- A+ Certification
- A+ 220-1001: Day 1: Intro, Resources & the Test
- A+ 220-1001: Day 2: CPUs
- A+ 220-1001: Day 3: RAM
- A+ 220-1001: Day 4: Firmware, Motherboards & Power Supplies
- A+ 220-1001: Day 5: Disks & Mass Storage
- A+ 220-1001: Day 6: Peripherals & PC Builds
- A+ 220-1001: Day 7: OS Operations, User Management & OS Maintenance
- A+ 220-1001: Day 8: Users, Permissions and System Management
- A+ 220-1002: Day 9: The Command Line & OS Troubleshooting
- A+ 220-1002: Day 10: Displays & Networking Basics
- A+ 220-1002: Day 11: LANs: Ethernet & WiFi
- A+ 220-1002: Day 12: The Internet & Virtualization
- A+ 220-1002: Day 13: Portable & Mobile Computing
- A+ 220-1002: Day 14: Mobile Administration & Printing
- A+ 220-1002: Day 15: Security & Operations
- A+ 220-1002: Day 16: Review & Test Preparation
VESA (ISA extended)
AGP (4 versions)
Component and Composite
DVI (-A, -D and -I)
DisplayPort (full and mini)
LCD (TN, IPS)
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:
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:
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)
(think of telegraph wire)
Fiber optic cable
Coaxial Cable: The Oldest Ethernet Media
RG-8 – 10Base5 Thicknet: Uses BNC connectors (“bayonet” or stick-and-twist)
RG-58 – 10Base2 Thinnet: Also uses BNC
MAU or MSAU
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.
-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:
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.
Ring: Token Ring
Mesh: Full vs Partial Mesh
Equipment racks: 19″ wide, 1.75″ U (height units)
Chapters 17 and 18