2.3 - Network cabling and connectors
CompTIA A+ Core 1 objective 2.3 covers network cabling and how it is terminated. Cat6a copper cabling is rated to reliably carry 10 Gbps over a short run, above older Cat5e and Cat6. Power over Ethernet (PoE) lets a single Ethernet cable both carry data and power a device such as an IP camera. A typical straight-through Ethernet patch cable uses the T568B wiring standard on both ends; mixing standards makes a crossover cable. You should also recognise fiber where longer distances or immunity to interference are needed. Expect scenario questions that describe a speed, a powered device or a wiring task and ask which cable category, standard or termination is correct. Category equals maximum speed and distance, so the fastest short-run copper answer is usually Cat6a.
10 Gbps short run = Cat6a. Data + power on one cable = PoE. Straight-through patch = T568B both ends (mismatched = crossover). Long distance / no interference = fiber.
Practice questions
1. Which copper cabling is rated to reliably carry 10 Gbps over a short run?
- Cat3
- Cat5
- Cat6a (correct answer)
- Coaxial RG-59
Cat6a supports 10GBASE-T to 100 m. Cat5 tops out at ~100 Mbps/1 Gbps; Cat3 is legacy phone-grade.
2. Which technology lets a single Ethernet cable power a device like an IP camera or access point?
- NAT (network address translation)
- A VLAN configuration
- PoE (Power over Ethernet) (correct answer)
- A DHCP scope
PoE delivers power and data over one Ethernet cable, simplifying APs, cameras and phones.
3. Which wiring standard pair is used to make a typical straight-through Ethernet patch cable?
- T568A on one end, T568B on the other
- T568B on both ends (correct answer)
- Different on every pin
- No standard
Straight-through cables use the SAME standard (usually T568B) on both ends. A crossover mixes A/B (legacy).
4. Which 802.11 standard operates ONLY on 5 GHz?
- 802.11n (dual)
- 802.11ac (Wi-Fi 5) (correct answer)
- 802.11g (2.4)
- 802.11b (2.4)
802.11ac (Wi-Fi 5) is 5 GHz only. n is dual-band; b/g are 2.4 GHz; ax (Wi-Fi 6/6E) is 2.4/5/6 GHz.
5. Which wireless tech is used for contactless access badges at very short range?
- Wi-Fi
- RFID/NFC (correct answer)
- Satellite
- Bluetooth Classic
RFID (and NFC) power passive tags/badges at very short range for access control and tap interactions.
6. Which Bluetooth feature reduces power use for wearables and sensors?
- Classic Bluetooth
- Bluetooth Low Energy (BLE) (correct answer)
- Peer-to-peer Wi-Fi Direct
- Passive RFID tags
BLE (Bluetooth Low Energy) is optimized for low-power devices like fitness bands, beacons and IoT sensors.