A+ cables and connectors
Every speed and distance on this sheet is a fair-game question on the CompTIA A+ Core 1 (220-1201) exam, and the cable objectives are pure memorization. Drill the numbers in each table until the "remember" column feels obvious, then use the FAQ to close the classic traps: the Cat 6 55-meter caveat, M.2 versus NVMe, and T568A versus T568B.
Copper network cabling
| Cable | Max speed | Max distance | Remember |
|---|---|---|---|
| Cat 5e | 1 Gbps | 100 m | Minimum grade for gigabit; usually UTP |
| Cat 6 | 10 Gbps | 55 m at 10 Gbps; 100 m at 1 Gbps | The 55 m caveat is the classic exam trap |
| Cat 6a | 10 Gbps | 100 m | Full 100 m at 10 Gbps; shielding optional, not required |
| Cat 8 | 25/40 Gbps | 30 m | Always shielded; data-center switch-to-server runs |
| RG-6 coax | RF broadband (cable TV/internet) | Long runs, low loss | 75-ohm, thicker 18 AWG core; F-type connector |
| RG-59 coax | Analog/baseband video (CCTV) | Short runs only | 75-ohm, thinner 20 AWG; higher loss than RG-6 |
T568A and T568B are RJ45 pin-out standards that swap only the orange and green pairs (pins 1/2 and 3/6). Same standard on both ends = straight-through cable; one of each = crossover. Shielded twisted pair (STP) is an option for any category, but only Cat 8 requires it.
Fiber optic
| Item | What it is | Distance / use | Remember |
|---|---|---|---|
| Single-mode fiber | Tiny 8-10 micron core, laser light source | Kilometers: 10 km typical, up to 40 km+ | Long-haul, campus and WAN links; yellow jacket typical |
| Multimode fiber | Wider 50 or 62.5 micron core, LED/VCSEL source | Up to ~550 m at 1 Gbps; ~300-400 m at 10 Gbps | In-building runs; cheaper optics; orange or aqua jacket |
| LC connector | Small form factor, snap-in latch | Fits SFP/SFP+ transceivers | "Little Connector"; the standard on modern gear |
| SC connector | Square body, push-pull | Patch panels, older equipment | "Stick and Click" mnemonic; square shape |
| ST connector | Round body, bayonet twist-lock | Legacy multimode installs | "Stick and Twist" mnemonic; twist like BNC |
Video cables
| Interface | Signal | Max capability | Remember |
|---|---|---|---|
| VGA (DE-15) | Analog only | No hard cap; degrades with length and resolution | 15 pins in 3 rows; the only analog-only interface here; no audio |
| DVI-D | Digital only | Single-link 1920x1200@60; dual-link 2560x1600@60 | Dual-link adds center pins for more bandwidth |
| DVI-I | Digital + analog | Same digital limits as DVI-D | The 4 pins around the flat blade carry analog; passive VGA adapters work |
| HDMI | Digital video + audio | HDMI 2.0: 18 Gbps, 4K60; HDMI 2.1: 48 Gbps, 4K120/8K60 | 19-pin; mini and micro variants exist; consumer default |
| DisplayPort | Digital video + audio | DP 1.4: 32.4 Gbps; DP 2.x: up to 80 Gbps | Locking connector; daisy-chaining via MST; USB-C Alt Mode carries it |
USB and Lightning
| Standard / connector | Speed | Cable / power | Remember |
|---|---|---|---|
| USB 2.0 (Hi-Speed) | 480 Mbps | 5 m max cable; 500 mA / 2.5 W | Low-speed 1.5 Mbps and full-speed 12 Mbps also live under 2.0 |
| USB 3.2 Gen 1 | 5 Gbps | ~3 m practical; 900 mA / 4.5 W | Formerly USB 3.0 / SuperSpeed; blue Type-A ports |
| USB 3.2 Gen 2 | 10 Gbps | ~1 m practical | Formerly USB 3.1; SuperSpeed+ |
| USB 3.2 Gen 2x2 | 20 Gbps | USB-C only | Two 10 Gbps lanes; needs USB-C on both ends |
| USB4 | 20/40 Gbps; USB4 v2: 80 Gbps | USB-C only | Thunderbolt 3 compatible |
| Connectors | Type-A: flat host port; Type-B: square, printers; mini/micro-B: legacy portables | USB-C: reversible, does data + video + power | USB-C is a connector shape, not a speed |
| USB Power Delivery | Power, not data | Up to 100 W (20 V/5 A); PD 3.1 EPR up to 240 W (48 V/5 A) | Negotiated over USB-C; above 60 W requires a 5 A e-marked cable |
| Lightning | USB 2.0 speeds on most devices | Apple proprietary 8-pin, reversible | Legacy but still on the exam; iPhones moved to USB-C starting with iPhone 15 (2023) |
Without Power Delivery, a plain USB-C port supplies up to 15 W (5 V/3 A). Port colors (blue, teal, red) hint at speed but are not guaranteed by the spec.
Storage and internal
| Interface | Speed | Connector | Remember |
|---|---|---|---|
| SATA III | 6 Gbps (~600 MB/s effective) | 7-pin data + 15-pin power, L-shaped keying | Revisions: SATA I 1.5 Gbps, II 3 Gbps, III 6 Gbps; data cable max 1 m |
| M.2 | Depends on the bus underneath | Edge slot; B, M, or B+M key; sizes like 2280 (22 mm x 80 mm) | A form factor, not a protocol; an M.2 drive can be SATA or NVMe |
| NVMe | PCIe 3.0 x4 ~3.5 GB/s; 4.0 x4 ~7 GB/s; 5.0 x4 ~14 GB/s | Usually M.2 M-key; also U.2 and add-in cards | A protocol over PCIe lanes; far faster than any SATA SSD |
| M.2 keys | B key: SATA or PCIe x2; M key: PCIe x4 (NVMe) | B+M keyed drives fit both slots | Key notches physically prevent wrong-slot installs |
| Molex | Power only | 4-pin peripheral: +5 V red, +12 V yellow, black grounds | Legacy power for fans, optical drives, older HDDs |
Reading a sheet is recognition; the exam tests recall. The fastest way to make this stick is answering questions that use it.
Common questions
How far can Cat 6 run at 10 Gbps?
Only about 55 meters, versus the usual 100-meter Ethernet limit, because of crosstalk at 10GBASE-T frequencies. If a scenario needs 10 Gbps over a full 100 meters, the answer is Cat 6a. This distance downgrade is one of the most repeated cable questions on Core 1.
What is the difference between M.2 and NVMe?
M.2 is a physical form factor (the small gum-stick slot); NVMe is a storage protocol that runs over PCIe lanes. An M.2 slot can host either a SATA drive capped at 6 Gbps or an NVMe drive running several times faster. On the exam, match the words: form factor questions want M.2, speed/protocol questions want NVMe.
What is the difference between T568A and T568B?
They are two RJ45 pin-out standards that differ only in swapping the orange and green wire pairs (pins 1/2 and 3/6). Terminating both ends the same way makes a straight-through cable; using A on one end and B on the other makes a crossover. Modern switches auto-negotiate with auto-MDIX, so crossover cables matter mostly on legacy gear and exams.
Is Lightning still on the A+ exam in 2026?
Yes. The 220-1201 objectives still list Lightning as a connector type, even though Apple moved iPhones to USB-C starting with the iPhone 15 in 2023. Know it as Apple's proprietary reversible 8-pin connector that typically runs at USB 2.0 speeds.
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