1. What Are Network Cables?
Network cables serve as the physical pathways for data transmission between devices like computers, routers, and switches. Cable selection depends on speed, distance, immunity to interference, and cost.
2. Cable Types
2.1 Coaxial Cable
Consists of a copper core, insulating layer, braided shield, and outer jacket (e.g., PVC or FEP with plenum rating). Types include:
- Thinnet (10Base2): RG-58, 5mm diameter, requires 50Ω terminators
- Thicknet (10Base5): RG-8, legacy cable no longer used
- Modern Use: RG-59 and RG-6 for cable TV and modems
Pros: Resistant to EMI/RFI interference
Cons: Obsolete for modern Ethernet networks
2.2 Twisted-Pair Cable
Consists of insulated wire pairs twisted to reduce crosstalk. Types include:
- UTP: Most common, affordable, flexible
- STP: Shielded for reduced interference, less used
UTP Categories:
- Cat 1: Voice only
- Cat 3: 10Mbps Ethernet (obsolete)
- Cat 5e: 1000BaseT, 100MHz
- Cat 6: 250MHz, ideal for vertical cabling
- Cat 6A: 500MHz, supports 10G up to 100m
- Cat 7/8: 10G+ Ethernet for short distances
2.3 Fiber-Optic Cable
Uses light pulses instead of electricity. Core surrounded by cladding and protective layers (Kevlar, PVC).
- SMF: Long distances (up to 40km), single light beam
- MMF: Short range (up to ~900m), multiple beams
Pros: Immune to EMI/RFI, secure, fast
Cons: Expensive, difficult installation
2.4 Twinaxial Cable
Used in short-range, high-speed data centers like 10G Ethernet. More affordable than fiber.
3. Connectors
- RJ-45: Ethernet (8 wires)
- RJ-11: Telephony (4 wires)
- RJ-48c: Shielded version for T1 WAN connections
- ST, SC, LC, MT-RJ: Fiber connectors
- APC vs UPC: APC has angled polish for lower reflection
4. Cabling Standards
Define how wires are arranged in connectors:
- T568A/T568B: Ethernet standards differing in pair order
- Straight-Through: Same standard both ends (host to switch)
- Crossover: Different standards (host to host)
- Rollover: Console port (e.g., Cisco devices)
- T1 Crossover: Swap pairs 1/2 and 4/5
5. Cable Distribution Equipment
- MDF: Main distribution frame for WAN and phone lines
- IDF: Floor-level flexible distribution
- Block 66: Legacy phone wiring
- Block 110: Modern RJ-45/RJ-11 terminations
- BIX Block: Ends up to 25 wire pairs
- Demarc: Boundary between provider and private network
- Smart Jack: Network interface device for signal testing
6. Media Converters
Convert signal between different cable types:
- SMF ↔ Ethernet
- MMF ↔ Ethernet
- Fiber ↔ Coaxial
- SMF ↔ MMF
7. Cable Features
| Type | Speed | Distance | Noise Immunity |
|---|
| Cat 5e | 1 Gbps | 100 meters | Medium |
| Cat 6A | 10 Gbps | 100 meters | High |
| SMF Fiber | 40 Gbps | Up to 40 km | Very High |
8. Conclusion
Choosing the right cable and adhering to cabling standards is critical to reliable network performance. UTP cables serve LANs, fiber optics ensure high-speed long-distance connectivity, and coaxial cables fulfill niche roles in data centers. Understanding cable architecture and deployment tools builds the foundation for efficient network infrastructure.
