Which VHF channel is used only for digital selective calling

• A. Channel 70
• B. Channel 16
• C. Channel 13
• D. Channel 9

Answer: (A)

Digital selective calling relies on a channel that is reserved exclusively for DSC signals. That channel is Channel 70, and it is not used for voice communications. When you place a DSC call on this channel, the message carries data such as the vessel’s MMSI and the type of call (distress, urgency, safety, or routine). If the called station acknowledges, you then switch to a voice channel to carry on the conversation. Other channels mentioned are used for voice communications or non-DSC purposes, such as Channel 16 for distress and calling by voice, Channel 13 for ship-to-ship safety communications, and Channel 9 as a general voice hailing channel in some regions. So Channel 70 is the DSC-only channel.