This specification defines the Audio Codec ‘97 (AC ‘97) Architecture and Digital Interface (AC-link) specifically designed for implementing audio and modem I/O functionality in mainstream PC systems. This specification does not explicitly define the companion AC ‘97 Digital Controller component (sometimes referred to or abbreviat ed as DC ‘97), which typically varies in features and implementation, but is AC ‘97 compliant with this specification. ed as DC ‘97), which typically varies in features and implementation, but is AC ‘97 compliant with this specification.