47 CFR 80.359 - Frequencies for digital selective calling (DSC).
(a) General purpose calling. The following table describes the calling frequencies for use by authorized ship and coast stations for general purpose DSC. There are three series of paried frequencies. One series is for worldwide use; the other two series are for regional use. The “Series A” designation includes coast stations along, and ship stations in, the Atlantic Ocean, the Gulf of Mexico, and the Caribbean Sea. The “Series B” designation includes stations in any remaining areas. Stations must initiate contact on the appropriate regional frequency depending upon the location of the called station and propagation conditions. Acknowledgement is made on the paired frequency. The worldwide frequencies may be used for international calling, if calls on the appropriate regional frequencies are unsuccessful, or the regional series does not contain the appropriate band (e.g., 2 MHz). During normal working hours, all public coast stations capable of DSC operations must monitor the worldwide and regional frequencies appropriate for its location. The specific frequencies to be monitored will vary with propagation conditions.
General Purpose DSC
[In kHz unless otherwise noted]
|Worldwide||Series A||Series B|
|2 156.525||2 156.525|
1 The frequency 2177.0 kHzs is also available to ship stations for intership calling and acknowledgement of such calls only.
(b) Distress and safety calling. The frequencies 2187.5 kHz, 4207.5 kHz, 6312.0 kHz, 8414.5 kHz, 12577.0 kHz, 16804.5 kHz and 156.525 MHz may be used for DSC by coast and ship stations on a simplex basis for distress and safety purposes, and may also be used for routine ship-to-ship communications provided that priority is accorded to distress and safety communications. The provisions and procedures for distress and safety calling are contained in ITU-R M.541-9 (incorporated by reference, see § 80.7), and § 80.103(c).
(c) Working frequencies. Coast and ship stations may use DSC techniques for general calling purposes on their assigned working frequencies in the 2000-27500 kHz band and on those frequencies in the 156-162 MHz band which are allocated for maritime control, commercial, non-commercial and public correspondence communications.