What are the key characteristics of Unshielded Twisted-Pair (UTP) cable?

UTP has four twisted pairs of color-coded wires in a plastic jacket, no metal shielding, terminated with RJ-45; the twists (not shielding) fight interference.

Unshielded Twisted-Pair (UTP) is the most common networking media — it is what runs from a wall jack or switch port to a computer. Its design is deliberately simple, which is what keeps it cheap. Three structural elements do the work:

1. Outer jacket — protects the copper wires from physical damage.
2. Twisted pairs — the heart of UTP; twisting the two wires of each pair makes their interference cancel, protecting the signal without needing metal shielding.
3. Color-coded plastic insulation — electrically isolates each wire and lets a technician identify which wire belongs to which pair when terminating the cable.

UTP is terminated with RJ-45 connectors and is used to interconnect hosts with intermediary network devices like switches and routers. The key thing to remember is that UTP has no metallic shielding at all — it relies entirely on the twisting for noise cancellation, which is exactly why keeping the twists intact right up to the connector matters so much.

Go deeper:

• Twisted pair — Wikipedia — UTP construction, the role of the twist, and how it improves electromagnetic compatibility.

• 8P8C / RJ-45 modular connector — Wikipedia — the connector UTP is terminated with, including standardization and pinout.