Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Components (hierarchy name)
4. components (objects parts)
5. [components by specific context]
6. [tool and equipment components]
7. computer components
8. [data connectors]

Anotations

Scope note:

Modems that connect to telephone systems and convert digital data into sound signals, which are then transmitted through telephone lines. Historically, for acoustic couplers to connect to telephone systems, telephone handsets would rest in soundproof enclosures which have loudspeakers and microphones that are close to the earpieces and mouthpieces of the phone handsets.