Cables & Connectors
Key Takeaways
- Cat 5e supports Gigabit Ethernet (1 Gbps) up to 100 meters, Cat 6 supports 10 Gbps up to 55 meters, and Cat 6a supports 10 Gbps up to the full 100 meters.
- Fiber optic cables come in single-mode (long distance, up to 100+ km, yellow jacket) and multimode (shorter distance, up to 2 km, orange/aqua jacket).
- Straight-through Ethernet cables connect different device types (PC to switch), while crossover cables connect same types (PC to PC); modern Auto-MDI-X devices erase the distinction.
- Coaxial cable types include RG-6 (cable TV/internet, 75 ohm) and RG-59 (short runs, legacy CCTV); both use F-type connectors.
- DisplayPort supports daisy-chaining multiple monitors via Multi-Stream Transport, while HDMI does not — a key differentiator for multi-monitor setups.
Network Cables (Copper)
Domain 3 (Hardware) is 25% of the CompTIA A+ Core 1 (220-1201) exam, and cable identification is among the most heavily tested topics because performance-based questions (PBQs) routinely ask you to drag the correct cable or connector onto a diagram. Memorize the speed/distance ceilings exactly.
Ethernet Cable Categories
| Category | Max Speed | Max Distance (Full Speed) | Shielding | Common Use |
|---|---|---|---|---|
| Cat 5 | 100 Mbps | 100m | Unshielded (UTP) | Legacy — avoid for new installs |
| Cat 5e | 1 Gbps | 100m | UTP | Most common existing cabling |
| Cat 6 | 10 Gbps | 55m (1 Gbps at 100m) | UTP or STP | New office installs |
| Cat 6a | 10 Gbps | 100m | STP (Shielded) | Data centers, high-performance |
| Cat 7 | 10 Gbps | 100m | Fully shielded (S/FTP) | Industrial, data center |
| Cat 8 | 25/40 Gbps | 30m | Fully shielded (S/FTP) | Server-to-switch short runs |
Exam Tip: The maximum distance for copper Ethernet is 100 meters (328 feet) — except Cat 8, which drops to 30m to hit 40 Gbps. Beyond the limit you need a switch, repeater, or fiber. A frequent trap: Cat 6 at 10 Gbps is only 55m, NOT 100m.
Ethernet Cable Types
| Cable Type | Wiring | Use Case |
|---|---|---|
| Straight-through | T-568B on both ends | PC↔switch, PC↔router, router↔switch |
| Crossover | T-568A one end, T-568B other | PC↔PC, switch↔switch (legacy gear) |
| Rollover (Console) | Reversed pin-out | PC serial port to router/switch console |
| Plenum | Fire-rated jacket (FEP) | Air-handling spaces above ceilings (required by code) |
Note: Most modern devices support Auto-MDI-X, which auto-detects cable type, so crossover cables are rarely needed. RJ-45 is the 8-pin Ethernet connector; RJ-11 is the smaller 6-position telephone connector — do not confuse them on a PBQ.
Fiber Optic Cables
| Type | Core Diameter | Wavelength | Max Distance | Jacket Color | Use Case |
|---|---|---|---|---|---|
| Single-Mode (SMF) | 8–10 μm | 1310/1550 nm | 100+ km | Yellow | WAN, long-haul, telco |
| Multimode (MMF) | 50/62.5 μm | 850/1300 nm | up to 2 km | Orange / Aqua | LAN, campus, data center |
Fiber is immune to electromagnetic interference (EMI) and supports far greater distances than copper, which is why it is mandatory for backbone and inter-building runs.
Fiber Connectors
| Connector | Description | Memory Aid |
|---|---|---|
| SC | Square push-pull, snap-in | Square Connector |
| LC | Small latching, dominant today | Little Connector |
| ST | Round bayonet twist-lock | Straight Tip |
| MTRJ | Tiny dual-fiber, both strands in one body | Multi-fiber Termination |
Coaxial Cable
| Type | Impedance | Use Case |
|---|---|---|
| RG-6 | 75 ohm | Cable TV, cable internet, satellite |
| RG-59 | 75 ohm | Short runs, legacy CCTV, patch |
Coax uses an F-type screw-on connector for TV/internet and a BNC bayonet connector for some video/CCTV. RG-6 has thicker conductor and better shielding than RG-59, so it carries high-frequency signals farther — choose RG-6 for a modem feed.
Video Cables & Connectors
| Connector | Type | Max Resolution | Audio | Notes |
|---|---|---|---|---|
| HDMI | Digital | 8K@60Hz (HDMI 2.1) | Yes | Consumer standard; TVs, consoles |
| DisplayPort | Digital | 8K@60Hz (DP 2.0) | Yes | Monitor standard; daisy-chains (MST) |
| USB-C (Alt Mode) | Digital | 8K@60Hz | Yes | Tunnels DisplayPort/HDMI over USB-C |
| DVI-D | Digital | 2560x1600 (Dual-Link) | No | Legacy digital only |
| DVI-I | Digital + Analog | 2560x1600 (Dual-Link) | No | Accepts passive VGA adapter |
| VGA (DE-15) | Analog | 2048x1536 | No | Legacy; blue 15-pin connector |
HDMI vs. DisplayPort (high-yield comparison)
| Feature | HDMI | DisplayPort |
|---|---|---|
| Primary market | TVs, consoles, home theater | Computer monitors |
| Daisy-chaining | No | Yes (MST — Multi-Stream Transport) |
| Passive cable length | up to 15m | up to 3m (longer with active) |
| Locking | Friction fit | Latching clip on most plugs |
| Licensing | Royalty payment required | Royalty-free |
Scenario: A user wants three daisy-chained monitors from one port. The correct answer is DisplayPort with MST, not HDMI. HDMI requires one cable per display or an MST hub.
USB Connectors
| Type | Shape | Notes |
|---|---|---|
| USB-A | Flat rectangle | Most common host port |
| USB-B | Square | Printers, scanners |
| Mini-USB | Small trapezoid | Legacy cameras |
| Micro-USB | Small flat | Legacy phones |
| USB-C | Oval, reversible | Modern universal, up to 40 Gbps (USB4) |
| Lightning | Apple proprietary 8-pin | Older iPhones/iPads (pre-USB-C) |
USB Speed Standards
| Standard | Marketing Name | Max Speed | Connector |
|---|---|---|---|
| USB 2.0 | Hi-Speed | 480 Mbps | A, B, Mini, Micro |
| USB 3.2 Gen 1 | SuperSpeed | 5 Gbps | A (blue), C |
| USB 3.2 Gen 2 | SuperSpeed+ | 10 Gbps | A, C |
| USB 3.2 Gen 2x2 | SuperSpeed 20Gbps | 20 Gbps | C only |
| USB4 / Thunderbolt 3/4 | USB4 | 40 Gbps | C only |
Exam Tip: USB 3.x USB-A ports are color-coded blue (and the connector tongue is blue). Thunderbolt 3 and 4 use the USB-C connector and add a lightning-bolt icon; they carry 40 Gbps plus DisplayPort and PCIe, so a single port can drive displays, storage, and an external GPU. A common trap: a USB-C port is not automatically Thunderbolt — check for the bolt icon.
What is the maximum cable distance for Cat 6a Ethernet running at 10 Gbps?
A technician needs to drive three monitors daisy-chained from a single port on a workstation. Which connector supports this natively?
Which connector type is used to terminate RG-6 coaxial cable for a cable internet modem?
Match each fiber optic connector to its description:
Match each item on the left with the correct item on the right