IEC 61097-4:2012

IEC 61097-4 ®
Edition 3.1 2016-08
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
colour
inside
Global maritime distress and safety system (GMDSS) –
Part 4: Inmarsat-C ship earth station and Inmarsat enhanced group call (EGC)
equipment – Operational and performance requirements, methods of testing
and required test results
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IEC 61097-4 ®
Edition 3.1 2016-08
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
colour
inside
Global maritime distress and safety system (GMDSS) –

Part 4: Inmarsat-C ship earth station and Inmarsat enhanced group call (EGC)

equipment – Operational and performance requirements, methods of testing

and required test results
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 47.020.70 ISBN 978-2-8322-3605-5

IEC 61097-4 ®
Edition 3.1 2016-08
CONSOLIDATED VERSION
REDLINE VERSION
colour
inside
Global maritime distress and safety system (GMDSS) –
Part 4: Inmarsat-C ship earth station and Inmarsat enhanced group call (EGC)
equipment – Operational and performance requirements, methods of testing
and required test results
– 2 – IEC 61097-4:2012+AMD1:2016 CSV

© IEC 2016
CONTENTS
FOREWORD. 4

1 Scope . 6

2 Normative references . 6

3 Performance requirements . 7

3.1 Overview . 7

3.2 Non-operational requirements . 8

3.2.1 General . 8

3.2.2 Warning of radiation hazard . 8
3.2.3 Power supply changeover . 8
3.3 Operational requirements for ship earth stations . 8
3.3.1 Capabilities . 8
3.3.2 Ship station identity . 8
3.3.3 Distress alerting . 8
3.3.4 Position updating . 9
3.4 Operational requirements for EGC receivers . 9
3.4.1 Capabilities . 9
3.4.2 General . 10
3.4.3 Position and area code updating . 10
3.4.4 Indication of receipt of priority message . 10
3.4.5 Indication of tuning and synchronisation . 10
3.4.6 Printing selection . 11
3.4.7 Printing device . 11
3.5 Performance related requirements from IEC 60945 . 11
3.6 Other requirements . 11
3.7 Long-range identification and tracking . 12
3.7.1 General . 12
3.7.2 Capabilities . 12
3.7.3 Functionality . 13
3.7.4 Communication system . 14
4 Technical characteristics . 14
4.1 Overview . 14
4.2 Environmental and electromagnetic compatibility requirement . 14

4.3 Radiated spurious emissions . 15
4.4 Interfaces . 15
5 Methods of testing and required test results . 15
5.1 Overview . 15
5.1.1 General . 15
5.1.2 Performance requirements . 16
5.1.3 Technical characteristics . 16
5.2 Tests of non-operational requirements . 16
5.3 Tests of operational requirements for ship earth stations . 16
5.3.1 Capabilities . 16
5.3.2 Ship station identity . 16
5.3.3 Distress alerting . 16
5.3.4 Position updating . 17
5.4 Tests of operational requirements for EGC receivers . 17

© IEC 2016
5.4.1 Capabilities . 17

5.4.2 General . 17

5.4.3 Position and area code updating . 17

5.4.4 Indication of receipt of priority message . 17

5.4.5 Indication of tuning and synchronisation . 18

5.4.6 Printing selection . 18

5.4.7 Printing device . 18

5.5 Tests of performance related requirements from IEC 60945 . 18

5.6 Tests of other requirements . 18

5.7 Long-range identification and tracking . 18

5.7.1 General . 18
5.7.2 Capabilities . 18
5.7.3 Functionality . 19
5.7.4 Communication system . 19
5.8 Tests of technical characteristics . 20
5.8.1 Inmarsat tests . 20
5.8.2 Tests for environmental and electromagnetic compatibility . 20
5.8.3 Interfaces . 20
Annex A (normative) Requirements relating to installation . 21
Annex B (normative) Radiated unwanted emissions . 22
Annex C (informative) Inmarsat RTP schedule of tests. 25
Bibliography . 29

Table 1 – Data to be transmitted from the shipborne equipment . 14
Table 2 – Environmental conditions . 15
Table B.1 – Limits of unwanted emissions up to 1 000 MHz . 22
Table B.2 – Limits of unwanted emissions above 1 000 MHz . 23
Table B.3 – Limits of unwanted emission within the operating band with carrier-on . 24
Table C.1 – Phase I Inmarsat-C schedule of tests . 25
Table C.2 – Phase I EGC receiver schedule of tests . 27
Table C.3 – Phase II schedule of tests . 28

– 4 – IEC 61097-4:2012+AMD1:2016 CSV

© IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
GLOBAL MARITIME DISTRESS
AND SAFETY SYSTEM (GMDSS) –
Part 4: Inmarsat-C ship earth station and

Inmarsat enhanced group call (EGC) equipment –

Operational and performance requirements,

methods of testing and required test results
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This consolidated version of the official IEC Standard and its amendment has been prepared
for user convenience.
IEC 61097-4 edition 3.1 contains the third edition (2012-05) [documents 80/659/FDIS and 80/666/
RVD] and its amendment 1 (2016-08) [documents 80/789/CDV and 80/808/RVC].
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendment 1. Additions are in green text, deletions are in strikethrough red text.
A separate Final version with all changes accepted is available in this publication.

© IEC 2016
International Standard IEC 61097-4 has been prepared by IEC technical committee 80:
Maritime navigation and radiocommunication equipment and systems.

This edition constitutes a technical revision. The main changes with respect to the
previous edition are:
– the IMO references and requirements have been updated to the new performance

standards for enhanced group call equipment adopted in 2010 as resolution MSC.306(87).

The new performance standards incorporate new requirements for an indication of ship’s
position which has not been updated (3.4.3) and an alarm for paper low condition (3.4.7).
These two requirements are, however, derived from Inmarsat documentation so there is
no technical change to equipment;
– a new subclause has been added (3.7) concerning long-range identification and tracking
(LRIT) to support IMO performance standards given in resolution MSC.263(84) adopted in
2008;
– references to Inmarsat documentation have been simplified by moving the content of
Tables 1, 2, 4 and 5 into a new Annex C;
– the text has been editorially updated to conform to the ISO/IEC Directives.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 61097 series, published under the general title Global maritime
distress and safety system (GMDSS), can be found on the IEC website.
The committee has decided that the contents of the base publication and its amendment will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – IEC 61097-4:2012+AMD1:2016 CSV

© IEC 2016
GLOBAL MARITIME DISTRESS
AND SAFETY SYSTEM (GMDSS) –
Part 4: Inmarsat-C ship earth station and

Inmarsat enhanced group call (EGC) equipment –

Operational and performance requirements,

methods of testing and required test results

1 Scope
This part of IEC 61097 specifies the performance requirements and methods of testing for
Inmarsat-C ship earth stations (SES) capable of transmitting and receiving direct-printing
communications, and for enhanced group call (EGC) receivers, for use in the GMDSS and for
use for long-range identification and tracking (LRIT). The available variants are:
Class 0: An EGC receiver, either stand-alone or an element of a GMDSS installation in
accordance with the Inmarsat design and installation guidelines (DIGs) for
GMDSS installations.
Class 1: A basic SES providing shore-to-ship and ship-to-shore message transfer only.
Class 2: As class 1 but with EGC as an alternative to shore-to-ship transfer using a
shared receiver.
Class 3: As class 1 but with EGC using an independent receiver.
th
NOTE 1 The 34 session of the IMO Sub-Committee on Radiocommunications decided that class 2 equipment
would be adequate to provide sufficient availability for the reception of maritime safety information for the GMDSS.
The standard complies with IMO performance requirements stated in the normative
references, Inmarsat technical characteristics and test procedures, and IEC 60945 general
requirements except where modifications are explicitly stated in this standard. Technical
characteristics essential to GMDSS and LRIT operation as defined by the IMO are identified.
All text of this standard, whose wording is identical to that in IMO SOLAS Convention 1974 as
amended in 1988 and Resolutions A.807(19), MSC.263(84) and MSC.306(87) is printed in
italics and reference made to the Resolution/Recommendation and subclause number.
This standard covers equipment construction and testing. Matters relating to installation may
also be found in the Inmarsat Maritime design and installation guidelines (see Bibliography).
Those to be found in IMO Resolutions A.807(19), MSC.263(84) and MSC.306(87) are

reproduced in Annex A.
Responsibility for type approval of Inmarsat-C and Inmarsat-EGC is vested in Inmarsat by
IMO Resolutions A.807(19) and MSC.306(87) (see 3.2.1). Therefore, this standard does not
reproduce Inmarsat test procedures in full, but refers to where they are given in Inmarsat
documentation cited in the normative references to this standard (Annex C).
NOTE 2 For the purposes of this standard the terms Inmarsat-C, Inmarsat Standard-C, Standard-C refer to the
same equipment.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
© IEC 2016
IEC 60945:2002, Maritime navigation and radiocommunication equipment and systems –

General requirements – Methods of testing and required test results

IEC 61108 (all parts), Maritime navigation and radiocommunication equipment and systems

– Global navigation satellite systems (GNSS)

IEC 61162-1, Maritime navigation and radiocommunication equipment and systems – Digital

interfaces – Part 1: Single talker and multiple listeners

IMO, International Convention for the safety of life at sea (SOLAS),1974 as amended

IMO Resolution A.694(17):1991, General requirements for shipborne radio equipment
forming part of the global maritime distress and safety system (GMDSS) and for electronic
navigational aids
IMO Resolution A.807(19):1995, Performance Standards for INMARSAT-C ship earth
stations capable of transmitting and receiving direct-printing communications as amended by
Resolution MSC.68(68) Annex 4
IMO Resolution MSC.263(84):2008, Revised performance standards and functional
requirements for the long-range identification and tracking of ships.
IMO Resolution MSC.306(87):2010, Revised performance standards for enhanced group call
(EGC) equipment
Inmarsat, Inmarsat-C System definition manual (SDM) Volume 2 – Part 2, Application Note
2, Position reporting service
Inmarsat, Inmarsat-C System definition manual (SDM) Volume 2 – Part 2, Application Note
3, Application developers guide to data reporting and polling
Inmarsat, Inmarsat-C System definition manual (SDM) Volume 3 – Part 2, Chapter 2, Mobile
earth station technical requirements
Inmarsat, Inmarsat-C System definition manual (SDM) Volume 3 – Part 2, Chapter 5, Ship
earth station technical requirements
Inmarsat, Inmarsat-C System definition manual (SDM) Volume 3 – Part 2, Chapter 8,
Technical requirements for an EGC receiver

Inmarsat, Recommended test procedures (RTP) for the type approval of Inmarsat-C mobile
earth stations
3 Performance requirements
3.1 Overview
Subclauses 3.2 through 3.4 of this standard describe performance requirements directly
attributable to IMO Resolutions A.807(19) and MSC.306(87) as listed in the normative
references. Subclause 3.5 is provided to highlight those requirements of IMO Resolution
A.694(17) which are not included in the normal Inmarsat requirements for Inmarsat-C SES
type approval. Subclause 3.6 describes other requirements which are required to make the
equipment suitable for GMDSS applications. Subclause 3.7 describes performance
requirements attributable to IMO Resolution MSC.263(84) for long-range identification and
tracking.
– 8 – IEC 61097-4:2012+AMD1:2016 CSV

© IEC 2016
3.2 Non-operational requirements

3.2.1 General
(A.807(19) A1.1/MSC.306(87) A1.1) The Inmarsat Standard-C ship earth station installation
capable of transmitting and receiving direct-printing communications, and the enhanced group

call equipment to be used in the GMDSS shall comply with the general requirements set out in

Assembly resolution A.694(17) as detailed in IEC 60945 and this IEC standard.

(A.807(19) A2/MSC.306(87) 2) The ship earth station and the EGC equipment shall be type-

approved by Inmarsat and shall comply with the environmental conditions and

electromagnetic compatibility requirements specified in IEC 60945.

3.2.2 Warning of radiation hazard
(A.807(19) A4) In order to permit a warning of potential radiation hazards to be displayed in
appropriate locations, a label shall be attached to the radome indicating the distances
2 2 2
external to the radome at which radiation levels of 100 W/m , 25 W/m and 10 W/m exist.
However, the distances which are within the radome need not be indicated.
NOTE Due to the low transmitted power of Inmarsat-C transmitters (less than 16 dBW) and the omnidirectional
antenna used, this label is not normally required.
3.2.3 Power supply changeover
(See 5.2)
(A.807(19) A5.2/MSC.306(87) A4.2) Changing from one source of supply to another or any
interruption of up to 60 s duration of the supply of electrical energy shall not require the
equipment to be manually re-initialized and shall not result in loss of received messages
stored in the memory.
3.3 Operational requirements for ship earth stations
3.3.1 Capabilities
(See 5.3.1)
The equipment shall comply with regulations IV/8 through IV/10 of SOLAS 1974, as amended,
which prescribe the capabilities of Inmarsat ship earth stations to meet the GMDSS
requirements for ships in the various sea areas. The four capabilities are:
– (SOLAS IV/8.1.5.1/IV/9.1.3.3 and IV/10.1.4.3): means of initiating the transmission of ship-
to-shore distress alerts.
– (SOLAS IV/10.1.1.1): transmitting and receiving distress and safety communications
using direct-printing telegraphy.
– (SOLAS IV/10.1.1.2): initiating and receiving distress priority calls.
– (SOLAS IV/9.3.2/IV/10.1.1.4): transmitting and receiving general radiocommunications,
using either radiotelephony or direct-printing telegraphy.
NOTE In the case of this equipment only direct-printing telegraphy applies.
3.3.2 Ship station identity
(See 5.3.2)
(A.807(19) A3.1): No control external to the equipment shall be available for alteration of the
ship station identity.
3.3.3 Distress alerting
(See 5.3.3)
© IEC 2016
(A.807(19) A3.2): It shall be possible to initiate and make distress calls from the position from

which the ship is normally navigated and from at least one other position designated for

distress alerting.
(A.807(19) A3.3): A distress alert shall be activated only by means of a dedicated distress

button. This button shall not be any key of an ITU-T digital input panel or an ISO keyboard

provided on the equipment.
(A.807(19) A3.4): The dedicated distress button shall:

1) be clearly identified; and
2) be protected against inadvertent operation.
(A.807(19) A3.5): The distress alert initiation shall require at least two independent actions.
(A.807(19) A3.6): The equipment shall indicate the status of the distress alert transmission.
(A.807(19) A3.7): It shall be possible to interrupt and initiate distress messages at any time.
It shall be possible to select the content of, but not initiate a distress alert using the
equipment keyboard or other means, before depressing one of the dedicated buttons to
initiate the distress alert. It shall also be possible to activate an undesignated (see Note)
distress alert by depressing one of the buttons, at any time.
NOTE Undesignated – unspecified distress alert, i.e. the default setting. All other selectable alerts are
"designated".
3.3.4 Position updating
(See 5.3.4)
(A.807(19) A3.8): Facilities shall be provided 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 shall include a suitable interface conforming to
IEC 61162.
The integral electronic position-fixing aid shall comply with the applicable requirements of the
IEC 61108 series.
As a minimum, the interface shall support the sentences GNS, RMC and ZDA described in

IEC 61162-1.
(A.807(19) A3.9): Provision shall also be made for manual entry of position information and of
the time at which the position was determined.
(A.807(19) A3.10): An alarm shall be activated 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 24 hours shall be clearly
identified. See also 3.4.3.
NOTE Subclause 3.3.7, which is referenced in the Inmarsat-C SDM, is 3.3.3 in this edition of this standard.
3.4 Operational requirements for EGC receivers
3.4.1 Capabilities
(See 5.4.1)
– 10 – IEC 61097-4:2012+AMD1:2016 CSV

© IEC 2016
The equipment shall comply with regulations IV/7 and IV/10 of SOLAS 1974, as amended,

which prescribe the capabilities of EGC receivers to meet the GMDSS requirements for ships

in the various sea areas. The two capabilities are:

– (SOLAS IV/7.1.5): a radio facility for reception of maritime safety information by the

Inmarsat enhanced group calling system.

– (SOLAS IV/10.1.1.3): an Inmarsat ship earth station capable of maintaining watch for

shore-to-ship distress alerts, including those directed to specifically defined geographical

areas.
3.4.2 General
(See 5.4.2)
(MSC.306(87) A1.2): The equipment shall be capable of producing a printed copy of received
information. Received EGC messages may be stored, for later printing with an indication to
the operator that the message has been received, except for the vital messages referred to
in A.3.2 which shall be printed out upon receipt.
(MSC.306(87) A1.3): The enhanced group call installation may be either separate or
combined with other installations. Elements of other installations, e.g. the antenna, low noise
amplifier and down converter of the ship earth system, may be shared for the reception of
enhanced group call messages.
3.4.3 Position and area code updating
(See 5.4.3)
(MSC.306(87) A3.1): The equipment shall provide a visual indication that the ship’s position
has not been updated during the last 12 hours. It shall only be possible to reset this indication
by revalidating the ship’s position. See also 3.3.4.
(MSC.306(87) A3.2): Means shall be provided to enter the ship's position and current and
planned NAVAREA/METAREA codes manually so that area group calls can be received.
Means shall also be provided to enter current and planned coastal warning service coverage
areas and different classes of messages. Optionally, the ship's position, as determined by the
navigational equipment may be entered automatically and the NAVAREA/METAREA code
automatically derived therefrom.
NOTE NAVAREAs and METAREAs are geographical sea areas established for the purpose of co-ordinating the
broadcast of navigational and meteorological safety information. The world is currently divided into 21 areas (I to
XXI). The boundaries are shown in the IMO International SafetyNET Manual.

3.4.4 Indication of receipt of priority message
(See 5.4.4)
(MSC.306(87) A3.3): Provision shall be made for a specific aural alarm and visual indication
at the position from which the ship is normally navigated to indicate receipt of a distress or
urgency priority EGC message. It shall not be possible to disable this alarm and it shall only
be possible to reset it manually and only from the position where the message is displayed
or printed.
3.4.5 Indication of tuning and synchronisation
(See 5.4.5)
(MSC.306(87) A3.4): The equipment shall indicate when it is not correctly tuned or
synchronized to the enhanced group call carrier.

© IEC 2016
3.4.6 Printing selection
(See 5.4.6)
(MSC.306(87) A3.5): Any message shall be printed regardless of the character error rate of its

reception. The equipment shall print a low-line mark if a character is received corrupted.

(MSC.306(87) A3.6): Acceptance or rejection of service codes shall be under the operator's

control except that equipment shall always receive navigational and meteorological warnings

and forecasts, search and rescue information, and shore-to-ship distress alerts, which are

directed to a fixed or absolute geographical area in which the ship is operating.

NOTE The service codes (C ) are described in the IMO International SafetyNET Manual. They have similar
meanings as the subject indicator characters (B ) in the NAVTEX system described in the IMO NAVTEX Manual
and Recommendation ITU-R M.540.
(MSC.306(87) A3.7): Means shall be provided to prevent the reprinting of a message once it
has been received without error.
3.4.7 Printing device
(See 5.4.7)
(MSC.306(87) A3.8): The printing device shall be capable of printing at least the standard
International Alphabet Number 5 (IA5) character set. Other character sets are optionally used
according to ISO 2022 standards.
(MSC.306(87) A3.9): The printing device shall be able to print at least 40 characters per line.
(MSC.306(87) A3.10): The signal processor and printing device shall ensure that if a word
cannot be accommodated in full on one line, it shall be transferred to the next line. The
printing device shall automatically feed five lines after completing the printed messages.
(MSC.306(87) A3.11): A local audible alarm shall be sounded to give advanced warning of the
printing device “paper low” condition. It shall not be possible to confuse the sound of the
“paper low” alarm with that of the distress or urgency alarm caused by the reception of a
distress or urgency priority message.
3.5 Performance related requirements from IEC 60945
(See 5.5)
The equipment shall comply with those clauses of IEC 60945 appropriate to its equipment
class. The subclauses of IEC 60945 referenced below, amend or augment the corresponding

requirements of the Inmarsat-C SDM.
– 4.1 General
– 4.2 Design and operation
– 4.3 Power supply
– 4.4 Durability and resistance to environmental conditions (see 4.2)
– 4.5 Interference (see 4.2)
– 4.6 Safety precautions
– 4.7 Maintenance
– 4.8 Equipment manuals
– 4.9 Marking and identification
3.6 Other requirements
(See 5.6)
– 12 – IEC 61097-4:2012+AMD1:2016 CSV

© IEC 2016
Message display facilities shall be suitable for displaying received distress-related messages.

It is recommended that the display facilities should comply with the corresponding

requirements for EGC receivers in 3.4.6 and 3.4.7.

Any programming material or software that forms part of the equipment and which is

necessary for meeting the GMDSS requirements shall be permanently installed in the

equipment. Any software needed to fulfil any distress and safety requirements of the GMDSS

shall not be stored on any medium which can be accessed, modified or corrupted.

Any ancillaries associated with Inmarsat-C equipment, such as visual display units, keyboards

and printers, shall be available immediately on demand to service GMDSS functional

requirements. These ancillaries shall also be provided with fixing arrangements to prevent
unauthorized removal or disconnection.
3.7 Long-range identification and tracking
3.7.1 General
(See 5.7.1)
Long-range identification and tracking of ships (LRIT) is a requirement of regulation V/19-1 of
SOLAS 1974 as amended.
NOTE IEC 62729 contains general information on requirements and testing for LRIT.
For the purposes of LRIT the Inmarsat-C SES shall support the Inmarsat enhanced pre-
assigned data reporting service (reserved access) the enhanced data reporting service
(unreserved access), and the polling service.
NOTE Enhanced and enhanced pre-assigned data reporting offers additional capabilities and features over the
Inmarsat data reporting service particularly; use of an internal data reporting checksum, inclusion of the ship earth
station identification to ensure unambiguous identification of stations, an acknowledgement mechanism managing
multiple assignments inside the ocean region and across ocean regions, changing reporting intervals, controlling
and querying assignments and status request facility to ensure reliable transfer.
3.7.2 Capabilities
3.7.2.1 Transmission of information
(See 5.7.2)
(MSC.263(84) A4.1.1) Shipborne equipment shall be capable of automatically and without
human intervention on board the ship transmitting the ship’s LRIT information at 6-hour
intervals to an LRIT Data Centre

(MSC.263(84) A4.4.1) When a ship is undergoing repairs, modifications or conversions in dry-
dock or in port or is laid up for a long period, the master or the Administration may reduce the
frequency of the transmission LRIT information to one transmission every 24-hour period, or may
temporarily stop the transmission of such information.
NOTE LRIT Data Centres are set up by Governments, either individually or in cooperation with other
Governments. Administrations decide to which LRIT Data Centre ships entitled to fly their flag are required to
transmit the LRIT information. The LRIT information is described in Table 1.
This requirement is achieved by the reserved data reporting service using a Data Network
Identity (DNID) and a Member Number to associate the LRIT information with an LRIT Data
Centre. Information about the DNID and Member Number is downloaded by polling commands
(see 3.7.2.2) under the control of an Administration.
There shall be no control external to the equipment to set up or remove DNIDs. However,
facilities shall be provided to stop the transmission of LRIT information and to increase the
intervals between transmissions to 24 h, by controls external to the equipment. Facilities shall

© IEC 2016
also be provided to re-enable the transmissions at 6 h intervals. These facilities shall be

security protected so that access can be restricted to the master only.

3.7.2.2 Remote configuration
(MSC.263(84) A4.1.2) Shipborne equipment shall be capable of being configured remotely to

transmit LRIT information at variable intervals (Pre-scheduled position reports)

The equipment shall be capable of being remotely configured to transmit LRIT information at

intervals ranging from a minimum of 15 min to periods of 6 h to the LRIT Data Centre,

irrespective of where the ship is located and without human interaction on board the ship.

The equipment shall also be capable of being remotely configured to stop the transmission of
LRIT information.
This requirement is achieved by the polling service and by using control/query commands
supported by the enhanced pre-assigned data reporting service. The equipment shall support
polling command types 00H to 0BH as described in the Inmarsat-C SDM Volume 2, Part 2,
Application Note 3.
Configuration information, as described in the Inmarsat-C SDM Volume 2, Part 2, Application
Note 3 shall be stored in non-volatile memory to allow recovery after a power outage. There
shall be provision within the non-volatile memory to store at least 64 16-bit DNIDs.
3.7.2.3 On-demand reports
(MSC.263(84) A4.1.3) Shipborne equipment shall be capable of transmitting LRIT information
following receipt of polling commands (On-demand position reports)
NOTE 1 On-demand position reports means transmission of LRIT information as a result of either receipt of polling
command or of remote configuration of the equipment so as to transmit at intervals other than the preset ones.
The equipment shall be capable of responding to a request to transmit LRIT information on
demand without human interaction on board the ship, irrespective of where the ship is
located.
This requirement is achieved by the polling and data reporting service.
The equipment shall transmit the LRIT information within 8 min of receiving the polling
command.
NOTE 2 The worst case signalling exchange for a polling command takes 44 frames plus 1 min (7,3 min).

MSC.263(84) A13 requires that on-demand information be provided to an LRIT data user within 30 min of the time
that the LRIT data user requested the information.
3.7.3 Functionality
(See 5.7.3)
(MSC.263(84) A4.2) In addition to the provisions specified in 3.7.2, the shipborne equipment
shall provide the functionality specified in Table 1.

– 14 – IEC 61097-4:2012+AMD1:2016 CSV

© IEC 2016
Table 1 – Data to be transmitted from the shipborne equipment

Parameter Comments
Identity of the ship The identifier used by the shipborne equipment.

Position of the ship The Global Navigation Satellite System (GNSS) position (latitude and

(latitude and longitude) longitude) of the ship (based on the WGS 84 datum).

Date and time of the position The date and time, indicated as Universal Coordinated Time (UTC),
provided associated with the GNSS position. In the LRIT system this is known
as Time Stamp 1.The equipment should be capable of transmitting the

time associated with the GNSS position with each transmission of LRIT

information.
NOTE The format of the data report is described in the Inmarsat-C SDM Volume 2, Part 2, Application
Note 2. The enhanced data reporting protocol permits the 24-bit codes allocated to the ship earth station as
“to-mobile” and “from-mobile” identifiers to be included, together with the 8-bit code identifier for the land
earth station used. The category of the report is 01B (maritime position report). The latitude and longitude of
the position is coded to an accuracy of 0,04 of a Minute. The Macro Encoded Message (MEM code) is set to
11 (time of position). The date is coded as current or next month and day. The time is coded as hour and
minutes to an accuracy of 2 min.

3.7.4 Communication system
(See 5.7.4)
(MSC.263(84) A4.3) The shipborne equipment shall transmit the LRIT information using a
communication system which provides coverage in all areas where the ship operates.
The Inmarsat-C shipborne equipment operates in the coverage area defined by Inmarsat
which comprises the Pacific Ocean Region, Atlantic Ocean Region-West, Atlantic Ocean
Region-East and In
...

IEC 61097-4 ®
Edition 3.2 2019-06
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
colour
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Global maritime distress and safety system (GMDSS) –
Part 4: Inmarsat-C ship earth station and Inmarsat enhanced group call (EGC)
equipment – Operational and performance requirements, methods of testing
and required test results
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IEC 61097-4 ®
Edition 3.2 2019-06
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
colour
inside
Global maritime distress and safety system (GMDSS) –

Part 4: Inmarsat-C ship earth station and Inmarsat enhanced group call (EGC)

equipment – Operational and performance requirements, methods of testing

and required test results
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 47.020.70 ISBN 978-2-8322-7116-2

IEC 61097-4 ®
Edition 3.2 2019-06
CONSOLIDATED VERSION
REDLINE VERSION
colour
inside
Global maritime distress and safety system (GMDSS) –
Part 4: Inmarsat-C ship earth station and Inmarsat enhanced group call (EGC)
equipment – Operational and performance requirements, methods of testing
and required test results
– 2 – IEC 61097-4:2012+AMD1:2016

+AMD2:2019 CSV © IEC 2019
CONTENTS
FOREWORD . 4

INTRODUCTION to Amendment 2 . 6

1 Scope . 7

2 Normative references . 7

3 Performance requirements . 9

3.1 Overview . 9

3.2 Non-operational requirements . 9
3.2.1 General . 9
3.2.2 Warning of radiation hazard . 9
3.2.3 Power supply changeover . 9
3.3 Operational requirements for ship earth stations . 9
3.3.1 Capabilities . 9
3.3.2 Ship station identity . 10
3.3.3 Distress alerting . 10
3.3.4 Position updating . 10
3.4 Operational requirements for EGC receivers . 11
3.4.1 Capabilities . 11
3.4.2 General . 11
3.4.3 Position and area code updating . 11
3.4.4 Indication of receipt of priority message . 12
3.4.5 Indication of tuning and synchronisation . 12
3.4.6 Printing selection . 12
3.4.7 Printing device . 12
3.5 Performance related requirements from IEC 60945 . 13
3.6 Other requirements . 13
3.7 Long-range identification and tracking . 13
3.7.1 General . 13
3.7.2 Capabilities . 14
3.7.3 Functionality . 15
3.7.4 Communication system . 15
4 Technical characteristics . 16
4.1 Overview . 16

4.2 Environmental and electromagnetic compatibility requirement . 16
4.3 Radiated spurious emissions . 17
4.4 Interfaces . 17
5 Methods of testing and required test results . 17
5.1 Overview . 17
5.1.1 General . 17
5.1.2 Performance requirements . 18
5.1.3 Technical characteristics . 18
5.2 Tests of non-operational requirements . 18
5.3 Tests of operational requirements for ship earth stations . 18
5.3.1 Capabilities . 18
5.3.2 Ship station identity . 18
5.3.3 Distress alerting . 18
5.3.4 Position updating . 19

+AMD2:2019 CSV © IEC 2019
5.4 Tests of operational requirements for EGC receivers . 19

5.4.1 Capabilities . 19

5.4.2 General . 19

5.4.3 Position and area code updating . 19

5.4.4 Indication of receipt of priority message . 20

5.4.5 Indication of tuning and synchronisation . 20

5.4.6 Printing selection . 20

5.4.7 Printing device . 20

5.5 Tests of performance related requirements from IEC 60945 . 20

5.6 Tests of other requirements . 20

5.7 Long-range identification and tracking . 20
5.7.1 General . 20
5.7.2 Capabilities . 21
5.7.3 Functionality . 21
5.7.4 Communication system . 21
5.8 Tests of technical characteristics . 22
5.8.1 Inmarsat tests . 22
5.8.2 Tests for environmental and electromagnetic compatibility . 22
5.8.3 Interfaces . 22
Annex A (normative) Requirements relating to installation . 24
Annex B (normative) Radiated unwanted emissions . 25
Annex C (informative) Inmarsat RTP schedule of tests. 28
Bibliography . 32

Table 1 – Data to be transmitted from the shipborne equipment . 15
Table 2 – Environmental conditions . 16
Table B.1 – Limits of unwanted emissions up to 1 000 MHz . 25
Table B.2 – Limits of unwanted emissions above 1 000 MHz . 26
Table B.3 – Limits of unwanted emission within the operating band with carrier-on . 27
Table C.1 – Phase I Inmarsat-C schedule of tests . 28
Table C.2 – Phase I EGC receiver schedule of tests . 30
Table C.3 – Phase II schedule of tests . 31

– 4 – IEC 61097-4:2012+AMD1:2016

+AMD2:2019 CSV © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
GLOBAL MARITIME DISTRESS
AND SAFETY SYSTEM (GMDSS) –
Part 4: Inmarsat-C ship earth station and

Inmarsat enhanced group call (EGC) equipment –

Operational and performance requirements,

methods of testing and required test results
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This consolidated version of the official IEC Standard and its amendments has been
prepared for user convenience.
IEC 61097-4 edition 3.2 contains the third edition (2012-05) [documents 80/659/FDIS and
80/666/RVD], its amendment 1 (2016-08) [documents 80/789/CDV and 80/808/RVC] and its
amendment 2 (2019-06) [documents 80/926/FDIS and 80/929/RVD].
In this Redline version, a vertical line in the margin shows where the technical content
is modified by amendments 1 and 2. Additions are in green text, deletions are in
strikethrough red text. A separate Final version with all changes accepted is available in
this publication.
+AMD2:2019 CSV © IEC 2019
International Standard IEC 61097-4 has been prepared by IEC technical committee 80:
Maritime navigation and radiocommunication equipment and systems.

This edition constitutes a technical revision. The main changes with respect to the previous
edition are:
– the IMO references and requirements have been updated to the new performance

standards for enhanced group call equipment adopted in 2010 as resolution MSC.306(87).
The new performance standards incorporate new requirements for an indication of ship’s
position which has not been updated (3.4.3) and an alarm for paper low condition (3.4.7).
These two requirements are, however, derived from Inmarsat documentation so there is
no technical change to equipment;
– a new subclause has been added (3.7) concerning long-range identification and tracking
(LRIT) to support IMO performance standards given in resolution MSC.263(84) adopted in
2008;
– references to Inmarsat documentation have been simplified by moving the content of
Tables 1, 2, 4 and 5 into a new Annex C;
– the text has been editorially updated to conform to the ISO/IEC Directives.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 61097 series, published under the general title Global maritime
distress and safety system (GMDSS), can be found on the IEC website.
The committee has decided that the contents of the base publication and its amendments will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – IEC 61097-4:2012+AMD1:2016

+AMD2:2019 CSV © IEC 2019
INTRODUCTION to Amendment 2
NOTE This amendment adds a requirement for an interface for alert management and removes the requirement to

produce a printed copy of received safety information providing there is an interface to other navigation display

equipment. This results from amendments to the performance standards for enhanced group call equipment agreed
by the International Maritime Organization in resolution MSC.431(98) in 2017. It can be noted that the technical

provisions for the interface for the transfer of received data to other navigation display equipment were included in

+AMD2:2019 CSV © IEC 2019
GLOBAL MARITIME DISTRESS
AND SAFETY SYSTEM (GMDSS) –
Part 4: Inmarsat-C ship earth station and

Inmarsat enhanced group call (EGC) equipment –

Operational and performance requirements,

methods of testing and required test results

1 Scope
This part of IEC 61097 specifies the performance requirements and methods of testing for
Inmarsat-C ship earth stations (SES) capable of transmitting and receiving direct-printing
communications, and for enhanced group call (EGC) receivers, for use in the GMDSS and for
use for long-range identification and tracking (LRIT). The available variants are:
Class 0: An EGC receiver, either stand-alone or an element of a GMDSS installation in
accordance with the Inmarsat design and installation guidelines (DIGs) for
GMDSS installations.
Class 1: A basic SES providing shore-to-ship and ship-to-shore message transfer only.
Class 2: As class 1 but with EGC as an alternative to shore-to-ship transfer using a
shared receiver.
Class 3: As class 1 but with EGC using an independent receiver.
th
NOTE 1 The 34 session of the IMO Sub-Committee on Radiocommunications decided that class 2 equipment
would be adequate to provide sufficient availability for the reception of maritime safety information for the GMDSS.
The standard complies with IMO performance requirements stated in the normative
references, Inmarsat technical characteristics and test procedures, and IEC 60945 general
requirements except where modifications are explicitly stated in this standard. Technical
characteristics essential to GMDSS and LRIT operation as defined by the IMO are identified.
All text of this standard, whose wording is identical to that in IMO SOLAS Convention 1974 as
amended in 1988 and Resolutions A.807(19), MSC.263(84) and MSC.306(87) is printed in
italics and reference made to the Resolution/Recommendation and subclause number.
This standard covers equipment construction and testing. Matters relating to installation may
also be found in the Inmarsat Maritime design and installation guidelines (see Bibliography).
Those to be found in IMO Resolutions A.807(19), MSC.263(84) and MSC.306(87) are

reproduced in Annex A.
Responsibility for type approval of Inmarsat-C and Inmarsat-EGC is vested in Inmarsat by
IMO Resolutions A.807(19) and MSC.306(87) (see 3.2.1). Therefore, this standard does not
reproduce Inmarsat test procedures in full, but refers to where they are given in Inmarsat
documentation cited in the normative references to this standard (Annex C).
NOTE 2 For the purposes of this standard the terms Inmarsat-C, Inmarsat Standard-C, Standard-C refer to the
same equipment.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
– 8 – IEC 61097-4:2012+AMD1:2016

+AMD2:2019 CSV © IEC 2019
IEC 60945:2002, Maritime navigation and radiocommunication equipment and systems –

General requirements – Methods of testing and required test results

IEC 61108 (all parts), Maritime navigation and radiocommunication equipment and systems

– Global navigation satellite systems (GNSS)

IEC 61162-1, Maritime navigation and radiocommunication equipment and systems – Digital

interfaces – Part 1: Single talker and multiple listeners

IEC 62923-1, Maritime navigation and radiocommunication equipment and systems – Bridge

alert management – Part 1: Operational and performance requirements, methods of testing

and required test results
IEC 62923-2, Maritime navigation and radiocommunication equipment and systems – Bridge
alert management – Part 2: Alert and cluster identifiers and other additional features
IMO, International Convention for the safety of life at sea (SOLAS),1974 as amended
IMO Resolution A.694(17):1991, General requirements for shipborne radio equipment
forming part of the global maritime distress and safety system (GMDSS) and for electronic
navigational aids
IMO Resolution A.807(19):1995, Performance Standards for INMARSAT-C ship earth
stations capable of transmitting and receiving direct-printing communications as amended by
Resolution MSC.68(68) Annex 4
IMO Resolution MSC.263(84):2008, Revised performance standards and functional
requirements for the long-range identification and tracking of ships.
IMO Resolution MSC.302(87) (2010), Performance standards for bridge alert management
IMO Resolution MSC.306(87):2010, Revised performance standards for enhanced group call
(EGC) equipment
Inmarsat, Inmarsat-C System definition manual (SDM) Volume 2 – Part 2, Application Note
2, Position reporting service
Inmarsat, Inmarsat-C System definition manual (SDM) Volume 2 – Part 2, Application Note
3, Application developers guide to data reporting and polling

Inmarsat, Inmarsat-C System definition manual (SDM) Volume 3 – Part 2, Chapter 2, Mobile
earth station technical requirements
Inmarsat, Inmarsat-C System definition manual (SDM) Volume 3 – Part 2, Chapter 5, Ship
earth station technical requirements
Inmarsat, Inmarsat-C System definition manual (SDM) Volume 3 – Part 2, Chapter 8,
Technical requirements for an EGC receiver
Inmarsat, Recommended test procedures (RTP) for the type approval of Inmarsat-C mobile
earth stations
+AMD2:2019 CSV © IEC 2019
3 Performance requirements
3.1 Overview
Subclauses 3.2 through 3.4 of this standard describe performance requirements directly

attributable to IMO Resolutions A.807(19) and MSC.306(87) as listed in the normative

references. Subclause 3.5 is provided to highlight those requirements of IMO Resolution

A.694(17) which are not included in the normal Inmarsat requirements for Inmarsat-C SES

type approval. Subclause 3.6 describes other requirements which are required to make the

equipment suitable for GMDSS applications. Subclause 3.7 describes performance
requirements attributable to IMO Resolution MSC.263(84) for long-range identification and

tracking.
3.2 Non-operational requirements
3.2.1 General
(A.807(19) A1.1/MSC.306(87) A1.1) The Inmarsat Standard-C ship earth station installation
capable of transmitting and receiving direct-printing communications, and the enhanced group
call equipment to be used in the GMDSS shall comply with the general requirements set out in
Assembly resolution A.694(17) as detailed in IEC 60945 and this IEC standard.
(A.807(19) A2/MSC.306(87) 2) The ship earth station and the EGC equipment shall be type-
approved by Inmarsat and shall comply with the environmental conditions and
electromagnetic compatibility requirements specified in IEC 60945.
3.2.2 Warning of radiation hazard
(A.807(19) A4) In order to permit a warning of potential radiation hazards to be displayed in
appropriate locations, a label shall be attached to the radome indicating the distances
2 2 2
external to the radome at which radiation levels of 100 W/m , 25 W/m and 10 W/m exist.
However, the distances which are within the radome need not be indicated.
NOTE Due to the low transmitted power of Inmarsat-C transmitters (less than 16 dBW) and the omnidirectional
antenna used, this label is not normally required.
3.2.3 Power supply changeover
(See 5.2)
(A.807(19) A5.2/MSC.306(87) A4.2) Changing from one source of supply to another or any
interruption of up to 60 s duration of the supply of electrical energy shall not require the
equipment to be manually re-initialized and shall not result in loss of received messages
stored in the memory.
3.3 Operational requirements for ship earth stations
3.3.1 Capabilities
(See 5.3.1)
The equipment shall comply with regulations IV/8 through IV/10 of SOLAS 1974, as amended,
which prescribe the capabilities of Inmarsat ship earth stations to meet the GMDSS
requirements for ships in the various sea areas. The four capabilities are:
– (SOLAS IV/8.1.5.1/IV/9.1.3.3 and IV/10.1.4.3): means of initiating the transmission of ship-
to-shore distress alerts.
– (SOLAS IV/10.1.1.1): transmitting and receiving distress and safety communications
using direct-printing telegraphy.
– (SOLAS IV/10.1.1.2): initiating and receiving distress priority calls.

– 10 – IEC 61097-4:2012+AMD1:2016

+AMD2:2019 CSV © IEC 2019
– (SOLAS IV/9.3.2/IV/10.1.1.4): transmitting and receiving general radiocommunications,

using either radiotelephony or direct-printing telegraphy.

NOTE In the case of this equipment only direct-printing telegraphy applies.

3.3.2 Ship station identity
(See 5.3.2)
(A.807(19) A3.1): No control external to the equipment shall be available for alteration of the
ship station identity.
3.3.3 Distress alerting
(See 5.3.3)
(A.807(19) A3.2): It shall be possible to initiate and make distress calls from the position from
which the ship is normally navigated and from at least one other position designated for
distress alerting.
(A.807(19) A3.3): A distress alert shall be activated only by means of a dedicated distress
button. This button shall not be any key of an ITU-T digital input panel or an ISO keyboard
provided on the equipment.
(A.807(19) A3.4): The dedicated distress button shall:
1) be clearly identified; and
2) be protected against inadvertent operation.
(A.807(19) A3.5): The distress alert initiation shall require at least two independent actions.
(A.807(19) A3.6): The equipment shall indicate the status of the distress alert transmission.
(A.807(19) A3.7): It shall be possible to interrupt and initiate distress messages at any time.
It shall be possible to select the content of, but not initiate a distress alert using the
equipment keyboard or other means, before depressing one of the dedicated buttons to
initiate the distress alert. It shall also be possible to activate an undesignated (see Note)
distress alert by depressing one of the buttons, at any time.
NOTE Undesignated – unspecified distress alert, i.e. the default setting. All other selectable alerts are
"designated".
3.3.4 Position updating
(See 5.3.4)
(A.807(19) A3.8): Facilities shall be provided 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 shall include a suitable interface conforming to
IEC 61162.
The integral electronic position-fixing aid shall comply with the applicable requirements of the
IEC 61108 series.
As a minimum, the interface shall support the sentences GNS, RMC and ZDA described in
IEC 61162-1.
+AMD2:2019 CSV © IEC 2019
(A.807(19) A3.9): Provision shall also be made for manual entry of position information and of

the time at which the position was determined.

(A.807(19) A3.10): An alarm shall be activated 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 24 hours shall be clearly

identified. See also 3.4.3.
NOTE Subclause 3.3.7, which is referenced in the Inmarsat-C SDM, is 3.3.3 in this edition of this standard.

3.4 Operational requirements for EGC receivers

3.4.1 Capabilities
(See 5.4.1)
The equipment shall comply with regulations IV/7 and IV/10 of SOLAS 1974, as amended,
which prescribe the capabilities of EGC receivers to meet the GMDSS requirements for ships
in the various sea areas. The two capabilities are:
– (SOLAS IV/7.1.5): a radio facility for reception of maritime safety information by the
Inmarsat enhanced group calling system.
– (SOLAS IV/10.1.1.3): an Inmarsat ship earth station capable of maintaining watch for
shore-to-ship distress alerts, including those directed to specifically defined geographical
areas.
3.4.2 General
(See 5.4.2)
(MSC.306(87) A1.2): The equipment shall be capable of producing a printed copy of received
information. Received EGC messages may be stored, for later printing with an indication to
the operator that the message has been received, except for the vital messages referred to
in A.3.2 which shall be printed out upon receipt.
(MSC.306(87) A1.3): Alternatively to the requirement in paragraph MSC.306(87) A1.2, the
equipment need not provide means to produce a printed copy of received information if it is
installed in combination with an interface connecting it to navigation equipment that is
compliant with resolution MSC 252(83), as amended, on Revised Performance standards for
integrated navigation systems (INS). Provisions for interconnection to a shipborne integrated
radiocommunication system (IRCS) when used in the GMDSS (resolution A.811(19)) shall
also be included.
If no means are provided by the equipment to produce a printed copy of received information

then the manufacturer’s documentation shall clearly describe that the equipment can only be
used when connected to an equipment enabled for the display of enhanced group calls in
compliance with the applicable IEC 61924-2 requirements.
NOTE The testing standard for compliance with INS (Resolution MSC 252(83)) is IEC 61924-2. The testing
standard for compliance with IRCS (Resolution A.811(19)) is IEC 62940.
(MSC.306(87) A1.34): The enhanced group call installation may be either separate or
combined with other installations. Elements of other installations, e.g. the antenna, low noise
amplifier and down converter of the ship earth system, may be shared for the reception of
enhanced group call messages.
3.4.3 Position and area code updating
(See 5.4.3)
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(MSC.306(87) A3.1): The equipment shall provide a visual indication that the ship’s position

has not been updated during the last 12 hours. It shall only be possible to reset this indication

by revalidating the ship’s position. See also 3.3.4.

(MSC.306(87) A3.2): Means shall be provided to enter the ship's position and current and

planned NAVAREA/METAREA codes manually so that area group calls can be received.

Means shall also be provided to enter current and planned coastal warning service coverage

areas and different classes of messages. Optionally, the ship's position, as determined by the

navigational equipment may be entered automatically and the NAVAREA/METAREA code

automatically derived therefrom.

NOTE NAVAREAs and METAREAs are geographical sea areas established for the purpose of co-ordinating the
broadcast of navigational and meteorological safety information. The world is currently divided into 21 areas (I to
XXI). The boundaries are shown in the IMO International SafetyNET Manual.
3.4.4 Indication of receipt of priority message
(See 5.4.4)
(MSC.306(87) A3.3): Provision shall be made for a specific aural alarm and visual indication
at the position from which the ship is normally navigated to indicate receipt of a distress or
urgency priority EGC message. It shall not be possible to disable this alarm and it shall only
be possible to reset it manually and only from the position where the message is displayed
or printed.
3.4.5 Indication of tuning and synchronisation
(See 5.4.5)
(MSC.306(87) A3.4): The equipment shall indicate when it is not correctly tuned or
synchronized to the enhanced group call carrier.
3.4.6 Printing selection
(See 5.4.6)
(MSC.306(87) A3.5): Any message shall be printed regardless of the character error rate of its
reception. The equipment shall print a low-line mark if a character is received corrupted.
(MSC.306(87) A3.6): Acceptance or rejection of service codes shall be under the operator's
control except that equipment shall always receive navigational and meteorological warnings
and forecasts, search and rescue information, and shore-to-ship distress alerts, which are
directed to a fixed or absolute geographical area in which the ship is operating.

NOTE The service codes (C ) are described in the IMO International SafetyNET Manual. They have similar
meanings as the subject indicator characters (B ) in the NAVTEX system described in the IMO NAVTEX Manual
and Recommendation ITU-R M.540.
(MSC.306(87) A3.7): Means shall be provided to prevent the reprinting of a message once it
has been received without error.
3.4.7 Printing device
(See 5.4.7)
(MSC.306(87) A3.8): The printing device shall be capable of printing at least the standard
International Alphabet Number 5 (IA5) character set. Other character sets are optionally used
according to ISO 2022 standards.
(MSC.306(87) A3.9): The printing device shall be able to print at least 40 characters per line.

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(MSC.306(87) A3.10): The signal processor and printing device shall ensure that if a word

cannot be accommodated in full on one line, it shall be transferred to the next line. The

printing device shall automatically feed five lines after completing the printed messages.

(MSC.306(87) A3.11): A local audible alarm shall be sounded to give advanced warning of the

printing device “paper low” condition. It shall not be possible to confuse the sound of the

“paper low” alarm with that of the distress or urgency alarm caused by the reception of a

distress or urgency priority message.

3.5 Performance related requirements from IEC 60945

(See 5.5)
The equipment shall comply with those clauses of IEC 60945 appropriate to its equipment
class. The subclauses of IEC 60945 referenced below, amend or augment the corresponding
requirements of the Inmarsat-C SDM.
– 4.1 General
– 4.2 Design and operation
– 4.3 Power supply
– 4.4 Durability and resistance to environmental conditions (see 4.2)
– 4.5 Interference (see 4.2)
– 4.6 Safety precautions
– 4.7 Maintenance
– 4.8 Equipment manuals
– 4.9 Marking and identification
3.6 Other requirements
(See 5.6)
Message display facilities shall be suitable for displaying received distress-related messages.
It is recommended that the display facilities should comply with the corresponding
requirements for EGC receivers in 3.4.6 and 3.4.7.
Any programming material or software that forms part of the equipment and which is
necessary for meeting the GMDSS requirements shall be permanently installed in the
equipment. Any software needed to fulfil any distress and safety requirements of the GMDSS
shall not be stored on any medium which can be accessed, modified or corrupted.
Any ancillaries associated with Inmarsat-C equipment, such as visual display units, keyboards

and printers, shall be available immediately on demand to service GMDSS functional
requirements. These ancillaries shall also be provided with fixing arrangements to prevent
unauthorized removal or disconnection.
3.7 Long-range identification and tracking
3.7.1 General
(See 5.7.1)
Long-range identification and tracking of ships (LRIT) is a requirement of regulation V/19-1 of
SOLAS 1974 as amended.
NOTE IEC 62729 contains general information on requirements and testing for LRIT.

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For the purposes of LRIT the Inmarsat-C SES shall support the Inmarsat enhanced pre-

assigned data reporting service (reserved access) the enhanced data reporting service

(unreserved access), and the polling service.

NOTE Enhanced and enhanced pre-assigned data reporting offers additional capabilities and features over the

Inmarsat data reporting service particularly; use of an internal data reporting checksum, inclusion of the ship earth
station identification to ensure unambiguous identification of stations, an acknowledgement mechanism managing

multiple assignments inside the ocean region and across ocean regions, changing reporting intervals, controlling

and querying assignments and status request facility to ensure reliable transfer.

3.7.2 Capabilities
3.7.2.1 Transmission of information
(See 5.7.2)
(MSC.263(84) A4.1.1) Shipborne equipment shall be capable of automatically and without
human intervention on board the ship transmitting the ship’s LRIT information at 6-hour
intervals to an LRIT Data Centre
(MSC.263(84) A4.4.1) When a ship is undergoing repairs, modifications or conversions in dry-
dock or in port or is laid up for a long period, the master or the Administration may reduce the
frequency of the transmission LRIT information to one transmission every 24-hour period, or may
temporarily stop the transmission of such information.
NOTE LRIT Data Centres are set up by Governments, either individually or in cooperation with other
Governments. Administrations decide to which LRIT Data Centre ships entitled to fly their flag are required to
transmit the LRIT information. The LRIT information is described in Table 1.
This requirement is achieved by the reserved data reporting service using a Data Network
Identity (DNID) and a Member Number to associate the LRIT information with an LRIT Data
Centre. Information about the DNID and Member Number is downloaded by polling commands
(see 3.7.2.2) under the control of an Administration.
There shall be no control external to the equipment to set up or remove DNIDs. However,
facilities shall be provided to stop the transmission of LRIT information and to increase the
intervals between transmissions to 24 h, by controls external to the equipment. Facilities shall
also be provided to re-enable the transmissions at 6 h intervals. These facilities shall be
security protected so that access can be restricted to the master only.
3.7.2.2 Remote configuration
(MSC.263(84) A4.1.2) Shipborne equipment shall be capable of being configured remotely to
transmit LRIT information at variable intervals (Pre-scheduled position reports)

The equipment shall be capable of being remotely configured to transmit LRIT information at
intervals ranging from a minimum of 15 min to periods of 6 h to the LRIT Data Centre,
irrespective of where the ship is located and without human interaction on board the ship.
The equipment shall also be capable of being remotely configured to stop the transmission of
LRIT information.
This requirement is achieved by the polling service and by using control/query commands
supported by the enhanced pre-assigned data reporting service. The equipment shall support
polling command types 00H to 0BH as described in the Inmarsat-C SDM Volume 2, Part 2,
Application Note 3.
Configuration information, as described in the Inmarsat-C SDM Volume 2, Part 2, Application
Note 3 shall be stored in non-volatile memory to allow recovery after a power outage. There
shall be provision within the non-volatile memory to store at least 64 16-bit DNIDs.

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3.7.2.3 On-demand reports
(MSC.263(84) A4.1.3) Shipborne equipment shall be capable of transmitting LRIT information

following receipt of polling commands (On-demand position reports)

NOTE 1 On-demand position reports means transmission of LRIT information as a result of either receipt of polling
command or of remote configuration of the equipment so as to transmit at intervals other than the preset ones.

The equipment shall be capable of responding to a request to transmit LRIT
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