"คุณต้องใช้สาย Ethernet แบบชีลด์" — เมื่อไหร่ถึงจะสำคัญจริงๆ

## The Myth

Shielded (STP/FTP) Ethernet cable is always better than unshielded (UTP).

## The Reality

For most homes and offices, **unshielded Cat6/Cat6a is fine**.

## When You DO Need Shielding

- Running cable parallel to power lines (within 30cm)
- Industrial environments with heavy electromagnetic interference
- 10 Gbps runs over 55m+ (Cat6a STP recommended)
- Data centers and server rooms

## When Shielding HURTS

Improperly grounded shielded cable is **worse** than unshielded because:
- The shield becomes an antenna for interference
- Ground loops between devices cause noise
- You need shielded jacks, patch panels, and proper grounding throughout

## Recommendation

- **Home/Office**: Cat6a UTP (unshielded) — sufficient for 10 Gbps
- **Near power cables**: Cat6a F/UTP (foil shield, simpler grounding)
- **Industrial/Datacenter**: Cat6a S/FTP with proper grounding