Assertion: quindar tone | /r/HasProperty | necessary
Facets:
value: no longer
type: TEMPORAL
value: with modern digital communication systems
type: OTHER
Source sentences:
text: With modern digital communication systems, Quindar tones are no longer necessary because a single communication line (such as a fiber optic cable) can simultaneously carry multiple communication channels in the form of data comprising both speech and signaling (the PTT signal), as well as video and telemetry.[citation needed]