SIST EN 300 338-2 V1.5.1:2020

Final draft ETSI EN 300 338-2 V1.5.1 (2020-03)

EUROPEAN STANDARD
Technical characteristics and methods of measurement
for equipment for generation, transmission
and reception of Digital Selective Calling (DSC)
in the maritime MF, MF/HF and/or VHF mobile service;
Part 2: Class A DSC
2 Final draft ETSI EN 300 338-2 V1.5.1 (2020-03)

Reference
REN/ERM-TGMAR-593
Keywords
DSC, GMDSS, maritime, radio
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: +33 4 92 94 42 00  Fax: +33 4 93 65 47 16

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

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ETSI
3 Final draft ETSI EN 300 338-2 V1.5.1 (2020-03)
Contents
Intellectual Property Rights . 6
Foreword . 6
Modal verbs terminology . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 7
3 Definition of terms, symbols and abbreviations . 8
3.1 Terms . 8
3.2 Symbols . 10
3.3 Abbreviations . 10
4 Controls and Indicators in Class A DSC Equipment . 10
4.1 Visual indication . 10
5 Technical requirements . 11
5.1 Facilities for DSC transmission and reception . 11
5.1.1 Multi-frequency distress alert attempts and watch receiver capabilities (MF/HF) . 11
5.1.2 Watch receiver capabilities (VHF) . 11
5.2 Remote alarms . 11
5.3 Galvanic isolation . 11
5.4 Manuals . 11
6 Automated and Non-Automated Procedure Requirements in Class A DSC Equipment . 11
6.1 Introduction . 11
6.2 Non-automated features . 12
6.2.0 General . 12
6.2.1 DSC Message Composition . 12
6.2.2 Transmission of DSC messages and prioritized wait . 13
6.2.3 Alarms . 14
6.3 Standby . 14
6.4 Sending distress automated procedure . 15
6.4.1 Procedure . 15
6.4.2 Tasks . 17
6.4.3 Display . 17
6.4.3.0 General Display Requirements . 17
6.4.3.1 Examples of sending distress procedure displays on VHF equipment . 18
6.4.4 Dedicated distress button sub procedure . 19
6.4.5 Transmission of the alert attempt . 20
6.4.6 Updating position . 20
6.4.7 Handling received DSC Messages . 20
6.4.8 Alarms . 20
6.4.9 Determining Subsequent communications . 21
6.4.10 Automated tuning . 21
6.4.11 Cancelling the Distress Alert . 21
6.4.11.0 General Requirements . 21
6.4.11.1 Examples of cancel-distress displays on VHF equipment. 22
6.4.12 Acknowledgments . 23
6.4.13 Termination. 23
6.4.14 Warnings . 23
6.5 Receiving distress automated procedure . 23
6.5.1 Procedure . 23
6.5.2 Tasks . 25
6.5.3 Display . 25
6.5.3.0 General Display Requirements . 25
6.5.3.1 Examples of received distress procedure displays on VHF equipment . 26
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4 Final draft ETSI EN 300 338-2 V1.5.1 (2020-03)
6.5.4 Handling received DSC Messages . 27
6.5.5 Alarms . 27
6.5.6 Determining Subsequent communications . 27
6.5.7 Automated tuning . 27
6.5.8 Acknowledgments . 28
6.5.9 Sending Relays and Acknowledgments . 28
6.5.10 Termination. 28
6.5.11 Warnings . 28
6.5.12 Handling events from man overboard devices (VHF only) . 29
6.5.12.1 General . 29
6.5.12.2 Display and tasks . 29
6.5.12.3 Handling received DSC messages pertinent to the procedure . 30
6.6 Sending non-distress automated procedure . 30
6.6.1 Procedure . 30
6.6.2 Tasks . 31
6.6.3 Display . 32
6.6.3.0 General Display Requirements . 32
6.6.3.1 Examples of sending non-distress procedures displays on VHF equipment . 33
6.6.4 Handling received DSC Messages . 33
6.6.5 Alarms . 33
6.6.6 Automated tuning . 33
6.6.7 Delayed Acknowledgements . 34
6.6.8 Termination. 34
6.6.9 Warnings . 34
6.7 Receiving non-distress automated procedure . 34
6.7.1 Procedure . 34
6.7.2 Tasks . 36
6.7.3 Display . 36
6.7.3.0 General Display Requirements . 36
6.7.3.1 Examples of receiving non-distress procedures displays on VHF equipment . 37
6.7.4 Handling received DSC messages . 38
6.7.5 Alarms . 38
6.7.6 Automated tuning . 38
6.7.7 Acknowledgments . 38
6.7.8 Termination. 39
6.7.9 Warnings . 39
6.8 Communications automated procedure . 39
6.8.1 Procedure . 39
6.8.2 Tasks . 39
6.8.3 Display . 40
6.8.4 Handling received DSC Messages . 40
6.8.5 Tuning of the general receiver and transmitter . 40
6.8.6 Termination. 40
6.9 Multiple automated procedures and parallel event handling . 40
6.9.1 Procedure . 40
6.9.2 Tasks . 40
6.9.3 Examples of multiple procedure screens . 41
Annex A (normative): DSC Message Composition . 43
A.1 Default values . 43
A.2 The default DROBOSE . 44
A.3 Allowable non-distress DSC message parameters . 44
Annex B (normative): Radius-Centre point conversion and rounding algorithm . 45
B.1 Radius-centre point conversion . 45
B.2 Rounding . 46
B.3 Special cases for either form of area data entry . 46
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5 Final draft ETSI EN 300 338-2 V1.5.1 (2020-03)
Annex C (normative): Automated Non-Distress Channel/Frequency Selection Algorithm . 47
C.0 General . 47
C.1 VHF . 47
C.2 HF . 47
Annex D (normative): Alarms . 48
D.1 Alarm specifications . 48
D.2 Alarming with critical errors . 49
D.3 Default alarm sounds . 49
D.4 Other alarm sounds . 50
History . 51

ETSI
6 Final draft ETSI EN 300 338-2 V1.5.1 (2020-03)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This final draft European Standard (EN) has been produced by ETSI Technical Committee Electromagnetic
compatibility and Radio spectrum Matters (ERM), and is now submitted for the Vote phase of the ETSI standards EN
Approval Procedure.
The present document is part 2 of a multi-part deliverable. Full details of the entire series can be found in part 1 [i.1].
The present document covers the operator interfaces and operating system for Class A DSC equipment.

Proposed national transposition dates
Date of latest announcement of this EN (doa): 3 months after ETSI publication
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 6 months after doa
Date of withdrawal of any conflicting National Standard (dow): 18 months after doa

Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI
7 Final draft ETSI EN 300 338-2 V1.5.1 (2020-03)
1 Scope
The present document states the minimum requirements for equipment to be used for generation, transmission and
reception of Class A Digital Selective Calling (DSC) for use on board ships.
DSC is intended to be used in the Medium Frequency (MF), High Frequency (HF) and Very High Frequency (VHF)
bands of the Maritime Mobile Service (MMS), for both distress, safety and general communications.
The present document is part 2 of a multi-part deliverable that covers the requirements to be fulfilled by equipment that
is either integrated with a transmitter and/or a receiver or equipment that is a stand-alone DSC terminal and has the
following class of DSC:
• Class A: includes all the facilities defined in annex 1 of Recommendation ITU-R M.493-15 [3] and complies
with the IMO Global Maritime Distress and Safety System (GMDSS) carriage requirements for MF/HF
installations and/or VHF installations.
These requirements include the relevant provisions of the ITU Radio Regulations [2] and Recommendation
ITU-R RM.493-15 [3], the International Convention for the Safety Of Life At Sea (SOLAS) [1], and the relevant
resolutions of the International Maritime Organization (IMO) [4].
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://docbox.etsi.org/Reference/.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are necessary for the application of the present document.
[1] International Convention for the Safety of Life at Sea (SOLAS), 1974.
[2] ITU Radio Regulations (2016).
[3] Recommendation ITU-R M.493-15 (01/2019): "Digital selective-calling system for use in the
maritime mobile service".
[4] IMO resolution MSC.97(73), section 14.6.4: "Adoption of the International Code of Safety for
High-Speed Craft, 2000 (2000 HSC Code)".
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
ETSI
8 Final draft ETSI EN 300 338-2 V1.5.1 (2020-03)
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI EN 300 338-1: "Technical characteristics and methods of measurement for equipment for
generation, transmission and reception of Digital Selective Calling (DSC) in the maritime MF,
MF/HF and/or VHF mobile service; Part 1: Common requirements".
[i.2] MSC 302(87): "Adoption of performance standards for bridge alert management".
[i.3] IEC 61924-2 (Edition 1): "Maritime navigation and radiocommunication equipment and systems --
integrated navigation systems -- Part 2: Modular structure for INS -- operational and performance
requirements, methods of testing and required test results" (including IEC 61924-2 Corrigendum 1
November 2013).
[i.4] ETSI EN 300 338-6: "Technical characteristics and methods of measurement for equipment for
generation, transmission and reception of Digital Selective Calling (DSC) in the maritime MF,
MF/HF and/or VHF mobile service; Part 6: Class M DSC".
[i.5] Recommendation ITU-R M.541-10: "Operational procedures for the use of digital selective-calling
equipment in the maritime mobile service".
[i.6] Recommendation ITU-R M.585-8: "Assignment and use of identities in the maritime mobile
service".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the terms given in ETSI EN 300 338-1 [i.1] and the following apply:
acknowledged: when the objective of the initial DSC message has been achieved
active: automated procedure which has control of the general receiver and transmitter and is thus able to engage in
subsequent communications and receive DSC messages on both the watch receiver and general receiver
automated procedure: set of actions necessary to complete the objective of an initiating DSC message or non DSC
communication event
NOTE 1: Four DSC automated procedures are designed to process these. They are the receiving of distress DSC
messages, the receiving of non-distress DSC messages, the sending of distress DSC alert attempts and the
sending of non-distress DSC messages. In addition a fifth procedure is designed to handle non DSC
communication events.
NOTE 2: These automated procedures are called:
 Received distress automated procedure.
 Sending distress automated procedure.
 Received non-distress automated procedure.
 Sending non-distress automated procedure.
 Communications automated procedure.
closed loop operation: MOB devices supporting closed loop can be programmed to transmit either an individual
distress relay call (subsequent communication 126) to a vessel or group distress relay call to a group of vessels as
described in Recommendation ITU-R M.493-15 [3]
NOTE: Acknowledgement of these calls is possible.
default: value selected or an action taken by the equipment software in the absence of any operator input
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9 Final draft ETSI EN 300 338-2 V1.5.1 (2020-03)
distress DSC message: DSC message or acknowledgement containing the distress information
distress event: unique distress situation identified by two (VHF) or three (MF/HF) parameters of the distress
information; the MMSI of the vessel in distress and the nature of distress and on MF/HF the mode of subsequent
communication
engaged: equipment that is busy handling an automated procedure
factory default: default value that is set by the manufacturer such that the field or behaviour is defined prior to any
operator intervention
general receiver: receiver part of the transceiver used for the reception of all subsequent communications and on HF
the reception of DSC acknowledgements on the duplex DSC channels
NOTE: It is important to distinguish this unit from the watch receiver.
information characters: set of symbols in a DSC message that contains the items of interest for the recipient and is
used to compute the ECC symbol that terminates the message
NOTE: These symbols are repeated in the DX/RX time diversity pattern.
initial DSC message: DSC message that starts an automated procedure
non-distress DSC message: DSC messages or acknowledgments that do not have the format specifier or category of
"distress"
objective: intent of the DSC message either to establish subsequent communications or request information
on hold: automated procedure which does not have access to the transmitter and general receiver and therefore cannot
engage in subsequent communications and is only able to receive DSC messages on the watch receiver
open loop operation: MOB device is in a state where it transmits distress alerts (Recommendation
ITU-R M.493-15 [3])
operator options: any choices the operator can make while the automated procedure is engaged
parallel event handling: background process of handling a received DSC message that is not pertinent to the active
automated procedure
pertinent to the automated procedure: DSC messages that have something to do with the procedure and are therefore
"handled" by the procedure
NOTE: A DSC message is pertinent to an automated procedure if the set of information characters in the DSC
message has the correct values.
pertinent to the station: any DSC message that would start an automated procedure if the transceiver were in standby
self-terminating alarm: short alarm that stops by itself without operator intervention
NOTE: The purpose of this alarm is to inform the operator that a DSC message is received but it does not require
his immediate attention.
symbol (as part of the DSC sentence): term used to describe the 7 binary bits of a 10 bit DSC word that have the
information content
toggle (between automated procedures): ability to make one automated procedure active assuring that all other
procedures go on hold
top level: items, buttons, or functions are present and visible without requiring any action by the operator
NOTE: Such as scrolling, opening up menus, or removing any obscuring covers, etc.
two-tone alarm: alarm consisting of a repetition of the 2 200 Hz frequency for 250 ms followed by a 1 300 Hz
frequency for 250 ms
NOTE: This alarm is used for the initiation of the received distress DSC automated procedure.
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10 Final draft ETSI EN 300 338-2 V1.5.1 (2020-03)
urgency alarm: alarm consisting of a repetition of the 2 200 Hz frequency for 250 ms followed by 250 ms period of
silence
NOTE: This alarm is used for the initiation of the received non-distress DSC automated procedure when the
category of the initiating DSC message is "urgency".
watch receiver: separate receiver in DSC radios that continuously monitors the DSC distress frequencies on MF/HF,
2 187,5 kHz on MF, and channel 70 on VHF
NOTE: On MF/HF it is sometimes referred to as the scanning receiver.
word (as part of the DSC sentence): 10 binary bits that make up the coded entities of a transmitted DSC message
NOTE: The 10 bits consist of a 7 bit "symbol" that gives the information content and 3 bit error check that gives
the number of 0 binary bits in the 7 bit symbol.
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the abbreviations given in ETSI EN 300 338-1 [i.1] and the following apply:
ALE Automatic Linking Exchange
DROBOSE Distress Relay On Behalf Of Someone Else
MOB Man Over Board
NBDP Narrow Band Direct Printing
4 Controls and Indicators in Class A DSC Equipment
4.1 Visual indication
Any visual display of the information content shall be clearly legible under all ambient light conditions.
The display shall be large enough to hold enough information from the active procedure to safely guide the operator
through operator options in any engaged DSC procedure (distress or non-distress). It shall at any time hold information
on how to instantly recall any waiting procedure, or put any active procedure on hold.
The amount of information to display simultaneously on the display shall correspond to the information that can be
written in plain text with a minimum of 160 characters, each character having a minimum height of 3,5 mm, and a
nominal character width/height ratio of 0,7.
Where logic flows and procedural guidance, expressed by graphical symbols, have an advantage over text, this shall be
allowed. Any graphical symbols shall be clearly defined in the operation manual.
All DSC displays at all operating positions shall comply with these requirements.
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11 Final draft ETSI EN 300 338-2 V1.5.1 (2020-03)
5 Technical requirements
5.1 Facilities for DSC transmission and reception
5.1.1 Multi-frequency distress alert attempts and watch receiver
capabilities (MF/HF)
The equipment shall either:
• be capable of receiving DSC messages on all distress frequencies (except for the transmit frequency in use)
whilst the distress alert is being transmitted; or
• be able to complete the multi-frequency distress alert attempt within 1 minute and then be capable of receiving
DSC messages on all frequencies used in that multi-frequency attempt.
5.1.2 Watch receiver capabilities (VHF)
The watchkeeping receiver part of the DSC equipment shall be designed for continuous operation on channel 70 but the
receiver need not operate when the transmitter is in use on that channel.
5.2 Remote alarms
The equipment shall be provided with facilities for connecting remote alarms as recommended in chapter IV/6.6,
regulation X/3 of the SOLAS Convention [1] and IMO resolution MSC.97 (73), section 14.6.4 [4].
5.3 Galvanic isolation
No exposed metallic part of the equipment shall cause any terminal of the source of electrical energy to be earthed.
5.4 Manuals
Maintenance or service manuals shall be available and shall contain:
• If the equipment is so constructed that fault diagnosis and repair is practicable down to component level, the
maintenance instructions shall include full circuit diagrams, component layouts and components parts lists.
• If the equipment contains modules in which fault diagnosis and repair down to component level is not
practicable, the maintenance instructions shall contain sufficient information to enable localization and
replacement of the defective module.
6 Automated and Non-Automated Procedure
Requirements in Class A DSC Equipment
6.1 Introduction
This clause covers the minimum level of software automation, operational simplicity, and interface consistency
requirements for shipborne fixed installations using class A Digital Selective Calling equipment as specified in
Recommendation ITU-R M.493-15 [3], annexes 1, 3 and 4.
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12 Final draft ETSI EN 300 338-2 V1.5.1 (2020-03)
Perhaps the most important issue concerns an implied expectation for the use of the terminology "automated procedure"
as used in the present document to appear in the user interface. The terminology "automated procedure" describes the
set of algorithms that are used to encapsulate all the activities necessary to perform multitasking, DSC, and non DSC
communication events. The operator does not need to know anything about the existence of automated procedures in
order to operate a radio that makes use of these algorithms. Though the present document refers to items such as the
"Sending Distress Automated Procedure" such language shall not appear on the user interface of the equipment.
The primary purpose of DSC signalling is to provide the means to set-up subsequent communications between vessels
and/or coast stations. A call may be considered as being the total duration from the start of the DSC signalling until the
end of the subsequent communications, and the automated procedure is terminated.
The operational functionality described in this part has the objective of not disturbing any ongoing call. Furthermore,
the equipment shall assist the operator by providing simple audible indication of a received DSC call whilst the
equipment is engaged, and provide a facility to manage activation amongst initiated automated procedures.
6.2 Non-automated features
6.2.0 General
This clause describes the features of the equipment that are necessary to assure compliance to the ITU-R DSC
functionality standards and support a smoother operation of the automation algorithms, but are not directly related to the
automation algorithms.
6.2.1 DSC Message Composition
The equipment shall provide factory default values for all non-distress DSC messages as specified in Recommendation
ITU-R M.493-15 [3], annex 3 and summarized in figure A.1 for all parameters where the operator has the option to
select or enter more than one value and has not already done so.
The default values for the Distress Relay On Behalf Of Someone Else (DROBOSE) shall be as given in table A.1.
The default values for the operator-composed distress alert shall be the default distress alert as specified in the sent
distress automated procedure.
A destination MMSI that does not have at least 9 digits entered is invalid.
The MMSI "unknown" indicator shall only be able to be used for the MMSI of the vessel in distress when composing a
DROBOSE.
No DSC message shall be able to be sent that has an invalid parameter.
For simplicity of the user interface:
a) the DSC message composition interface shall be such that the operator needs no user manual to initiate the
desired DSC message;
b) it shall require a maximum of two keystrokes, button pushes or menu actions plus the entry or selection of a
destination MMSI and working channel (where appropriate) for the operator to send the default (routine
individual) DSC message from standby;
c) parameter descriptions and terms shall be provided in plain language;
d) all parameters of the DSC message that do not require an operator choice shall be entered automatically;
e) guidance and/or prompting shall be provided for the entry of any necessary parameters of the DSC message if
these parameters and/or their values are not plainly visible from context or on the display.
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13 Final draft ETSI EN 300 338-2 V1.5.1 (2020-03)
For data entry:
a) the equipment shall only allow the operator to compose and send DSC messages that are compliant with the
latest version of Recommendation ITU-R M.493-15 [3];
b) acknowledgements shall be automatically composed by the equipment and user options for these
acknowledgements are provided by the automated procedures;
c) the equipment shall provide the operator with the choice of specifying the geographic area parameters as either
a circle of radius "r" about a centre point or the traditional latitude-longitude Mercator box and northwest
corner point or about a centre point;
d) the equipment shall convert and round the radius-centre point entry according to the algorithm given in
annex B;
e) the equipment shall provide an automatic determination of the channel and or frequencies of subsequent
communication according to the algorithm given in Recommendation ITU-R M.493-15 [3], annex 3 and
summarized in annex C.
The automated channel selection shall be able to be overridden.
It shall not be possible to select a distress channel for subsequent communications for DSC messages of priority routine.
The equipment shall automatically set the dot pattern length to 20 bits for all transmitted DSC messages on VHF, and
on MF/HF all DSC messages addressed to a coast station and all individual acknowledgements with format specifiers
120 and 123.
Furthermore MF/HF equipment shall automatically set the dot pattern length to 200 bits for all transmitted DSC
messages for:
• distress alerts;
• distress acknowledgements;
• distress relays addressed to a geographic area;
• distress relay acknowledgements addressed to all ships;
• all calls addressed to a ship station other than messages addressed to a coast station or all individual
acknowledgements with format specifiers 120 and 123.
6.2.2 Transmission of DSC messages and prioritized wait
If the channel is free after the transmitter has powered up, the transmission shall begin immediately. If the channel is
not free, and the DSC message is a distress alert, the alert shall be transmitted as soon as the channel becomes free or
after 10 seconds on MF or HF or 1 second on VHF, whichever occurs first. (The 10 seconds and 1 second values are
approximate average times for HF and VHF DSC messages, respectively.) For all other DSC messages, the equipment
shall wait for the channel to become free and then the equipment shall delay transmission of the DSC message for a
specified wait time.
The specified wait time shall depend upon the message type and priority. Distress DSC messages (except for alerts),
urgency, safety, routine and test DSC messages shall wait one, two, three, and four "fixed" units of time plus a random
addition described below, respectively, before attempting to transmit. Transmission occurs if and only if the channel is
still free after this wait time has elapsed, otherwise the process is repeated.
The fixed "unit" of time shall be 100 ms on MF and HF and 50 ms on VHF. The randomly generated component shall
be some positive integer with resolution in milliseconds between zero and the fixed interval. The random component
serves as a tie-breaker when multiple DSC messages of the same priority and type are waiting to be transmitted. The
randomly generated part of the wait time shall be recomputed for every transmission attempt.
For example, on HF, the random interval would be some positive integer of milliseconds between 0 ms and 100 ms, for
example, 56 ms. Thus the wait time for a routine DSC message in this example
...

EUROPEAN STANDARD
Technical characteristics and methods of measurement
for equipment for generation, transmission
and reception of Digital Selective Calling (DSC)
in the maritime MF, MF/HF and/or VHF mobile service;
Part 2: Class A DSC
2 ETSI EN 300 338-2 V1.5.1 (2020-06)

Reference
REN/ERM-TGMAR-593
Keywords
DSC, GMDSS, maritime, radio
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: +33 4 92 94 42 00  Fax: +33 4 93 65 47 16

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

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ETSI
3 ETSI EN 300 338-2 V1.5.1 (2020-06)
Contents
Intellectual Property Rights . 6
Foreword . 6
Modal verbs terminology . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 7
3 Definition of terms, symbols and abbreviations . 8
3.1 Terms . 8
3.2 Symbols . 10
3.3 Abbreviations . 10
4 Controls and Indicators in Class A DSC Equipment . 10
4.1 Visual indication . 10
5 Technical requirements . 11
5.1 Facilities for DSC transmission and reception . 11
5.1.1 Multi-frequency distress alert attempts and watch receiver capabilities (MF/HF) . 11
5.1.2 Watch receiver capabilities (VHF) . 11
5.2 Remote alarms . 11
5.3 Galvanic isolation . 11
5.4 Manuals . 11
6 Automated and Non-Automated Procedure Requirements in Class A DSC Equipment . 11
6.1 Introduction . 11
6.2 Non-automated features . 12
6.2.0 General . 12
6.2.1 DSC Message Composition . 12
6.2.2 Transmission of DSC messages and prioritized wait . 13
6.2.3 Alarms . 14
6.3 Standby . 14
6.4 Sending distress automated procedure . 15
6.4.1 Procedure . 15
6.4.2 Tasks . 17
6.4.3 Display . 17
6.4.3.0 General Display Requirements . 17
6.4.3.1 Examples of sending distress procedure displays on VHF equipment . 18
6.4.4 Dedicated distress button sub procedure . 19
6.4.5 Transmission of the alert attempt . 20
6.4.6 Updating position . 20
6.4.7 Handling received DSC Messages . 20
6.4.8 Alarms . 20
6.4.9 Determining Subsequent communications . 21
6.4.10 Automated tuning . 21
6.4.11 Cancelling the Distress Alert . 21
6.4.11.0 General Requirements . 21
6.4.11.1 Examples of cancel-distress displays on VHF equipment. 22
6.4.12 Acknowledgments . 23
6.4.13 Termination. 23
6.4.14 Warnings . 23
6.5 Receiving distress automated procedure . 23
6.5.1 Procedure . 23
6.5.2 Tasks . 25
6.5.3 Display . 25
6.5.3.0 General Display Requirements . 25
6.5.3.1 Examples of received distress procedure displays on VHF equipment . 26
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4 ETSI EN 300 338-2 V1.5.1 (2020-06)
6.5.4 Handling received DSC Messages . 27
6.5.5 Alarms . 27
6.5.6 Determining Subsequent communications . 27
6.5.7 Automated tuning . 27
6.5.8 Acknowledgments . 28
6.5.9 Sending Relays and Acknowledgments . 28
6.5.10 Termination. 28
6.5.11 Warnings . 28
6.5.12 Handling events from man overboard devices (VHF only) . 29
6.5.12.1 General . 29
6.5.12.2 Display and tasks . 29
6.5.12.3 Handling received DSC messages pertinent to the procedure . 30
6.6 Sending non-distress automated procedure . 30
6.6.1 Procedure . 30
6.6.2 Tasks . 31
6.6.3 Display . 32
6.6.3.0 General Display Requirements . 32
6.6.3.1 Examples of sending non-distress procedures displays on VHF equipment . 33
6.6.4 Handling received DSC Messages . 33
6.6.5 Alarms . 33
6.6.6 Automated tuning . 33
6.6.7 Delayed Acknowledgements . 34
6.6.8 Termination. 34
6.6.9 Warnings . 34
6.7 Receiving non-distress automated procedure . 34
6.7.1 Procedure . 34
6.7.2 Tasks . 36
6.7.3 Display . 36
6.7.3.0 General Display Requirements . 36
6.7.3.1 Examples of receiving non-distress procedures displays on VHF equipment . 37
6.7.4 Handling received DSC messages . 38
6.7.5 Alarms . 38
6.7.6 Automated tuning . 38
6.7.7 Acknowledgments . 38
6.7.8 Termination. 39
6.7.9 Warnings . 39
6.8 Communications automated procedure . 39
6.8.1 Procedure . 39
6.8.2 Tasks . 39
6.8.3 Display . 40
6.8.4 Handling received DSC Messages . 40
6.8.5 Tuning of the general receiver and transmitter . 40
6.8.6 Termination. 40
6.9 Multiple automated procedures and parallel event handling . 40
6.9.1 Procedure . 40
6.9.2 Tasks . 40
6.9.3 Examples of multiple procedure screens . 41
Annex A (normative): DSC Message Composition . 43
A.1 Default values . 43
A.2 The default DROBOSE . 44
A.3 Allowable non-distress DSC message parameters . 44
Annex B (normative): Radius-Centre point conversion and rounding algorithm . 45
B.1 Radius-centre point conversion . 45
B.2 Rounding . 46
B.3 Special cases for either form of area data entry . 46
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5 ETSI EN 300 338-2 V1.5.1 (2020-06)
Annex C (normative): Automated Non-Distress Channel/Frequency Selection Algorithm . 47
C.0 General . 47
C.1 VHF . 47
C.2 HF . 47
Annex D (normative): Alarms . 48
D.1 Alarm specifications . 48
D.2 Alarming with critical errors . 49
D.3 Default alarm sounds . 49
D.4 Other alarm sounds . 50
History . 51

ETSI
6 ETSI EN 300 338-2 V1.5.1 (2020-06)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This European Standard (EN) has been produced by ETSI Technical Committee Electromagnetic compatibility and
Radio spectrum Matters (ERM).
The present document is part 2 of a multi-part deliverable. Full details of the entire series can be found in part 1 [i.1].
The present document covers the operator interfaces and operating system for Class A DSC equipment.

National transposition dates
Date of adoption of this EN: 29 May 2020
Date of latest announcement of this EN (doa): 31 August 2020
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 28 February 2021
Date of withdrawal of any conflicting National Standard (dow): 28 February 2022

Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI
7 ETSI EN 300 338-2 V1.5.1 (2020-06)
1 Scope
The present document states the minimum requirements for equipment to be used for generation, transmission and
reception of Class A Digital Selective Calling (DSC) for use on board ships.
DSC is intended to be used in the Medium Frequency (MF), High Frequency (HF) and Very High Frequency (VHF)
bands of the Maritime Mobile Service (MMS), for both distress, safety and general communications.
The present document is part 2 of a multi-part deliverable that covers the requirements to be fulfilled by equipment that
is either integrated with a transmitter and/or a receiver or equipment that is a stand-alone DSC terminal and has the
following class of DSC:
• Class A: includes all the facilities defined in annex 1 of Recommendation ITU-R M.493-15 [3] and complies
with the IMO Global Maritime Distress and Safety System (GMDSS) carriage requirements for MF/HF
installations and/or VHF installations.
These requirements include the relevant provisions of the ITU Radio Regulations [2] and Recommendation ITU-R
RM.493-15 [3], the International Convention for the Safety Of Life At Sea (SOLAS) [1], and the relevant resolutions of
the International Maritime Organization (IMO) [4].
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://docbox.etsi.org/Reference/.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are necessary for the application of the present document.
[1] International Convention for the Safety of Life at Sea (SOLAS), 1974.
[2] ITU Radio Regulations (2016).
[3] Recommendation ITU-R M.493-15 (01/2019): "Digital selective-calling system for use in the
maritime mobile service".
[4] IMO resolution MSC.97(73), section 14.6.4: "Adoption of the International Code of Safety for
High-Speed Craft, 2000 (2000 HSC Code)".
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
ETSI
8 ETSI EN 300 338-2 V1.5.1 (2020-06)
[i.1] ETSI EN 300 338-1: "Technical characteristics and methods of measurement for equipment for
generation, transmission and reception of Digital Selective Calling (DSC) in the maritime MF,
MF/HF and/or VHF mobile service; Part 1: Common requirements".
[i.2] MSC 302(87): "Adoption of performance standards for bridge alert management".
[i.3] IEC 61924-2 (Edition 1): "Maritime navigation and radiocommunication equipment and systems --
integrated navigation systems -- Part 2: Modular structure for INS -- operational and performance
requirements, methods of testing and required test results" (including IEC 61924-2 Corrigendum 1
November 2013).
[i.4] ETSI EN 300 338-6: "Technical characteristics and methods of measurement for equipment for
generation, transmission and reception of Digital Selective Calling (DSC) in the maritime MF,
MF/HF and/or VHF mobile service; Part 6: Class M DSC".
[i.5] Recommendation ITU-R M.541-10: "Operational procedures for the use of digital selective-calling
equipment in the maritime mobile service".
[i.6] Recommendation ITU-R M.585-8: "Assignment and use of identities in the maritime mobile
service".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the terms given in ETSI EN 300 338-1 [i.1] and the following apply:
acknowledged: when the objective of the initial DSC message has been achieved
active: automated procedure which has control of the general receiver and transmitter and is thus able to engage in
subsequent communications and receive DSC messages on both the watch receiver and general receiver
automated procedure: set of actions necessary to complete the objective of an initiating DSC message or non DSC
communication event
NOTE 1: Four DSC automated procedures are designed to process these. They are the receiving of distress DSC
messages, the receiving of non-distress DSC messages, the sending of distress DSC alert attempts and the
sending of non-distress DSC messages. In addition a fifth procedure is designed to handle non DSC
communication events.
NOTE 2: These automated procedures are called:
 Received distress automated procedure.
 Sending distress automated procedure.
 Received non-distress automated procedure.
 Sending non-distress automated procedure.
 Communications automated procedure.
closed loop operation: MOB devices supporting closed loop can be programmed to transmit either an individual
distress relay call (subsequent communication 126) to a vessel or group distress relay call to a group of vessels as
described in Recommendation ITU-R M.493-15 [3]
NOTE: Acknowledgement of these calls is possible.
default: value selected or an action taken by the equipment software in the absence of any operator input
distress DSC message: DSC message or acknowledgement containing the distress information
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9 ETSI EN 300 338-2 V1.5.1 (2020-06)
distress event: unique distress situation identified by two (VHF) or three (MF/HF) parameters of the distress
information; the MMSI of the vessel in distress and the nature of distress and on MF/HF the mode of subsequent
communication
engaged: equipment that is busy handling an automated procedure
factory default: default value that is set by the manufacturer such that the field or behaviour is defined prior to any
operator intervention
general receiver: receiver part of the transceiver used for the reception of all subsequent communications and on HF
the reception of DSC acknowledgements on the duplex DSC channels
NOTE: It is important to distinguish this unit from the watch receiver.
information characters: set of symbols in a DSC message that contains the items of interest for the recipient and is
used to compute the ECC symbol that terminates the message
NOTE: These symbols are repeated in the DX/RX time diversity pattern.
initial DSC message: DSC message that starts an automated procedure
non-distress DSC message: DSC messages or acknowledgments that do not have the format specifier or category of
"distress"
objective: intent of the DSC message either to establish subsequent communications or request information
on hold: automated procedure which does not have access to the transmitter and general receiver and therefore cannot
engage in subsequent communications and is only able to receive DSC messages on the watch receiver
open loop operation: MOB device is in a state where it transmits distress alerts (Recommendation ITU-R
M.493-15 [3])
operator options: any choices the operator can make while the automated procedure is engaged
parallel event handling: background process of handling a received DSC message that is not pertinent to the active
automated procedure
pertinent to the automated procedure: DSC messages that have something to do with the procedure and are therefore
"handled" by the procedure
NOTE: A DSC message is pertinent to an automated procedure if the set of information characters in the DSC
message has the correct values.
pertinent to the station: any DSC message that would start an automated procedure if the transceiver were in standby
self-terminating alarm: short alarm that stops by itself without operator intervention
NOTE: The purpose of this alarm is to inform the operator that a DSC message is received but it does not require
his immediate attention.
symbol (as part of the DSC sentence): term used to describe the 7 binary bits of a 10 bit DSC word that have the
information content
toggle (between automated procedures): ability to make one automated procedure active assuring that all other
procedures go on hold
top level: items, buttons, or functions are present and visible without requiring any action by the operator
NOTE: Such as scrolling, opening up menus, or removing any obscuring covers, etc.
two-tone alarm: alarm consisting of a repetition of the 2 200 Hz frequency for 250 ms followed by a 1 300 Hz
frequency for 250 ms
NOTE: This alarm is used for the initiation of the received distress DSC automated procedure.
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10 ETSI EN 300 338-2 V1.5.1 (2020-06)
urgency alarm: alarm consisting of a repetition of the 2 200 Hz frequency for 250 ms followed by 250 ms period of
silence
NOTE: This alarm is used for the initiation of the received non-distress DSC automated procedure when the
category of the initiating DSC message is "urgency".
watch receiver: separate receiver in DSC radios that continuously monitors the DSC distress frequencies on MF/HF,
2 187,5 kHz on MF, and channel 70 on VHF
NOTE: On MF/HF it is sometimes referred to as the scanning receiver.
word (as part of the DSC sentence): 10 binary bits that make up the coded entities of a transmitted DSC message
NOTE: The 10 bits consist of a 7 bit "symbol" that gives the information content and 3 bit error check that gives
the number of 0 binary bits in the 7 bit symbol.
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the abbreviations given in ETSI EN 300 338-1 [i.1] and the following apply:
ALE Automatic Linking Exchange
DROBOSE Distress Relay On Behalf Of Someone Else
MOB Man Over Board
NBDP Narrow Band Direct Printing
4 Controls and Indicators in Class A DSC Equipment
4.1 Visual indication
Any visual display of the information content shall be clearly legible under all ambient light conditions.
The display shall be large enough to hold enough information from the active procedure to safely guide the operator
through operator options in any engaged DSC procedure (distress or non-distress). It shall at any time hold information
on how to instantly recall any waiting procedure, or put any active procedure on hold.
The amount of information to display simultaneously on the display shall correspond to the information that can be
written in plain text with a minimum of 160 characters, each character having a minimum height of 3,5 mm, and a
nominal character width/height ratio of 0,7.
Where logic flows and procedural guidance, expressed by graphical symbols, have an advantage over text, this shall be
allowed. Any graphical symbols shall be clearly defined in the operation manual.
All DSC displays at all operating positions shall comply with these requirements.
ETSI
11 ETSI EN 300 338-2 V1.5.1 (2020-06)
5 Technical requirements
5.1 Facilities for DSC transmission and reception
5.1.1 Multi-frequency distress alert attempts and watch receiver
capabilities (MF/HF)
The equipment shall either:
• be capable of receiving DSC messages on all distress frequencies (except for the transmit frequency in use)
whilst the distress alert is being transmitted; or
• be able to complete the multi-frequency distress alert attempt within 1 minute and then be capable of receiving
DSC messages on all frequencies used in that multi-frequency attempt.
5.1.2 Watch receiver capabilities (VHF)
The watchkeeping receiver part of the DSC equipment shall be designed for continuous operation on channel 70 but the
receiver need not operate when the transmitter is in use on that channel.
5.2 Remote alarms
The equipment shall be provided with facilities for connecting remote alarms as recommended in chapter IV/6.6,
regulation X/3 of the SOLAS Convention [1] and IMO resolution MSC.97 (73), section 14.6.4 [4].
5.3 Galvanic isolation
No exposed metallic part of the equipment shall cause any terminal of the source of electrical energy to be earthed.
5.4 Manuals
Maintenance or service manuals shall be available and shall contain:
• If the equipment is so constructed that fault diagnosis and repair is practicable down to component level, the
maintenance instructions shall include full circuit diagrams, component layouts and components parts lists.
• If the equipment contains modules in which fault diagnosis and repair down to component level is not
practicable, the maintenance instructions shall contain sufficient information to enable localization and
replacement of the defective module.
6 Automated and Non-Automated Procedure
Requirements in Class A DSC Equipment
6.1 Introduction
This clause covers the minimum level of software automation, operational simplicity, and interface consistency
requirements for shipborne fixed installations using class A Digital Selective Calling equipment as specified in
Recommendation ITU-R M.493-15 [3], annexes 1, 3 and 4.
ETSI
12 ETSI EN 300 338-2 V1.5.1 (2020-06)
Perhaps the most important issue concerns an implied expectation for the use of the terminology "automated procedure"
as used in the present document to appear in the user interface. The terminology "automated procedure" describes the
set of algorithms that are used to encapsulate all the activities necessary to perform multitasking, DSC, and non DSC
communication events. The operator does not need to know anything about the existence of automated procedures in
order to operate a radio that makes use of these algorithms. Though the present document refers to items such as the
"Sending Distress Automated Procedure" such language shall not appear on the user interface of the equipment.
The primary purpose of DSC signalling is to provide the means to set-up subsequent communications between vessels
and/or coast stations. A call may be considered as being the total duration from the start of the DSC signalling until the
end of the subsequent communications, and the automated procedure is terminated.
The operational functionality described in this part has the objective of not disturbing any ongoing call. Furthermore,
the equipment shall assist the operator by providing simple audible indication of a received DSC call whilst the
equipment is engaged, and provide a facility to manage activation amongst initiated automated procedures.
6.2 Non-automated features
6.2.0 General
This clause describes the features of the equipment that are necessary to assure compliance to the ITU-R DSC
functionality standards and support a smoother operation of the automation algorithms, but are not directly related to the
automation algorithms.
6.2.1 DSC Message Composition
The equipment shall provide factory default values for all non-distress DSC messages as specified in Recommendation
ITU-R M.493-15 [3], annex 3 and summarized in figure A.1 for all parameters where the operator has the option to
select or enter more than one value and has not already done so.
The default values for the Distress Relay On Behalf Of Someone Else (DROBOSE) shall be as given in table A.1.
The default values for the operator-composed distress alert shall be the default distress alert as specified in the sent
distress automated procedure.
A destination MMSI that does not have at least 9 digits entered is invalid.
The MMSI "unknown" indicator shall only be able to be used for the MMSI of the vessel in distress when composing a
DROBOSE.
No DSC message shall be able to be sent that has an invalid parameter.
For simplicity of the user interface:
a) the DSC message composition interface shall be such that the operator needs no user manual to initiate the
desired DSC message;
b) it shall require a maximum of two keystrokes, button pushes or menu actions plus the entry or selection of a
destination MMSI and working channel (where appropriate) for the operator to send the default (routine
individual) DSC message from standby;
c) parameter descriptions and terms shall be provided in plain language;
d) all parameters of the DSC message that do not require an operator choice shall be entered automatically;
e) guidance and/or prompting shall be provided for the entry of any necessary parameters of the DSC message if
these parameters and/or their values are not plainly visible from context or on the display.
ETSI
13 ETSI EN 300 338-2 V1.5.1 (2020-06)
For data entry:
a) the equipment shall only allow the operator to compose and send DSC messages that are compliant with the
latest version of Recommendation ITU-R M.493-15 [3];
b) acknowledgements shall be automatically composed by the equipment and user options for these
acknowledgements are provided by the automated procedures;
c) the equipment shall provide the operator with the choice of specifying the geographic area parameters as either
a circle of radius "r" about a centre point or the traditional latitude-longitude Mercator box and northwest
corner point or about a centre point;
d) the equipment shall convert and round the radius-centre point entry according to the algorithm given in
annex B;
e) the equipment shall provide an automatic determination of the channel and or frequencies of subsequent
communication according to the algorithm given in Recommendation ITU-R M.493-15 [3], annex 3 and
summarized in annex C.
The automated channel selection shall be able to be overridden.
It shall not be possible to select a distress channel for subsequent communications for DSC messages of priority routine.
The equipment shall automatically set the dot pattern length to 20 bits for all transmitted DSC messages on VHF, and
on MF/HF all DSC messages addressed to a coast station and all individual acknowledgements with format specifiers
120 and 123.
Furthermore MF/HF equipment shall automatically set the dot pattern length to 200 bits for all transmitted DSC
messages for:
• distress alerts;
• distress acknowledgements;
• distress relays addressed to a geographic area;
• distress relay acknowledgements addressed to all ships;
• all calls addressed to a ship station other than messages addressed to a coast station or all individual
acknowledgements with format specifiers 120 and 123.
6.2.2 Transmission of DSC messages and prioritized wait
If the channel is free after the transmitter has powered up, the transmission shall begin immediately. If the channel is
not free, and the DSC message is a distress alert, the alert shall be transmitted as soon as the channel becomes free or
after 10 seconds on MF or HF or 1 second on VHF, whichever occurs first. (The 10 seconds and 1 second values are
approximate average times for HF and VHF DSC messages, respectively.) For all other DSC messages, the equipment
shall wait for the channel to become free and then the equipment shall delay transmission of the DSC message for a
specified wait time.
The specified wait time shall depend upon the message type and priority. Distress DSC messages (except for alerts),
urgency, safety, routine and test DSC messages shall wait one, two, three, and four "fixed" units of time plus a random
addition described below, respectively, before attempting to transmit. Transmission occurs if and only if the channel is
still free after this wait time has elapsed, otherwise the process is repeated.
The fixed "unit" of time shall be 100 ms on MF and HF and 50 ms on VHF. The randomly generated component shall
be some positive integer with resolution in milliseconds between zero and the fixed interval. The random component
serves as a tie-breaker when multiple DSC messages of the same priority and type are waiting to be transmitted. The
randomly generated part of the wait time shall be recomputed for every transmission attempt.
For example, on HF, the random interval would be some positive integer of milliseconds between 0 ms and 100 ms, for
example, 56 ms. Thus the wait time for a routine DSC message in this example would be 456 ms the first attempt. If the
channel was once again busy after the wait time expired, the new wait time might be 417 ms the second attempt, etc.
ETSI
14 ETSI EN 300 338-2 V
...

SLOVENSKI STANDARD
01-september-2020
Tehnične karakteristike in merilne metode za naprave, ki generirajo, oddajajo in
sprejemajo digitalni selektivni klic (DSC) v pomorski mobilni storitvi, ki deluje v
območju MF, MF/HF oziroma VHF - 2. del: Digitalni selektivni klic razreda A
Technical characteristics and methods of measurement for equipment for generation,
transmission and reception of Digital Selective Calling (DSC) in the maritime MF, MF/HF
and/or VHF mobile service - Part 2: Class A DSC
Ta slovenski standard je istoveten z: ETSI EN 300 338-2 V1.5.1 (2020-06)
ICS:
33.060.20 Sprejemna in oddajna Receiving and transmitting
oprema equipment
47.020.70 Navigacijska in krmilna Navigation and control
oprema equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
Technical characteristics and methods of measurement
for equipment for generation, transmission
and reception of Digital Selective Calling (DSC)
in the maritime MF, MF/HF and/or VHF mobile service;
Part 2: Class A DSC
2 ETSI EN 300 338-2 V1.5.1 (2020-06)

Reference
REN/ERM-TGMAR-593
Keywords
DSC, GMDSS, maritime, radio
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: +33 4 92 94 42 00  Fax: +33 4 93 65 47 16

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

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3 ETSI EN 300 338-2 V1.5.1 (2020-06)
Contents
Intellectual Property Rights . 6
Foreword . 6
Modal verbs terminology . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 7
3 Definition of terms, symbols and abbreviations . 8
3.1 Terms . 8
3.2 Symbols . 10
3.3 Abbreviations . 10
4 Controls and Indicators in Class A DSC Equipment . 10
4.1 Visual indication . 10
5 Technical requirements . 11
5.1 Facilities for DSC transmission and reception . 11
5.1.1 Multi-frequency distress alert attempts and watch receiver capabilities (MF/HF) . 11
5.1.2 Watch receiver capabilities (VHF) . 11
5.2 Remote alarms . 11
5.3 Galvanic isolation . 11
5.4 Manuals . 11
6 Automated and Non-Automated Procedure Requirements in Class A DSC Equipment . 11
6.1 Introduction . 11
6.2 Non-automated features . 12
6.2.0 General . 12
6.2.1 DSC Message Composition . 12
6.2.2 Transmission of DSC messages and prioritized wait . 13
6.2.3 Alarms . 14
6.3 Standby . 14
6.4 Sending distress automated procedure . 15
6.4.1 Procedure . 15
6.4.2 Tasks . 17
6.4.3 Display . 17
6.4.3.0 General Display Requirements . 17
6.4.3.1 Examples of sending distress procedure displays on VHF equipment . 18
6.4.4 Dedicated distress button sub procedure . 19
6.4.5 Transmission of the alert attempt . 20
6.4.6 Updating position . 20
6.4.7 Handling received DSC Messages . 20
6.4.8 Alarms . 20
6.4.9 Determining Subsequent communications . 21
6.4.10 Automated tuning . 21
6.4.11 Cancelling the Distress Alert . 21
6.4.11.0 General Requirements . 21
6.4.11.1 Examples of cancel-distress displays on VHF equipment. 22
6.4.12 Acknowledgments . 23
6.4.13 Termination. 23
6.4.14 Warnings . 23
6.5 Receiving distress automated procedure . 23
6.5.1 Procedure . 23
6.5.2 Tasks . 25
6.5.3 Display . 25
6.5.3.0 General Display Requirements . 25
6.5.3.1 Examples of received distress procedure displays on VHF equipment . 26
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4 ETSI EN 300 338-2 V1.5.1 (2020-06)
6.5.4 Handling received DSC Messages . 27
6.5.5 Alarms . 27
6.5.6 Determining Subsequent communications . 27
6.5.7 Automated tuning . 27
6.5.8 Acknowledgments . 28
6.5.9 Sending Relays and Acknowledgments . 28
6.5.10 Termination. 28
6.5.11 Warnings . 28
6.5.12 Handling events from man overboard devices (VHF only) . 29
6.5.12.1 General . 29
6.5.12.2 Display and tasks . 29
6.5.12.3 Handling received DSC messages pertinent to the procedure . 30
6.6 Sending non-distress automated procedure . 30
6.6.1 Procedure . 30
6.6.2 Tasks . 31
6.6.3 Display . 32
6.6.3.0 General Display Requirements . 32
6.6.3.1 Examples of sending non-distress procedures displays on VHF equipment . 33
6.6.4 Handling received DSC Messages . 33
6.6.5 Alarms . 33
6.6.6 Automated tuning . 33
6.6.7 Delayed Acknowledgements . 34
6.6.8 Termination. 34
6.6.9 Warnings . 34
6.7 Receiving non-distress automated procedure . 34
6.7.1 Procedure . 34
6.7.2 Tasks . 36
6.7.3 Display . 36
6.7.3.0 General Display Requirements . 36
6.7.3.1 Examples of receiving non-distress procedures displays on VHF equipment . 37
6.7.4 Handling received DSC messages . 38
6.7.5 Alarms . 38
6.7.6 Automated tuning . 38
6.7.7 Acknowledgments . 38
6.7.8 Termination. 39
6.7.9 Warnings . 39
6.8 Communications automated procedure . 39
6.8.1 Procedure . 39
6.8.2 Tasks . 39
6.8.3 Display . 40
6.8.4 Handling received DSC Messages . 40
6.8.5 Tuning of the general receiver and transmitter . 40
6.8.6 Termination. 40
6.9 Multiple automated procedures and parallel event handling . 40
6.9.1 Procedure . 40
6.9.2 Tasks . 40
6.9.3 Examples of multiple procedure screens . 41
Annex A (normative): DSC Message Composition . 43
A.1 Default values . 43
A.2 The default DROBOSE . 44
A.3 Allowable non-distress DSC message parameters . 44
Annex B (normative): Radius-Centre point conversion and rounding algorithm . 45
B.1 Radius-centre point conversion . 45
B.2 Rounding . 46
B.3 Special cases for either form of area data entry . 46
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5 ETSI EN 300 338-2 V1.5.1 (2020-06)
Annex C (normative): Automated Non-Distress Channel/Frequency Selection Algorithm . 47
C.0 General . 47
C.1 VHF . 47
C.2 HF . 47
Annex D (normative): Alarms . 48
D.1 Alarm specifications . 48
D.2 Alarming with critical errors . 49
D.3 Default alarm sounds . 49
D.4 Other alarm sounds . 50
History . 51

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6 ETSI EN 300 338-2 V1.5.1 (2020-06)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This European Standard (EN) has been produced by ETSI Technical Committee Electromagnetic compatibility and
Radio spectrum Matters (ERM).
The present document is part 2 of a multi-part deliverable. Full details of the entire series can be found in part 1 [i.1].
The present document covers the operator interfaces and operating system for Class A DSC equipment.

National transposition dates
Date of adoption of this EN: 29 May 2020
Date of latest announcement of this EN (doa): 31 August 2020
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 28 February 2021
Date of withdrawal of any conflicting National Standard (dow): 28 February 2022

Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
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7 ETSI EN 300 338-2 V1.5.1 (2020-06)
1 Scope
The present document states the minimum requirements for equipment to be used for generation, transmission and
reception of Class A Digital Selective Calling (DSC) for use on board ships.
DSC is intended to be used in the Medium Frequency (MF), High Frequency (HF) and Very High Frequency (VHF)
bands of the Maritime Mobile Service (MMS), for both distress, safety and general communications.
The present document is part 2 of a multi-part deliverable that covers the requirements to be fulfilled by equipment that
is either integrated with a transmitter and/or a receiver or equipment that is a stand-alone DSC terminal and has the
following class of DSC:
• Class A: includes all the facilities defined in annex 1 of Recommendation ITU-R M.493-15 [3] and complies
with the IMO Global Maritime Distress and Safety System (GMDSS) carriage requirements for MF/HF
installations and/or VHF installations.
These requirements include the relevant provisions of the ITU Radio Regulations [2] and Recommendation ITU-R
RM.493-15 [3], the International Convention for the Safety Of Life At Sea (SOLAS) [1], and the relevant resolutions of
the International Maritime Organization (IMO) [4].
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://docbox.etsi.org/Reference/.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are necessary for the application of the present document.
[1] International Convention for the Safety of Life at Sea (SOLAS), 1974.
[2] ITU Radio Regulations (2016).
[3] Recommendation ITU-R M.493-15 (01/2019): "Digital selective-calling system for use in the
maritime mobile service".
[4] IMO resolution MSC.97(73), section 14.6.4: "Adoption of the International Code of Safety for
High-Speed Craft, 2000 (2000 HSC Code)".
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
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8 ETSI EN 300 338-2 V1.5.1 (2020-06)
[i.1] ETSI EN 300 338-1: "Technical characteristics and methods of measurement for equipment for
generation, transmission and reception of Digital Selective Calling (DSC) in the maritime MF,
MF/HF and/or VHF mobile service; Part 1: Common requirements".
[i.2] MSC 302(87): "Adoption of performance standards for bridge alert management".
[i.3] IEC 61924-2 (Edition 1): "Maritime navigation and radiocommunication equipment and systems --
integrated navigation systems -- Part 2: Modular structure for INS -- operational and performance
requirements, methods of testing and required test results" (including IEC 61924-2 Corrigendum 1
November 2013).
[i.4] ETSI EN 300 338-6: "Technical characteristics and methods of measurement for equipment for
generation, transmission and reception of Digital Selective Calling (DSC) in the maritime MF,
MF/HF and/or VHF mobile service; Part 6: Class M DSC".
[i.5] Recommendation ITU-R M.541-10: "Operational procedures for the use of digital selective-calling
equipment in the maritime mobile service".
[i.6] Recommendation ITU-R M.585-8: "Assignment and use of identities in the maritime mobile
service".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the terms given in ETSI EN 300 338-1 [i.1] and the following apply:
acknowledged: when the objective of the initial DSC message has been achieved
active: automated procedure which has control of the general receiver and transmitter and is thus able to engage in
subsequent communications and receive DSC messages on both the watch receiver and general receiver
automated procedure: set of actions necessary to complete the objective of an initiating DSC message or non DSC
communication event
NOTE 1: Four DSC automated procedures are designed to process these. They are the receiving of distress DSC
messages, the receiving of non-distress DSC messages, the sending of distress DSC alert attempts and the
sending of non-distress DSC messages. In addition a fifth procedure is designed to handle non DSC
communication events.
NOTE 2: These automated procedures are called:
 Received distress automated procedure.
 Sending distress automated procedure.
 Received non-distress automated procedure.
 Sending non-distress automated procedure.
 Communications automated procedure.
closed loop operation: MOB devices supporting closed loop can be programmed to transmit either an individual
distress relay call (subsequent communication 126) to a vessel or group distress relay call to a group of vessels as
described in Recommendation ITU-R M.493-15 [3]
NOTE: Acknowledgement of these calls is possible.
default: value selected or an action taken by the equipment software in the absence of any operator input
distress DSC message: DSC message or acknowledgement containing the distress information
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9 ETSI EN 300 338-2 V1.5.1 (2020-06)
distress event: unique distress situation identified by two (VHF) or three (MF/HF) parameters of the distress
information; the MMSI of the vessel in distress and the nature of distress and on MF/HF the mode of subsequent
communication
engaged: equipment that is busy handling an automated procedure
factory default: default value that is set by the manufacturer such that the field or behaviour is defined prior to any
operator intervention
general receiver: receiver part of the transceiver used for the reception of all subsequent communications and on HF
the reception of DSC acknowledgements on the duplex DSC channels
NOTE: It is important to distinguish this unit from the watch receiver.
information characters: set of symbols in a DSC message that contains the items of interest for the recipient and is
used to compute the ECC symbol that terminates the message
NOTE: These symbols are repeated in the DX/RX time diversity pattern.
initial DSC message: DSC message that starts an automated procedure
non-distress DSC message: DSC messages or acknowledgments that do not have the format specifier or category of
"distress"
objective: intent of the DSC message either to establish subsequent communications or request information
on hold: automated procedure which does not have access to the transmitter and general receiver and therefore cannot
engage in subsequent communications and is only able to receive DSC messages on the watch receiver
open loop operation: MOB device is in a state where it transmits distress alerts (Recommendation ITU-R
M.493-15 [3])
operator options: any choices the operator can make while the automated procedure is engaged
parallel event handling: background process of handling a received DSC message that is not pertinent to the active
automated procedure
pertinent to the automated procedure: DSC messages that have something to do with the procedure and are therefore
"handled" by the procedure
NOTE: A DSC message is pertinent to an automated procedure if the set of information characters in the DSC
message has the correct values.
pertinent to the station: any DSC message that would start an automated procedure if the transceiver were in standby
self-terminating alarm: short alarm that stops by itself without operator intervention
NOTE: The purpose of this alarm is to inform the operator that a DSC message is received but it does not require
his immediate attention.
symbol (as part of the DSC sentence): term used to describe the 7 binary bits of a 10 bit DSC word that have the
information content
toggle (between automated procedures): ability to make one automated procedure active assuring that all other
procedures go on hold
top level: items, buttons, or functions are present and visible without requiring any action by the operator
NOTE: Such as scrolling, opening up menus, or removing any obscuring covers, etc.
two-tone alarm: alarm consisting of a repetition of the 2 200 Hz frequency for 250 ms followed by a 1 300 Hz
frequency for 250 ms
NOTE: This alarm is used for the initiation of the received distress DSC automated procedure.
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10 ETSI EN 300 338-2 V1.5.1 (2020-06)
urgency alarm: alarm consisting of a repetition of the 2 200 Hz frequency for 250 ms followed by 250 ms period of
silence
NOTE: This alarm is used for the initiation of the received non-distress DSC automated procedure when the
category of the initiating DSC message is "urgency".
watch receiver: separate receiver in DSC radios that continuously monitors the DSC distress frequencies on MF/HF,
2 187,5 kHz on MF, and channel 70 on VHF
NOTE: On MF/HF it is sometimes referred to as the scanning receiver.
word (as part of the DSC sentence): 10 binary bits that make up the coded entities of a transmitted DSC message
NOTE: The 10 bits consist of a 7 bit "symbol" that gives the information content and 3 bit error check that gives
the number of 0 binary bits in the 7 bit symbol.
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the abbreviations given in ETSI EN 300 338-1 [i.1] and the following apply:
ALE Automatic Linking Exchange
DROBOSE Distress Relay On Behalf Of Someone Else
MOB Man Over Board
NBDP Narrow Band Direct Printing
4 Controls and Indicators in Class A DSC Equipment
4.1 Visual indication
Any visual display of the information content shall be clearly legible under all ambient light conditions.
The display shall be large enough to hold enough information from the active procedure to safely guide the operator
through operator options in any engaged DSC procedure (distress or non-distress). It shall at any time hold information
on how to instantly recall any waiting procedure, or put any active procedure on hold.
The amount of information to display simultaneously on the display shall correspond to the information that can be
written in plain text with a minimum of 160 characters, each character having a minimum height of 3,5 mm, and a
nominal character width/height ratio of 0,7.
Where logic flows and procedural guidance, expressed by graphical symbols, have an advantage over text, this shall be
allowed. Any graphical symbols shall be clearly defined in the operation manual.
All DSC displays at all operating positions shall comply with these requirements.
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11 ETSI EN 300 338-2 V1.5.1 (2020-06)
5 Technical requirements
5.1 Facilities for DSC transmission and reception
5.1.1 Multi-frequency distress alert attempts and watch receiver
capabilities (MF/HF)
The equipment shall either:
• be capable of receiving DSC messages on all distress frequencies (except for the transmit frequency in use)
whilst the distress alert is being transmitted; or
• be able to complete the multi-frequency distress alert attempt within 1 minute and then be capable of receiving
DSC messages on all frequencies used in that multi-frequency attempt.
5.1.2 Watch receiver capabilities (VHF)
The watchkeeping receiver part of the DSC equipment shall be designed for continuous operation on channel 70 but the
receiver need not operate when the transmitter is in use on that channel.
5.2 Remote alarms
The equipment shall be provided with facilities for connecting remote alarms as recommended in chapter IV/6.6,
regulation X/3 of the SOLAS Convention [1] and IMO resolution MSC.97 (73), section 14.6.4 [4].
5.3 Galvanic isolation
No exposed metallic part of the equipment shall cause any terminal of the source of electrical energy to be earthed.
5.4 Manuals
Maintenance or service manuals shall be available and shall contain:
• If the equipment is so constructed that fault diagnosis and repair is practicable down to component level, the
maintenance instructions shall include full circuit diagrams, component layouts and components parts lists.
• If the equipment contains modules in which fault diagnosis and repair down to component level is not
practicable, the maintenance instructions shall contain sufficient information to enable localization and
replacement of the defective module.
6 Automated and Non-Automated Procedure
Requirements in Class A DSC Equipment
6.1 Introduction
This clause covers the minimum level of software automation, operational simplicity, and interface consistency
requirements for shipborne fixed installations using class A Digital Selective Calling equipment as specified in
Recommendation ITU-R M.493-15 [3], annexes 1, 3 and 4.
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12 ETSI EN 300 338-2 V1.5.1 (2020-06)
Perhaps the most important issue concerns an implied expectation for the use of the terminology "automated procedure"
as used in the present document to appear in the user interface. The terminology "automated procedure" describes the
set of algorithms that are used to encapsulate all the activities necessary to perform multitasking, DSC, and non DSC
communication events. The operator does not need to know anything about the existence of automated procedures in
order to operate a radio that makes use of these algorithms. Though the present document refers to items such as the
"Sending Distress Automated Procedure" such language shall not appear on the user interface of the equipment.
The primary purpose of DSC signalling is to provide the means to set-up subsequent communications between vessels
and/or coast stations. A call may be considered as being the total duration from the start of the DSC signalling until the
end of the subsequent communications, and the automated procedure is terminated.
The operational functionality described in this part has the objective of not disturbing any ongoing call. Furthermore,
the equipment shall assist the operator by providing simple audible indication of a received DSC call whilst the
equipment is engaged, and provide a facility to manage activation amongst initiated automated procedures.
6.2 Non-automated features
6.2.0 General
This clause describes the features of the equipment that are necessary to assure compliance to the ITU-R DSC
functionality standards and support a smoother operation of the automation algorithms, but are not directly related to the
automation algorithms.
6.2.1 DSC Message Composition
The equipment shall provide factory default values for all non-distress DSC messages as specified in Recommendation
ITU-R M.493-15 [3], annex 3 and summarized in figure A.1 for all parameters where the operator has the option to
select or enter more than one value and has not already done so.
The default values for the Distress Relay On Behalf Of Someone Else (DROBOSE) shall be as given in table A.1.
The default values for the operator-composed distress alert shall be the default distress alert as specified in the sent
distress automated procedure.
A destination MMSI that does not have at least 9 digits entered is invalid.
The MMSI "unknown" indicator shall only be able to be used for the MMSI of the vessel in distress when composing a
DROBOSE.
No DSC message shall be able to be sent that has an invalid parameter.
For simplicity of the user interface:
a) the DSC message composition interface shall be such that the operator needs no user manual to initiate the
desired DSC message;
b) it shall require a maximum of two keystrokes, button pushes or menu actions plus the entry or selection of a
destination MMSI and working channel (where appropriate) for the operator to send the default (routine
individual) DSC message from standby;
c) parameter descriptions and terms shall be provided in plain language;
d) all parameters of the DSC message that do not require an operator choice shall be entered automatically;
e) guidance and/or prompting shall be provided for the entry of any necessary parameters of the DSC message if
these parameters and/or their values are not plainly visible from context or on the display.
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13 ETSI EN 300 338-2 V1.5.1 (2020-06)
For data entry:
a) the equipment shall only allow the operator to compose and send DSC messages that are compliant with the
latest version of Recommendation ITU-R M.493-15 [3];
b) acknowledgements shall be automatically composed by the equipment and user options for these
acknowledgements are provided by the automated procedures;
c) the equipment shall provide the operator with the choice of specifying the geographic area parameters as either
a circle of radius "r" about a centre point or the traditional latitude-longitude Mercator box and northwest
corner point or about a centre point;
d) the equipment shall convert and round the radius-centre point entry according to the algorithm given in
annex B;
e) the equipment shall provide an automatic determination of the channel and or frequencies of subsequent
communication according to the algorithm given in Recommendation ITU-R M.493-15 [3], annex 3 and
summarized in annex C.
The automated channel selection shall be able to be overridden.
It shall not be possible to select a distress channel for subsequent communications for DSC messages of priority routine.
The equipment shall automatically set the dot pattern length to 20 bits for all transmitted DSC messages on VHF, and
on MF/HF all DSC messages addressed to a coast station and all individual acknowledgements with format specifiers
120 and 123.
Furthermore MF/HF equipment shall automatically set the dot pattern length to 200 bits for all transmitted DSC
messages for:
• distress alerts;
• distress acknowledgements;
• distress relays addressed to a geographic area;
• distress relay acknowledgements addressed to all ships;
• all calls addressed to a ship station other than messages addressed to a coast station or all individual
acknowledgements with format specifiers 120 and 123.
6.2.2 Transmission of DSC messages and prioritized wait
If the channel is free after the transmitter has powered up, the transmission shall begin immediately. If the channel is
not free, and the DSC message is a distress alert, the alert shall be transmitted as soon as the channel becomes free or
after 10 seconds on MF or HF or 1 second on VHF, whichever occurs first. (The 10 seconds and 1 second values are
approximate average times for HF and VHF DSC messages, respectively.) For all other DSC message
...