11 Digital Selective Calling Facility
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Resolutions - Assembly - IMO Resolution A.803(19) Performance Standards for Shipborne VHF Radio Installations Capable of Voice Communication and Digital Selective Calling (Adopted on 23 November 1995) - Annex - Recommendation on Performance Standards for Shipborne VHF Radio Installations Capable of Voice Communication and Digital Selective Calling - 11 Digital Selective Calling Facility

11 Digital Selective Calling Facility

  11.1 The facility should conform to the provisions of the relevant ITU-R Recommendations pertaining to the DSC system.footnote

  11.2 The DSC facility should comprise:

  • .1 means to decode and encode DSC messages;

  • .2 means necessary for composing the DSC message;

  • .3 means to verify the prepared message before it is transmitted;

  • .4 means to display the information contained in a received call in plain language;

  • .5 facilities to automatically update the ship's position and the time at which the position was determined from a suitable electronic position-fixing aid which may be an integral part of the equipment. For equipment which does not have an integral position-fixing aid, such facilities should include a suitable interface conforming to the appropriate international standard;footnote

  • .6 means for manual entry of position information and the time at which the position was determined; and

  • .7 means to activate an alarm when no position data is received from the electronic position-fixing aid or, in the case of manual input, the position information is over 4 hours old. Any position information not updated for more than 23 hours should be erased.

  11.3 Distress message storage

  • 11.3.1 If the received messages are not printed immediately, sufficient capacity should be provided to enable at least 20 received distress messages to be stored in the DSC facility.

  • 11.3.2 These messages should be stored until readout and should be erased 48 hours after their reception.

  11.4 It should be possible to initiate and make distress and safety calls from the position from which the ship is normally navigated. The means for initiating a distress alert should be as prescribed in 2.6 to 2.8.

  11.5 Initiation of DSC distress calls should supersede any other operation of the facility.

  11.6 Self-identification data should be stored in the DSC unit. It should not be possible for the user easily to change these data.

  11.7 Means should be provided to enable routine testing of the DSC facilities without radiation of signals.

  11.8 Provision should be made for:

  • .1 a specific aural alarm and visual indication to indicate receipt of a distress or urgency call or a call having distress category. It should not be possible to disable this alarm and indication. Provision should be made to ensure that they can be reset only manually; and

  • .2 aural alarms and visual indication for calls other than distress and urgency.


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