- Emergency alarms (13)
- Burglar alarm apparatus, electric (3)
- Fire alarm apparatus, electric (1)
- Metal detectors (4)
- Sirens, electric: vehicle, marine, industrial, and air raid (2)
- Smoke detectors (1)
- Transportation signaling devices (10)
- Pedestrian traffic control equipment (2)
- Signaling apparatus, electric (2)
- Traffic signals, electric (7)
- Intercommunication systems, electric (8)
- Visual communication systems (8)
