Domain 2 — Networking
| Port(s) |
Protocol |
Full Name |
TCP/UDP |
What It Does / Exam Trigger |
| 20 / 21 | FTP | File Transfer Protocol | TCP | File transfer — unencrypted. Port 20 = data, Port 21 = commands |
| 22 | SSH / SFTP / SCP | Secure Shell | TCP | Encrypted remote access + secure file transfer. "Secure" = port 22 |
| 23 | Telnet | Teletype Network | TCP | Insecure remote access. Replaced by SSH. Never use on exam |
| 25 | SMTP | Simple Mail Transfer Protocol | TCP | Sends email between mail servers (outgoing) |
| 53 | DNS | Domain Name System | TCP+UDP | Resolves domain names to IP addresses. UDP for queries, TCP for zone transfers |
| 67 / 68 | DHCP | Dynamic Host Config Protocol | UDP | Auto IP assignment. 67 = server, 68 = client |
| 80 | HTTP | Hypertext Transfer Protocol | TCP | Unencrypted web traffic |
| 110 | POP3 | Post Office Protocol v3 | TCP | Downloads email, deletes from server. Single device use |
| 137–139 | NetBIOS/NetBT | Network Basic I/O System | TCP+UDP | Legacy Windows networking, name resolution on older networks |
| 143 | IMAP | Internet Mail Access Protocol | TCP | Email syncs across multiple devices — leaves mail on server |
| 389 | LDAP | Lightweight Directory Access Protocol | TCP | Directory services — queries Active Directory / user databases |
| 443 | HTTPS | HTTP Secure | TCP | Encrypted web traffic (TLS/SSL). "HTTPS doesn't work" = port 443 blocked |
| 445 | SMB / CIFS | Server Message Block | TCP | Windows file & printer sharing. "Can't access shared folders" = check 445 |
| 3389 | RDP | Remote Desktop Protocol | TCP | Full GUI remote desktop. "Remote control with graphics" = RDP = 3389 |
TCP (Connection-Oriented): FTP, SSH, Telnet, SMTP, HTTP, POP3, IMAP, LDAP, HTTPS, SMB, RDP — most protocols are TCP
UDP (Connectionless): DHCP (67/68), DNS (53 queries), NTP (123) — fast, no handshake, fire-and-forget
KEY EXAM TRAP: POP3 (110) = downloads and deletes from server. IMAP (143) = syncs and keeps on server. Multiple devices = IMAP. Single device = POP3.
| Standard |
Wi-Fi Name |
Frequency Band(s) |
Max Speed |
Key Notes |
| 802.11a | — | 5 GHz only | 54 Mbps | Older, limited business adoption; early 5 GHz |
| 802.11b | — | 2.4 GHz only | 11 Mbps | First widely adopted standard; prone to microwave/Bluetooth interference |
| 802.11g | — | 2.4 GHz only | 54 Mbps | Backward compatible with b; same interference issues |
| 802.11n | Wi-Fi 4 | 2.4 AND 5 GHz | 300–600 Mbps | First dual-band standard. Introduced MIMO. Backward compatible with b/g |
| 802.11ac | Wi-Fi 5 | 5 GHz only | ~1–6.9 Gbps | 5 GHz only. MU-MIMO for multiple devices simultaneously |
| 802.11ax | Wi-Fi 6 / 6E | 2.4 + 5 + 6 GHz | ~9.6 Gbps | Wi-Fi 6E adds 6 GHz band. OFDMA + MU-MIMO. Most efficient standard |
| 802.11be | Wi-Fi 7 | 2.4 + 5 + 6 GHz | 46+ Gbps | Awareness only — emerging. Not yet on most exam questions |
🔴 MUST KNOW: 802.11ac = Wi-Fi 5 = 5 GHz ONLY (no 2.4 GHz)
🟡 MUST KNOW: 802.11n = Wi-Fi 4 = FIRST dual-band (2.4 + 5 GHz)
🟢 MUST KNOW: 802.11ax (Wi-Fi 6E) = ONLY standard with 6 GHz band
| Band |
Range |
Speed |
Interference |
Non-Overlapping Channels |
Notes |
| 2.4 GHz | Longest | Slowest | HIGH — microwaves, Bluetooth, baby monitors | 3 → channels 1, 6, 11 | US: Ch 1–11. World: Ch 1–13. Japan: Ch 1–14 |
| 5 GHz | Medium | Fast | LOW | 24 | More channels, faster, less congested |
| 6 GHz | Shortest | Fastest | MINIMAL | 59 | Wi-Fi 6E / 802.11ax only. No legacy device interference |
🔴 HIGHEST TESTED FACT: The 3 non-overlapping channels on 2.4 GHz are 1, 6, and 11. When setting up multiple access points in the same area, assign them these three channels to prevent interference.
| Record | Name | What It Does | Exam Trigger |
|---|
| A | Address | Maps domain → IPv4 address | "Resolve domain to IPv4" |
| AAAA | Quad-A | Maps domain → IPv6 address | "Resolve domain to IPv6" |
| CNAME | Canonical Name | Domain alias — points one name to another name (not an IP) | "Domain alias / redirect / multiple names same server" |
| MX | Mail Exchanger | Directs email to correct mail server. Lower number = higher priority | "Email delivery for a domain" |
| TXT | Text | Free-form text — used for domain verification and email security (SPF/DKIM/DMARC) | "Spam prevention / email authentication" |
SPF — Lists which servers are allowed to send email for your domain. Prevents spoofed "from" addresses.
DKIM — Adds a digital signature to emails. Proves the email wasn't tampered with in transit.
DMARC — Policy for what to do when SPF or DKIM fails. Reject, quarantine, or report.
| Standard | Name | Max Wattage per Port | Notes |
|---|
| 802.3af | PoE | 15.4W | Original PoE spec. Powers basic VoIP phones, simple cameras |
| 802.3at | PoE+ | 30W | Powers WAPs, advanced IP cameras |
| 802.3bt | PoE++ | 60W (Type 3) / 100W (Type 4) | Powers laptops, smart TVs, high-powered devices. Backward compatible with 802.3af/at |
Power Injector: Adds PoE capability to a non-PoE switch — connects inline between the switch and the device. Max distance = 100 meters (same as standard Ethernet).
| Range | Class | Type | Subnet Mask | Notes |
|---|
| 10.0.0.0 – 10.255.255.255 | A | Private | 255.0.0.0 (/8) | Largest block. Used in large enterprises |
| 172.16.0.0 – 172.31.255.255 | B | Private | 255.255.0.0 (/16) | Medium block. Enterprise use |
| 192.168.0.0 – 192.168.255.255 | C | Private | 255.255.255.0 (/24) | Most common — home routers default to 192.168.1.x or 192.168.0.x |
| 169.254.0.0 – 169.254.255.255 | — | APIPA | 255.255.0.0 (/16) | Auto-assigned when DHCP fails. Device can only talk to other APIPA addresses on same network. No internet. |
| 127.0.0.1 | — | Loopback | — | Tests local TCP/IP stack. "Ping yourself." Never routable. |
🔴 APIPA EXAM TRIGGER: User's IP is 169.254.x.x = DHCP server unreachable / DHCP failure. Can't reach internet. Fix = check DHCP server or set a static IP.
Domain 3 — Hardware
| Category | Max Speed | Max Distance | Notes |
|---|
| Cat 5 | 100 Mbps | 100m | Obsolete. Fast Ethernet. Not on most modern installs |
| Cat 5e | 1 Gbps | 100m | Most common in older home/office installs. "e" = enhanced (reduced crosstalk) |
| Cat 6 | 1 Gbps (10 Gbps @ 55m) | 100m (55m for 10G) | Thicker wire, better shielding. Current standard for most new installs |
| Cat 6a | 10 Gbps | 100m | "a" = augmented. Full 100m at 10 Gbps. Stiffer, harder to route. Required for PoE++ |
All copper Ethernet cables max at 100 meters (328 ft). STP = Shielded Twisted Pair (used near EMI sources). UTP = Unshielded (standard). Plenum-rated = fire-safe insulation for use in HVAC plenum spaces.
T568A — "Government / older"
1White-Green
2Green
3White-Orange
4Blue
5White-Blue
6Orange
7White-Brown
8Brown
T568B — "Business standard / most common"
1White-Orange
2Orange
3White-Green
4Blue
5White-Blue
6Green
7White-Brown
8Brown
Straight-through cable: Both ends same standard (T568B–T568B). Used for PC to switch, switch to router. Crossover cable: One end T568A, one end T568B. Used to connect same-type devices (PC to PC, switch to switch — though modern devices auto-negotiate).
| Connector | Used For |
|---|
| RJ-11 | Telephone/DSL — 4 or 6 pins, small |
| RJ-45 | Ethernet networking — 8 pins |
| F-type | Coaxial cable — cable TV, cable modem |
| ST | Fiber — Straight Tip. Bayonet twist-lock. Older |
| SC | Fiber — Subscriber Connector. Square push-pull |
| LC | Fiber — Lucent Connector. Small form factor, common in data centers |
| Punchdown | Terminates copper wire to patch panels / keystone jacks. Requires punchdown tool |
| Connector | Used For |
|---|
| microUSB | Older Android devices, peripherals |
| miniUSB | Older devices — slightly larger than micro |
| USB-C | Modern universal connector — reversible, supports USB/DisplayPort/HDMI/Thunderbolt |
| Lightning | Apple proprietary — 8-pin, reversible. iPhone/iPad (pre USB-C models) |
| Molex | 4-pin power connector for older drives and fans |
| DB-9 | 9-pin serial connector. Legacy RS-232 serial ports |
| Version | Max Speed | Connector Color | Notes |
|---|
| USB 1.1 | 12 Mbps | Black/White | Legacy. Rarely seen now |
| USB 2.0 | 480 Mbps | Black | Hi-Speed. Still common for keyboards, mice, flash drives |
| USB 3.0 / 3.1 Gen 1 | 5 Gbps | Blue | SuperSpeed. Blue port = visual identifier |
| USB 3.1 Gen 2 | 10 Gbps | Teal/Teal | SuperSpeed+ |
| USB 3.2 Gen 2x2 | 20 Gbps | Red | Two 10 Gbps lanes. USB-C required |
| Thunderbolt 3 | 40 Gbps | USB-C connector | Also carries DisplayPort + PCIe. Powers devices up to 100W. Daisy-chain up to 6 devices |
| Thunderbolt 4 | 40 Gbps | USB-C connector | Same speed as TB3 but mandatory standards compliance. Dual 4K displays |
Thunderbolt visual identifier: ⚡ lightning bolt icon on the port. Max cable length: USB = 5m at 3.0 / Thunderbolt = 2m passive, 60m with active cable.
| Type | Core Size | Distance | LED/Laser | Cost | Use Case |
|---|
| Multimode (MMF) | 50 or 62.5 µm | Up to ~2km | LED | Lower | Short runs — inside buildings, data centers, campus networks |
| Single-mode (SMF) | 8–10 µm | Up to 100km+ | Laser | Higher | Long runs — between buildings, WAN connections, ISP infrastructure |
Memory trick: Single-mode = Single path of light = farther. Multimode = Multiple paths = shorter distances but cheaper.
| Cable | Signal | Audio? | Max Resolution | Notes |
|---|
| VGA | Analog | No | Up to 2048×1536 | 15-pin blue trapezoidal connector. Legacy. No audio. |
| DVI | Digital (+ analog DVI-I) | No | Up to 2560×1600 | White rectangular connector. DVI-D = digital only. DVI-I = digital+analog. |
| HDMI | Digital | Yes | 8K (v2.1) | Most common consumer connector. Carries audio + video. HDMI 2.1 supports 4K@144Hz, 8K@60Hz. |
| DisplayPort | Digital | Yes | 8K+ (v2.0) | Locking connector. Preferred for PC monitors. Supports daisy-chaining. DP 2.1 supports dual 4K@144Hz. |
| Type | Max per DIMM | Pins (DIMM) | Pins (SODIMM) | Voltage | Notes |
|---|
| DDR3 | 16 GB | 240 | 204 | 1.5V | Older systems. Not compatible with DDR4 slots |
| DDR4 | 64 GB | 288 | 260 | 1.2V | Current mainstream standard. Faster frequencies than DDR3 |
| DDR5 | 128 GB+ | 288 | 262 | 1.1V | Newest. Faster & more efficient. NOT backward compatible with DDR4 (key notch moved) |
Form Factors
| DIMM | Desktop RAM — full size (133.35mm) |
| SODIMM | Laptop/small form factor RAM — about half the length. Used in laptops, NUCs, mini-PCs |
Channel Configurations
| Single | 1 module — baseline bandwidth |
| Dual-channel | 2 matched modules — 2x bandwidth. Most common |
| Triple-channel | 3 modules — older Intel platforms |
| Quad-channel | 4 modules — workstations/servers |
ECC RAM (Error Correcting Code): Detects and corrects single-bit memory errors. Used in servers and workstations where data integrity is critical. NOT used in typical consumer PCs. Requires ECC-compatible motherboard and CPU.
Virtual RAM / Paging: When physical RAM is full, the OS uses a portion of the storage drive as overflow RAM. Called pagefile.sys in Windows, swap in Linux/macOS. Much slower than physical RAM. High disk activity + slowness = system is paging. Solution: add more physical RAM.
| RAID Level | Name | Min Drives | Fault Tolerance | Performance | Capacity | How it Works |
|---|
| RAID 0 | Striping | 2 | NONE — 1 drive fails = ALL data lost | Best read/write speed | 100% of all drives | Data split across drives. Pure speed, zero protection |
| RAID 1 | Mirroring | 2 | 1 drive can fail | Normal read, slower write | 50% (n/2) | Exact duplicate on both drives. Mirror image |
| RAID 5 | Striping + Parity | 3 | 1 drive can fail | Good read, moderate write | (n-1) drives | Parity spread across all drives. Rebuild on failure |
| RAID 6 | Striping + Double Parity | 4 | 2 drives can fail | Good read, slower write | (n-2) drives | Two parity blocks. Better protection than RAID 5 |
| RAID 10 | Mirror + Stripe (1+0) | 4 | 1 per mirrored pair | Best of both | 50% | RAID 1 mirrors, then striped. Speed + redundancy |
RAID 0 = NO fault tolerance. One drive fails, everything is gone. Only for speed-critical, replaceable data.
RAID 10 = Best performance + redundancy, but costs 50% of capacity. Go-to for databases and critical apps.
| Interface | Speed | Notes |
|---|
| SATA | ~600 MB/s | Slowest SSD interface. Used with 2.5" and some M.2 drives |
| NVMe (PCIe) | 3,500–7,000 MB/s | Fastest. Connects via M.2 slot or PCIe slot. NVMe = Non-Volatile Memory Express |
| SAS | ~1,200 MB/s | Enterprise/servers. More reliable than SATA. Hot-swappable |
| Form Factor | Notes |
|---|
| 2.5" | Traditional laptop/desktop bay. Uses SATA interface |
| 3.5" | Desktop HDD form factor. HDDs only, not SSDs |
| M.2 | Small rectangular card. Supports both SATA and NVMe protocols |
| mSATA | Mini-SATA. Older small form factor. Largely replaced by M.2 |
HDD Spindle Speeds: 5400 RPM (laptops, quiet) vs 7200 RPM (desktops, faster) vs 10,000–15,000 RPM (enterprise/servers). Higher RPM = faster access = more heat/noise.
| Form Factor | Size | Expansion Slots | Notes |
|---|
| ATX | 305×244mm | 7 slots | Full-size desktop standard. Most expandable. Most common |
| microATX (mATX) | 244×244mm | 4 slots | Smaller, fits in ATX cases. Good for mid-tower builds |
| Mini-ITX (ITX) | 170×170mm | 1 slot | Very small. HTPCs, compact builds. Limited expansion |
Compatibility note: ATX, microATX, and mini-ITX all share the same screw hole positions and can often fit in the same mid-tower or full-tower ATX case (smaller boards fit in bigger cases, not vice versa).
| Slot | Lanes | Typical Use | Notes |
|---|
| PCIe x1 | 1 lane | Sound cards, NICs, USB expansion cards | Small slot |
| PCIe x4 | 4 lanes | M.2 adapters, some SSDs, capture cards | Medium slot |
| PCIe x8 | 8 lanes | Some GPUs, RAID cards | Long slot, may only use 8 lanes electrically |
| PCIe x16 | 16 lanes | Primary GPU slot | Full-length slot. This is where the graphics card goes |
A larger card can fit in a smaller slot (x16 card in x8 slot) but runs at the slower slot's speed. Slots are backward/forward compatible in size.
| Connector / Spec | Details |
|---|
| 20+4 pin | Main motherboard power connector (24-pin total) |
| 4/8-pin EPS | CPU power connector |
| 6/8-pin PCIe | GPU power connector for dedicated graphics cards |
| SATA power | L-shaped connector for SATA drives |
| Molex | 4-pin for older devices, fans, case lighting |
| Voltage Rail | Powers |
|---|
| 3.3V | RAM, chipset, some circuit logic |
| 5V | USB ports, older drives, logic circuits |
| 12V | CPU, GPU, motors (HDDs/fans) — most power-hungry components |
Input voltage: US = 110–120 VAC. International = 220–240 VAC. Some PSUs are dual-voltage (auto-switching). Plugging a 120V PSU into 240V outlet without a converter = immediate damage. Modular PSU = detachable cables (cleaner builds). Redundant PSU = two power supplies, one takes over if the other fails (servers).
The 7 Steps in Order
- 1
Processing — RIP (Raster Image Processor) converts data to a bitmap image
- 2
Charging — Primary corona wire/roller charges the drum to a uniform −600V
- 3
Exposing — Laser beam draws the image on the drum, reducing charge to −100V where toner should stick
- 4
Developing — Toner (negatively charged) is attracted to the lighter areas drawn by the laser
- 5
Transferring — Transfer belt/roller gives paper a positive charge, pulling toner from drum to paper
- 6
Fusing — Fuser assembly (heat + pressure rollers) melts and bonds toner permanently to paper
- 7
Cleaning — Cleaning blade scrapes remaining toner off drum for next page
Mnemonic: "Please Charge Every Day, The Fuser Cleans"
Processing → Charging → Exposing → Developing → Transferring → Fusing → Cleaning
Troubleshooting links:
• Toner smears = Fuser failing
• Ghost image = Drum not cleaned / drum issue
• Vertical line full length = Scratched drum
• Faded output = Low toner or bad developer
• Multiple sheets feeding = Worn separation pad
• Paper not picking up = Worn pickup rollers
Maintenance kit includes: fuser, pickup rollers, transfer roller, separation pads. Replace at manufacturer-recommended page count intervals.
| Type | Technology | Maintenance | Exam Trigger |
|---|
| Laser | Toner + heat fusing. EP process (7 steps) | Replace toner, fuser, rollers. Clean drum | Office workhorse. Toner smear = fuser. Ghost image = drum |
| Inkjet | Liquid ink sprayed through nozzles | Clean printhead, replace cartridges, calibrate | Photo printing. Clogged head = streaky output |
| Thermal | Heat-sensitive paper darkens with heat | Clean with IPA 90%+. No ink/toner | Receipt printers. Blank output = paper loaded backwards |
| Impact / Dot Matrix | Pin strikes ink ribbon against paper | Replace ribbon, check tractor feed | Only printer that can print multipart/NCR forms |
| 3D (FDM) | Filament melted and layered (PLA/ABS) | Level print bed, replace filament, unclog nozzle | Bed must be level. FDM = most common type |
Domain 4 — Virtualization & Cloud
| Model | Name | You Manage | Exam Trigger |
|---|
| IaaS | Infrastructure as a Service | OS, apps, data | "Raw compute/storage/networking" — AWS EC2, Azure VMs |
| PaaS | Platform as a Service | Apps, data | "Development platform" — Heroku, Azure App Service |
| SaaS | Software as a Service | Only data/settings | "Use software over browser" — Google Workspace, Office 365, Salesforce |
Memory trick: IaaS = you build the house (provider gives the land). PaaS = you decorate the house (provider built it). SaaS = you just live there (provider does everything).
| Deployment | Definition |
|---|
| Public | Shared infrastructure over the internet (AWS, Azure, GCP). Pay-as-you-go |
| Private | Cloud infrastructure exclusively for one organization. On-premises or hosted |
| Hybrid | Mix of public + private cloud. Sensitive data on-prem, other workloads in public cloud |
| Community | Shared by organizations with common interests (e.g., government agencies) |
| Type | Name | How It Works | Examples | Use Case |
|---|
| Type 1 | Bare Metal | Runs directly on hardware — no host OS underneath | VMware ESXi, Microsoft Hyper-V, Citrix XenServer | Servers, data centers, enterprise virtualization |
| Type 2 | Hosted | Runs as an application on top of a host OS (Windows/macOS/Linux) | VMware Workstation, VirtualBox, Parallels | Developers, testing, running multiple OSes on a desktop |
VM Network Modes:
• NAT = VM shares host's IP. VM → internet works, external → VM blocked
• Bridged = VM gets its own IP on network. Appears as separate device
• Host-only = VM can only talk to host, isolated from network
VM Requirements:
• CPU with Intel VT-x or AMD-V (must be enabled in BIOS/UEFI)
• RAM is additive (host + all VMs running simultaneously)
• VM escaping = biggest security threat (guest VM breaks out to host)
Domains 1 & 5 — Mobile Devices & Troubleshooting
| Technology | IEEE Standard | Range | Key Uses |
|---|
| Bluetooth | 802.15.1 | ~10m (class 2) | Headsets, keyboards, mice, speakers, car integration |
| NFC | — | ~4cm (1.5 in) | Tap-to-pay (Apple Pay, Google Pay), access cards, Bluetooth pairing bootstrap |
| RFID | — | Meters (varies) | Asset tracking, inventory, access badges, pet microchips. Mostly one-way |
| Wi-Fi Hotspot | 802.11 | Normal Wi-Fi | Phone acts as wireless router, shares cellular data |
| Tethering | — | Cable | USB cable from phone to laptop to share cellular data. Wired hotspot |
| Cellular Gen | Typical Speed | Notes |
|---|
| 3G | ~1–3 Mbps | Legacy. HSPA+ |
| 4G LTE | ~10–50 Mbps | Standard today. LTE = Long Term Evolution |
| 5G | ~100Mbps–10Gbps | Low-band (coverage), mid-band (balance), mmWave (speed, short range) |
SIM vs eSIM: SIM (Subscriber Identity Module) = physical card identifying you to cellular network. eSIM = embedded chip programmable without physical card swap. IMEI = hardware ID of the phone itself (hardcoded). IMSI = identity of the user/account (stored on SIM).
| Type | Response Time | Color Accuracy | Viewing Angles | Best For |
|---|
| TN (Twisted Nematic) | Fastest (~1ms) | Poor | Narrow | Gaming (high refresh rate priority). Cheapest |
| IPS (In-Plane Switching) | Medium (~4ms) | Excellent | 178° wide | Design work, photo editing, professional use |
| VA (Vertical Alignment) | Medium-slow | Good | Medium | Compromise — best contrast ratio. General use |
| OLED | Fastest (<1ms) | Best (true black) | Best | Premium phones, TVs. Self-emissive — no backlight needed |
| Mini-LED | Fast | Very good | Good | Premium laptops/monitors. Better backlight control than LCD |
Backlight + Inverter: LCD panels need a backlight (CCFL fluorescent lamp OR LED). Laptops with CCFL backlight need an inverter (converts DC to AC). Dim screen visible at angle = backlight failure. No image but laptop makes sounds = backlight or inverter failed.
| Hardware Symptoms |
|---|
| Computer shuts off after 10–15 min | Overheating — check fans/thermal paste |
| Inaccurate date/time every boot | Dead CMOS battery — replace coin cell |
| POST beep codes | RAM or video failure — check mobo manual |
| Swollen capacitors on motherboard | Replace motherboard immediately |
| Random crashes across multiple programs | Bad RAM — run MemTest86 |
| HDD clicking/grinding | Physical failure imminent — backup NOW |
| S.M.A.R.T. warning appears | Drive predicting failure — backup and replace |
| No POST, fans spin, no display | RAM not seated, or no RAM installed |
| Network Symptoms |
|---|
| IP address starts with 169.254.x.x | DHCP failure — APIPA assigned. Check DHCP server |
| Can ping by IP, not by name | DNS failure — check DNS settings |
| VoIP calls choppy / words drop | Jitter — enable QoS, use 5 GHz |
| Everything slow, near kitchen | 2.4 GHz microwave interference — switch to 5 GHz |
| Port flapping (link cycling) | Bad cable or failing NIC |
| Intermittent internet drops | Ping gateway first — if OK, ISP issue |
| Authentication failure on Wi-Fi | Wrong passphrase, encryption mismatch, expired cert |
| Slow wireless speeds near router | Interference — check channel overlap, try 5 GHz |
| Symptom | Likely Cause / Action |
|---|
| Fuzzy / blurry image | Resolution not set to native. Set to monitor's native resolution |
| Dead pixels (stuck black) | Manufacturing defect — cannot fix. May qualify for replacement |
| Burn-in / image ghosting (LCD) | Static image displayed too long. Run solid white screen for extended period |
| Projector dims, then goes dark | Bulb failure. Replace metal-halide bulb. Reset lamp timer after replacement |
| Dim laptop screen (visible at extreme angle) | Backlight failure — replace backlight or display assembly |
| Flickering display | Check/reseat video cable. Try different cable or port |
| Projector shuts off intermittently | Clogged dust filter → thermal shutdown. Clean filter |
| Wrong color tint | Check Night Light / Night Mode setting. Check monitor color preset |
| Tool | What It Does | Exam Scenario Trigger |
|---|
| Crimper | Attaches RJ-45 or RJ-11 connectors to the end of a cable | "Making a patch cable" |
| Cable Stripper | Removes outer jacket of cable without damaging inner wires | "Preparing cable for termination" |
| Toner Probe | Generates a tone on one end; probe on other end finds the cable in a bundle without cutting | "Find which cable in a wall/bundle" |
| Punchdown Tool | Seats wires into 66-block or 110-block patch panels and keystone jacks | "Wiring a patch panel" |
| Cable Tester | Verifies continuity and correct wiring of both ends of a cable | "Check if a cable works before installing" |
| Loopback Plug | Plugs into a port and loops the signal back to test the NIC or port | "Testing a NIC without connecting to network" |
| Wi-Fi Analyzer | Shows Wi-Fi networks, signal strength, channel usage — used for site surveys | "Find channel congestion or coverage dead zones" |
| Network Tap | Passively copies network traffic for analysis without disrupting traffic flow | "Monitor traffic without interrupting the network" |