GB 15215-1994 Performance requirements for Global Maritime Distress and Safety System (GMDSS) Digital Selective Calling (DSC) equipment
Some standard content:
National Standard of the People's Republic of China
Global maritime distress and safety systemPerformance requirements for digltelselectlve calllng (DSC) equlpmentGB 15215—94
This standard refers to Chapter 4 of the 1988 Amendment to the International Convention for the Safety of Life at Sea (SOLAS), 1974, Radiocommunications and International Radio Consultative Committee (CCIR) Recommendations 493 and 541.1 Subject matter and scope of application
This standard specifies the terminology, performance requirements and technical characteristics of digital selective calling (DSC) equipment (hereinafter referred to as DSC equipment). This standard applies to the DSC equipment required to be equipped for the Global Maritime Distress and Safety System (GMDSS), MF, HF and VHF maritime mobile communications, and public correspondence services.
2 Terminology
2.1 Dot pattern
The dot pattern is an alternating BY code sequence bit synchronization signal. B code is the binary number 0", and Y code is the binary number \1\. 2.2 Phasing
The process of achieving bit synchronization and word synchronization during the communication process of the system. 2.3 Call attempt callattempt
In a short period of time (such as a few minutes), one or more call sequences are transmitted to the same station at one or more rates. 3 Performance requirements of DSC equipment
3.1 General requirements
3.1.1 DSC equipment should be able to realize the following types of calls: a. distress, urgency and safety; b. Ship business; c. Normal communication. 3.1.2 Type A DSC equipment should comply with the requirements specified in Article 3.3. 3.1.3 Type B DSC The equipment should at least provide: a. distress alarm, distress confirmation and distress relay. The format of the distress message is shown in Appendix A (Supplement). b. Calls and confirmations for daily communications. c. Calls related to semi-automatic/automatic services. See Appendix B (Supplement) for detailed requirements. 3.1.4 Type C DSC equipment is an additional device for VHF equipment and is used for distress alarms that only give the ship identification code. Its requirements are shown in Appendix C (Supplement). State Administration of Technical Supervision 1994-08-0B Approved 1995-05-01 Implementation GB15215-94 3.1.5 DSC equipment can be an independent device or combined with a radio transceiver/transmitter. 3.1.6 Signal input and output of independent DSC equipment should meet the following requirements: Input and output are balanced, with an impedance of 6000. Input and output levels should be within 0±10 b.
The input and output ports should be able to be connected to the audio ports of external radio equipment. 3.1.7DSC equipment can be equipped with a printing interface. 3DSC equipment can be set with a logic level interface.
9DSC equipment can be set with a ship position data interface. 3. 1. 9
DSC equipment should be able to work continuously.
3.1.11 Requirements for working environment
Ambient temperature: -10～+55℃,
Relative humidity: 93%±3% (40±3℃). 3.1. 12
DSC equipment requirements for power supply
When using a single-phase AC power supply, the voltage is 220V±10%, and the frequency should be 50/60Hz±5%. When using a DC power supply, the voltage is 24 V%.
3-2 Composition and functional requirements of DSC equipment
3.2.1DSC equipment should include encoding and decoding devices. 3-2.2DSC equipment should have the necessary devices to generate DSC messages, such as devices for manually inputting addresses, selecting call types, categories and various information.
3.2.3DSC equipment must be equipped with devices for checking sent messages. DSC equipment should have a character display device and display the following information sent and received in plain language: 3.2.41
Format specifier
Category,
Identification of calling station
Information of numbers and letters,
Type of "terminator\";
Errors detected.
3.2.5DSC equipment can input ship position and ship position determination time manually or automatically. 3.2.6
DSC equipment should be easy to operate when transmitting distress calls and have a function to prevent misoperation. 3-2.7DSC equipment must have priority over any other operation when transmitting distress calls. 3.2.8DSC equipment should be able to store at least 20 distress messages; these messages should be stored at least until they are read out. 3.2.9DSC equipment should be able to activate the distress alarm from the ship's driving position. 3.2.10 Self-identification data should be stored inside the DSC equipment. The stored data should be stable and reliable, and it should be difficult for the operator to change these data.
3.2.11DSC equipment should ensure that it can carry out its own daily tests without transmitting signals. 3.2.12DSC equipment should be equipped with special auditory and visual alarm devices to report the receipt of distress or emergency calls or calls with distress categories. The auditory and visual push alarm indications should only be reset manually. 3.2.13DSC equipment should be equipped with audible and visual alarms for calls other than distress and emergency calls. 4 Technical characteristics requirements
4.1 General requirements
4.1.1DSC equipment is a synchronization system using a ten-unit error detection code. The ten-unit error detection code is shown in Appendix D (Supplement). The first seven bits of the ten-unit code are information bits, and the last three bits are check bits, which are used to indicate the number of B codes in the first seven bits. This system uses a total of 128 ten-unit codes from 00 to 127: comGB 1521594
. 00 to 99 are data codes, and 100 to 127 are function instruction codes. 4.12 Time diversity technology is used in the call sequence. Except for the phased signal, each signal is transmitted twice in a time-spreading manner. After the first signal is transmitted (DX position), the other 4 signals are transmitted, followed by the second signal (RX position). The allowed time expansion interval is:
. In MF and HF channels: 400ms!
b. In VHF channel: 33%ms.
4.1.3 Frequency shift and modulation rate of the signal
a, frequency shift is ±85Hz at MF and HF; modulation mode is frequency shift keying (FSK), center frequency is 1700Hz, transmission mode is F1B or J2B; single tone frequency tolerance is ±10Hz; modulation rate is 100Baud; frequency shift is ±400Hz at VHF; modulation mode is frequency modulation (phase modulation); subcarrier is 1700Hz; single tone frequency tolerance h
is ±10 Hz. Modulation rate is 1200Baud, modulation coefficient is 2.0±10%4.1.4 The higher frequency corresponds to the B state of the ten-unit error detection code signal, and the lower frequency corresponds to the Y state of the signal. 4.1.5 The decoder of the receiver should make maximum use of the received signal, including the use of the check symbol. 4.1.6 Call repetition (see 4.11) should meet the following conditions:. The transmitter encoder should be able to provide the transmission of call repetitions, and the call repetition should have no gap between the end symbol of a call and the dot signal of the following call to ensure that the bit synchronization is maintained; b. The receiver decoder should make the maximum use of the received signal, including the use of the check symbol and the use of the optional decoding processing results.
4-2 Technical format of the call sequence
Phasing sequence
Message 1|Message 2Message 3
4.3 Dot diagram and phasing sequence
Format distinguisher
Message 4 (for exit only)
Self-identification
End symbol Check symbol
4.3.1 The purpose of the phasing sequence is to enable the receiver to achieve correct bit synchronization and determine the position of each signal in the call sequence. 4.3.2 The phasing sequence is formed by a special signal transmitted alternately in the DX and RX positions. The phasing signal code of the DX position is 125, and a total of six signals are transmitted.
The phased signal codes transmitted by the RX position are 111, 110, 109, 108, 107, 106, 105, and 104. See Appendix E (Supplement) Table E1 for details.
4.3.3 The phased signal is considered to be successful if any of the following three conditions are achieved: a. Two codes of the DX position and one code of the RX position are successfully received; b.Two codes for the RX position and one code for the DX position are successfully received; c.
Three codes for the valid RX position are received. 4.3.4 The dot diagram can speed up the bit synchronization of the system and allow the station to use scanning equipment on MF and HF rates. The dot diagram is located before the phasing sequence.
a. On MF/HF, the dot diagram digits should be 200 bits for distress calls, distress acknowledgements, distress relays, distress relay acknowledgements and calls to all ships, and 20 bits for other calls; b. On VHF, the dot diagram digits for all calls are 20 bits. 4.4 Format Specifier
4.4.1 The format specifier is transmitted twice in the DX and RX positions respectively. 4.4.2 During the "return to danger call" and "all call", the receiver decoder shall detect the format specifier twice. For other calls, the format specifier only needs to be detected once.
4.4.3 The signal name and category code of the format specifier are detailed in Table E2 in Appendix E. 4.5 Address
GB 15215—94
4.5.1 In the case of “distress call\ and “all call\, there is no address. 4.5.2 When calling directly to a ship station or shore station or to a group of stations with common interests, the address consists of the maritime mobile service identification code corresponding to the station.
4.5.3 When calling a group of ships in a certain sea area, the address should consist of the geographical coordinates of a rectangular area on the Cartograph chart with 10 digits (5 codes). The composition of the ship position information is shown in Appendix F (Supplement). 4.6 Category
4.6.1 “Category\ is used to specify the priority of the call sequence, see Table E3 of Appendix E. 4.6.2 “Distress calls should consist of a code, and its priority has been defined by the format specifier. Distress calls do not contain categories, see Figure A1 of Appendix A.
4.6.3 For calls related to safety, the “Category\ information should be return to danger, urgent or safety. 4.6.4 For other calls, the “category” information shall be either ship service or routine communication service. 4.7 Self-identification
Self-identification is the maritime mobile service identification code assigned to the calling station. 4.8 Messages
4.8.1 For the distress call, the messages include message 1, message 2, message 3 and message 4. 4.8-1.1 Message 1 is "Nature of distress", see Appendix E Table E4 for details 4.8.1.2 Message 2 is "Departure coordinates", consisting of 10 digits to indicate the longitude and latitude coordinates of the distressed ship; if the distressed ship's position is not provided, 10 "9"s should be automatically transmitted after "Nature of distress". 4.8-1.3 Message 3 is the time (UTC) of determining the distressed ship's position, consisting of 4 digits, 2 digits for hours and minutes respectively. If the time is not provided, four "8"s should be automatically transmitted,
4.8-1.4 Message 4 is the communication method after distress (telephone or telex), which is a code. It can be selected by the distress station. 4.8.2 The message formats of “distress relay” call (including shore-to-ship alarm), “distress relay confirmation” and “distress confirmation” are shown in Figures A2 and A3 of Appendix A. For distress relays where the identification of the retreating ship is unclear, “identification of the distressed ship” shall be replaced by automatically transmitting code “126” five times. 4.8.3 Other types of calls, the messages include message 1, message 2 or message 3. 4.8.3.1 Message 1 is “telecommand”, which consists of the first telecommand and the second telecommand, see Tables E6 and E7 of Appendix E and Appendix G (Supplement). If the second telecommand is not required after the first command, the second telecommand is “no information”, that is, code “126”. If no telecommand is required, code “126” shall be transmitted twice. 4.8. 3.2 Message 2 may contain frequency, channel or ship position information. 4.8.3.2. 1 When message 2 contains two rate information units, each information unit consists of three codes. The rate information indicates the working frequency to be constructed (in F1B/T2B mode, the assigned rate is used. Frequencies below 30 MHz are expressed in multiples of 100 Hz. The three codes represent 6 digits.
4.8.3.2.2 When message 2 contains two channel information units, each information unit always consists of six digits (three codes). If the first digit is 3, the following five digits are the ITU-M F/HF working channel number (single-frequency or dual-frequency channel). If the first digit is 9, the following five digits are VHF. Working channel number. 4.8.3.2.3 The first channel or frequency information unit of message 2 indicates the receiving channel (single frequency or paired dual frequency channel or frequency) of the called station. The second channel or frequency information unit specifies the transmitting frequency or channel number of the called station. When the calling station only gives the receiving frequency of the called station (for broadcast mode transmission) or gives a (paired) dual frequency channel, the second frequency information unit should be replaced by three "126\ characters.
4.8.3.2.4 When message 2 does not contain a frequency or channel information unit, the character "126" should be transmitted six times; for calls using semi-automatic/automatic services, message 2 contains only one channel or frequency information unit, which is the paired working channel number. No second channel or frequency information unit, code \126\ should be transmitted three times. 4.8.3.2.5 Message 2 may contain ship position information. In this case, message 2 consists of the number \5\ repeated twice and ten digits representing the ship position (five codes GB15215-94
codes). If this call is a response to a call sequence requesting the ship's position, message 2 consists of ten digits (five codes) and code *126\, where the ten digits are the ship's position code. In this case, if the ship's position is a valid position, message 3 following message 2 indicates the time (UTC).
4.B.3.3 When the ship's station DSC system transmits a semi-automatic/automatic business call, message 3 contains the public switching network number (such as a telephone number).
4. 8-4 Test calls on MF and HF non-distress and safety reversal rates, the call sequence contains two messages, message 1 and message 2.4.B.4.1 Message 1 consists of the first telecommand code \118\ and the second telecommand code "126". 4.8.4.2 Message 2 consists of the code "126" repeated six times. 4.B.4.3 Technical measures should be taken to prevent the test call sequence from being transmitted on VHF. The first telecommand code "118\ is only used in the test call sequence.
4.9 End character
is the "sequence end\ signal. At the end of the call sequence, the end character should be transmitted three times in the DX position and once in the RX position. See Appendix E Table E5.
4.10 Check character
4.10.1 The check character is the last character transmitted in the call sequence and is used by the receiver to detect errors in the entire receive sequence that have not been detected by the ten-unit error detection code and time diversity mode. The first seven bits of the check character are the modulo 2 sum of the corresponding bits of all information bits (vertical even parity). The phasing signal is not used as an information code. Only one format character and one end character participate in the check character. Automatic answering can only be started when the check character is received and decoded correctly.
4.10.2 Automatic answering transmission cannot be carried out unless the check character is received and decoded correctly. 4.11 Call repetition
4.11.1 Normally a call attempt consists of only one call sequence. However, in special circumstances, and when only domestic DSC frequencies are used, a call attempt may consist of multiple transmissions of the same call sequence, but no more than five transmissions. A single call attempt always consists of five consecutive transmissions of the call sequence.
4.11.2 When a call attempt contains more than one consecutive call sequence, no time is allowed between the end of one call and the beginning of the dot pattern of the next call during the transmission to maintain correct bit synchronization. Distress call
Phasing sequence
Format character
Distress relay and distress relay confirmation
Dot diagram phased sequence format characterAddress
Category (retreat)
A3 Confirmation of distress
Dot diagram phased sequence
Format character
(All call)
Message composition
Format specifier
Distress call;
Category (distress)
Call to all ships;
Single station call,
Semi-automatic/automatic business call.
B1.2 Called station identification code
B1.3 Self identification code
B1.4 Category
Distress;
Safety·
Daily.
B1.5 Commands
B1.5.1 Telecommands for distress calls
MF: F3E or J3E,
Self-identification
Self-identification
Self-identification
GB 15215—94
Appendix A
Distress message format
(Supplement)
Nature of escape
Distress coordinates
Communication command
(Distress transfer)
Communication mode
End character
Verification character
Distressed ship identification Nature of escape Distress coordinates time Communication mode End character Comparison character Figure A2
Return command
(Distress confirmation)
Retreating ship identification Nature of escape Distress coordinates time Communication mode End character Control verification diagram A3
Appendix B
Type B DSC Equipment requirements
(supplement)
b.VHF.F3E/G3E, simplex.
B1.5.2 Telecommands for distress relay
, first telecommand
MF/VHF: Distress relay (DistreBsrelay): b Second telecommand (subsequent communication mode) GB15215-94
MF/VHF: Distress command in received patrol report, etc. or H3E/J3E or F3E/G3E.B1.5.3 Communication commands for distress confirmation
First telecommand
MF/VHF: Distress confirmation:
b. Second telecommand (subsequent communication mode) MF/VHF: Distress command included in received distress alert. B1.5.4 Distress commands for other calls
a. First encounter command
MF: single call uses H3EJ3E or \TEST" semi-automatic/automatic MF service uses H3E, J3E or \endof call", VHF: single call uses H3E/G3E simplex or duplex, semi-automatic/automatic VHF service uses F3E/G3E simplex or duplex on \endofcall\, b.
Second telecommand
Code 126.
B1.6 Distress call
Nature of distress: Undesignated. B1.7 Distress coordinates and time (only distress call): see 4.8.1. B1.8 Frequency, channel or ship position information: see 4.8.3.2. B1.9 Optional information (semi-automatic/automatic service): telephone number of public telephone user. B1.10 End sequence character: see 4.9.
B2 Receiving function
B2.1. Receive and display all the information listed in B1, as well as distress relays with the format symbol "sea call" and all "unanswerable" calls.
B2.2. Make an audible alarm after receiving any DSC call. Appendix C
C-type DSC equipment requirements
(Supplement)
C1. Transmit distress calls with fixed content
C1-1. The format symbol is distress call and the code is 112.C1. 2. Self-identification.
C1.3. The nature of the distress is "unspecified" and the code is 107.C1.4. The coordinates of retreat are ten \9\.
C1.5 The time of distress is four \8\.
C1.6 The communication mode is: F3E/G3E simplex, the code is 100. :com code
Bit diagram of signal and bit
0123456789
BHBBBBBYYY
YBBEBBBYYB
BYBHBBBYYB
YYHRRBYBY
BBYBBEBYYB
YBYBBBBYBY
BYYBBBBYBY
YYYBBBBYEE
BBBYHBBYYB
YBBYBBBYBY
BYBYBBBYBY
YYBYBBBYBE
BBYYBRBYBY|| tt||YBYYRRBYBB
BYYYBBBYBE
YYYYBEBBYY
BBBBYBBYYB
YBBBYHBYB Y
BYBBYBBYBY
YYBBYHBYBE
BBYRYBBYBY
YBYBYHBYBE
BYYEYBB YER
YYYEYBBBYY
BBBYYBBYBY
YBBYYEBYBB
BYBYYBBYBB
YYBY YBBBYY
BBYYYBBYBB
YBYYYBBBYY
BYYYYBHBYY
YYYYYRBBYE
Note, @ B=0,Y-1.
GB 1521594
Appendix D
Ten-unit error detection code
(Supplement)
Ten-unit error detection code
Signal and bit position
0123456789
BBBBBYBYYE
YBABBYBYBY
BYEBHYBYBY
YYEBBYBYEB
B BYBBYBYBY
YBYBBYEYBB
BYYBBYBYBB
YYYBHYEBYY
BBEYBYBYRY
YBBYBYBYBB
BYEYBYBYBE
YYBYBYBBYY
BBYYEYBYBE
YBYYBYBHYY
BYYYBYBBYY
YYYYBYBEYH
BBBBYYTYBY
YBEBYYBYBE
BYBBYY BYBB
YYEBYYBEYY
BBYHYYBYBB
YBYBYYBBYY
BYYBYYBBYY
YYY HYYBBYE
RRBYYYBYHB
YHBYYYBBYY
LYYYYBBYY
YYEYYYBBYB
BEYYYYBBYY
YBYYYYBBB
BYYYYYBBYB
YYYYYYBBBY
② Avoid the high bit (bit 0) to be transmitted first. | |tt | YBB
YYYBBBYBYY
BBBYBEYYBY
YHBYBYB ||tt | t||HBBYYBYYBB
YBBYYBYHYY
BYBYYBYBYY
YYBYYBYHYE
HBYYYBYBYY
YBYYYEYBYB
BYYYYRYHYB
YYYYYBYBBY
Signal and bit position | |tt | BYYBYB | |BBBBYYYYEB
YBBBYYYBYY
BYBBYYYBYY
YYBBYYYBYB
BBYBYYYBYY
YBYBYYYBYB
BYYBYYYBYB
YYYBYYYBBY
BBBYYYYBYY
YBBYYYYBYB
BYHYYYBYB
YYBYYYYYBBY
BBYYYYYBYB
YEYYYYYBBY
BYYYYYYBHY
YYYYYYYHBE
E1 Phasing signal
Phasing signal see Table E1.
E2 Format specifier signal
Format specifier signal see Table E2.
E3 Category signal
Category signal see Table E3.
E4 Distress signal
Retreat signal see Table E4.
E5 End character signal
End character signal see Table E5.
E6 First remote command signal
The first remote command signal is shown in Table E6.
Second remote command signal
The second remote command signal is shown in Table E7.
Symbol name
Format specifier
Category code
GB 15215—94
Appendix E
Signals for DSC sequence and English-Chinese comparison
(Supplement)
Phasing signal
Table E2 Format specifier signal
Format specifier Signal name
Distress call
Sea area call
Semi-automatic/automatic service
Distreas call
All shipa call
Individual station
Shipe in a particular geagraphic areaShips having a commqn interestSemi-nutomatic/automatic serviceww.bzsoso:comRx
GB 15215-94
Table E3 Category Signals
Distress Signals Category
Ships Business
Urgeney
Safety
Ships businese
Routine
Table E4 Back to danger Signals
Back to danger Signals Category
Fire, explosion
Dumping,In danger of capszingSinking
Disabled and adrift
Undesignated distress
Abandoning ship
EPIRB emission
Acknowledge RQ
Acknowledge BQ
Table E6 First telecommand signal
Purpose/mode
F3E/G3E simplex
F3E/G3E duplex
Not to rich
Terminate call
F3E/G3E simplex
F3F/G3Eduplex
Polling
Unable to comply
End of callbzxz.net
Terminal equipment
Telephone
Telephone
Distress confirmation
Distress relay
F1B/J2BFEC
F1B/J2B ARQ
F1B/J2E receive
F1B/J2B
A1A Schels
Purpose/mode
GB 15215—94
Continued Table E6
Diatress acknawledgement
Distress relay
H1B/J2B FEC
FIB/J2R ARQ
F1B/J2B receive
F1b/J2B
AiA Morse
Vessel position or position record update
A1A Morse
F1C/F2C/F3C
No information
No reason given
Maritime exchange center congestion
Queue indication
Radio blocked
No operator
No operator
Equipment failure
Cannot use the suggested channel
Cannot use the suggested mode
Shippositionorlocation
registing up dating
AlA Mores
F1C/F2C/F3C
Noinformation
Moderator/demodulator
Printing telegram
Terminal equipment
User telegram/printing telegram
Printing telegram
Printing telegram
Record recorder
Key/earphone
Fax machine
Table E7 Second remote command signal
Signal meaning
No resson given
Telephone
Telephone
Teleprinter
Telex/Teleprinter
Teleprinter
Telepnnter
Tape recorder
Morse key/heed-set
Facsimile machine
Congestion at Maritime Switehing CenlerBusy
Queue indication
Station barred
No operator available
Operator temporarily unavailbleEpuipment disabled
Unable to use proposed chennelUneble to use proposed mode
Ship and sireraft according to Resolution No. 18 (mob—83)
Medical transport
Pay-phone public call officeDataV.21
DataV.22
DataV.26
DataV.32
No information
GB15215-94
Continued Table E7
Data V.22
Lrata V. 22 b1e
Date V. 23
Data V. 26
Data V. 26 ter
Data V. 27 tcr
Data V. 32
No information
Appendix F
Composition of ship position information
(Supplement)
F1 The first digit is the quadrant, indicating the direction of the ship’s accident site. F1.1 If it is the northeast (NE) direction, it is replaced by the number \0\; F1.2 If it is the northwest (NW) direction, it is replaced by the number \1": F1.3 If it is the southeast (SE) direction, it is replaced by the number \2* F1.4 If it is the southwest (SW) direction, it is replaced by the number \3\. F2 The second, third, fourth and fifth digits represent the degrees and minutes of latitude. The sixth, seventh, eighth, ninth and tenth digits represent the degrees and minutes of longitude. F3
Appendix G
Commands for DSC equipment on the ship platform
(Supplement)
G1A type, MF/HF equipment
The first command code: 103~106, 109113,115116118 The second command code is 100～111,115～121,123,12 4 and 126. Type 2A, VHF equipment
First telecommand code: 100, 101, 103106, 110, 112, 115, 121, 124126; Second telecommand code: 100～111, 115～121123, 124 and 126. G3
Type 3B, MF equipment
First telecommand code: 105, 109, 110, 111, 112, 118 and 126; English: ...118 and 126; English118 and 126; EnglishThe fifth digit represents the degree and minute of latitude. The sixth, seventh, eighth, ninth and tenth digits represent the degree and minute of longitude. F3
Appendix G
Ship DSC Equipment Emergency Commands
(Supplement)
G1A type, MF/HF equipment
First emergency command code: 103~106, 109113,115116118 Second emergency command code 100～111,115～121,123,124 and 126. 2A type, VHF equipment
First telecommand code: 100,101,103106,110,112,115,121,124126; Second telecommand code: 100～111,115～121123,124 and 126. G3
3B type, MF equipment
First telecommand code: 105, 109, 110, 111, 112, 118 and 126; EnglishThe fifth digit represents the degree and minute of latitude. The sixth, seventh, eighth, ninth and tenth digits represent the degree and minute of longitude. F3
Appendix G
Ship DSC Equipment Emergency Commands
(Supplement)
G1A type, MF/HF equipment
First emergency command code: 103~106, 109113,115116118 Second emergency command code 100～111,115～121,123,124 and 126. 2A type, VHF equipment
First telecommand code: 100,101,103106,110,112,115,121,124126; Second telecommand code: 100～111,115～121123,124 and 126. G3
3B type, MF equipment
First telecommand code: 105, 109, 110, 111, 112, 118 and 126; English
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.