| Clue | Source | Date |
|---|---|---|
| What zero bars on a cellphone indicates | New York Times | 04 Apr 2017 |
| What zero bars on a cellphone indicates | ||
| What zero bars means on a cellphone | New York Times | 27 Sep 2015 |
| What zero bars means on a cellphone | ||
| See 49-Across | ||
| See 28-Across | ||
| iPhone error message |