Global maritime distress and safety system (GMDSS) - Part 13: Inmarsat F77 ship earth station equipment - Operational and performance requirements, methods of testing and required test results

Specifies the minimum operational and performance requirements, technical characteristics, methods of testing and required test results for INMARSAT F77 ship earth stations (SES), capable of transmitting and receiving distress and safety communications, initiating and receiving distress priority calls and transmitting and receiving general radiocommunications, using radiotelephony (voice), as required within the relevant IMO Regulations.

General Information

Status
Published
Publication Date
03-Jan-2022
Current Stage
WPUB - Publication withdrawn
Completion Date
04-Jan-2022
Ref Project

Buy Standard

Standard
IEC 61097-13:2003 - Global maritime distress and safety system (GMDSS) - Part 13: Inmarsat F77 ship earth station equipment - Operational and performance requirements, methods of testing and required test results
English language
25 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

INTERNATIONAL IEC
STANDARD
61097-13
First edition
2003-05
Global maritime distress and safety
system (GMDSS) –
Part 13:
INMARSAT F77 ship earth station equipment –
Operational and performance requirements,
methods of testing and required test results
Reference number
IEC 61097-13:2003(E)
---------------------- Page: 1 ----------------------
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.
Consolidated editions

The IEC is now publishing consolidated versions of its publications. For example,

edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the

base publication incorporating amendment 1 and the base publication incorporating

amendments 1 and 2.
Further information on IEC publications

The technical content of IEC publications is kept under constant review by the IEC,

thus ensuring that the content reflects current technology. Information relating to

this publication, including its validity, is available in the IEC Catalogue of
publications (see below) in addition to new editions, amendments and corrigenda.
Information on the subjects under consideration and work in progress undertaken

by the technical committee which has prepared this publication, as well as the list

of publications issued, is also available from the following:
• IEC Web Site (www.iec.ch)
• Catalogue of IEC publications

The on-line catalogue on the IEC web site (http://www.iec.ch/searchpub/cur_fut.htm)

enables you to search by a variety of criteria including text searches, technical

committees and date of publication. On-line information is also available on
recently issued publications, withdrawn and replaced publications, as well as
corrigenda.
• IEC Just Published
This summary of recently issued publications (http://www.iec.ch/online_news/
justpub/jp_entry.htm) is also available by email. Please contact the Customer
Service Centre (see below) for further information.
• Customer Service Centre
If you have any questions regarding this publication or need further assistance,
please contact the Customer Service Centre:
Email: custserv@iec.ch
Tel: +41 22 919 02 11
Fax: +41 22 919 03 00
---------------------- Page: 2 ----------------------
INTERNATIONAL IEC
STANDARD
61097-13
First edition
2003-05
Global maritime distress and safety
system (GMDSS) –
Part 13:
INMARSAT F77 ship earth station equipment –
Operational and performance requirements,
methods of testing and required test results
 IEC 2003  Copyright - all rights reserved

No part of this publication may be reproduced or utilized in any form or by any means, electronic or

mechanical, including photocopying and microfilm, without permission in writing from the publisher.

International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland

Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch

PRICE CODE
Commission Electrotechnique Internationale
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue
---------------------- Page: 3 ----------------------
– 2 – 61097-13  IEC:2003(E)
CONTENTS

FOREWORD .......................................................................................................................... 3

1 Scope .............................................................................................................................. 4

2 Normative references....................................................................................................... 5

3 Definitions and abbreviations ........................................................................................... 5

3.1 Definitions .............................................................................................................. 5

3.2 Abbreviations.......................................................................................................... 7

4 General and operational requirements ............................................................................. 8

4.1 General requirements ............................................................................................. 8

4.2 Operational requirements for INMARSAT F77 SES ................................................. 8

5 Technical requirements...................................................................................................10

5.1 Pre-emption by distress calls (ship originated).......................................................10

5.2 Electromagnetic compatibility (EMC)......................................................................11

5.3 Spurious emissions................................................................................................11

5.4 Power supply.........................................................................................................11

5.5 Excessive conditions .............................................................................................11

5.6 Power supply interruption ......................................................................................11

5.7 Interfaces ..............................................................................................................11

6 Methods of testing and required test results....................................................................12

6.1 General .................................................................................................................12

6.2 Test using local distress button..............................................................................14

6.3 Test using remote distress button ..........................................................................14

6.4 Operational tests (without pre-emption) .................................................................14

6.5 Operational tests (with pre-emption) ......................................................................15

6.6 Power supply testing..............................................................................................21

6.7 Interface testing.....................................................................................................21

Annex A (informative) Requirements relating to installation ...................................................22

Annex B (informative) Reception of maritime safety information (MSI)...................................23

Annex C (informative) List of INMARSAT F77 type-approval tests .........................................24

Bibliography..........................................................................................................................25

---------------------- Page: 4 ----------------------
61097-13  IEC:2003(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GLOBAL MARITIME DISTRESS AND SAFETY SYSTEM (GMDSS) –
Part 13: INMARSAT F77 ship earth station equipment –
Operational and performance requirements,
methods of testing and required test results
FOREWORD

1) The IEC (International Electrotechnical Commission) is a world wide organization for standardization

comprising all national electrotechnical committees (IEC National Committees). The object of the IEC is to

promote international co-operation on all questions concerning standardization in the electrical and electronic

fields. To this end and in addition to other activities, the IEC publishes International Standards. Their

preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt

with may participate in this preparatory work. International, governmental and non-governmental organizations

liaising with the IEC also participate in this preparation. The IEC collaborates closely with the International

Organization for Standardization (ISO) in accordance with conditions determined by agreement between the

two organizations.

2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an

international consensus of opinion on the relevant subjects since each technical committee has representation

from all interested National Committees.

3) The documents produced have the form of recommendations for international use and are published in the form

of standards, technical specifications, technical reports or guides and they are accepted by the National

Committees in that sense.

4) In order to promote international unification, IEC National Committees undertake to apply IEC International

Standards transparently to the maximum extent possible in their national and regional standards. Any

divergence between the IEC Standard and the corresponding national or regional standard shall be clearly

indicated in the latter.

5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any

equipment declared to be in conformity with one of its standards.

6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject

of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 61097-13 has been prepared by IEC technical committee 80:

Maritime navigation and radiocommunication equipment and systems.
The text of this standard is based on the following documents:
FDIS Report on voting
80/358/FDIS 80/370/RVD

Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

The committee has decided that the contents of this publication will remain unchanged until

2008-01. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
---------------------- Page: 5 ----------------------
– 4 – 61097-13  IEC:2003(E)
GLOBAL MARITIME DISTRESS AND SAFETY SYSTEM (GMDSS) –
Part 13: INMARSAT F77 ship earth station equipment –
Operational and performance requirements,
methods of testing and required test results
1 Scope

This part of IEC 61097 specifies the minimum operational and performance requirements,

technical characteristics, methods of testing and required test results for INMARSAT F77 ship

earth stations (SES), capable of transmitting and receiving distress and safety

communications, initiating and receiving distress priority calls and transmitting and receiving

general radiocommunications, using radiotelephony (voice), as required within Regulation

IV/10.1 and 14.1 of the 1988 amendments to the 1974 International Convention for the Safety

of Life at Sea (SOLAS), for use in the GMDSS.

The INMARSAT F77 is intended to meet the voice requirements of IMO Resolution A.888(21).

In order to meet the GMDSS carriage requirements of SOLAS in respect of receipt of

SafetyNET broadcasts and direct printing telegraphy, it is necessary to install a combined

INMARSAT C/EGC transceiver in addition to the INMARSAT F77 equipment. Annex B

provides more information. Since Class 1 INMARSAT A and B ship earth stations meet the

data requirement of GMDSS, although not necessarily those of MSC.130(75), the F77 cannot

necessarily be considered as a direct replacement for these ship earth stations.

This standard also takes into account the priority access (voice pre-emption) requirements of

IMO Resolution A.888(21).

This standard takes account of IMO Resolution A.694(17) to which is associated IEC 60945.

When a requirement in this standard is different from IEC 60945, the requirement in this

standard shall take precedence.

This standard incorporates the performance standards of IMO Resolution MSC.130(75) and

the clarifications of certain requirements in IMO performance standards for GMDSS

Equipment defined in IMO MSC Circular 862. It also incorporates the relevant ITU Radio

Regulations.

All text of this standard, whose wording is identical to that in the IMO SOLAS Convention

1974 as amended, IMO Resolutions and IMO MSC Circular 862, is printed in italics and the

Resolution or Recommendation and paragraph number indicated between brackets.

It is a requirement of INMARSAT Ltd that all INMARSAT F77 mobile earth station models be

type-approved by INMARSAT before they can be allowed access to the INMARSAT space

segment. This testing is designed to demonstrate that the equipment under test will be

compatible with the INMARSAT F77 system and will not cause interference to other satellite

users. It is recommended that approval authorities accept testing organized and supervised

by INMARSAT, which results in INMARSAT type approval, without additional testing other

than that defined in this standard.

It is also recommended that equipment manufacturers rationalize the test requirements of this

standard and those of INMARSAT before embarking on the approval process.

NOTE This standard does not incorporate the INMARSAT system requirements needed for INMARSAT type

approval. For these, the latest edition of “INMARSAT mini-M SDM Change Note No. 65” should be consulted. When

a requirement in this standard is different from one in the above-mentioned INMARSAT document, reference shall

be made to the most recent IMO and ITU applicable documents to resolve the difficulty.

---------------------- Page: 6 ----------------------
61097-13  IEC:2003(E) – 5 –
2 Normative references

The following referenced documents are indispensable for the application of this document.

For dated references, only the edition cited applies. For undated references, the latest edition

of the referenced document (including any amendments) applies.

IEC 60945, Maritime navigation and radio communication equipment and systems – General

requirements – Methods of testing and required test results

IEC 61162 (all parts), Maritime navigation and radio communication equipment and systems –

Digital interfaces

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

interfaces – Part 1: Single talker and multiple listeners

ISO/IEC 17025, General requirements for the competence of testing and calibration

laboratories
IMO International Convention for the Safety of Life at Sea (SOLAS)

IMO Resolution A.694(17), 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.888(21), Criteria for the provision of mobile-satellite communication

systems in the Global Maritime Distress and Safety System (GMDSS)

IMO Resolution MSC.130(75), Performance standards for INMARSAT ship earth stations

capable of two-way communications

IMO MSC Circular 862, Clarifications of certain requirements in IMO performance standards

for GMDSS Equipment
INMARSAT mini-M SDM Change Note No. 65
ITU Radio Regulations
3 Definitions and abbreviations
3.1 Definitions

For the purposes of this International Standard, the following definitions apply.

3.1.1
carrier-to-noise density ratio
ratio of unmodulated carrier power-to-noise power normalized to a 1 Hz bandwidth
3.1.2
INMARSAT priorities
priority 3 = distress
priority 2 = urgency
priority 1 = safety
priority 0 = routine
---------------------- Page: 7 ----------------------
– 6 – 61097-13  IEC:2003(E)
3.1.3
INMARSAT type approval

testing of a ship earth station design by INMARSAT. This approval is required for access to

the INMARSAT space segment and is essential before approvals can be granted by national

administrations
3.1.4
L-band

frequency band in the range 1,4 GHz to 1,7 GHz allocated to the mobile satellite service and

in which the EUT transmits and receives
3.1.5
necessary bandwidth

for a given class of emission, width of the frequency band which is just sufficient to ensure the

transmission of information at the rate and with the quality required under specified conditions

3.1.6
out-of-band emission

emission on a frequency or frequencies immediately outside the necessary bandwidth which

results from the modulation process, but excluding spurious emissions
3.1.7
performance check

short functional test carried out during or after a technical test to confirm that the equipment

operates
[IEC 60945]
3.1.8
performance test

measurement or group of measurements carried out during or after a technical test to confirm

that the equipment complies with selected parameters as defined in this standard
[IEC 60945]
3.1.9
physical layer test-set (PLT)

item of test equipment designed to simulate the combined operation of an INMARSAT satellite

and an INMARSAT F77 Land Earth Station. The PLT interfaces to the EUT at L-band, either

by means of a small antenna or via coaxial cable. It permits voice calls to be set up in

accordance with the relevant INMARSAT F77 protocols
3.1.10
pre-emption

automatic clearance of an ongoing call to enable a call of higher priority to be established

3.1.11
radiofrequency hazards

hazards caused by electromagnetic radiofrequency radiation, the level of which would require

safety rules to be applied in the vicinity of the radiating equipment
3.1.12
radome
radiofrequency transparent cover placed over an antenna system
3.1.13
SafetyNET

service provided over a dedicated INMARSAT-C carrier, for the dissemination of maritime

safety information, such as distress alerts, weather forecasts and coastal warnings

---------------------- Page: 8 ----------------------
61097-13  IEC:2003(E) – 7 –
3.1.14
spurious emissions

emissions on a frequency or frequencies which are outside the necessary bandwidth, the level

of which may be reduced without affecting the corresponding transmission of information.

Spurious emissions include harmonic emissions, parasitic emissions, intermodulation products

and frequency conversion products but exclude out-of-band emissions
3.1.15
standard tests

two tests defined in this document as Test A – Duplex Telephone Test (ship-originated) and

Test B – Duplex Telephone Test (shore-originated) which together form the performance test

required by IEC 60945
3.1.16
unwanted emissions
spurious emissions and out-of-band emissions
3.2 Abbreviations
ACSE Access control and signalling equipment
BER Bit error rate
BPSK Binary phase shift keying
C/No Carrier-to-noise density ratio in 1 Hz bandwidth
EGC Enhanced group call
EIRP Effective isotropic radiated power
EMC Electromagnetic compatibility
EUT Equipment under test
GMDSS Global maritime distress and safety system
G/T Satellite receiver “figure of merit”
HPA High power amplifier
ID Identity
IEC International Electrotechnical Commission
IMO International Maritime Organization
INMARSAT INMARSAT Ltd.
ISO International Organization for Standardization
ITU International Telecommunications Union
LES Land earth station
LESP Land earth station packet data channel
MES Mobile earth station
MESP Mobile earth station packet data channel
MPDS INMARSAT’s mobile packet data service (for example, Internet access)
MSI Maritime safety information
16-QAM Quaternary amplitude modulation (16-state)
O-QPSK Offset quaternary phase shift-keying
PLT Physical layer test-set
RCC Rescue coordination centre
SDM System definition manual (published by INMARSAT)
SES Ship earth station
SOLAS International convention for the safety of life at sea
---------------------- Page: 9 ----------------------
– 8 – 61097-13  IEC:2003(E)
4 General and operational requirements
This Clause 4 includes the requirements taken from IMO SOLAS and IMO Resolutions

MSC.130(75) and A.694(17) for which no repeatable or verifiable test can be specified or for

which the test is limited to the verification of documentation presented by the manufacturer. It

contains all operational tests, particularly those involving subjective judgement and which

shall be conducted by personnel approved by national administrations. Some of the

requirements listed in this clause are in addition to the relevant operational requirements of

IEC 60945, which are also applicable.
4.1 General requirements
4.1.1 Definition
An INMARSAT F77 ship earth station, which is defined in the “INMARSAT mini-M SDM
Change Note No. 65”, shall be capable of
a) transmitting and receiving distress and safety communications;
b) initiating and receiving distress priority calls; and

c) transmitting and receiving general radio communications, using radiotelephony.

4.1.2 INMARSAT type approval

(MSC.130/A.2) The equipment shall be type approved by INMARSAT and shall comply with

the environmental conditions specified in its technical requirements for INMARSAT ship earth

stations capable of two-way communications. INMARSAT type approval is required for access

to the INMARSAT space segment and is essential before approvals can be granted by

national administrations.
4.1.3 Ship earth station installation requirements

(MSC.130/A.1) The ship earth station installation (which will normally comprise an

INMARSAT F77 transceiver and an additional INMARSAT-C/EGC transceiver) capable of

telephony and data communications shall comply with the applicable general requirements set

out in IMO resolution A.694(17) as detailed in IEC 60945.
4.2 Operational requirements for INMARSAT F77 SES
4.2.1 Prevention of alteration of ship earth station identity

(MSC.130/A.3.1) No control external to the equipment shall be available for alteration of the

ship earth station identity.
4.2.2 Initiation of distress calls

(MSC.130/A.3.2) It shall be possible to initiate and make distress calls by telephony or data

communications from the position at which the ship is normally navigated and from any

position designated for distress alerting. In addition, where a room is provided for radio

communications, means to initiate distress calls shall also be fitted in that room. A suitable

interface on the EUT to enable these two requirements to be achieved shall be provided by

the equipment manufacturer.
4.2.3 Dedicated distress button
4.2.3.1 Distress activation

(MSC.130/A.3.5) A distress call 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.
---------------------- Page: 10 ----------------------
61097-13  IEC:2003(E) – 9 –

(MSC.130/A.3.4) It shall be possible to interrupt and initiate distress calls at any time.

(MSC.130/A.3.6) The dedicated button shall
.1 be clearly identified; and
.2 be protected against inadvertent operation.

(MSC.130/A.3.7) The distress call initiation shall require at least two independent actions.

4.2.3.2 Clarification (MSC Circular 862)
MSC Circular 862 provides the following clarifications by IMO:

“DEDICATED DISTRESS BUTTON” – This button should not be any key of an ITU-T input

panel or an ISO keyboard associated with the equipment and should be physically separated

from functional buttons/keys used for normal operation. This button should be a single button

for no other purpose than to initiate a distress alert.
“CLEARLY IDENTIFIED” – The distress button should be red in colour and marked

“DISTRESS”. Where a non-transparent protective lid or cover is used, it should also be

marked “DISTRESS”.
“PROTECTED AGAINST INADVERTENT ACTIVATION” – The required protection of the

distress button should consist of a spring-loaded lid or cover permanently attached to the

equipment for example, hinges. It should not be necessary for the user to remove additional

seals or to break the lid or cover in order to operate the distress button.

The operation of the distress button should generate a visible and audible indication. The

distress button should be kept pressed for at least 3 seconds. A flashing light and an

intermittent acoustic signal should start immediately. After 3 seconds the transmission of the

distress alert is initiated, the visible indication shall become steady and the acoustic indication

shall cease.

NOTE INMARSAT F 1 Service definition provides the following clarification. The MES should ensure that

selection of Maritime Distress priority shall not become effective until the switch contacts have been continuously

held closed for a period of at least 5 s.
“AT LEAST TWO INDEPENDENT ACTIONS” – Lifting of the protective lid or cover is

considered as the first action. Pressing the distress button as specified above is considered

the second independent action.
4.2.3.3 Indications of distress call initiation

Audible and visible indications shall be made at all positions from where a distress call may

be initiated, irrespective of the telephone terminal from which the distress call is originated.

The visible indications shall continue until reset manually. This reset facility shall only be

available to authorized personnel. It shall be possible to initiate further distress calls without

re-setting the first indication. During performance testing with distress priority, indications

shall be identical to those generated by initiation of a real distress call.
4.2.4 Alarm on reception of shore-originated duplex calls with distress priority
(MSC.130/A.3.3) Where no other means of receiving distress, urgency and safety

broadcasts or an additional distress alert relay are provided and existing levels of aural

signals produced by the telephone or printer are considered to be inadequate, the ship earth

station equipment shall provide an aural/visual alarm of appropriate level. An output shall be

provided to actuate an external aural/visual alarm on the receipt of a distress priority duplex

call. (Distress, urgency and safety broadcasts are received by associated INMARSAT-C/EGC

receiving equipment – Annex B refers)
---------------------- Page: 11 ----------------------
– 10 – 61097-13  IEC:2003(E)
4.2.5 Radiofrequency hazards

(MSC.130/A.4) In order to permit warnings of potential hazards to be displayed in

appropriate places, a label shall be attached to the radome by the equipment manufacturer,

2 2 2

indicating the distance at which radiation levels of 100 W/m , 25 W/m and 10 W/m exist.

The label shall have characters at least 20 mm high and be clearly readable in the normally

installed position from a distance of at least 5 m. The maximum distance from the EUT

at which the power density level of 100 W/m has been measured by the equipment

manufacturer shall be included in the equipment manual. The power density at this distance

shall be re-measured and the level specified in the equipment manual and on the label

confirmed. The readability of the label at a distance of 5 m shall also be confirmed.

4.2.6 Safety precautions

The EUT shall satisfy the requirements for safety as stated in IMO resolution A.694(17) and

detailed in IEC 60945 (A.694/A.7).
4.2.7 Equipment manual
The manual shall comply with the requirements of IEC 60945 as applicable.

The manual shall contain information for the installation to comply with IMO requirements as

detailed in Annex A.

The manual shall also address the issue of reception of maritime safety information (MSI)

(see Annex B).

The manual shall also include a cautionary note to the effect that, before clearance of a

distress priority call is initiated, the RCC must be advised as to why the call is being cleared.

The manual shall include the maximum distance from the radome at which a power density of

100 W/m has been measured by the manufacturer of the EUT.
4.2.8 Marking and identification

Marking and identification shall comply with the requirements of IEC 60945 as applicable and

with the special requirements of 4.2.6 above.
4.2.9 Maintenance

The EUT shall comply with the maintenance requirements of IEC 60945 as applicable.

5 Technical requirements

This Clause 5 includes all IMO/ITU requirements not covered by the INMARSAT mini-M SDM

Change Note 65 and for which a repeatable method of measurement has been specified. The

related test methods and required test results can be found in Clause 6.

The equipment shall, in addition to meeting the requirements of the Radio Regulations, the

relevant ITU Recommendations, the relevant INMARSAT technical requirements (INMARSAT

mini-M SDM Change Note 65) and the general requirements set out in IMO resolution

A.694(17), as detailed in IEC 60945, comply with the requirements of this standard.

5.1 Pre-emption by distress calls (ship originated)

On initiation of a distress priority call the EUT shall interrupt any on-going call of lower

priority, if necessary, and then set up the distress priority call automatically.

---------------------- Page: 12 ----------------------
61097-13  IEC:2003(E) – 11 –
5.2 Electromagnetic compatibility (EMC)
The equipment shall meet the requirements of IEC 60945.
5.3 Spurious emissions
The requirements set out in Appendix 3 of the ITU radio regulations shall apply.
5.4 Power supply

Equipment shall continue to operate in accordance with the requirements of this standard in

the presence of variations of the power supply normally to be expected in a ship. (A.694/4.1)

5.5 Excessive conditions

Means shall be incorporated for the protection of equipment from the effects of excessive

current and voltage, transients and accidental reversal of power supply polarity or phase

sequence (A.694/4.2).
5.6 Power supply interruption

(MSC.130/5.2) Changing from one source of supply to another or any interruption up to 60 s

of the supply of electrical energy shall not render the equipment inoperative or require the

equipment to be manually re-initialized.

Programmable functions stored in memory shall not be lost on power-down and power-up of

the equipment.
5.7 Interfaces

If interfaces to external sensors and sources, which comply with IMO Resolutions and ITU

Recommendations are provided, they shall comply with IEC 61162-1.

INMARSAT F77 equipment has no mandatory minimum sentences that the equipment shall

receive as a Listener and transmit (generate) as a Talker.

Any sentences provided for, however, shall be documented and include the approved

sentence forma
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.