IT
Type F
(Snap-N-Seal compression connector - RG-6 - we passed one around in class along with the compression tool. https://youtu.be/c_hOCZZ23YA)
What is the maximum length end-to-end for 100BASE-T? Now deduct for patch cords. What is the permanent link maximum length?
100 meters or about 300-328 feet
Base band designations:
10BASE-T, etc
ANSI/TIA 606B labeling - use a machine to create labels
1A(Telecom Room).1(Rack)-35(patch panel at rack unit).08(08).LNK(Horizontal Link )
What is the maximum percent that a raceway should be filled with cables?
60 percent
How far away should high-voltage wiring be from low-voltage network cable?
6ft the 6 feet rule
IEEE designations: 802.3, 802.11, 802.8
802.3 is ethernet 802.11 is for wifi 802.8 is for fiber
What is the difference between dark fiber and abandoned cable? What should be done with abandoned (old) cable?
A dark fiber or unlit fiber is an unused optical fiber, available for use in fiber-optic communication. Dark fiber originally referred to the potential network capacity of telecommunication infrastructure. Dark fiber may be leased from a network service provider. Dark fiber is OK to have abandoned cable should be removed and either donated, recycled, or disposed
TDR vs. other cable testers. How are they different in terms of costs and information provided? What type of problems can a copper media tester like the Fluke 620 LAN Cablemeter that we used in class detect?
A time-domain reflectometer (TDR) works much like radar, by transmitting a signal on a cable with the opposite end left open and measuring the amount of time that it takes for the signal's reflection to return to the transmitter, Time-domain reflectometry measures the time needed for a pulse to travel to the end of a cable and back. these give you a percentage of the speed of light (60 percent .6c)
ANSI, OSI, BICSI, UL, IEEE, NEC
ANSI - American National Standards Institute - non profit organization that administers and coordinates US standards and \ conformity assessment system OSI - Open Systems Interconnection - is the reference model for how applications communicate over a network. It's a 7 layer system BICSI - Global Leader in ICT education and certification IEEE is the institute of electrical and electronic engineers. They're deticated to
Convergence
An access point in a passive optical network where the feeder cables are broken out into multiple distribution cables.
Loose-tube vs. tight-buffered cabling.
In the loose buffer construction, the fiber is contained in a plastic tube that has an inner diameter considerably larger than the fiber itself. The interior of the plastic tube is usually filled with a gel material. The loose tube isolates the fiber from the exterior mechanical forces acting on a cable. Tight buffer constructions are able to withstand much greater crush and impact forces without fiber breakage. The tight buffer design, however, results in lower isolation for the fiber from the stresses of temperature variation. While relatively more flexible than loose buffer, if the tight buffer is deployed with sharp bends or twists, optical losses are likely to exceed nominal specifications due to microbending.
inductance
Inductance is the ability of an inductor to store energy and it does this in the magnetic field that is created by the flow of electrical current.
Bonding and grounding practices. Types of devices and cable used. Designations. What is the proper way to get a good ground connection? What is earthing? What is the purpose of grounding electrical equipment?
An accessible means for connecting intersystem bonding and grounding shall be provided at the service entrance. Grounding A conducting connection, whether intentional or unintentional, between electrical circuits or equipment and the earth, or some conducting body that serves in place of the earth bonding The permanent joining of the metallic conducting parts of equipment and conductor enclosures to assure and electrically conductive path between them that will ensure electrical continuity and have sufficient capacity to safely conduct any foreign current likely to be imposed to ground. (1) A set of terminals securely mounted to the meter enclosure and electrically connected to the meter enclosure (2) A bonding bar near the service equipment enclosure, meter enclosure, or raceway for service \ conductors (3) A bonding bar near the grounding electrode conductor Conductor must be green
Safety around electricity: lockout best practices
Application of a secured lockout device on an energy isolating device (valve, switch etc.) per the established procedure Can't be removed until maintenance complete
What is a popular open-source PBX software?
Asterisks and freePBX GNU general
Attenuation
Attenuation is a general term that refers to any reduction in the strength of a signal.Attenuation occurs with any type of signal, whether digital or analog. Sometimes called loss, attenuation is a natural consequence of signal transmission over long distances.
Capacitance
Cable capacitance is defined as the measurement of the electrical charges stored within it. The capacitor in the cable is constructed by two conductive material which is separated by an insulator or dielectric. The capacitance of the cable determines the charging current, charging KVA, and the dielectric loss.
Crossover cable, rollover cable, null modem cable
Connectors
Continuity
Continuity is the presence of a complete path for current flow. A circuit is complete when its switch is closed. A digital multimeter's Continuity Test mode can be used to test switches, fuses, electrical connections,
Identify parts of a fiber cable: core, cladding, buffer, Aramid Yarn, sheathing. Why is cladding always 125u? What is the purpose of cladding? What color is sheathing for MM, SM? What is OM1, OM3, etc. cabling? How many light wavelengths are used in MM? What are those wavelengths (i.e. 850nm, 1300nm)? 850nm is a common wavelength for an LED light source over 62.5/125 OM1 fiber-optic cable.
Core: This is the light transmission area of the fiber, either glass or plastic. The larger the core, the more light that will be transmitted into the fiber. The core of the single mode fiber is extremely small, approximately five to ten microns. Cladding: The function of the cladding is to provide a lower refractive index at the core interface in order to cause reflection within the core so that light waves are transmitted through the fiber. The cladding is a special coating that keeps the light from escaping the glass core. Coating: Coatings are usually multi-layers of plastics applied to preserve fiber strength, absorb shock and provide extra fiber protection. These buffer coatings are available from 250 microns to 900 microns.
Bi-direction Testing with an OTDR article. What is Encircled Flux (EF) and why is a test reference cord used?
Encircled flux (EF) is a new metric for defining launch conditions on multimode fiber. It was developed by optical experts to reduce variability in link-loss. With OLTS 1 reporting 1.06 dB and OLTS 2 reporting 0.66 dB, there will be an argument as to which one is correct. That's why ANSI/TIA and ISO/IEC standards bodies collaborated on creating a standard to define the launch from a multimode source. This controlled launch is called "Encircled Flux"
Impedance
Impedance is a term expressing the ratio of voltage to current in a cable of infinite length.
What is an Insertion Loss Budget and how does it relate to fiber certification?
Insertion loss is measured by determining the output of a system before and after the device is inserted into the system. Loss in an optical fiber can be due to absorption, dispersion, scattering, microbending, diffusion, and the methods of coupling the fiber to the power. Usually measured in dB per item—for example, a coupler, connector, splice, or fiber. To be able to judge whether a fiber optic cable plant is good, one does a insertion loss test with a light source and power meter and compares that to an estimate of what is a reasonable loss for that cable plant. The estimate, called a "loss budget" is calculated using typical component losses for each part of the cable plant - the fiber, splices and/or connectors. If the measured loss exceed the calculated loss by a significant amount (remembering the inherent uncertainty in all measurements), the system should be tested segment-by-segment to determine the cause of high loss.
MGB (PBB), GBB (SBB), ANSI/TIA 607B
MGB Main grounding bar - Busways, or bus ducts, are long busbars with a protective cover. Rather than branching from the main supply at one location, they allow new circuits to branch off anywhere along the route of the busway. GBB ground bus bar - Use to connect multiple ground conductors/lugs in panels Includes stand-off bracket
What type of connector is used to achieve 40 Gbps or higher data rates in a data center?
MPO
Building and electrical codes: local codes take precedence. What is the relationship between the NFPA and the NEC? When does the next NEC come out?
NEC is the national electric code. It sets the foundation for electrical safety in residential, commercial, and industrial occupancies NFPA is the national fire protection association NFPA 70®, National Electrical Code® (NEC®) sets the foundation for electrical safety in residential, commercial, and industrial occupancies. NFPA creates the NEC every 3 years
NEXT and what causes it, FEXT, ELFEXT, PSNEXT, AXT
NEXT near end crosstalk - crosstalk where the cable is started and being sent FEXT far end crosstalk - crosstalk at the receiving pair on the far end PSNEXT power sum near end cross talk - the sum of the total NEXT power copuled to a wire pair from all other adjacent pairs. NEXT (Near-end crosstalk) is the level of interference that occurs between one pair and another pair within a four-pair cable AXT alien cross talk - cross talk coming from a different cable
Troubleshooting tools and techniques: What does each do and what can it tell you? Know how each tool works. Digital Volt-Ohm Multimeter (DVOM), tone and probe, etc.
OSI Model
Recognize the different types of unguided media discussed in class: radio, optical, sonar, microwave, etc.
Phone Systems
RFPs - Who responds to an RFP?
RFP request for proposal the vendor/buyer
What are the advantages/disadvantages of the various network topologies?
Ring It is called ring topology because it forms a ring as each computer is connected to another computer, with the last one connected to the first. Exactly two neighbours for each device. Advantages of Ring Topology 1. Transmitting network is not affected by high traffic or by adding more nodes, as only the nodes having tokens can transmit data. 2. Cheap to install and expand Disadvantages of Ring Topology 1. Troubleshooting is difficult in ring topology. 2. Adding or deleting the computers disturbs the network activity. 3. Failure of one computer disturbs the whole network. Star In this type of topology all the computers are connected to a single hub through a cable. This hub is the central node and all others nodes are connected to the central node. Advantages of Star Topology 1. Fast performance with few nodes and low network traffic. 2. Hub can be upgraded easily. 3. Easy to troubleshoot. 4. Easy to setup and modify. 5. Only that node is affected which has failed, rest of the nodes can work smoothly. Disadvantages of Star Topology 1. Cost of installation is high. 2. Expensive to use. 3. If the hub fails then the whole network is stopped because all the nodes depend on the hub. 4. Performance is based on the hub that is it depends on its capacity Mesh In routing, the nodes have a routing logic, as per the network requirements. Like routing logic to direct the data to reach the destination using the shortest distance. Or, routing logic which has information about the broken links, and it avoids those node etc. We can even have routing logic, to re-configure the failed nodes. Advantages of Mesh Topology 1. Each connection can carry its own data load. 2. It is robust. 3. Fault is diagnosed easily. 4. Provides security and privacy. Disadvantages of Mesh Topology 1. Installation and configuration is difficult. 2. Cabling cost is more. 3. Bulk wiring is required.
SC / ST / LC (Lucent Connector)
SC - stab and click ST - stab and twist LC - Lucent Connector - small form factor MPO - Multi Fiber Push on - used with 4 - 24 fiber cables
Given a fiber type, how far can it reach? (Ch.3 - Table 3.3 - page 123.)
SMF - single mode fiber MMF - multimode fiber OM3/4 are cable standards for fiber
T568A, T568B, USOC
T568A and B are standards for terminating ethernet. USOC is for RJ jacks
What does each layer do?
The Open Systems Interconnection model (OSI model) isa conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to its underlying internal structure and technology.
Banjo Adapter, BOB with a DVOM (we used this in a lab when testing existing cable, such as at a wall plate where we don't have access to the individual wires.)
You can stick the banjo in and you now have access to all 8 wires and can check your pairs if you see a negative on a pair you have a reverse.
Customer support
after the job is done keep in contact for any issues
What is the purpose of a bridge clip on a 66-block? (p. 243)
electronically and mechanically joins two sides together. Sides could be disconnected easily if you have a problem
110-block with 25-pair - what color group gets punched down first when bringing a cable from either the left or the right?
farthest side white blue if coming in from the right slate violet if coming in from the left
Why is a fiberglass ladder preferred for cable installations?
fiberglass doesn't conduct electricity
When using a DVOM and a banjo adapter, what would a negative voltage where apositive voltage should be indicate?
if it's negative it's a reversal wire fault
What does a flashlight test tell you when working with fiber optics?
if light is going though or not
How are binary signals represented with light?
if the laser is on it's a 1 if it's off it's a 0
What will prevent the fiber core from cleaving?
if you don't strip off all of the cladding
When using the OptiFiber OTDR with the attached 400x camera, be able to identify problems and how to correct them.
if you see oily smudges it's from finger prints if you see dust particles it's from dust
When terminating a coax cable, is impedance important?
impedance is important there is 50 ohm for commercial applications and 75 is for domestic and tv. 50 gives minimum loss for weigh and 75 gives minimum weight for loss The impedance of the RF coax cable is chiefly governed by the diameters of the inner and outer conductors The coax impedance is one of the major specifications associated with any piece of coax cable. As it will determine the matching within the system and hence the level of standing waves and power transfer, it is a crucial element. It is therefore necessary to ensure that the correct coax impedance is chosen for any system.
What is industrial ethernet and what type of environment would it be used?
industrial ethernet is ethernet that is rated to handle exceess vibration, heat, and noise for industrial environments.
Finishing
make sure everything is done
LED vs. LASER light sources (what types of cable are used by these light sources, i.e. single-mode and multi-mode?)
multimode is LED single mode is laser
Cabling is implementing which layer(s)?
physical layer
Identify various wire maps (Ch. 15). Open pairs, shorted pairs, short between pairs, reversed pairs (reversal), crossed pairs, and split pairs.
picture
Types of network cabling: Plenum and riser cable
plenum is rated for fire and sits in the area above the seiling
Propagation delay
propagation delay The difference in time between when a signal is transmitted and when it is received.
Rough-in
pull your cable leave 18 inches of space
What type of core should patch cords use?
stranded core solid is to breakable and stiff
Trim-out
terminate and finish up everything
Phases of the Cable Installation Process (also, which tools are used, i.e. bullwheel, etc.)
the 5 phases of a cabling installation project are 1. pre sales/ sales 2. rough in pulled your cable use a bull wheel here 3. trim out go in and terminate and finish up everything 4, finish 5. customer support they may call you back and report a problem if there are issues
Markings on fiber cable show two numbers, such as 9/125, 50/125, 62.5/125. What do these numbers represent?
the first set of numbers is the core and the second set of numbers is the diameter of the outside of the fiber cables' cladding 9/125 refers to a single mode fiber cable. 50/125 and 62.5/125 refer to multimode fiber cable.
When are Velcro (hook-and-loop) fasteners used?
these are used for tie wraps for copper and fiber cables to prevent over cinching can quickly wrap a bundle together. They don't over cinch.
What is the purpose of a J-hook?
to hang wires neatly
Installing through a pipe chase, rebar, safety issues, using a bullwheel, kellum grip, cable reel tree (cable tree)
use lubricant and a bull wheel. Kellum grip is like the Chinese finger trap but for cables.
Fire stopping procedures and practices. NEC Article 770.8
use putty in the conduits have fire proof paint
Be able to identify a wire pair color in a 25 pair cable.
we ride big yellow vans, because old guys break stuff
Termination safety and cleanliness. What did we use in class to secure fiber scraps so they can be properly disposed?
we used black electric tape. Use a matt black matt and a flashlight to make sure no fibers were left.
Tip/Ring (Know for 25 pair and CAT 5e)
wrbyv - tip (white, red, black, yellow, violet) bogbs - ring (blue, orange, green, brown, slate)
What device did we use when installing fiber-optic connectors to ensure light is flowing through the cable?
you can use a flashlight vista fault locator