Peripheral cables are the physical links between a PC and the devices around it, your keyboard, phone, printer, external drive, or even a network switch in a closet. For the CompTIA A+ 220-1201 Objective 3.2, you’re expected to recognize common cable types on sight and match them to real support tasks.
The exam also cares about the practical details: connector shapes, basic speed tiers, power limits, and what still works when you mix old and new hardware. Cable naming can be messy, especially with USB versions, so this guide keeps the focus on fast, test-ready differences across four cable families: USB 2.0, USB 3.x (often labeled as USB 3.0, 3.1, or 3.2), Serial (RS-232), and Thunderbolt.
USB 2.0 vs USB 3.x: what changes, what stays the same
USB is the default cable family for peripherals, but it has two exam traps. First, connectors and speeds aren’t the same thing. Second, USB version names are confusing, even in product listings. CompTIA may refer to “USB 3.0” broadly, but questions often test what you can infer from the speed rating and the port marking.
At a high level, USB 2.0 tops out at 480 Mbps, which is fine for low-bandwidth devices. USB 3.x jumps into multi-gigabit speeds and usually supports more available power, which matters for portable drives and docks. Most USB generations keep backward compatibility, but that doesn’t mean you always get full speed.
Here is the quick comparison that usually matches exam expectations:
| USB standard (common exam wording) | Max theoretical speed | Common port cues | Typical use |
|---|---|---|---|
| USB 2.0 | 480 Mbps | Often black or unmarked Type-A | Mouse, keyboard, basic printer, older flash drive |
| USB 3.0 (USB 3.1 Gen 1) | 5 Gbps | Blue Type-A, “SS” logo | External HDD/SSD, fast flash drives |
| USB 3.1 Gen 2 | 10 Gbps | “SS 10” or similar marking | External SSDs, higher-end docks |
| USB 3.2 (2x2) | Up to 20 Gbps | Markings vary, cable matters | Very fast external storage |
A key test habit: treat marketing names as hints, then anchor your answer on the Gbps number and whether the port and cable are “SuperSpeed” rated.
USB 2.0 basics you must recognize on sight
USB 2.0 is easy to underestimate because it still shows up everywhere. You should recognize these connector shapes quickly:
- Type-A: the flat, rectangular plug used on PCs, chargers, and many hubs.
- Type-B: the squarish plug found on many older printers and some scanners.
- Mini-USB: common on older cameras and MP3 players.
- Micro-USB: common on older Android phones and small accessories.
USB 2.0 supports a maximum theoretical data rate of 480 Mbps. In a support setting, that points to basic peripherals where latency and bandwidth are low: keyboards, mice, simple headsets, and older printers. It can also handle flash drives, but large file copies will feel slow.
Cables and hubs also matter at this level. USB 2.0 has practical length limits, so long runs often fail or become unstable. When a user needs more ports, a USB hub extends connectivity, but a bus-powered hub can run short on power with multiple devices. That often explains “it connects but keeps disconnecting” tickets.
Backward compatibility is simple: plug a USB 2.0 device into a USB 3.x port and it will work, but it will run at USB 2.0 speeds.
USB 3.x quick rules: faster data, more power, same familiar plugs
USB 3.x raises throughput and usually improves power delivery, while keeping many familiar connector shapes. The most common visual cue is a blue Type-A port or an SS (SuperSpeed) logo near the port.