Telegraph

The engine-order telegraph (EOT) is the bridge-to-engine-room device by which the officer of the watch orders engine speed and direction (Full Ahead, Slow Astern, Stop, Stand By). The bridge handle moves a pointer on a matching dial in the engine room, where the engineer acknowledges by setting a reply pointer to the same order. Early units were mechanical chain-and-sprocket or electric; modern ships use electronic EOTs integrated with direct bridge control. All orders are logged in the engine-room movement book and bell book.