Copper Cable Issues: Pinouts, Ports, Opens, Shorts (Vocabulary)

Vocabulary flashcards covering copper cable issues such as incorrect pinouts, bad ports, opens, and shorts, plus testing tools and procedures.

Patch panel

A termination point with a punch-down block for cable terminations; commonly uses the TIA-568-B pinout and features a back with color-to-pin mappings.

TIA-568-B pinout

The wiring standard for Ethernet: pins 1–8 are 1 white/orange, 2 orange, 3 white/green, 4 blue, 5 white/blue, 6 green, 7 white/brown, 8 brown.

Keystone wall jack

A wall-mounted RJ-45 jack (keystone) with eight pins arranged in two sides; labeled pins 1–8 or color-coded to show location.

RJ-45 connector

Eight-pin modular plug used for Ethernet; pins are counted 1–8 from left to right when the clip faces downward, and wires follow the color sequence for the chosen standard.

Pinout verification

The process of visually inspecting the patch panel, wall jack, or RJ-45 end to ensure correct wire-to-pin color mapping.

Cable tester / wire mapping tool

Devices used to test end-to-end wiring to confirm that each wire is properly connected from one end to the other.

Open (cable test result)

A fault indicating no continuity at one end or a break in the conductors, meaning the circuit is disconnected.

Short (cable test result)

A fault where two wires are unintentionally connected, causing a short across pins and typically indicating poor construction or damage.

Bad port

A faulty Ethernet port on a NIC, switch, or router; diagnosed with loopback tests and software, then replaced or re-routed.

Loopback plug

A plug used to test a network port by sending signals back to the port for verification of proper operation.

NIC (Network Interface Card)

Hardware that provides network connectivity to a device; can be onboard or expansion card and may need replacement if faulty.

Re-termination / repunching

Restriping and punching wires again into a patch panel, wall jack, or replacing an RJ-45 to correct pinouts.

Replacement RJ-45 connector

Replacing the RJ-45 plug on a cable when the connector is damaged or incorrectly terminated.

Testing flow for fault isolation

Test the patch cable first; if good, test the patch panel or wall jack; use loopback and testers to identify faulty segments and ports.