1.5 Compare and contrast transmission media and transceivers
Wired Media
📘CompTIA Network+ (N10-009)
Overview
In networking, cable speed refers to how fast data can travel through a cable. Different cable types support different maximum data transfer rates (bandwidth) and distances.
Understanding cable speeds is important because choosing the right cable type ensures that the network can handle the required data load efficiently.
CompTIA Network+ (N10-009) expects you to know the speed, bandwidth, and distance limitations of the most common wired media types, such as twisted-pair, coaxial, and fiber-optic cables.
1. Twisted-Pair Cable Speeds
Twisted-pair cables are the most common network cables used in Ethernet networks. They contain pairs of copper wires twisted together to reduce interference. There are two main types:
- Unshielded Twisted Pair (UTP)
- Shielded Twisted Pair (STP)
Common Twisted-Pair Categories and Speeds
| Cable Type | Maximum Speed | Maximum Distance | Common Standard Used | Notes |
|---|---|---|---|---|
| Cat 3 | 10 Mbps | 100 meters | 10BASE-T | Outdated; used in early Ethernet networks |
| Cat 5 | 100 Mbps | 100 meters | 100BASE-TX | Obsolete; replaced by Cat 5e |
| Cat 5e (Enhanced) | 1 Gbps (1000 Mbps) | 100 meters | 1000BASE-T | Reduced crosstalk; supports Gigabit Ethernet |
| Cat 6 | 10 Gbps (at up to 55 meters) | 100 meters (1 Gbps) | 10GBASE-T | Tighter twists and better insulation |
| Cat 6a (Augmented) | 10 Gbps | 100 meters | 10GBASE-T | Shielded to reduce interference |
| Cat 7 / 7a | 10 Gbps (and up to 40 Gbps for short runs) | 100 meters | 10GBASE-T / 40GBASE-T (proposed) | Fully shielded; supports high-speed data centers |
| Cat 8 | 25–40 Gbps | 30 meters | 25GBASE-T / 40GBASE-T | Designed for short, high-speed data center connections |
Key Notes for the Exam
- Cat 5e is the minimum standard for modern Ethernet networks.
- Cat 6/6a are commonly used in enterprise networks.
- Cat 8 supports data centers where extremely high-speed connections are needed over short distances.
- All twisted-pair Ethernet cables use RJ-45 connectors.
2. Coaxial Cable Speeds
Coaxial cables have a single copper conductor with insulation and shielding that protect against interference. They are less common in modern LANs but still used in broadband Internet, cable television, and radio frequency (RF) transmissions.
Common Coaxial Cable Types and Speeds
| Cable Type | Impedance | Common Speed/Use | Maximum Distance | Common Use |
|---|---|---|---|---|
| RG-6 | 75 ohms | Up to 1 Gbps (varies by service) | Hundreds of meters | Broadband Internet, TV distribution |
| RG-59 | 75 ohms | Up to 100 Mbps | Short runs | Analog video or CCTV |
| RG-11 | 75 ohms | Up to 1 Gbps | Longer runs (up to 500 m) | Backbone connections in coax systems |
Key Notes for the Exam
- RG-6 is most common in modern networks for broadband connections.
- Coaxial cables are less affected by electromagnetic interference (EMI) due to their shielding.
- Coax cables use BNC, F-type, or N-type connectors, depending on the use case.
3. Fiber-Optic Cable Speeds
Fiber-optic cables transmit data using light signals instead of electrical signals. This allows very high speeds and long distances without interference.
There are two main types:
- Single-Mode Fiber (SMF) — uses a single light path (laser light)
- Multimode Fiber (MMF) — uses multiple light paths (LED light)
Common Fiber-Optic Standards and Speeds
| Fiber Type | Common Standard | Maximum Speed | Maximum Distance | Notes |
|---|---|---|---|---|
| Multimode (OM1) | 1000BASE-SX | 1 Gbps | 275 meters | Older MMF type |
| Multimode (OM2) | 1000BASE-SX | 1 Gbps | 550 meters | Improved over OM1 |
| Multimode (OM3) | 10GBASE-SR | 10 Gbps | 300 meters | Laser-optimized |
| Multimode (OM4) | 40GBASE-SR4 / 100GBASE-SR10 | 40–100 Gbps | 150–400 meters | Common in high-speed networks |
| Multimode (OM5) | 100GBASE-SR4.2 | 100 Gbps | 150 meters | Supports multiple wavelengths (SWDM) |
| Single-Mode (OS1/OS2) | 10GBASE-LR / 40GBASE-LR4 / 100GBASE-LR4 | 10–400 Gbps | Up to 40 km or more | Used for long-distance or backbone connections |
Key Notes for the Exam
- Single-mode fiber is used for long distances (up to kilometers).
- Multimode fiber is used for shorter distances (within buildings or campuses).
- Fiber cables are immune to EMI and crosstalk.
- Common connectors include LC, SC, ST, and MTP/MPO.
4. Summary Table – Cable Speed Comparison
| Media Type | Example Cable | Max Speed | Max Distance | Typical Use |
|---|---|---|---|---|
| Twisted-Pair | Cat 5e | 1 Gbps | 100 m | Standard Ethernet |
| Twisted-Pair | Cat 6a | 10 Gbps | 100 m | High-speed LANs |
| Coaxial | RG-6 | ~1 Gbps | 500+ m | Internet/TV |
| Fiber (MMF) | OM3 | 10 Gbps | 300 m | Data centers |
| Fiber (SMF) | OS2 | 100+ Gbps | 40+ km | Long-distance links |
5. Exam Tips
- Remember “Category = Speed + Distance” for twisted-pair cables.
- Fiber offers highest speed and longest range.
- Coax is still used but mainly for broadband and legacy systems.
- Know connector types (RJ-45 for copper, LC/SC/ST for fiber).
- Always check whether the question refers to speed or distance limits — both are important for cable selection.
Conclusion
Understanding cable speeds helps network technicians design and maintain networks that perform efficiently. For the CompTIA Network+ (N10-009) exam, focus on matching cable categories to their speeds, distances, and appropriate use cases.
These values are frequently tested, especially in scenario-based questions where you need to choose the correct cable for a given network requirement.
