| Clue | Source | Date |
|---|---|---|
| A talk likewise about radio telephones (6,7) | ||
| Handheld radios | ||
| Devices for "over"-hearing? | Universal | 05 Feb 2023 |
| 'Copy' machines? | New York Times | 14 Jan 2023 |
| They copy everything useful for speaking on the wireless? | Irish Times Crosaire | 28 Jul 2018 |
| Staples of old police work | ||
| G. I. communication sets. |