Within SEA AREA A1, which VHF DSC frequency is used for data transmissions?

Within SEA AREA A1, which VHF DSC frequency is used for data transmissions?

• A. 156.525 MHz (Channel 70 Data)
• B. 156.8 MHz (Audible Alarm)
• C. 2187.5 kHz (Data)
• D. 2182 kHz (Audible Alarm)

Answer: (A)

VHF DSC data transmissions in SEA AREA A1 are carried on a dedicated data channel at 156.525 MHz, known as Channel 70 Data. This channel is reserved for digital selective calling, allowing automatic, text-like calls that identify the requesting and target MMSIs without voice. The other options aren’t used for VHF data in this area: 156.8 MHz (Channel 16) is the safety voice/hailing channel, not a data channel; and the 2187.5 kHz and 2182 kHz frequencies are MF bands used for DSC data and audible alarm/distress on MF, not the VHF data channel used in Area A1.

VHF DSC data transmissions in SEA AREA A1 are carried on a dedicated data channel at 156.525 MHz, known as Channel 70 Data. This channel is reserved for digital selective calling, allowing automatic, text-like calls that identify the requesting and target MMSIs without voice. The other options aren’t used for VHF data in this area: 156.8 MHz (Channel 16) is the safety voice/hailing channel, not a data channel; and the 2187.5 kHz and 2182 kHz frequencies are MF bands used for DSC data and audible alarm/distress on MF, not the VHF data channel used in Area A1.