Pairkabels

Pairkabels, or twisted pair cables, are a category of copper cabling used for voice and data transmission. They consist of two or more insulated conductors twisted together to reduce electromagnetic interference and crosstalk. The twisting enables differential signaling, which improves noise rejection and allows reliable communication over comparatively inexpensive copper conductors. Pairkabels are widely used in telephone networks, local area networks, and many building interconnect applications.

There are two main types: unshielded twisted pair (UTP) and shielded twisted pair (STP or FTP). UTP is common in everyday networking for its flexibility and cost, while shielded variants provide additional protection against external interference, useful in industrial or high-electromagnetic environments. Cables are manufactured in several standardized categories that define performance, shielding, and physical characteristics. The most familiar are Cat5, Cat5e, Cat6, Cat6a, Cat7, and Cat8. Higher categories support higher frequencies, greater data rates, and improved crosstalk mitigation. Conductor gauges are typically around 24 AWG, with shielding and jacket materials varying by category and application.

Performance and limits: The nominal impedance of most pairkabels used for Ethernet is about 100 ohms. Cat5e supports up to 1 Gbps, Cat6 up to 10 Gbps over short distances, Cat6a up to 10 Gbps across 100 meters, and Cat8 targets high-speed data center applications with very high frequencies over shorter runs. The standard maximum length for copper Ethernet segments is 100 meters.

Connectors and usage: RJ-45 connectors are common for Ethernet; shielded variants may require proper grounding. Pairkabels remain a foundational option for cost-effective, flexible, and scalable networking and telecommunications infrastructure.