🌐EnglishEnglishEspañolFrançaisРусскийالعربية中文日本語EntityQ3556577· pop 7· linked from 1,068 articleshydraulic telegraphSemaphore systems using water-based mechanismsConnectionshydraulicsEntityUnited KingdomCountryCategoriesAncient Greek military equipmentAncient Greek military terminologyAncient Greek technologyCommunications in GreeceHistory of telecommunicationsOptical communicationsSemaphoreTelegraphy