ITU-T Z 314-1988 The character set and basic elements《字符集和基本元素》.pdf

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1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 : TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU-!.G13-!#().%G0G0,!.5!%4(%G0G0#(!2!#4%2G0G03%4G0G0!.$G0G0“!3)#%,%-%.43)45G134G0G0RecommendationG0G0: (Extract from the “LUEG0“OOK)NOTES1 ITU-T Recommendation Z.314 was published in Fascicle X.7 of the Blue Bo

2、ok. This file is an extract from theBlue Book. While the presentation and layout of the text might be slightly different from the Blue Book version, thecontents of the file are identical to the Blue Book version and copyright conditions remain unchanged (see below).2 In this Recommendation, the expr

3、ession “Administration” is used for conciseness to indicate both atelecommunication administration and a recognized operating agency. ITU 1988, 1993All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic ormechanical, including photocopy

4、ing and microfilm, without permission in writing from the ITU.Fascicle X.7 - Rec. Z.314 1Recommendation Z.314Fascicle X.7 - Rec. Z.314THE CHARACTER SET AND BASIC ELEMENTS1 GeneralThe character set and the basic elements used in the syntax are essential components of MML inputs, MMLoutputs and the ma

5、n-machine dialogue procedures.2 The character setThe character set to be used for the CCITT MML is a sub-set of the CCITT International Alphabet No. 5 whichhas been established jointly by the CCITT and the International Organization for Standardization.To allow for possible implementation of the CCI

6、TT MML using national languages, the sub-set is taken fromthe basic code table given in Recommendation T.50 1. The code positions reserved in this table for national use arenot contained in the basic character set of the CCITT MML, but may be used in these national implementations.According to Recom

7、mendation T.50 1 transmission control characters and information separators areintended to control or to facilitate transmission of information over telecommunication networks. Hence these controlcharacters are not used in the MML. This will avoid interference with data transmission procedures when

8、informationin the MML is transmitted via a data transmission network.It is furthermore recommended when information is printed or displayed that devices are used which print ordisplay different graphic symbols for the digit zero and the capital letter O.The characters selected for use in the CCITT M

9、ML are given in Table 1/Z.314.TABLE 1/Z.314Character set to be used for the CCITT man-machine language2 Fascicle X.7 - Rec. Z.314General remarks The characters proper to the open positions are considered as outside the MML. They areimplementation dependent and, together with the characters named in

10、the table but not included in the MML, may beused in accordance with the rules given in Recommendation T.50 1. The position of a character in the table can beindicated by its column and row number, e.g., Pos. 3/1 gives the position of the digit 1 in the table. The table gives alsothe binary codes al

11、located to the table positions according to Recommendation T.50 1. The bits are identified by b7,b6, . b1, where b7is the highest order, or most significant bit, and b1is the lowest order, or least significant bit.3 Summary of use of charactersThe use of characters in the character set, except for l

12、etters, digits, and characters used solely as graphiccharacters and format effectors, is described in Table 2/Z.314. CCITT International Alphabet No. 5 code is indicatedby position number (see Table 1/Z.314).3.1 LetterA letter is one of the characters listed in Table 1/Z.314, columns 4, 5, 6 and 7.

13、However, positions 5/15 and7/15 are excluded. The characters reserved for national use may be used as letters or as graphic characters.3.2 DigitA digit is one of the characters listed in Table 1/Z.314, column 3, positions 0 to 9.3.3 Graphic charactersGraphic characters are a collection of characters

14、 one or more of which may be used to improve readability.Graphic characters which have other syntactic uses are listed in Table 2/Z.314. The $ (position 2/4 in Table 1/Z.314) isthe only character used solely as a graphic character.3.4 Format effectorThe format effectors used in MML are the character

15、s FE1 to FE5 and SP (space) as defined in Table 1/Z.314.The character BACK SPACE (FE0 in Recommendation T.50 1) is not regarded as a format effector in the MML.4 Basic elements used in the syntaxSyntax diagrams of the basic elements used in the syntax are given in 5 in sub-paragraphs with numberscor

16、responding to those in 4.4.1 IdentifierAn identifier is a string of one or more characters which begins with a letter and, if applicable, subsequentlycontains only digits and/or letters e.g., U, UPDATE, UPD8.4.2 Symbolic nameA symbolic name is a string of one or more characters used for the purpose

17、of representing an entity whichcannot be adequately represented by numerals or identifiers. The string contains at least one letter and/or at least one ofthe graphic characters + (plus sign), # (number sign), % (percent sign) plus any number of digits, including none. Thecharacters may appear in any

18、 order. For example a time duration of 6 hours may be represented by the symbolic name06H, a 10 percent threshold value by 10%, a signalling system such as CCITT No. 6 by SS#6.4.3 Decimal numeralA decimal numeral is a character combination, consisting of a digit or digits and an optional . (full sto

19、p),preceded by the special character combination D (D apostrophe). If the numeric default base for an information unit(see Recommendation Z.315) is decimal, then the D is optional.4.4 Nondecimal numeralsA nondecimal numeral is a character combination preceded by a special character combination indic

20、ating thetype of numeral.4.4.1 H (H apostrophe) is used to indicate a hexadecimal numeral, the following characters thus being any of: digits0 to 9 or letters A, B, C, D, E, F.4.4.2 O (letter O apostrophe) is used to indicate an octal numeral, the following characters thus being any of: digits0, 1,

21、2, 3, 4, 5, 6, 7.4.4.3 B (B apostrophe) is used to indicate a binary numeral, the following characters thus being digit(s) 0 and/orFascicle X.7 - Rec. Z.314 3digit(s) 1.4.4.4 K (K apostrophe) is used to indicate a keyed numeral, the following characters thus being any of: digits 0-9, *(asterisk), #

22、(number sign), or letters A, B, C, D.4.4.5 When the default base for an information unit (see Recommendation Z.315) is one of the nondecimal numeralse.g., hexadecimal, the corresponding character combination, i.e. H in this example, is optional.TABLE 2/Z.314Summary of use of charactersCCITT Internat

23、ional Alphabet No. 5(Recommendation T.50) 1Character orcharacterstringPositionnumberNameMan-machine language useCAN 1/8 Cancel Used as a deletion character.! 2/1 exclamation mark An indicator used in dialogue procedures (continuation character in inputlanguage).” 2/2 quotation mark A text string del

24、imiter and a graphic character.# 2/3 number sign A character which may be used in symbolic names and keyed numerals andas a graphic character.% 2/5 percent sign A character which may be used in symbolic names and as a graphiccharacter.3/11 semicolon An indicator used to terminate a command (executio

25、n character).3/14 greater than sign A separator to terminate the destination identifier and a relationaloperator used in a selection argument.3/12 3/14 less than or greater than sign A relational operator used in a selection argument. = 3/14 3/13 greater than or equal sign A relational operator used

26、 in a selection argument.? 3/15 question mark An indicator used for prompting or help.(semi colon), - (hyphen) orcorrection characters as data. In such systems an escape indication may be used in order to introduce the followingcharacter as data.A specific escape indication is not proposed due to th

27、e diverse nature of terminals.No syntax diagram is given.Fascicle X.7 - Rec. Z.314 54.7.3 Format effectorA format effector (see 3.4) is used to format input and output in a suitable manner. Format effectors have nosignificance in a command and may appear anywhere in input.No syntax diagram is given.

28、4.8 SeparatorA separator is a character or a string of characters used to separate items of information in the input or outputand it may, in addition, have structural, semantic or other significance.No syntax diagram is given.4.9 IndicatorAn indicator is a character used to indicate a state or make

29、a request.No syntax diagram is given.5 Definition of the basic elements used in the syntax in diagramsAll these elements may be used in both input and output but for simplicity only the input elements are shown inthe diagrams. The output elements are identical to the input elements.5.1 Identifier5.2

30、 Symbolic name5.3 Index number6 Fascicle X.7 - Rec. Z.3145.4 Decimal numeral5.5 Nondecimal numerals5.5.1 Hexadecimal numeral5.5.2 Octal numeralFascicle X.7 - Rec. Z.314 75.5.3 Binary numeral5.5.4 Keyed numeral5.6 Text string8 Fascicle X.7 - Rec. Z.3145.7 Arithmetical expression5.8 Ancillary facilities5.8.1 CommentReference1 CCITT Recommendation International Alphabet No. 5, Rec. T.50.