(link to articles that go into more detail.)
A '''plug-compatible''' machine is one that has been designed to be [[backwards compatible]] with a prior machine. In particular, a new [[computer system]] that is plug-compatible has not only the same connectors and protocol interfaces to peripherals, but also runs the same
The term may also be used to define replacement criteria for other components available from multiple sources. For example, a plug-compatible cooling fan may need to have not only the same physical size and shape, but also similar capability, run from the same voltage, use similar power, attach with a standard electrical connector, and have similar mounting arrangements. Some non-conforming units may be re-packaged or modified to meet plug-compatible requirements, as where an adapter plate is provided for mounting, or a different tool and instructions are supplied for installation, and these modifications would be reflected in the [[bill of materials]] for such components. Similar issues arise for computer system interfaces when competitors wish to offer an easy upgrade path.
[[Category:Classes of computers]]