Digital selective calling

A Sailor VHF DSC unit

Digital selective calling (DSC) is a standard for transmitting predefined digital messages via the medium-frequency (MF), high-frequency (HF) and very-high-frequency (VHF) maritime radio systems. It is a core part of the Global Maritime Distress Safety System (GMDSS).[1]

A DSC touch screen control panel showing a (simulated) distress message. This unit made by ICS controls DSC messaging for VHF, MF and HF transceivers
  1. ^ Bréhaut (2009): 35