- Emergency Radio
Station to Officer CommunicationThe telegraph allowed communicating from the patrolling police officer to the police station. The telegraph keys were placed into ‘Call Boxes'. The boxes were first developed as fire alarm boxes in 1852.
The box contained a telegraph that could send a location code to the nearest fire station. The message was sent by breaking a seal and then pulling a lever. The police started to use similar boxes in 1870. The police box allowed reporting different crimes by turning a dial to point a specific crime and then pull the lever.
- Wikipedia – Police
- WikiPedia – James Hudson (inventor)
- LAPD – history 1926 – 1950
- IEEE Milestones – One-way Police Radio Communication
- IEEE Milestones – Two-Way Police Radio Communication
- IEEE Milestones – FM Police Radio Communication
- Virtual Museum of the City of San Francisco – Mayor’s Emergency Telephone System