The pinout can typically be shown as a table or diagram. While one usage of the word pin is to refer to electrical contacts of, specifically, the male gender, its usage in pinout does not imply gender: the contact-to-function cross-reference for a connector that has only female socket contacts is still called a pinout. Many connectors have multiple standard pinouts in use for different manufacturers or applications. In any multi-pin connector, there are multiple ways to map wires to pins, so different configurations may be created that superficially look identical but function differently. In that case, the order in which different color wires are attached to pins of an electrical connector defines the wiring scheme.

Suppose one has specified wires within a cable (for instance, the colored Ethernet cable wires in ANSI/TIA-568 T568A). Therefore, pinouts are a vital reference when building and testing connectors, cables, and adapters.

If contacts of disparate functions are allowed to make contact, the connection may fail, and damage may result. Each connector contact must mate with the contact on the other connector with the same function. The functions of contacts in electrical connectors, be they power- or signaling-related, must be specified for connectors to be interchangeable. The EIA (Electronic Industries Alliance) now has many sectors reporting to it and sets what is known as EIA standards where all registered pinouts and registered jacks can be found. The RMA started its standardization in 1934, collecting and correlating tube data for registration at what was to become the EIA. 'Pinout' now supersedes the term 'basing diagram' which was the standard terminology used by the manufacturers of vacuum tubes and the RMA. In electronics, a pinout (sometimes written ' pin-out') is a cross-reference between the contacts, or pins, of an electrical connector or electronic component, and their functions.

A pinout diagram of a very common 555 timer integrated circuit showing its eight pins (numbered 1-8) and their corresponding functions ('ground', 'trigger', 'output', etc.)

Lm741 pinout download