You receive a Routine DSC call to your vessel, without specifying an alternate working voice frequency & emission. Your transceiver frequency display reads: 2177 kHz transmit 2177 kHz receive. What must you do?

Correct Answer: Option D — Call other vessel on 2182.0 kHz and shift to a proper working frequency.

When a DSC call lacks a specified working frequency, the calling station expects a voice response on the international distress and calling frequency, 2182 kHz. Once contact is established on 2182 kHz, both stations must immediately shift to a non-distress working frequency to comply with ITU watchkeeping regulations.