Digital Selective Calling Communications

The Coast Guard has begun offering a new MF/HF radiotelephone service to mariners as part of the new Global Maritime Distress and Safety System. This new service, called digital selective calling (DSC), will allow mariners to instantly send an automatically formatted distress alert to the Coast Guard or other rescue authority anywhere in the world. Digital selective calling will also allow mariners to initiate or receive distress, urgency, safety and routine radiotelephone calls to or from any similarly equipped vessel or shore station, without requiring either party to be near a radio loudspeaker. DSC acts like the dial and bell of a telephone, allowing you to " direct dial" and " ring" other radios, or allow others to " ring" you, without having to listen to a speaker. New VHF and HF radiotelephones have or soon will have DSC capability.

On February 1, 1999, the Safety of Life at Sea (SOLAS) Convention, a treaty document, will require all passenger ships and most other ships 300 grt and larger on international voyages, including all cargo ships, to carry DSC- equipped radios. Ships will be allowed to turn off their 2182 kHz radio listening watch on that date, and their VHF channel 16 listening watch on February 1, 2005.

It will not be possible to initiate radio Communications with these vessels outside the U.S. territorial limit without DSC-capable radios after these listening watches are suspended. These ships, however, will still be required to keep watch on the VHF bridge-to-bridge voice channel 13, and the U.S. Coast Guard plans to require these ships to continue their channel 16 watch within U.S. territorial waters, at least until VHF DSC facilities can be established on shore.

Because of the safety problems that lack of communications interoperability would cause between SOLAS-regulated vessels (mostly cargo ships) and other vessels (recreational boaters, commercial fishing vessels, etc.), the Coast Guard petitioned the Federal Communications Commission in 1992 to require all marine radios made or sold in the U.S. have a DSC capability. The Coast Guard also asked the Radio Technical Commission for Maritime Services (RTCM), a non-profit standards organization, to develop a standard which would allow incorporation of DSC in a marine radio without affecting the low-end market price of that radio. The FCC solicited comments on that petition in 1992 and 1993, and prepared a Notice of Proposed Rulemaking on that and other maritime radiocommunications matters in early 1994. The FCC requested comments concerning that rulemaking from May to November 1995. On 27 June 1997, the FCC adopted a Report and Order requiring radios type accepted on or after 17 June 1999 to include this minimum DSC capability.