A+ 220-1002: Day 10: Displays & Networking Basics

  1. A+ Certification
  2. A+ Certification Syllabus (220-1001, 2220-1002)
  3. A+ 220-1001: Day 1: Intro, Resources & the Test
  4. A+ 220-1001: Day 2: CPUs
  5. A+ 220-1001: Day 3: RAM
  6. A+ 220-1001: Day 4: Firmware, Motherboards & Power Supplies
  7. A+ 220-1001: Day 5: Disks & Mass Storage
  8. A+ 220-1001: Day 6: Peripherals & PC Builds
  9. A+ 220-1001: Day 7: OS Operations, User Management & OS Maintenance
  10. A+ 220-1001: Day 8: Users, Permissions and System Management
  11. A+ 220-1002: Day 9: The Command Line & OS Troubleshooting
  12. A+ 220-1002: Day 10: Displays & Networking Basics
  13. A+ 220-1002: Day 11: LANs: Ethernet & WiFi
  14. A+ 220-1002: Day 12: The Internet & Virtualization
  15. A+ 220-1002: Day 13: Portable & Mobile Computing
  16. A+ 220-1002: Day 14: Mobile Administration & Printing
  17. A+ 220-1002: Day 15: Security & Operations
  18. A+ 220-1002: Day 16: Review & Test Preparation



VESA (ISA extended)


AGP (4 versions)

PCIX (CAD/medical)





Component and Composite

DVI (-A, -D and -I)

DisplayPort (full and mini)





Color wheel


CCFL backlights

LED backlights



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:

Television resolutions do not exactly match these PC display resolutions. See this in depth:

Aspect Ratios





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:

(Thanks Herbbie!)

Client / Server Model


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)


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


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:

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.


Shielded Twisted Pair

Was used with Token Ring.

Use in high-EMI/RFI areas where shielding is needed.


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.




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

Early Gigabit Media

1000BaseCX (copper, 25 yd)

1000BaseSX (“short” fiber-optic)

1000BaseLX (“long” fiber-optic)


ST – Stick and Twist
SC – Stick and Click
LC – the “Little Connector” (actually Lucent)


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


Media Access Control


Full vs. Half-duplex

In full duplex, switch and station can send and receive simultaneously, and therefore modern Ethernets are completely collision-free.


Addresses in Ethernet: MAC Addresses

NICs have “permanent” hardware addresses (Physical Addresses in Windows): MAC Addresses.

All local network traffic is sent to and from MAC Addresses. Think of them as the room numbers in a hotel, used for things like Room Service.


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:




The formal specification for MAC addresses calls for them to be lower-case letters, BUT: Microsoft will and CompTIA may show them as upper-case letters.
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.


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


Cable testers

Textbook Time

Chapters 17 and 18