When to Use Each Cable Type
- Straight-Through (Droit): Used to connect devices of different types. This is the standard cable for most applications.
- PC / Laptop ↔︎ Switch / Hub
- Router ↔︎ Switch / Hub
- Server ↔︎ Switch
- Crossover (Croisé): Used to connect devices of the same type directly to each other without a switch.
- PC ↔︎ PC
- Switch ↔︎ Switch (on older models without Auto-MDIX)
- Router ↔︎ PC (for direct configuration)
Note on Auto-MDIX: Most modern network devices support Auto-MDIX, which automatically detects the cable type and adjusts accordingly. On these devices, you can use a straight-through cable even where a crossover is traditionally required. However, knowing the difference is still crucial for older hardware and for network certification exams.
Ethernet Cable Categories Explained
The "Cat" number refers to the cable's performance specifications, primarily its maximum speed and bandwidth.
| Category | Max Speed | Max Bandwidth | Notes |
|---|---|---|---|
| Cat 5e | 1 Gbps | 100 MHz | Enhanced version of Cat 5. Minimum for modern networks. |
| Cat 6 | 10 Gbps (up to 55 m) | 250 MHz | Tighter winding, often includes a spline. Good for new installations. |
| Cat 6a | 10 Gbps (up to 100 m) | 500 MHz | "Augmented" Cat 6. Better shielding against crosstalk. |
| Cat 7 | 10 Gbps | 600 MHz | Requires extensive shielding (S/FTP) and special connectors (GG45). Not common. |
| Cat 8 | 25/40 Gbps (up to 30 m) | 2000 MHz | For high-speed data-center applications. |