pinout

thumb|A pinout diagram of a very common 555 timer IC|555 timer integrated circuit showing its eight pins (numbered 1-8) and their corresponding functions ("ground", "trigger", "output", etc.) 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. "Pinout" now supersedes the term "basing diagram" which was the standard terminology used by the manufacturers of vacuum tubes and the Radio Manufacturers Association (RMA). The RMA started its standardization in 1934, collecting and correlating tube data for registration at what was to become the Electronic Industries Alliance (EIA), which 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.

== Purpose == The functions of contacts in electrical connectors, be they power- or signaling-related, must be specified for connectors to be interchangeable. Each connector contact must mate with the contact on the other connector with the same function. If contacts of disparate functions are allowed to make contact, the connection may fail, and damage may result. Therefore, pinouts are a vital reference when building and testing connectors, cables, and adapters.