Field telephone
Query URLs
https://term.museum-digital.de/md-de/tag/24446
- Note
- Field telephones replaced flag signals and the telegraph as an efficient means of communication. The first field telephones had a battery to power the voice transmission, a hand-cranked generator to signal another field telephone or a manually-operated telephone exchange, and an electromagnetic ringer which sounded when current from a remote generator arrived. This technology was used from the 1910s to the 1980s. Later the ring signal was operated by a pushbutton or automatically as on domestic telephones. Manual systems are still widely used, and are often compatible with the older equipment.
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