| Clue | Source | Date |
|---|---|---|
| HS setups for broadcasting messages to all classrooms | ||
| Lines of communication in schools? | New York Times | 29 May 2021 |
| Computer networks used by one's father? | The Washington Post Sunday | 17 Nov 2019 |
| They're often talked over | USA Today | 28 Jun 2015 |
| They're often talked over | ||
| Sales might be advertised on them | ||
| Sales might be advertised on them | ||
| Elec. announcement facilitators |