Assertion: speaker's sound | /r/CapableOf | travel in one direction
Facets:
value: at a time
type: TEMPORAL
Source sentences:
text: Half-duplex speakerphones only allow sound to travel in one direction at a time, either: 1) into the speakerphone from the telephone line and out of its internal speaker to its user, or 2) from its user, into the microphone, and out through the telephone line.