heliographs
Sun-flash communication devices
Heliographs are devices that use mirrors to flash sunlight as a signaling method, transmitting messages in Morse code or similar systems across long distances.
Before radio, militaries relied on heliographs for battlefield communication: The scouts sent heliographs from the ridge.
The verb means to signal by this method.
A heliograph is also an early type of photograph made using sunlight exposure.
Symbolic communication system
- flashBrief burst of light
- semaphoreFlag-based signaling system
- visualOf or concerning sight
- distressSevere anxiety or suffering
sos · alert · beacon · message · transmission · relay · dispatch · encode
code
Symbolic communication system
distress · sos · alert · beacon · message · transmission · relay · dispatch · encode · decode
mirror
Reflective viewing surface
beam · flash · portable · tripod · lens · aperture · sighting · alignment · surveying · military
military
Armed forces collectively
colonial · Victorian · surveying · exploration · cavalry · outpost · campaign · battlefield · desert · mountain
heliographsradio transmitters
Devices emitting wireless signals
telephones · telephone lines · underwater cables · fiber optics · messengers