| Clue | Source | Date |
|---|---|---|
| Phone system connection | Newsday | 12 May 2019 |
| Private phone connection | The Washington Post | 17 Jun 2017 |
| Private phone connection | LA Times Daily | 17 Jun 2017 |
| Private phone connection | ||
| Private phone channel between offices | ||
| Private link | ||
| Private link | ||
| Private telephone channel | ||
| Phone-system connection | ||
| Phone channel | ||
| Phone channel | ||
| Private phone channel between offices | ||
| Phone link | ||
| Phone-system connection | ||
| Phone feature | ||
| Telecomunications link | ||
| Surveying aid | ||
| Type of telephone hookup. | ||
| Surveyor's string. |