Copper Cabling Media, Connectors and Termination
What this domain covers
Copper media, connectors and termination tests category performance, pinouts, installation limits, and the field-test parameters that prove a link will support its intended application.
Media and categories
100-ohm balanced twisted-pair: Cat5e 100 MHz, Cat6 250 MHz, Cat6A 500 MHz, Cat8 2000 MHz for 25/40GBASE-T at 30 m. UTP versus F/UTP and S/FTP: any shield must be bonded to ground at both ends per the design. Conductors are typically 22-24 AWG. T568A and T568B differ only in pairs 2 and 3: T568B puts pair 2 (orange) on pins 1-2 and pair 3 (green) on 3-6; T568A reverses those. Use the same pinout at both ends.
Termination
Keep the jacket inside the jack; untwist no more than 13 mm (0.5 in) for Cat6/6A; maintain pair twists to the IDC; do not over-tighten cable ties. Bend radius is 4x outside diameter installed and 8x during pulling; pull tension is about 25 lbf (110 N) for 4-pair cable. PoE (802.3af/at/bt) adds heat, so bundled cables need derating.
Testing
A field tester reports wire map, length (90 m permanent link, 100 m channel), insertion loss, NEXT, PS-NEXT, ACR-N, ACR-F, return loss, propagation delay, and delay skew. Cat6A also requires alien crosstalk testing.
Worked example
A tester shows correct pin-to-pin continuity but fails NEXT on a Cat6 link. Continuity is not enough: if pair 2 is punched on pins 3/6 and pair 3 on pins 1/2, DC resistance still looks right but the signal sees a split pair. Re-terminate both ends to the same pinout (for example T568B) and retest; swapping only one end cannot fix a split pair.
Traps
Untwisting more than 13 mm; jacket outside the jack; mixing A and B; using Cat5e jacks on Cat6A; lifting shield grounding; assuming a continuity test proves performance; exceeding the 90 m permanent link.