VHF DSC Class of controller

[lockswell1]

Does anyone know a source which sets out the requirements for each of the different classes of DSC controller. Class D which is for most of us cannot acknowledge a distress call. Class A on the other hand can and can also send a DSC relay. Is there somewhere where the requirements of each of the classes is laid out say in a table form.

 

[BrendanS]

Class A:
All DSC options provided. Required on MF/HF and VHF radios used by SOLAS-regulated ships. Class A includes polling and vessel tracking, data, and numerous other functions in addition to voice.

Class B:
Required on VHF and MF radios used by SOLAS-regulated ships, though most such radios in fact meet Class A. Class B required capabilities include:

Distress call
All-ships call
Individual station call
Semi-automatic/automatic service call
Use of distress, urgency, safety and routine priorities
Nature of distress
Distress coordinates
Time for last (distress) position update
Type of subsequent communications
Distress relay
Distress acknowledgment
Test call (for MF/HF only)
Radio frequency or channel
Display
Receive geographical area calls
Alarm
Optional means for canceling a distress alert

Class C:

Only capable of transmitting a distress alert. No longer recognized by the ITU or FCC. CAUTION: The U.S. Coast Guard does NOT recommend purchase or use of a radio having this class of DSC.

Class D:
Minimum DSC capability for VHF marine radios carried by recreational boaters, commercial fishing vessels, and other non-SOLAS regulated vessels. Class D required capabilities include:

Distress call
All-ships call
Individual station call
Use of distress, urgency, safety and routine priorities
Nature of distress
Distress coordinates
Time for last (distress) position update
Type of subsequent communications
Radio VHF channel
Display
Receive distress relay and distress acknowledgment calls
Alarm

Class E:
Minimum DSC capability for HF marine radios carried by recreational boaters, commercial fishing vessels, and other non-SOLAS regulated vessels. Class E required capabilities include:

Distress call
All-ships call
Individual station call
Use of distress, urgency, safety and routine priorities
Nature of distress
Distress coordinates
Time for last (distress) position update
Type of subsequent communications
Radio channel or frequency
Display
Receive distress relay and distress acknowledgment calls
Alarm

Class F: (Class F has been discontinued by ITU and is not recognized by the FCC) VHF. Similar to Class D, but cannot make an individual or routine call, and does not require a display. Voice calls default to channel 16. Not recommended for use in U.S. on other types of radios. Class F required capabilities include:

Distress call
All-ships call
Use of distress, urgency, and safety priorities
Distress coordinates
Time for last (distress) position update
Receive acknowledgment of its own distress calls

Class G: (Class G has been discontinued by ITU and is not recognized by the FCC)
Similar to Class F, but applies to MF/HF. Voice calls default to 2182 kHz. Not recommended for use in U.S. Class G required capabilities include:

Distress call
All-ships call
Use of distress, urgency, and safety priorities
Distress coordinates
Time for last (distress) position update
Receive acknowledgment of its own distress calls

RTCM SC101
RTCM Recommended Minimum Standard for DSC, Version 1.0, 10 Aug 1995, RTCM Paper 56-95/SC101-STD. Applies to VHF and to MF/HF. This standard, which is recognized by the FCC but is not generally recognized outside of the U.S., should be soon replaced by ITU Class D and E. SC101 required capabilities include:

Distress call
All-ships call
Individual station call
Use of distress and routine priorities
Use of safety priority (MF/HF only)
Distress coordinates
Time for last (distress) position update
Acknowledgment or unable to comply response
Receive distress relay and distress acknowledgment calls
Receive Geographical area calls
Test call (MF/HF only)
Alarm

ITU-R Rec. M.825-3:
DSC transponder system for Vessel Traffic Services or ship- to-ship interrogation and identification. Rec. M.825 is superceded by the Universal Shipborne Automatic Identification System.

ITU-R Rec. M.821:
Optional expansion to DSC protocol. Perhaps the most important M.821 expansion, which soon will be incorporated in all new DSC-equipped radios, improves the accuracy of distress position from 1 mile to the accuracy of your interconnected GPS receiver (about 13 meters).

 

[lockswell1]

BrendanS
Thanks for your reply it is most useful. I am trying to fill in a few gaps in my knowledge and your reply will help. I had come across some VHF discusions which were dated last year concerning training and the volume of distress alerts. which brought the Forum to my attention.

 

[BrendanS]

I've tried myself to find a table of comparison, but if there is one, it's well hidden.