| 100% | LEETSPEAK | 9 | Communication system that 15 57Y11Z3D 11K3 7H15 |
| 40% | WIRELESS | 8 | Communication system that uses radio signals |
| 40% | ASL | 3 | Communication system that uses hands: Abbr. |
| 40% | ASL | 3 | Communication system that uses hand signals (Abbr.) |
| 40% | ASL | 3 | Communication system that includes fingerspelling, for short |
| 39% | ASL | 3 | Communication system that doesn't involve speaking: Abbr. |
| 33% | NATO | 4 | With 115-Across, communication system that's a hint to the answer to each starred clue |
| 30% | MORSE | 5 | ___ code (communication system that uses dots and dashes) |
| 29% | RADIO | 5 | Communication system |
| 27% | TELEX | 5 | Communication system of old |
| 27% | SPRINKLER | 9 | System that waters lawn |
| 27% | USENET | 6 | System that popularized ''FAQ'' |
| 27% | JOBROTATION | 11 | System that varies tasks* |
| 27% | OLFACTORY | 9 | System that controls smell |
| 27% | LANGUAGE | 8 | Communication system, e.g. Yoruba |
| 27% | LAN | 3 | System that connects computers: Abbr. |
| 27% | SPRINKLER | 9 | System that waters plants automatically |
| 27% | TSARISM | 7 | System that collapsed in 1917 |
| 27% | TSARISM | 7 | System that ended in 1917 |
| 27% | TELEGRAPH | 9 | Old communication system |
| 27% | SNAPCHAT | 8 | Disappearing communication system? |
| 27% | INTRANET | 8 | Companywide communication system |
| 27% | INTERCOM | 8 | Internal communications system |
| 26% | ASL | 3 | Communication system for the deaf: Abbr. |
| 26% | ASL | 3 | Communication system with hand motions (Abbr.) |
| 26% | ASL | 3 | Communication system with hand gestures: Abbr. |
| 26% | ASL | 3 | Communication system with hand signals: Abbr. |
| 26% | ASL | 3 | Communication system used at Gallaudet U |
| 26% | ASL | 3 | Communication system for Deaf people: Abbr. |
| 26% | PHONETREE | 9 | Communication system structured like a pyramid |