compass repeater indicator
1Electrical telegraph — A printing electrical telegraph receiver, and a transmitter key at bottom right An electrical telegraph is a telegraph that uses electrical signals, usually conveyed via telecommunication lines or radio. The electromagnetic telegraph is a device… …
2Automatic Identification System — The Automatic Identification System (AIS) is a system used by ships and Vessel Traffic Services (VTS) principally for identification and locating vessels. AIS provides a means for ships to electronically exchange ship data including:… …
