Displays
Slots
VESA (ISA extended)
PCI
AGP (4 versions)
PCIX (CAD/medical)
PCIe
Connectors
VGA
S-video
Component and Composite
DVI (-A, -D and -I)
DisplayPort (full and mini)
HDMI
Technologies
CRT
Plasma
Color wheel
LCD (TN, IPS)
CCFL backlights
LED backlights
OLED
Resolutions
VGA – 640×480
SVGA – 800×600
XGA – 1024×768
This article provides some insight into these classic resolutions, and as a bonus covers the topic of projectors, which you’ll see almost for certain on the tests:
http://www.theprojectorexpert.com/projector-resolution-guide-svga-vs-xga-vs-wxga/
Television resolutions do not exactly match these PC display resolutions. See this in depth:
https://www.digitalcitizen.life/what-screen-resolution-or-aspect-ratio-what-do-720p-1080i-1080p-mean/
Aspect Ratios
4:3
3:2
16:9
21:9
Essentials of Networking
If you’re doing my CompTIA courses, you’ll hear me mention IEEE often. You should be aware of their site and what they do on it. It’s pretty interesting:
https://spectrum.ieee.org/the-institute
(Thanks Herbbie!)
Client / Server Model
Hosts
Clients: Either a physical machine like your PC or workstation, or more accurately, a “receiving end” application like your web browser.
Servers: either physical machines or service daemons, like web servers, mail servers, streaming servers, etc.)
Local Area Networks (LANs)
Physical Layer
(think of telegraph wire)
Wire
Fiber optic cable
Radio waves
Coaxial Cable: The Oldest Ethernet Media
Ethernet Coaxial
RG-8 – 10Base5 Thicknet: Uses BNC connectors (“bayonet” or stick-and-twist)
RG-58 – 10Base2 Thinnet: Also uses BNC
MAU or MSAU
Vampire Tap
Cable Network Coaxial
RG-6 – Cable service, analog service, security cameras Cable TV/Internet Service Co-ax (uses screw-in F-type connectors)
RG-62 – TV
RG-59 – Cable service : Siamese cable: coax bonded to two conductor wires (a primitive “power over ethernet” analog)
TwinAxial Cable: Something completely different
twisted Pair Ethernet Cable
Twisted pair Ethernet cable has 4 pairs (8 wires), but only 2 pairs are used. Theoretically this supports 2 Ethernet ports per cable, though this feature usually goes unused. Ports and jacks use the RJ-45 standard, similar to the telephone RJ-11 jack.
Get familiar with the T-568A & B jack and plug pinout configuration. Memorize the B pinouts and learn to use the acronym GO to get the A pinouts. For some reason everyone uses B most of the time. This site is clear and to-the-point:
https://incentre.net/ethernet-cable-color-coding-diagram/
Almost all standards for Twisted Pair call for runs of a maximum of 100 meters. In-wall cable is usually limited to 90 meters to allow patch cables at both ends.
STP
Shielded Twisted Pair
Was used with Token Ring.
Use in high-EMI/RFI areas where shielding is needed.
UTP
Unshielded Twisted Pair
10BaseT: minimum of Cat 3, maximum distance 100 meters.
100BaseTX, which became simply
100BaseT: minimum Cat 5, maximum distance 100 meters.
100BaseT4: an early alternative that could use all 4 pairs in a Cat 3 cable.
1000BaseT or 1GBaseT: Cat5e, maximum distance 100 meters.
10GBaseT: Cat 6 will get you 55 meters, Cat 6a will get you 100 meters.
PVC vs Plenum Cable
Death-smoke versus less death-smoke.
Horizontal
Plenum
Riser
Fiber Optic Cable
LEDs – short distance
Lasers – long distance
Multimode fiber: short distance – uses multiplexing, for instance three different signals: red, green and blue
Single-mode fiber: long distance – simplex: only one signal stream
10BaseFL – early fiber optic
100BaseFX
…
Early Gigabit Media
1000BaseCX (copper, 25 yd)
1000BaseSX (“short” fiber-optic)
1000BaseLX (“long” fiber-optic)
Connectors
ST – Stick and Twist
SC – Stick and Click
LC – the “Little Connector” (actually Lucent)
Boxes
Repeater – usually for coaxial, but there are twisted pair repeaters too.
Bridge – also usually for coax, and essentially a 2-port switch.
Hub – has no MAC filtering.
Switch – isolates traffic based on MAC addresses.
Router – routes internet traffic based on IP addresses. This is the only Layer 3 box in this list.
Signal Protocols (think of Morse Code)
Ethernet, Token Ring, DECnet, X.25, IPX/SPX, Banyan Vines, etc.
Today, mostly Ethernet
Ethernet passes frames. (You could call them packets, but the other kids on the playground will make fun of you.)
Ethernet cards are NICs (network interface cards, also called “host adapters”).
The Data Link Layer
Layer 2 of the OSI is … a mistake. ISO ignores the fact that there are two protocols at work there: a Logical Link Control layer that sets up sessions and handles multiplexing, and a Media Access Control layer that handles addressing using MAC addresses.
Logical Link Control
https://en.wikipedia.org/wiki/Logical_link_control
Media Access Control
https://en.wikipedia.org/wiki/Data_link_layer
Full vs. Half-duplex
In full duplex, switch and station can send and receive simultaneously, and therefore modern Ethernets are completely collision-free.
https://en.wikipedia.org/wiki/Ethernet
Addresses in Ethernet: MAC Addresses
NICs have “permanent” hardware addresses (Physical Addresses in Windows): MAC Addresses.
Mac Addresses
-are written in hexadecimal
Base 16 notation, using 0-9 and A-F to express numbers from 0-15:
0 1 2 3 4 5 6 7 8 9 a b c d e f
-are grouped in six pairs of hex numbers with a separator in between
Generic hex numbers in the wild look like this:
0f38 – just the number
0x0f38 – “0x” means “hex”
0f38h – “h” means “hex”
So actual MAC addresses look like this:
92-fb-ad-07-64-3a
92:fb:ad:07:64:3a
92:FB:AD:07:64:3A
And the delimiter can be a colon ( : ), a dash ( – ), or anything else. The delimiters aren’t really there; they are put in for our feeble human minds.
Topologies
Bus Topology
Ring Topology
Ring: Token Ring
Star Topology
Mesh Topology
Mesh: Full vs Partial Mesh
Hybrid Topology
Structured Cabling
Telecom room
Work area
Equipment racks: 19″ wide, 1.75″ U (height units)
Patch panels
Punchdown tools
Crimpers
Cable testers
Textbook Time
Chapters 17 and 18