1、 Recommendation ITU-R M.541-10 (10/2015) Operational procedures for the use of digital selective-calling equipment in the maritime mobile service M Series Mobile, radiodetermination, amateur and related satellite services ii Rec. ITU-R M.541-10 Foreword The role of the Radiocommunication Sector is t
2、o ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functio
3、ns of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referen
4、ced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU
5、-R patent information database can also be found. Series of ITU-R Recommendations (Also available online at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting serv
6、ice (television) F Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and
7、 fixed service systems SM Spectrum management SNG Satellite news gathering TF Time signals and frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 20
8、15 ITU 2015 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R M.541-10 1 RECOMMENDATION ITU-R M.541-10* Operational procedures for the use of digital selective-calling equipment in the maritime mobile service (1
9、978-1982-1986-1990-1992-1994-1995-1996-1997-2004-2015) Scope The Recommendation contains the operational procedures for digital selective-calling (DSC) equipment whose technical characteristics are given in Recommendation ITU-R M.493. The Recommendation contains six annexes. In Annexes 1 and 2 the p
10、rovisions and procedures are described for distress, urgency and safety calls and for routine calls, respectively. In Annexes 3, 4 and 5 the operational procedures for ships, for coast stations and Man overboard devices are described and Annex 6 lists the frequencies to be used for DSC. Keywords Dig
11、ital selective-calling, equipment, operational procedures, GMDSS, distress alert Abbreviations/Glossary BQ End of sequence for an acknowledge message CS Coast station DSC Digital selective calling EOS End of sequence FEC Forward error correction kHz Kilohertz GMDSS Global maritime distress and safet
12、y system HF High frequency MF Medium frequency MHz Megahertz MOB Man overboard NBDP Narrowband direct-printing RCC Rescue coordination centre RQ End of sequence acknowledge required RR Radio Regulations SOLAS International convention for the safety of life at sea UTC Coordinated universal time VHF V
13、ery high frequency * This Recommendation should be brought to the attention of the International Maritime Organization (IMO) and the ITU Telecommunication Standardization Sector (ITU-T). 2 Rec. ITU-R M.541-10 The ITU Radiocommunication Assembly, considering a) that digital selective-calling (DSC) wi
14、ll be used as described in Recommendation ITU-R M.493; b) that the requirements of Chapter IV of the International Convention for the Safety of Life at Sea (SOLAS), 1974, as amended, for the global maritime distress and safety system (GMDSS) are based on the use of DSC for distress alerting and call
15、ing and that operational procedures are necessary for the use of that system; c) that, as far as is practicable, operational procedures in all frequency bands and for all types of communications should be similar; d) that DSC provides the primary means of transmitting a distress alert. Provisions of
16、 transmitting a distress alert by other methods and procedures are described in the Radio Regulations (RR); e) that conditions when alarms have to be actuated should be specified, recommends 1 that the technical characteristics of equipment used for DSC in the maritime mobile service should be in co
17、nformity with the relevant ITU-R Recommendations; 2 that the operational procedures to be observed in the MF, HF and VHF bands for DSC should be in accordance with Annex 1 for distress, urgency and safety calls and Annex 2 for other calls; 3 that provisions should be made at stations equipped for DS
18、C for: 3.1 the manual entry of address, type of call, category and various messages into a DSC sequence; 3.2 displaying the information in a user readable format; 3.3 the verification and if necessary the correction of such manually formed sequences; 3.4 automatically set the information when possib
19、le; 3.5 a specific aural alarm and visual indication to indicate receipt of a distress or urgency call or a call having distress category. It should not be possible to disable this alarm and indication. Provisions should be made to ensure that they can be reset only manually; 3.6 aural alarm(s) and
20、visual indication for calls other than distress and urgency. The aural alarm(s) may be capable of being disabled; 3.7 such visual indicators to indicate: 3.7.1 type of received call address (to all stations, to a group of stations, geographical, individual); 3.7.2 category; 3.7.3 identity of calling
21、 station; 3.7.4 numerical or alpha-numerical type of information, e.g. frequency information and telecommand; 3.7.5 type of “end of sequence” character; 3.7.6 detection of errors, if any; 4 that the equipment should be simple to operate; Rec. ITU-R M.541-10 3 5 that the operational procedures given
22、in Annexes 3, 4 and 5, which are based on the relevant procedures from RR Chapter VII, Articles 30, 31, 32 and 33, be used as guidance for ships and coast stations; 6 that the frequencies used for distress and safety purposes using DSC are those contained in Annex 6 to this Recommendation (see RR Ap
23、pendix 15). NOTE 1 The following definitions are used throughout this Recommendation: Single frequency: the same frequency is used for transmission and reception. Paired frequencies: frequencies which are associated in pairs; each pair consisting of one transmitting and one receiving frequency. Inte
24、rnational DSC frequencies: those frequencies designated in the RR for exclusive use for DSC on an international basis. National DSC frequencies: those frequencies assigned to individual coast stations or a group of stations on which DSC is permitted (this may include working frequencies as well as c
25、alling frequencies). The use of these frequencies must be in accordance with the RR. Automatic DSC operation at a ship station: a mode of operation employing automatic tuneable transmitters and receivers, suitable for unattended operation, which provide for automatic call acknowledgements upon recep
26、tion of a DSC and automatic transfer to the appropriate working frequencies. Call attempt: one or a limited number of call sequences directed to the same stations on one or more frequencies and within a relatively short time period (e.g. a few minutes). A call attempt is considered unsuccessful if a
27、 calling sequence contains the symbol RQ at the end of the sequence and no acknowledgement is received in this time interval. Annex 1 Provisions and procedures for distress, urgency and safety calls 1 Introduction The terrestrial elements of the GMDSS adopted by the 1988 Amendments to the Internatio
28、nal Convention for SOLAS, 1974, are based on the use of DSC for distress and safety communications. 1.1 Method of calling The provisions of RR Chapter VII are applicable to the use of DSC in cases of distress, urgency or safety. 2 Digital selective calling distress alert The DSC distress alert provi
29、des for alerting, self-identification, ships position including time, and nature of distress as defined in the RR (see RR Chapter VII). 4 Rec. ITU-R M.541-10 3 Procedures for digital selective calling distress alerts 3.1 Transmission by a mobile unit in distress 3.1.1 The DSC equipment should be cap
30、able of being pre-set to transmit the distress alert on at least one distress alerting frequency. 3.1.2 The distress alert shall be composed in accordance with Recommendation ITU-R M.493. Although the equipment may be able to automatically include the ships position information and the time the posi
31、tion was valid, if this information is not available to the equipment then the operator has to manually enter the ships position and time at which it was valid. Enter the nature of distress as appropriate. 3.1.3 Distress alert attempt At MF and HF a distress alert attempt may be transmitted as a sin
32、gle frequency or a multi-frequency call attempt. At VHF only single frequency call attempts are used. 3.1.3.1 Single frequency call attempt A distress alert attempt should be transmitted as 5 consecutive calls on one frequency. To avoid call collision and the loss of acknowledgements, this call atte
33、mpt may be transmitted on the same frequency again after a random delay of between 3 and 4 min from the beginning of the initial call. This allows acknowledgements arriving randomly to be received without being blocked by retransmission. The random delay should be generated automatically for each re
34、peated transmission, however it should be possible to override the automatic repeat manually. At MF and HF, single frequency call attempts may be repeated on different frequencies after a random delay of between 3 and 4 min from the beginning of the initial call. However, if a station is capable of
35、receiving acknowledgements continuously on all distress frequencies except for the transmit frequency in use, then single frequency call attempts may be repeated on different frequencies without this delay. 3.1.3.2 Multi-frequency call attempt A distress alert attempt may be transmitted as up to 6 c
36、onsecutive (see Note 1) calls dispersed over a maximum of 6 distress frequencies (1 at MF and 5 at HF). Stations transmitting multi-frequency distress alert attempts should be able to receive acknowledgements continuously on all frequencies except for the transmit frequency in use, or be able to com
37、plete the call attempt within 1 min. Multi-frequency call attempts may be repeated after a random delay of between 3 and 4 min from the beginning of the previous call attempt. NOTE 1 A VHF call may be transmitted simultaneously with an MF/HF call. 3.1.4 Distress In the case of distress the operator
38、should transmit a distress alert as described in Annex 3. 3.2 Reception The DSC equipment should be capable of maintaining a reliable watch on a 24-hour basis on appropriate DSC distress alerting frequencies. 3.3 Acknowledgement of distress alerts Acknowledgements of distress alerts should be initia
39、ted manually. Acknowledgements should be transmitted on the same frequency as the distress alert was received. Rec. ITU-R M.541-10 5 3.3.1 Distress alerts should normally be acknowledged by DSC only by appropriate coast stations. Coast stations should, in addition, set watch on radiotelephony and, i
40、f the “mode of subsequent communication” signal in the received distress alert indicates teleprinter, also on narrow-band direct-printing (NBDP) (see Recommendation ITU-R M.493). In both cases, the radiotelephone and NBDP frequencies should be those associated with the frequency on which the distres
41、s alert was received. 3.3.2 Acknowledgements by coast stations of DSC distress alerts transmitted on MF or HF should be initiated with a minimum delay of 1 min after receipt of a distress alert, and normally within a maximum delay of 2 min. This allows all calls within a single frequency or multi-fr
42、equency call attempt to be completed and should allow sufficient time for coast stations to respond to the distress alert. Acknowledgements by coast stations on VHF should be transmitted as soon as practicable. 3.3.3 The acknowledgement of a distress alert consists of a single DSC distress acknowled
43、gement call and includes the identification of the ship whose distress alert is being acknowledged. 3.3.4 Ships receiving a DSC distress alert from another ship should set watch on an associated radiotelephone distress and safety traffic frequency and acknowledge the call by radiotelephony (see RR N
44、os. 32.28 32.35). 3.3.5 The automatic repetition of a distress alert attempt should be terminated automatically on receipt of a DSC distress acknowledgement. 3.3.6 When distress, urgency, and safety traffic cannot be successfully conducted using radiotelephony, an affected station may indicate its i
45、ntention to conduct subsequent communications on the associated frequency for NBDP telegraphy. 3.4 Distress alert relays Distress alert relays should be initiated manually. 3.4.1 A distress alert relay should use the call format for distress alert relays as specified in Recommendation ITU-R M.493 an
46、d the calling attempt should follow the procedures described in 3.1.3 to 3.1.3.2 for distress alerts, except that the distress relay is sent manually as a single call on a single frequency. Ship stations not provided with the DSC distress alert relay function should relay the alert by radio telephon
47、y. 3.4.2 Any ship, receiving a distress alert on an HF channel which is not acknowledged by a coast station within 5 min, should transmit an individual distress alert relay addressed to the appropriate coast station. 3.4.3 Distress alert relays transmitted by coast stations, or by ship stations addr
48、essed to more than one vessel, should be acknowledged by ship stations using radiotelephony. Distress alert relays transmitted by ship stations should be acknowledged by a coast station transmitting a “distress alert relay acknowledgement” call in accordance with the procedures for distress acknowle
49、dgements given in 3.3 to 3.3.3. 4 Procedures for digital selective calling urgency and safety calls 4.1 DSC, on the distress and safety calling frequencies, should be used by coast stations to advise shipping, and by ships to advise coast stations and/or ship stations, of the impending transmission of urgency, vital navigational and safety messages, except where the transmissions take place at routine times. The call should indicate the working frequency which will be used for the subsequent transmission of an urgent, vital navigational or safety message. 6 Rec.
