Logical zones grouped by device function for D-307. Physical detection-zone boundaries (Clause 13) are defined on the as-designed drawing.
| Optical Smoke | 13 |
| Zone total | 13 |
| Manual Call Point | 3 |
| Zone total | 3 |
| Visual Alarm Device | 4 |
| Sounder + VAD | 5 |
| Zone total | 9 |
| I/O Interface | 2 |
| Zone total | 2 |