Fiber to Ethernet -Fiber to Coaxial -Single-Mode to Multimode Fiber

list the types of wiring standards

-T568A -T568B -Straight-through -Crossover -Rolled/rollover

How do cable properties differ?

-Transmission speeds (speed of a network to meet network traffic) -Distance -Duplex (half or full, which means either can talk and listen at the same time. half does either one, but not both) -Noise Immunity (types of cables to avoid tapping and suitable for the placement environment. avoiding magnetic sources, flammable cables, etc.) -Frequency (type of transmission bandwidth it can handle)

Benefits of twisted-pair?

-inexpensive -widely available -easy to work with -allows transmission rates that were impossible 10 years ago.

T568A uses which pins to make a connection?

1, 2, 3, 6

A crossover uses which pins to make a connection?

1/3 and 2/6

T1 Crossover Cable

A T1 crossover cable is used to connect two T1 CSU/DSU devices in a back-to-back configuration.

Fiber-Optic Cable

A cable that transmits digital signals using light impulses rather than electricity. its immune to EMI and RFI. -the cable is surrounded by a gladd or plastic cladding with a different refraction index that reflects the light back into the core. -either single mode fiber (SMF) or multimode fiber (MMF)

RJ-45

A connector that is slightly larger than an RJ-11 connector and contains eight wires. RJ-45 connectors most commonly attach twisted-pair cables to Ethernet network cards. -not shielded compared to RJ-48

What are Transreceivers?

A device made up of both a transmitter and a receiver, which are combined and share common circuitry or a single housing. The term applies to wireless communication devices such as cell phones, coreless telephone sets, handheld two way radios, and mobile.

RJ-11

A phone line connection or port found on modems, telephones, and house phone outlets.

Multimode Fiber

A type of fiber optic cable that uses light to communicate a signal, but with it, the light is dispersed on numerous paths as it travels through the core and is reflected back. -provides high bandwidth at high speeds over medium distances (up to about 3000 feet)l -most often used within a smaller area of one building -available in glass or plastic, makes installation easier and increases flexibility.

66 Block

A type of punch-down block designed to terminate telephone connections. The numeral 66 refers to the model number of the earliest blocks.

How is a T1 crossover cable wired?

A. A T1 cable uses pairs 1 and 2, so connecting two T1 CSU/DSU devices back-to-back requires a crossover cable that swaps these pairs. Specifically, pins 1, 2, 4, and 5 are connected to 4, 5, 1, and 2, respectively.

Which of the following provides the longest cable run distance? A. Single-mode fiber B. Multimode fiber C. Category 3 UTP D. Coax

A. Single-mode fiber allows for the maximum cable run distances.

Thin Ethernet

Also known as thinnet or 10Base2, is a thin coaxial cable. -only about 5mm or 2/10, diameter coaxial cable.

subscriber connector (SC)

Are latched-a mechanism holds the connector in securely and prevents it from falling out. Works with both single-mode and multimode optical fibers and will last for around 1000 mattings.

Why would a network administrator use plenum-rated cable during an installation? (choose two) A. Low combustion temperature B. High combustion temperature C. Reduces toxic gas released during a fire D. Is not susceptible to any interference

B, C. Plenum-rated means that the cable's coating doesn't begin burning until a much higher temperature of heat, doesn't release as many toxic fumes as PVC when it does burn, and is rated for use in air plenums that carry breathable air, usually as nonenclosed fresh-air return pathways that share space with cabling.

Which of the following are fiber-optic connectors? (Choose three.)

B, D, E. There are many different types of fiber-optic connectors. SC, ST, LC, and MT-RJ are some of the more typical connectors in use today.

How many wires are used in a 100BaseTX UTP transmission?

B. 100BaseTX utilizes only pins 1, 2, 3, and 6.

You need to make a T568B cable for a Fast Ethernet link. How many pairs will you use?

B. Fast Ethernet is 100BaseTX and this type of cable uses two pairs of wires.

On which type of cable does EMI have the least effect?

B. Fiber-optic cable transmits only light (not electricity like UTP), so EMI has zero effect on it.

How many hosts on a half-duplex segment can talk at one time?

B. In half-duplex communication, a device can either send communication or receive communication, but it cannot do both at the same time.

What type of cable transmits lights from end to end?

B. Remember that fiber-optic cable transmits a digital signal using light impulses. Light is carried on either a glass or a plastic core.

What is the main difference between single-mode fiber (SMF) and multimode fiber (MMF)?

B. The difference between single-mode fibers and multimode fibers is in the number of light rays (and thus the number of signals) they can carry. Generally speaking, multimode fiber is used for shorter-distance applications and single-mode fiber for longer distances.

You need to connect two devices on a network and they need to send voice traffic. Which of the following cables will you use?

B. To connect two devices for voice on a vertical connect, the minimum cable you can use is Category 5.

You need to crimp on a connector using an RJ-45 connector. Which pin-out configuration would you use to connect a host into a switch? A. UTP B. Straight-through C. Crossover D. Rolled

B. You would use a straight-through cable to connect a host to a switch, and the typical pin-out is called T568A.

Why is fiber-optic cable immune to electromagnetic interference (EMI) and radio frequency interference (RFI)? A. Because it transmits analog signals using electricity

C. Fiber-optic cable transmits digital signals using light impulses rather than electricity; therefore, it is immune to EMI and RFI.

How many devices can be connected to a full-duplex segment?

C. Full-duplex communication requires a point-to-point configuration between two directly connected devices because the collision-avoidance circuit is disabled.

What type of cable should be used if you need to make a cable run longer than 100 meters?

C. Standards limit UTP to a mere 100 meters. Different fiber-optic types have different maximum lengths, but fiber-optic is the only cable type that can extend well beyond 100 meters.

What type of connector does UTP cable typically use? A. BNC B. ST C. RJ-45

C. UTP usually connects with RJ-45. You use a crimper to attach an RJ connector to a cable.

Category 6 (cat 6) cable

Four twisted wire pairs (eight wires) used for 1000BaseTX (two pair wiring) and rated for 250 MHz. generally used as riser cables to connect floors together.

Category 5 (cat 5)

Four twisted wire pairs (eight wires) used for 100BaseTX, rated 100MHz. (pretty much obsolete because of Cat 5e)

Category 3 (cat 3)

Four twisted wire pairs (eight wires) with three twists per foot. Transmissions up to 16MHz and up to 10 Mbps Ethernet. Now, limited to telecommunication equipment and obsolete for networks.

How is UTP cable rated in categories?

Category 1 Category 2 Category 3 Category 4 Category 5 Category 5e (enhanced) Category 6 Category 6A (Augmented) Category 7 Category 8

Which UTP uses four twisted wire pairs (eight wires), is rated for 100MHz, and is capable of handling the disturbance on each pair caused by transmitting on all four pairs at the same time?

Category 5e

Which UTP wiring uses four twisted wire pairs (eight wires) and is rated for 250MHz?

Category 6

Quad Small Form Factor Pluggable (QSFP)

Compact, hot-pluggable optical module transceiver used for data communications applications. It interfaces networking hardware (Such as servers and switches) to a fiber-optic cable or active or passive electrical copper connections. -allows data rates from 4x1 Gb/s for QSFP and 4x10 Gbit/s for QSFP+ to the highest rate of 4x28 Gbit/known as QSFP28 used for 100 Gbit/s links.

Which type of cable will you use to connect two switches to eachother?

Crossover

A crossover cable is used to connect all of the following except ___________________.

D. All devices that are pinned the same for transmit and receive require a crossover cable to communicate directly. The current switches can autodetect the cable type.

The purpose of the demarcation point is to separate the customer from whom?

D. The demarcation point, or demarc, is the point at which the operational control or ownership changes from your company to a service provider. This is often at the MDF in relation to telephone connections and the CSU/DSU in regard to WAN connections.

Which of the following Ethernet unshielded twisted-pair cabling types is/are commonly used? A. 10BaseT B. 100BaseTX C. 1000BaseTX D. All of the above

D. UTP is commonly used in twisted-pair Ethernet like 10BaseT, 100BaseTX, 1000BaseTX, and so on.

In which of the following categories is UTP cable not rated? A. Cat 2 B. Cat 3 C. Cat 5e D. Cat 9

D. Unshielded twisted-pair has standards from Category 2 through 8 for use on Ethernet networks. There is no Category 9 defined.

The point at which the operational control or ownership changes from your company to a service provider is referred to as what?

Demarcation point, or demarc

Category 2 (cat 2)

Four twisted wire pairs (eight wires), rated for 20 MHz (Obsolete)

Local Connector (LC)

Fiber-optic cable connector that corresponds to the mini form-factor standard. Colloquially known as the "little connector." -newer style of SFF fiber-optic connector and popular for use with Fibre-Channel adapters (FCs) and is a standard used for fast storage area networks and Gigabit Ethernet adapters.

Angled Physical Contact (APC) Connector

Fiber-optic connector that makes physical contact between two fiber-optic cables. does not cause nearly as much dB loss when using this connector due to the pointy tip.

Category 4 (cat 4)

Four twisted wire pairs (eight wires) rated for 20 MHz; also obsolete.

Category 5e (enhanced)

Four twisted wire pairs (eight wires) recommended for 1000BaseT (Four pair wiring) and rated for 100 MHz but capable of handling the disturbance on each pair thats caused by transmitting on all four pairs at the same time- a feature thats needed for gigabit Ethernet. -uses rated components from end to end, patch cables from workstations to wall panel, cable from wall panel, cable from wall panel to patch panel, and patch cables from patch panel to hub.

MDF/IDF

Main Distribution Frame (MDF) and Intermediate Distribution Frame (IDF) define types of wiring closets. The main wiring closet for a network typically holds the majority of the network gear, including routers, switches, wiring, servers, and more.

Pros & Cons of fiber-optic cables:

Pros -Completely immune to EMI and RFI -Can transmit up to 40 kilometers (About 25 miles) Cons -its difficult to install -its more expensive than twisted-pair -troubleshooting equipment is more expensive than twisted-pair test equipment -its harder to troubleshoot.

Serial Cables

Serial communication cables transfer data 1 bit at a time.

Which RG rating of coax is used for cable modems?

RG-6

Universal Serial Bus (USB)

Standard for computer ports that support data transfer rates of up to 12 million bits per second.

T568A

Standards for wiring twisted-pair network cabling and RJ-45 connectors and have the green pair connected to pins 1 and 2 and the orange pair connected to pins 3 and 6.

T568B

Standards for wiring twisted-pair network cabling and RJ-45 connectors and have the orange pair using pins 1 and 2 and the green pair connected to pins 3 and 6.

List two most popular Fiber Optic Connectors

Straight tip(ST) and the Subscriber (or square) connector (SC).

You want to connect a host to a switch port. What type of Ethernet Cable will you use?

Straight-through

What are the advantages of using coax cable?

The braided shielding provides resistance to electronic pollution like electromagnetic interference (EMI), radio frequency interference (RFI), and other types of stray electronic signals that can make their way onto a network cable and cause communication problems.

110 Block

The most common connection used with structured cabling, connecting horizontal cable runs with patch panels.

Fiber to Coaxial

These devices accept a fiber connector and a coaxial connector and convert digital signals from optical to coax.

Single-Mode Fiber to Ethernet

These devices accept a fiber connector and an Ethernet connector and covert the signal from Ethernet and single-mode fiber.

Multimode Fiber to Ethernet

These devices accept a fiber connector and an ethernet connector and convert the signal from Ethernet and multimode fiber.

Single-Mode to Multimode Fiber

These devices accept a single-mode fiber connector and a multimode fiber connector and convert the signals between the two.

Bidirectional Fiber-optic transreceiver

This type of communication is possible if the cable used is following the EEE 802.3ah 1000BASE-BX10-D and 1000BASE-BX10-U standards. Communication over a single strand of fiber is achieved by separating the transmission wavelength of the two devices.

In what instance would you use T1 crossover cable?

To connect two CSU/DSUs

Category 1 (cat 1)

Two twisted wire pairs (four wires) that handles up to 4Mbps with a frequency limitation of 10 MHz (Obsolete)

Voice over IP (VoIP)

Uses IP technology to transmit telephone calls. it uses all eight pins, and its really common to have voice and data on the same wires at the same time in todays networks. Pins 4, 5, 7, and 8 are used in both standards. They are needed for 1000BaseT, PoE, and specialized versions of 100 Mbps networks.

How to accommodate to BNC connectors not fitting into UTP cable?

You would need to use a registered jack (RJ) connector.

25 pair cable

a cable type that consists of 25 individual pairs of wires inside a common insulating jacket. typically used for telephone cabling, reducing clutter. -referred to as the feeder cable because it supplies signal to many connected pairs.

Small Form Factor (SFF)

a connector which allows more fiber-optic terminations in the same amount of space than its standard-sized counterparts. -Two most popular versions: mechanical transfer registered jack (MT-RJ) and local connector (LC).

Ultra Physical Contact (UPC) Connector

a fiber-optic connector that reflects light back down to the core of the fiber cable, which causes a loss of dB called a return loss because the angled connector causes the light to reflect back into the cladding

F-type connector

a form of coaxial connector that is used for cable TV.

single-mode fiber-optic cable

a very high speed, long-distance media that consists of a single strand-sometimes two strands- of glass fiber that carries the signals. -employed to span really long distances because it can transmit data 50 times farther than multimode fiber at a faster rate. -used between multiple buildings.

Smart Jack

also called Network Interface Device (NID) or Network Interface Unit (NIU), is a special network interface thats often used between the service providers network and the internal network .

BIX Block

another type of punch-down block, it can terminate up to 25 cable pairs, and have a slip-in fitting that does not require the wires to be pre-stripped.

Copper:Twisted-Pair Cable

consists of multiple individually insulated wires that are twisted together in pairs. Sometimes a metallic shield is placed around them, hence the name shielded twisted pair (STP). without the outer shielding is called shielded twisted-pair (UTP), and its used in twisted-pair Ethernet (10BaseT, 100BaseTX, 10GBaseT)

Coaxial Cable

contains a center conductor made of copper that's surrounded by a plastic jacket with a braided shield over it. A plastic such as polyvinyl chloride (PVC) or fluoroethylene propylene (FEP commonly known as Teflon)covers this metal shield. -The Teflon-type covering is frequently referred to as a plenum-rated coating (expensive and mandated by local or municipal fire code when cable is hidden in walls and ceilings) -come in plenum and non-plenum cables (non-plenum cables are a serious hazard because its insulation gives off poisonous smoke and become wicks for fire.

straight-tip (ST) connector

developed by AT&T, one of the most widely used fiber-optic connector; it uses a BNC attachment mechanism similar to thinnets that makes connections and disconnections fairly frustration free.

Category 8 (Cat 8)

developed to address the ever-increasing speed of Ethernet and added support for 25G and 40G transmission with a distance of 30 meters, which is perfect for data center deployments.

Mechanical Transfer Registered Jack (MT-RJ)

first small form factor fiber-optic connector to be widely used. it offers these benefits: -small size -TX and RX strands in one connector -Keyed for single polarity -Pre-terminated ends that require no polishing or epoxy -Easy to use

Small Form-Factor Pluggable (SFP+)

is a compact optical module transreceiver used for both telecommunication and data communications that support data rates up to 16 Gbits/s. -SFP+ is a enhanced version to the SFP.

Rolled/Rollover Cable

isnt used to connect any ethernet connections together, you can use a rolled ethernet cable to connect a host EIA-TIA 232 interface to a router console serial communication (COM) port. -if you have a Cisco router or switch, you would use this cable to connect your PC, Mac, or a device like a tablet to the Cisco hardware. -Eight wires are used in this cable to connect serial devices, although not all eight are used to send information, just as in Ethernet networking.

Is there a difference between T568A and T568B?

not really, the only thing that is different is that pairs 2 and 3 (orange and green) are swapped. Note, you can use a UTP coupler in order to connect two RJ-45 connectors together to lengthen a cable or in order to make a straight-through cable into a crossover, and vice versa.

Category 6A (augmented)

rated for 500 MHz and has improved crosstalk characteristics, which allows 10GBaseT to be run for up to 100 meters.

DB-25

serial communications D-shell connector, 25 pins. The D was followed by A, B, C, D, or E, which described the shell size. -not in use today, replaced by USB.

demarcation

the last point of responsibility for the service provider. often located in the MDF, usually just an RJ-45 jack that your channel service unit/data service unit (CSU/DSU) connects from your router to wide area network (WAN) networks.

Why are a pair of wires twisted together in CAT cables?

to prevent crosstalk, EMI, and tapping.

Fiber-Optic Transreceiver can be either...

unidirectional (simplex) or bidirectional (duplex)

Straight-Through Cable

used to connect a host to a switch or hub or a router to a switch or hub. -Four wires are used in this cable type to connect 10/100 Ethernet devices. -only pins 1, 2, 3, and 6. connecting 1 to 1, 2 to 2, 3 to 3, and 6 to 6, then youll be up and networking in no time. Remember, that this would be a 10/100 ethernet-only cable, so it wouldnt work with 1000 Mbps or greater Ethernet.

Ethernet Cable Descriptions

using a code that follows this format: N <Signaling> X. -N = refers to the signaling rate in megabits per second -<Signaling> = stands for the signaling type-either baseband-and the X is a unique identifier for a specific Ethernet cabling scheme. EX: 100BaseX. 100 = transmission speed is 100 Mb. X value can mean several different things, for example, a T is short for twisted-pair.

Fiber Distribution Panel

• Permanent fiber installation - Patch panel at both ends • Fiber bend radius - Breaks when bent too tightly • Often includes a service loop • Extra fiber for future changes