| Clue | Source | Date |
|---|---|---|
| Features of landlines but not cellphones | Wall Street Journal | 06 Apr 2024 |
| Evidence of one's hang-ups? | New York Times | 10 Dec 2022 |
| Phone sounds | Thomas Joseph | 08 Sep 2022 |
| Telephone sounds | Premier Sunday | 14 Aug 2022 |
| Sounds heard on landlines | Universal | 14 May 2022 |
| Phone sounds | Wall Street Journal | 19 May 2020 |
| Sounds not heard on cellphones | The Washington Post Sunday | 13 Oct 2019 |
| Sounds from receivers | Wall Street Journal | 13 Sep 2018 |
| Sounds from receivers | ||
| Sounds after hang-ups | Premier Sunday | 20 Nov 2016 |
| Land line signals | LA Times Daily | 26 Nov 2015 |
| Land line signals | ||
| Availability indicators | ||
| Connection indicators | ||
| Phone sounds | ||
| Cell phones' lack | ||
| Phone sounds | ||
| Call preceders | ||
| Cells don't have them | ||
| Cells don't have them | ||
| Phone go-aheads | ||
| Surfing needs, perhaps | ||
| Signals from cells? | ||
| Phone sounds | ||
| Telephone sounds. | ||
| Familiar sounds. |