Shielded or unshielded keystone jacks? When to think of protection from EMI?

Shielded vs. Unshielded Keystone Jack Selection Guide

I. Unshielded Jacks (UTP) Applicable Scenarios

● Conventional office environments

Away from elevators/power distribution rooms (no strong interference sources within 30 meters)
Network cables are routed independently (not bundled with power lines)

● Home networks

Ordinary devices such as TVs/computers
Short-distance wiring (within a room ≤ 20 meters)

● Cost-sensitive projects

Prioritize when budget is limited (40% cheaper than shielded)
Advantages: Simple installation, compatible with all unshielded network cables

II. Scenarios Where Shielded Jacks (STP/FTP) are Required

● Industrial environments

Workshops with motors/frequency converters (electrical sparks interfere with network signals)
Network cables parallel to 380V cables (mandatory if distance < 15cm)

● Medical imaging rooms

Around MRI/CT equipment (high-frequency radiation interference)
Life support monitor data transmission lines

● High-risk outdoor areas

Near base station antennas (electromagnetic interference)
Areas prone to thunderstorms (shielding layer can guide induced lightning)
Core function:
The metal shielding layer acts like a "Faraday cage" surrounding the wire core, blocking external electromagnetic interference (EMI)

III. Three Golden Rules of Shielding Systems

● Full shielding:

Network cable + Keystone Jack + RJ45 connector must all be shielded (failure of any one component renders the system ineffective)

● Dual-end grounding:

Grounding the patch panel at the cabinet end
Grounding the switch metal casing at the equipment end

● Anti-oxidation maintenance:

Grounding contacts should be sanded every six months (to prevent rust from causing grounding failure)

IV. Common Pitfalls

V. Simple Interference Detection Methods

● Mobile phone interference test:

Hold the phone close to the network cable during a call → If you hear a "buzzing" sound, interference exists

● Multimeter detection method:

Measure the voltage between the network cable and the ground wire > 1V → Grounding needs to be checked

● Practical stress test:

Ping the gateway while the copier is working → If the packet loss rate exceeds 5%, it needs to be blocked.