Cabling
Keystone Jack
The termination module behind a wall plate or patch panel port — the component an RJ45 plug connects into, with the cable punched down on the back side.
When you plug an Ethernet cable into a wall outlet, the RJ45 jack you're plugging into is a keystone jack mounted in a wall plate. On the back, individual wires are punched down onto the connector's IDC (insulation displacement contacts) — a termination method that pierces the wire insulation to make contact without stripping.
Keystone jacks snap into standard cutouts in wall plates and patch panels. This modular system means you can swap out a single port without replacing the whole panel — useful when a jack gets damaged or when upgrading from Cat6 to Cat6a.
Key considerations when selecting keystone jacks:
Category matching — the jack must match or exceed the cable category. A Cat5e jack on Cat6a cable is a Cat5e installation, regardless of the cable spec.
Tool vs toolless — traditional punch-down requires a punch-down tool. Toolless keystone jacks (common in newer installations) terminate via a lever or cap that seats the wires without special tooling, speeding up large patch panel builds.
Shielding — for shielded cable runs, shielded keystone jacks maintain the shielding continuity through the termination point. Mixing shielded cable with unshielded jacks breaks the shield and introduces noise.