3.2 Summarize basic cable types and their connectors, features, and purposes
📘CompTIA A+ Core 1 (220-1201)
Network cables are used to connect computers, servers, switches, routers, and other network devices so that data can move from one device to another.
For the A+ exam, you must understand types of network cables, their features, and their purposes.
Network cables are mainly divided into:
- Copper cables
- Optical (fiber) cables
1. Copper Network Cables
Copper cables send data using electrical signals. They are commonly used in local area networks (LANs) such as offices, schools, and data centers.
A. Twisted Pair Copper Cables
Twisted pair cables contain pairs of copper wires twisted together.
The twisting helps reduce electrical interference.
There are two main types:
- Unshielded Twisted Pair (UTP)
- Shielded Twisted Pair (STP)
1. Unshielded Twisted Pair (UTP)
UTP is the most common network cable used today.
Key Features:
- No extra shielding around the wire pairs
- Lightweight and flexible
- Low cost
- Easy to install and terminate
- Uses RJ-45 connectors
Common Uses in IT:
- Connecting computers to switches
- Office Ethernet networks
- Home and small business networks
Exam Tip:
If the exam asks for the most commonly used Ethernet cable, the answer is UTP.
2. Shielded Twisted Pair (STP)
STP cables include metal shielding around the wire pairs or the entire cable.
Key Features:
- Extra protection against electromagnetic interference (EMI)
- Thicker and less flexible than UTP
- More expensive than UTP
- Requires proper grounding
Common Uses in IT:
- Networks near heavy electrical equipment
- Data centers with high interference
Exam Tip:
Choose STP when interference protection is required.
B. Copper Cable Categories (Ethernet Categories)
Ethernet cables are grouped into categories based on speed and performance.
| Category | Maximum Speed | Common Use |
|---|---|---|
| Cat 5 | 100 Mbps | Older networks |
| Cat 5e | 1 Gbps | Standard Ethernet |
| Cat 6 | 1–10 Gbps | High-speed networks |
| Cat 6a | 10 Gbps | Data centers |
| Cat 7 | 10+ Gbps | Shielded environments |
Exam Focus:
- Cat 5e and Cat 6 are the most important for the A+ exam
- Higher category = better speed and less interference
C. T568A and T568B Wiring Standards
T568A and T568B are RJ-45 pinout standards used to arrange the wire colors inside Ethernet cables.
Key Points:
- Both standards work the same
- The difference is the order of wire colors
- Both ends of a cable must use the same standard
T568A:
- Often used in government or older installations
T568B:
- Most common in commercial networks
Exam Tip:
Using T568A on one end and T568B on the other creates a crossover cable.
D. Direct Burial Copper Cables
Direct burial cables are designed to be installed underground without conduit.
Key Features:
- Thick protective jacket
- Resistant to moisture and soil
- Often shielded
Common Uses in IT:
- Connecting buildings on the same campus
- Outdoor network links
Exam Tip:
If a cable is placed underground, the correct choice is direct burial cable.
E. Coaxial Cable
Coaxial cable has:
- A central copper conductor
- Insulation layer
- Metal shielding
- Outer protective jacket
Key Features:
- Strong shielding against interference
- Thicker than twisted pair cables
Common Uses in IT:
- Cable internet connections
- Modems
- Older Ethernet networks (legacy)
Exam Tip:
Coaxial is not commonly used for modern Ethernet, but still appears on the exam.
F. Plenum-Rated Cables
Plenum-rated cables are designed for plenum spaces (air-handling areas above ceilings or below floors).
Key Features:
- Fire-resistant jacket
- Produces low smoke
- Safer for indoor air circulation
- More expensive than standard cables
Common Uses in IT:
- Office ceilings
- Air ventilation spaces
Exam Tip:
If a cable runs through air spaces, choose plenum-rated cable.
2. Optical (Fiber-Optic) Network Cables
Fiber-optic cables send data using light instead of electricity.
General Features:
- Very high speed
- Long-distance transmission
- Immune to electromagnetic interference
- More expensive than copper
- Requires special equipment
A. Single-Mode Fiber (SMF)
Single-mode fiber uses a very small core and a single light path.
Key Features:
- Extremely long distances
- Highest speed and performance
- Uses laser light
- Higher cost
Common Uses in IT:
- Internet service provider (ISP) networks
- Long-distance building connections
- Backbone networks
Exam Tip:
Choose single-mode for long-distance communication.
B. Multimode Fiber (MMF)
Multimode fiber has a larger core and allows multiple light paths.
Key Features:
- Shorter distance than single-mode
- Less expensive than single-mode
- Uses LED or laser light
Common Uses in IT:
- Data centers
- Server rooms
- Short-distance high-speed networks
Exam Tip:
Choose multimode for short-range, high-speed connections.
Exam Summary – Key Points to Remember
- UTP is the most common Ethernet cable
- STP provides extra interference protection
- Cat 5e and Cat 6 are important categories
- T568A and T568B are wiring standards
- Plenum-rated cables are required in air-handling spaces
- Direct burial cables are used underground
- Coaxial is mostly legacy but still tested
- Fiber-optic cables use light, not electricity
- Single-mode = long distance
- Multimode = short distance
