Pinout
Mapping of the physical contacts of an electronic component
- 2 min read
- 4 chapters
Related on Lably
Through Electronics
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.
Suppose one has specified wires within a cable (for instance, the colored Ethernet cable wires in ANSI/TIA-568 T568A). In that case, the order in which different color wires are attached to pins of an electrical connector defines the wiring scheme. 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. Pinouts define these configurations. Many connectors have multiple standard pinouts in use for different manufacturers or applications.
Sign in to keep reading
3 more chapters are free with a Lably account.
Terminology
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.
Representation
The pinout can typically be shown as a table or diagram. However, it is necessary to clarify how to view the diagram, stating if it shows the backside of the connector (where wires are attached) or the "mating face" of the connector. Published pinouts, which are particularly important when different manufacturers want to interconnect their products using open standards, are typically provided by the connector or equipment manufacturer. However, some pinouts are provided by 3rd parties since the manufacturer does not well document some connectors.
While repairing electronic devices, an electronics technician uses electronic test equipment to "pin out" each component on a PCB. The technician probes each pin of the component in turn, comparing the expected signal on each pin to the actual signal on that pin.
Example pinouts
USB pinout
Viewed from the front (outside) of Female Type A USB receptacle:
- +5V (Red)
- −Data (White)
- +Data (Green)
- GND (Black)