EN ISP 12070-1:1997

SLOVENSKI STANDARD
01-december-1997
Information technology - International Standardized Profiles FCSnnn - Character
set 8-bit code structure based on ISO/IEC 2022 - Part 1: FCS111 - 2022 Option 1
(ISO/IEC ISP 12070-1:1996)
Information technology - International Standardized Profiles FCSnnn - Character set 8-bit
code structure based on ISO/IEC 2022 - Part 1: FCS111 - 2022 Option 1 (ISO/IEC ISP
12070-1:1996)
Informationstechnik - Internationale Profilnorm FCSnnn - 8bit-Zeichensatz-Struktur
basierend auf ISO/IEC 2022 - Teil 1: FCS111 - 2022 Option 1 (ISO/IEC ISP 12070-
1:1996)
Technologies de l'information - Profils normalisés internationaux FCSnnn - Structure de
code a 8 éléments de jeu de caracteres basée sur l'ISO/CEI 2022 - Partie 1: FCS111 -
2022 Option 1 (ISO/IEC ISP 12070-1:1996)
Ta slovenski standard je istoveten z: EN ISP 12070-1:1997
ICS:
35.100.05 9HþVORMQHXSRUDEQLãNH Multilayer applications
UHãLWYH
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

lSO/IEC
INTERNATIONAL
ISP
STANDARDIZED
12070-I
PROFILE
First edition
1996-l 2-01
Information technology - International
Standardized Profiles FCSnnn - Character
set 8-bit code structure based on
ISOJIEC 2022 -
Part 1:
FCSIII - 2022 Option I
Technologies de /‘information - Profils normalis& in terna tionaux
FCSnnn - Structure de code ;i 8 &ments de jeu de caracMes bas6e sur
I’ISO/CEI 2022 -
- 2022 Option 7
Partie 7: FCS? 7 7
Reference number
lSO/lEC ISP 12070-I :I 996(E)
ISO/IEC ISP 12070=1:1996(E)
Page
Contents
1 Scope
2 Conformance and compliance
3 Normative references
. 2
4 Definitions
5 Abbreviations
6 Errors
7 The ISO/IEC 2022 code structure
8 The IS0 4873 code structure
9 The use of announcer escape sequences
10 The use of designation escape sequences
11 Invocation control functions
12 Character coding
13 The Characters SPACE and DEL
14 ASN.l type GeneralString
15 ASN.1 type GraphicString
16 ASN.1 type TeletexString
ANNEX A ICS proforma
ANNEX B TeletexString Compatibility
ANNEX C GeneralString and GraphicString Compatibility
0 ISO/IEC 1996
Unless otherwise specified, no part of this publication may be
All rights reserved.
electronic or mechanical, including
reproduced or utilized in any form or by any means,
photocopying and microfilm, without permission in writing from the publisher.
ISO/IEC Copyright Office l Case postale 56 l CHO1211 Genkve 20 l Switzerland
Printed in Switzerland
ii
0 ISO/IEC ISO/IEC ISP 12070=1:1996(E)
Foreword
IS0 (the International Organization for Standardization) and IEC (the International
Electrotechnical Commission) form the specialized system for worldwide standardization.
National bodies that are members of IS0 or IEC participate in the development of
International Standards through technical committees established by the respective
organization to deal with particular fields of technical activity. IS0 and IEC technical
committees collaborate in fields of mutual interest. Other international organizations,
governmental and non-governmental, in liaison with IS0 and IEC, also take part in this
work.
In the field of information technology, IS0 and IEC have established a joint technical
committee, ISO/IEC JTC 1. In addition to developing International Standards, ISO/IEC
JTC 1 has created a Special Group on Functional Standardization for the elaboration of
International Standardized Profiles.
An International Standardized Profile is an internationally agreed, harmonized document
which identifies a standard or group of standards, together with options and parameters,
necessary to accomplish a function or set of functions.
Draft International Standardized Profiles are circulated to national bodies for voting.
Publication as an International Standardized Profile requires approval by at least 75% of the
national bodies casting a vote.
International Standardized Profile ISO/IEC ISP 12070-l was prepared with the collaboration
- Asia-Oceana Workshop (AOW);
- European Workshop for Open Systems (EWOS);
- Open Systems Environment Implementors’ Workshop (OIW)
ISO/IEC ISP 12070 consists of the following parts, under the general title Information
technology - International Standardized Profiles FCSnnn - Character set a-bit code
structure based on ISO/IEC 2022:
- Part 1: FCSI 11 - 2022 Option 1
Other parts will follow.
Annex A is forms an integral part of this part of this part of ISOLIEC ISP 12070. Annexes B
and C are for information only.
. . .
ISOlIEC ISP 12070=1:1996(E) 8 ISO/IEC
Introduction
ISO/IEC ISP 12070 is defined within the context of Functional Standardization, in
accordance with the principles specified in ISOLIEC TR 10000, “Framework and Taxonomy
of International Standardized Profiles ”. The context of Functional Standardization is one
part of the overall field of Information Technology (IT) standardization activities, covering
base standards, profiles and registration mechanisms.
ISOLEX 2022 itself identifies and categorises a number of specific code structures. The
wide field of application of character set standards, the complexity of ISO/IEC 2022 and the
low level of awareness of character set issues within the functional standard development
groups has given rise to lack of precision and ambiguity in specifying the use of coded
character sets within the functional standards. This in turn has given rise to interoperability
problems for implementors and users of products which claim conformance to those
functional standards. It should be noted that a similar lack of awareness has also arisen in
the base standard development groups with similar consequences and a resulting effect on
the groups which are attempting to profile the base standards.
This part of ISO/IEC ISP 12070 has been studied by the three Regional OS1 Workshops,
namely the OS1 Implementors’ Workshop (OIW) of the United States, the European
The
Workshop for Open Systems (EWOS) and the OS1 Asia-Oceania Workshop (AOW).
constitutions of the three workshops ensure that the development process was open to all
interested parties. However, AOW and OIW indicated through the RWS-CC that they had
no interest in the development of this ISP part. It was developed under the editorship of
EWOS. The text has therefore only been ratified by the plenary assembly of EWOS.
iv
ISOIIEC ISP 120704: 1996(E)
INTERNATIONAL STANDARDIZED PROFILE 8 ISo ’IEC
Information technology - International Standardized Profiles
FCSnnn - Character set &bit code structure based on ISO/IEC
2022 -
Part 1:
FCSlll - 2022 Option 1
2 Conformance and compliance
1 Scope
Four categories of conformance are specified in this part of
Within the set of character set standards there are two generic
ISO/IEC ISP 12070.
code structures, that defined by ISO/IEC 2022 for 7 and 8 bit
transport mechanisms and that defmed by the new IS0 10646 for
1) Conformance to the requirements for ASN.1 type
a multi-octet transport mechanism. This part of ISO/IEC ISP
GraphicString,
12070 is concerned with the ISO/IEC 2022 code structure.
This part of ISO/IEC ISP 12070 is applicable in the following A claim for conformance shall support all the requirements
evaluating to mandatory that are listed in tables A.2 and A.3.
cases:
2) Conformance to the requirements for ASN.1 type
a) the use of ASN. 1 type GeneralString
GeneralString,
b) the use of ASN. 1 type GraphicString
c) the use of ASN. 1 type TeletexString
d) the use of non-ASN. 1 character strings (e.g. when a A claim for conformance shall support all the requirements
character string is embedded in the ASN.l evaluating to mandatory that are listed in tables A.4 and AS.
OCTET STRING as in ODA)
3) Conformance to the requirements for ASN.1 type
In many instances the requirements of this part of ISO/IEC ISP TeletexString,
12070 apply to all of these cases but where there are specific
requirements applying to particular cases, these are highlighted A claim for conformance shall support all the requirements
separately. evaluating to mandatory that are listed in tables A.6 and A.7.
This part of ISO/IEC ISP 12070 lays down requirements so that a 4) Conformance to the requirements for non-ASN. 1 string types.
consistent approach may be taken when specifying the use of
coded character sets in functional standards. A claim for conformance shall support all the requirements
evaluating to mandatory that are listed in tables A.8 and A. 9.
Some specifications relate to “pass-through” services (e.g. MHS
and Directory). Such services are outside the scope of this part of A compliant referencing specification shall indicate which
ISO/IEC ISP 12070. categories of conformance are required to be supported. A
compliant referencing specification may need to include a Profile
Requirements for the use of character sets in Telematic services Requirements List (PRL) which refers to the tables in Annex A
(eg Teletex and Videotex) are outside the scope of this part of when that specification makes selections of options available. A
ISO/IFC ISP 12070. compliant referencing specification shall require implementors of
that specification to complete the ICS proforma in Annex A of
The requirements specified in part of ISO/IEC ISP 12070 this part of ISO/IEC ISP 12070.
specifically apply to Western Europe but may be applicable in
other regions of the world.
ISO/IEC ISP 12070-1:1996(E)
8 ISO/IEC
Some base standards may have requirements on the handling of
character sets which differ from those recommended in this part - ISO/IEC 6429 : 1992, Information technology - Control
of ISO/IEC ISP 12070 (e.g. ODA). Where a requirement differs functions for coded character sets.
in this way, the base standard specification takes precedence over
this part of ISO/IEC ISP 12070.
- ISO/lEC 6937 : 1994 Information technology - Coded
graphic character set for text communication - Latin
alphabet.
3 Normative references
- CCITT Recommendation T.61 (1988), Character repertoire
and coded character sets for the International Teletex
The following documents contain provisions which, through
reference in this text, constitute provisions of this part of service.
ISO/IEC ISP 12070. At the time of publication, the editions
- ISOLEC 8859-l ‘, Information technoEoay - &bit single-byte
indicated are valid. All documents are subject to revision, and
parties to agreements based on this part of ISOLIEC 12070 are coded graphic character sets - Part I: Latin alphabet No. 1.
warned against automatically applying any more recent editions
of the documents listed below, since the nature of references
made by ISPs to such documents is that they may be specific to a
4 Definitions
particular edition. Members of IEC and IS0 maintain registers of
currently valid International Standards and ISPs, and ITU-T
4.1 ISO/IEC 2022 definitions
maintains published editions of its current recommendations.
This part of ISO/lEC ISP 12070 uses the following definitions
NOTE - Edition 2 and edition 3 of both ISO/IEC 8824 and ISO/IEC
contained in ISO/IEC 2022.
8825 will continue to be published together. Current editions of OS1
protocol specifications reference these second editions which make specific
reference to character set standards. This part of ISO/IEC ISP 12070 is
a> we
based upon the second editions. The latest editions of the character set
character
b)
standards are listed in 3.2 where such reference does not cause
coded character set; code
C>
inconsistency with the second editions of ISO/IEC 8824 and ISO/IEC
code table
d)
8825. Otherwise previous editions are listed.
control character
e>
control function
f)
to designate
g>
3.1 Paired CCITT Recommendations 1 International
escape sequence
h)
Standards equivalent in technical content
final byte
i>
graphic character
j>
- CCITT Recommendation X.208 : 1988, Specification of
to invoke
Q
abstract syntax notation one (ASN. 1)
repertoire
1)
ISO/IEC 8824 : 1990, Information technology - Open Systems
Interconnection - Specifkation of Abstract Syntax Notation
4.2 Basic terms
One (ASN. 1).
For the purposes of this part of ISO/EC ISP 12070, the following
- CCITT Recommendation X.209 : 1988, Speczfication of basic
term applies.
encoding rules for abstract syntax notation one (ASN. 1)
4.2.1 Instance of Communication: That part of a data stream
ISO/IEC 8825 : 1990, Information technology - Open Systems
that may be considered to be a single unit within which the scope
Interconnection - Specification of Basic Encoding Rules for
of a requirement of this part of ISO/IEC ISP 12070 applies.
Abstract Syntax Notation One (ASN. 1).
A single instance of the ASN. 1 type GraphicString when coded
in a data stream is considered to be an instance of
3.2 Additional references
communication.
- ISO/IEC 646 : 1991, Information technology - IS0 7-bit
A single instance of the ASN. 1 type GeneralString when coded in
coded character set for information interchange.
a data stream is considered to be an instance of communication.
- ISO/IEC 2022 : 1994, Information technology - Character
A single instance of the ASN. 1 type TeZetexString when coded in
code structure and extension techniques.
a data stream is considered to be an instance of communication.
- IS0 2375 : 1985, Data processing - Procedure for
These are defaults. Functional Standards which reference any of
registration of escape sequences.
the ASN. 1 types GraphicString, GeneralString and TeletexString
and wish to change the meaning of “instance of communication”
- ISO/IEC 4873 : 1991, Information technology - IS0 8-bit
should specify, in each case of use, its precise meaning.
code for information interchange - Structure and rules for
implementation.
’ To be published. (revision of IS0 8859-l: 1987)
0 ISO/IEC ISO/IEC ISP 12070-1:1996(E)
and specifies how these should be used. ISO/IEC 4873 profiles
A single instance of a non-ASN.1 string type when coded in a appear to cater for the majority of functional standard
requirements. However, ISO/IEC 4873 does not cater for all
data stream may be considered to be an instance of
communication and this is the default. Functional Standards scenarios where character sets are in use. Therefore, the
which reference a non-ASN. 1 string type should specify, in each requirements specified in this part of ISO/IEC ISP 12070 are
based on ISO/IEC 4873 wherever possible and where this is not
case of use, the precise meaning of instance ofcommunication.
the case, extra requirements are specifically highlighted.
5 Abbreviations
9 The use of announcer escape sequences
ASN. 1 Abstract Syntax Notation One
ICS Implementation Conformance Statement
ISOLIEC 4873 specifies the use of announcer escape sequences to
ODA Open Document Architecture
announce the use of a specific level of operation. In an open
OSE Open Systems Environment
ISOLEC 2022 code structure, announcer escape sequences should
IRnn International Register entry nn
always be used at the beginning of an instance of communication
IRV International Reference Version
(i.e. coded character string) to announce the code structure
MHS Message Handling Service
facilities that are proposed. This is the ISO/IEC 2022 method of
negotiation. However, few, if any, referencing base standards
actually specify the use of announcer control functions and
ISOLIEC 8825 specifically forbids their use for its character string
6 Errors
data types (e.g. GeneralString) unless the referencing base
standard specifically removes this restriction. None of the OSI,
Many requirements identified in the remainder of this part of
messaging or text processing (ODA) base standards ratified to
ISO/IEC ISP 12070 prohibit sending implementations from
date actually do this.
sending certain sequences of coded characters and allow
receiving implementations to treat the receipt of such a sequence
Where announcer sequences are not supported, it is still
of coded characters as an error. A sending implementation which
necessary for two communicating parties to come to a mutual
sends an illegal sequence of coded characters does not conform to
understanding of the code structure facilities to be used in an
this part of ISOLIEC ISP 12070 but in general it is not possible to
The precise action that a instance of communication. This may be done outside the scope
test this aspect of conformance.
of a coded character exchange by:
receiving implementation takes when an illegal sequence of
coded characters is received is outside the scope of this part of
1) bilateral private a priori arrangements;
ISOLIEC ISP 12070. A referencing specification shall specify the
2) unilateral decision (e.g. in a base or functional standard);
action that a receiving implementation takes when such an error
3) in a procurement specification (e.g. EPHOS);
is detected.
4) by a separate protocol exchange (e.g. using OCTET
STRING);
5) by some system management action.
7 The ISO/IEC 2022 code structure
ISOLEC 4873 defines 3 levels of operation. In the absence of
The major division within ISO/IEC 2022 is between the 7-bit and
announcement or other decision, the default level for a receiving
the 8-bit code structure. The 7-bit code structure is the older of
or a sending implementation is the highest level that is supported
the two and dates back to the early days of computing and data
by that implementation.
communications. The greater capacity of 8-bit transport
mechanisms, the ability of modern communications technology to
handle them and the widespread use of ASN.1 to specify OS1
9.1 Non-ASN.1 character string types
communications protocols leads naturally to the first requirement
to be capable of operating in the 8-bit ISOLIEC 2022 code
Support for announcer sequences is optional for both receiving
structure.
and sending implementations.
Requirement 1:
Requirement 2:
a) A sending implementation shall be capable of operating
A sending implementation which claims support of
a>
in the ISO/IEC 2022 &bit code structure.
announcer sequences shall send an announcer escape
sequence at the beginning of an instance of
b) A receiving implementation shall be capable of operating
communication to announce the level of ISOLIEC 4873
in the ISO/IEC 2022 8-bit code structure.
being proposed in that direction of data flow and shall
support the semantics of that announcer sequence.
8 The IS0 4873 code structure
A receiving implementation which claims support of
b)
announcer sequences shall be capable of receiving an
ISO/IEC 2022 defines a wide range of sub-structures for the use
announcer escape sequence to announce the level of
of 8-bit codes which could be considered to be profiles.
ISOLIEC 4873 being proposed in that direction of data
ISOLIEC 4873 chooses a nested set of 3 sub-structures (levels)
ISO/IEC ISP 12070=1:1996(E)
0 ISO/IEC
flow and shall support the semantics of that announcer
sequence. b) A receiving implementation that supports announcer
sequences shall support the semantics of a ISOLEC 4873
version designation subject to its
Requirement 3: support of
ISO/IEC 4873 levels.
a) A sending implementation which does not claim support
If redesignation of a G-set is required in the middle of an
of announcer sequences shall not send any announcer
instance of communication, then an announcer escape sequence
sequences.
shall precede it.
b) A receiving implementation that does not support
NOTE - ISO/IEC 2022 identifies levels of operation similar to the 3 levels
announcer sequences shall be capable of receiving an
of ISO/IEC 4873. The first three levels of ISO/IEC 2022 align with
announcer sequence without malfunction, but shall ignore
ISO/IEC 4873. The 4th level allows redesignation and but does not have an
it (i.e. take no action as a result).
equivalent in ISO/IEC 4873.
For completeness the announcer escape sequence is of the form
This part of ISOLEC ISP 12070 deprecates redesignation as
ESC 02/00 F where F takes the following values:
specified in ISO/IEC 4873. However, the following requirement
is included for completeness.
ISO/IEC 4873 level 1 0402
ISO/IEC 4873 level 2 0403
Requirement 6:
3 04/14
ISOLEC 4873 level
a) If a sending implementation that supports announcer
The action taken as the result of receiving or sending of any other
sequences wishes to redesignate a G-set during an
announcer escape sequence is outside the scope of this part of
instance of communication, it shall send an announcer
ISO/lEC ISP 12070.
sequence and a set of designation escape sequences.
A receiving implementation that supports announcer
W
9.2 ASN.1 character string types
sequences shall support redesi .gnation.
Requirement 4:
c) A receiving implementation which supports announcer
sequences may treat as an error the receipt of an escape
A sending implementation shall not send announcer
a> sequence redesignating a G-set which is not preceded by
sequences.
an announcer sequence.
as an error the
A receiving implementation may treat
W An implementation that does not support the sending of
reception of an announcer sequence.
announcer sequences may nevertheless identify a version of
ISOLEC 4873 to be used by assuming the level (communicated
by other means or by default) and using designation escape
10 The use of designation escape sequences
sequences. However, in this case, redesignation is prohibited by
this part of ISOLIEC ISP 12070.
A designation escape sequence is used to designate a G-set to a
registered coded character set as specified in ISO/IEC 2022.
Requirement 7:
a) A sending implementation that does not support
announcer sequences
10.1 Position of designation escape sequence may identify the version of
ISO/IEC 4873 to be used in that direction of data flow by
sending one or more designation escape sequences at the
ISOLIEC 4873 specifies that one or more designation escape
beginning of an instance of communication.
sequences shall occur at the beginning of an instance of
communication (i.e. coded character string) as part of the
b) A receiving implementation that does not support
announcement of the version of ISO/IEC 4873 to be used in that
announcer sequences shall support designation escape
direction of data flow.
sequences subject to its support of ISO/IEC 4873 levels.
Requirement 8:
10.1.1 Non-ASN. 1 character string types
a) A sending implementation that does not support
Requirement 5:
announcer sequences shall not attempt to redesignate
during an instance of communication.
a) A sending implementation that supports announcer
sequences shall identify the version of ISO/IEC 4873 to
b) A receiving implementation that does not support
be used in that direction of data flow by sending one or
announcer sequences may treat as an error the reception
more designation escape sequences immediately after the
of a redesignation escape sequence.
announcer escape sequence at the beginning of an
instance of communication.
ISO/IEC ISP 12070=1:1996(E)
8 ISO/IEC
a designation escape sequence for GO for IR 6.
A designation escape sequence may be omitted if the default
designation for that G-set is to apply.
10.2.2 ASN.l character string types
10.1.2 ASN.1 character string types
For ASN.1 types GraphicString and GeneraZStting the default
GO set isIR2.
Requirement 9:
a) A sending implementation may identify the version of Requirement 13:
ISO/IEC 4873 to be used in that direction of data flow by
sending one or more designation escape sequences at the For ASN. 1 types GraphicString and GeneralString:
beginning of an instance of communication.
a) A sending implementation shall send as part of its
ISO/IEC 4873 version designation (see requirement 9) a
b) A receiving implementation shall support designation
designation escape sequence to designate GO as IR 6.
escape sequences subject to its support of ISO/IEC 4873
levels.
b) A receiving implementation may treat as an error the
Designation sequences for default settings may be omitted from reception of a coded character in G-O before the reception
A sender may later in the string of a designation escape sequence for GO for IR 6.
the version announcement.
override a default designation but this practice is deprecated by
this part of ISO/IEC ISP 12070.
10.3 ISO/IEC 4873 level 1 requirements
Requirement 10:
Level 1 of ISO/IEC 4873 supports the use of GO, Gl, CO and C 1.
.ementation shall not attempt to
A sending imp1
a>
an instance of communication.
redesignate during
Requirement 14:
b) A receiving implementation may treat as an error the
a) A sending implementation shall support at least the
reception of a redesignation escape sequence.
operation of ISO/IEC 4873 level 1.
be omitted if the default
A designati .on escape sequence may
b) A receiving implementation shall support at least the
designation for that G-set is to apply.
operation of ISO/IEC 4873 level 1.
Requirement 15:
10.2 GO designation
A sending implementation which needs to support only 2
ISO/IEC 4873 prescribes the use of international register (IR) No coded graphic character sets concurrently as G-sets shall
6 (ASCIl) coded character set permanently as the GO set in its operate at ISO/IEC 4873 Level 1.
code structure.
Requirement 16:
Requirement 11:
a) A sending implementation that operates at ISO/IEC 4873
a) A sending implementation shall not send a designation level 1 (by announcement, by other decision or by
escape sequence which designates a coded character set default) shall not send designation escape sequences for
other than IR 6 as GO. G2 or G3.
b) A receiving implementation may treat as an error the b) A receiving implementation that operates at
reception of a designation escape sequence which ISO/IEC 4873 level 1 (by announcement, by other
designates a coded character set other than IR 6 as GO. decision or by default) may treat as an error the reception
of designation escape sequences for G2 or G3.
10.2.1 Non-ASN. 1 character string types Requirement 17:
The default GO set is IR 6. a) A sending implementation shall support, for each
registered character set it claims to support in GR over
and above the default G-set, the sending of the
Requirement 12:
designation escape sequence for Gl.
a) The requirement for a sending implementation to be
b) A sending implementation shall support, for each
capable of sending a designation escape sequence for GO
registered CO control set and each registered Cl control
for IR 6 is optional.
set it claims to support over and above the default C-sets,
the sending of designation escape sequences for CO and
b) A receiving implementation shall be capable of receiving
ISO/IEC ISP 12070=1:1996(E) 8 ISO/IEC
C 1 respectively. d) A receiving implementation shall support, for each
registered CO control set and each registered Cl control
set it claims to support, the reception of designation
c) A receiving implementation shall support, for each
escape sequences for CO and Cl respectively.
registered coded character set it claims to support in GR,
the reception of the designation escape sequence for Gl .
At Level 3, either but not both G2 and G3 may be empty. If
designation sequences are sent that result in both G2 and G3
d) A receiving implementation shall support, for each
being empty, subsequent operations are carried out at level 1.
registered CO control set and each registered Cl control
This is permitted.
set it claims to support, the reception of designation
escape sequences for CO and Cl respectively.
Requirement 21:
ISO/IEC 4873 states that at level 1, either or both Gl and Cl may
a) A sending implementation may optionally support the
be empty. The following requirement therefore applies.
sending of designation escape sequences for the empty
G2 or G3 sets.
Requirement 18:
b) A receiving implementation shall support the reception of
a) A sending implementation that operates at ISO/IEC 4873
the designation escape sequences for the empty G2 and
level 1 may optionally support the sending of designation
G3 sets.
escape sequences specifying an empty Gl or an empty
Cl.
b) A receiving implementation that operates at ISO/IEC
10.5 The form of designation escape sequences
4873 level 1 shall support the reception of designation
escape sequences specifying both an empty Gl and an
For completeness, the form of the designation sequences is laid
empty C 1.
out below:
GO ESC 02/08 04/02 designates IR6
10.4 ISODEC 4873 level 2 and 3 requirements
Gl ESC 02/09 F designates a 94 coded character set
ESC 0203 F designates a 96 coded character set
Levels 2 and 3 of ISO/IEC 4873 support the use of GO, Gl, G2,
ESC 02/09 0704 designates an empty Gl set
G3, CO and Cl.
G2 ESC 02/10 F
Requirement 19: designates a 94 coded character set
ESC 02/14 F designates a 96 coded character set
ESC 0200 0704 designates an empty G2 set
a) A sending implementation which needs to support 3 or 4
coded character sets concurrently as G-sets shall operate
G3 ESC 02/l 1 F designates a 94 coded character set
at ISO/IEC 4873 level 2 or level 3.
ESC 0205 F designates a 96 coded character set
ESC 02/l 1 07/14 designates an empty G3 set
b) A receiving implementation which needs to support 3 or 4
coded character sets concurrently as G-sets shall operate
CO ESC 02/01 F designates a CO set of control functions
at ISO/IEC 4873 level 3.
reasons of
NOTE - The requirement for receivers is made for
Cl ESC 02/02 F designates a Cl set of control functions
interoperability.
ESC 02/02 0704 designates an empty C 1 set
Requirement 20:
The final byte F forms part of the registration of the coded
character set.
a) A sending implementation shall support, for each
registered character set it claims to support in GR over
and above the default G-sets, the sending of designation
10.6 Teletex related operation
escape sequences for at least one of Gl , G2 and G3.
The Teletex service style of operation as defined in CCITT T-61
b) A sending implementation shall support, for each
and ISO/IEC 6937 uses a variable length coding to code
registered CO control set and each registered Cl control
characters which have diacritical marks. The use of this style of
set it claims to support over and above the default C-sets,
operation is deprecated by this part of ISO/IEC ISP 12070 for all
the sending of designation escape sequences for CO and
character string types apart from ASN. 1 type TeZetexString (also
C 1 respectively.
known as T6lString) which is specifically designed for it. This
means that the designation of IR 103 (Teletex Supplementary Set
c) A receiving implementation shall support, for each
of Graphic Characters for CCITT Recommendation T.61) and IR
registered coded character set it claims to support in GR,
156 (Supplementary Set of ISO/IEC 6937) as Gl, G2 or G3 is
the reception of designation escape sequences for Gl, G2,
prohibited for character string types other than TeZetexString.
and G3.
0 ISO/IEC ISODEC ISP 12070=1:1996(E)
NOTE-It is possible to code the Teletex repertoire by one byte 8-bit coding require control function repertoires containing more control
by using the registered character sets according to IR6, IRl 00, IRl 0 1 and
functions than the minimum required for the level of ISO/IEC
IR154.
4873 in use.
Requirement 22: Apart from ASN.1 type TeletexString:
Requirement 24:
A sending implementation shall not send a designation
For all levels, the CO set shall be used which contains
sequence specifying IR 103 or IR 156 or any other
ESCAPE coded as 01/l 1.
registered character set containing non-spacing diacritical
marks.
Requirement 25:
A receiving implementation may treat as an error the
For levels 2 and 3, the CO set and the C 1 set shall be used
reception of a designation sequence specifying IR 103 or
which contains SS2 coded as 08/14 and SS3 coded as 0805.
IR 156 or any other registered character set containing
non-spacing diacritical marks.
This part of ISO/IEC ISP 12070 does not specify or reference the
semantics associated with other control functions. A referencing
specification that needs other control functions shall specify them
10.7 Multibyte character set requirements
and the associated semantics.
The designation sequences listed above cater for the European
requirement and it is believed the North American requirement.
10.9 Designation Defaults
They fall within the scope and specification of ISO/IEC 4873.
Certain default settings for G-set designations may bring
NOTE - ISO/IEC 4873 does not allow the use of registered multibyte
implementation savings in certain instances. Also, the use of
coded character sets. It therefore does not support the use of Japanese,
defaults removes any ambiguity if designation sequences are
Chinese or Korean character sets.
missing or other defaults set by referencing specifications are not
in effect (e.g. for ASN.l type GeneralString). Where other
defaults apply, they take precedence over the defaults listed
10.8 Minimum level of support
below.
10.8.1 Graphic character repertoires
The use of an announcer sequence shall cause the reset of any
designation status to default values.
Requirement 23:
Requirement 26:
The minimum graphic ‘: haracter repertoire support required
in Western Europe for the ISO/IEC 2022 8-bit code structure
a) A implementation which sends an announcer sequence
is the 191 characters of ISO/IEC 8859-l which consist of the
shall reset all of its designation settings to default values.
graphic character repertoire of IR 6 (94 characters) plus the
graphic character repertoire of IR 100 (96 characters) plus
b) A receiving implementation which supports announcer
SPACE.
sequences shall reset all its designation settings to default
values when it receives an announcer sequence.
NOTE - This minimum requirement is a subset of the Minimum European
Subset of IS011 EC 10646-l currently being defined by CEN TC 304.
Requirement 27:
10.8.2 Control function repertoires
An implementation shall set its default designation settings to
default values at the beginning of an occurrence of an ASN. 1
This part of ISO/IEC ISP 12070 specifies, as a default, the use of
character string type.
minimum control function repertoires for use with levels 1, 2 and
3 of ISO/lEC 4873.
Requirement 28:
When operating at level 1, the minimum control function
The following designation defaults apply to ASN.l types
repertoire consists only of ESCAPE.
GraphicString, Genera&ring and to non-ASN. 1 string types.
When operating at level 2, the minimum control function
GO IR 6 ASCII (1eA hand part of ISO/IEC 8859-l)
repertoire consists of ESCAPE, SS2 and SS3.
Gl IR 100 Right hand part ofISO/IEC 8859-l
When operating at level 3 the minimum control function
repertoire consists of ESCAPE, SS2, SS3, LSlR, LS2R, LS3R.
The empty G2 set (ISO/IEC 4873 level 2 or 3
G2
The locking shift functions are escape sequences and are listed in
only >
clause 8.
G3 The empty G3 set (ISO/lEC 4873 level 2 or 3
These requirements may be satisfied by the use of appropriate
only)
registered control sets. Referencing application profiles may

ISO/IEC ISP 120704:1996(E) 8 ISO/IEC
Requirement 30:
co lR 1 CO set of IS0 646 (the IRV)
a) A sending implementation shall not send any control
Cl IR 105 Minimum Cl set for ISO/IEC 4873 function which is coded in an ESC Fe sequence.
(ISO/lEC 4873 level 2 or 3 only)
b) A receiving implementation may treat as an error the
A CO set consisting of ESCAPE only has registration no. 104. reception of any control function which is coded in an
However, choice of this default is felt to be too restrictive. The ESC Fe sequence.
default CO set is therefore chosen as the IR 1 - the CO control set
A single shift invocation control function may occur at any time
of IS0 646. (It should be noted that IR 1 is referred to in
ISO/IEC 646 as the CO set of IS0 6429). and as often as required during an instance of communication.
Each invocation is of a single character (that following the single
A Cl set consisting of SS2 and SS3 is defined in IR 105 and this shift function) into the GL of the code space. This part of
is chosen as the default. ISO/IEC ISP 12070 takes the view that the invocation of an
empty code table position is not allowed. An empty G-set is one
that consists entirely of empty code table positions.
11 Invocation control functions
The use of single shift or locking shift functions shall only be
used when levels for which they are defined are in use.
11.1 General requirements
Requirement 31:
The following locking shift invocation control functions are
a) A sending implementation that operates at ISO/IEC 4873
defined in ISO/IEC 2022 and are used in a ISO/IEC 4873 code
level 1 (by announcement, by other decision or by
structure at level 3:
default) shall not send any single shift nor any locking
shift function.
LSlR ESC 07/14 (IR 66) to invoke Gl in the GR of the code
space
b) A receiving implementation that operates at
LS2R ESC 0703 (IR 65) to invoke G2 in the GR of the code
ISO/IEC 4873 level 1 (by announcement, by other
space
decision or by default) may treat as an error the reception
LS3R ESC 0702 (IR 64) to invoke G3 in the GR of the code
of any single shift or any locking shift function.
space
Requirement 32:
No other locking shift functions are allowed.
A sending implementation that operates at ISO/IEC 4873
Requirement 29:
level 2 (by announcement, by other decision or by default)
shall not send any locking shift function.
a) A sending implementation shall not send locking shift
functions other than LSlR, LS2R and LS3R.
A sending implementation need only support the minimum set of
functions of ISO/IEC 4873 required to use 3 or 4 coded graphic
b) A receiving implementation may treat as an error the
character sets concurrently. A receiving implementation which
reception of locking shift functions other than LS lR,
needs to support 3 or 4 coded graphic character sets concurrently
LS2R and LS3R.
shall support the full operation of ISO/IEC 4873 level 3.
At ISO/IEC 4873 level 3, a locking shift invocation control
Requirement 33:
function may occur at any point and as often as required during
an instance of communication. In an instance of communication,
a) A sending implementation which claims to support the
the invocation caused by the use of a locking shift function
use of 3 coded graphic character sets concurrently shall
remains in effect until another locking shift function occurs.
optionally support the sending of LS 1 R, and shall support
the sending of at least one of SS2, LS2R, SS3 and LS3R
The following single shift invocation control functions are
as defined in ISO/IEC 4873 level 2 and level 3.
defined in ISO/IEC 2022 and are used in a ISO/IEC 4873 code
structure at levels 2 and 3:
b) A sending implementation which needs to support the use
of 4 coded graphic character sets concurrently shall
ss2
08/14
optionally support the sending of LS 1 R, and shall support
ss3 08/l 5
the sending of at least one of SS2 and LS2R and at least
one of SS3 and LS3R as defined in ISO/IEC 4873 level 2
The use of the alternative ISO/IEC 2022 ESC Fe sequences for
and level 3.
coding SS2 and SS3 is not permitted and may be treated by a
receiving implementation as an error.
c) A receiving implementation which needs to support the
use of 3 or 4 coded graphic character sets concurrently
shall support the reception and semantics of SS2, SS3,
LSlR, LS2R and LS3R as defined in ISO/IEC 4873 level
ISO/IEC ISP 12070=1:1996(E)
8 ISO/IEC
Requirement 40:
2 and level 3
a) A sending implementation shall not send any coded
Requirement 34:
character that has not been taken from the lowest
numbered G-set in which that character has been
a) A sending implementation that operates at ISO/IEC 4873
allocated.
level 2 or level 3 shall not send any single shift control
function which attempts to invoke an empty cell of a code
b) A receiving implementation may treat as an error any
table into GL.
coded character that has not been taken from the lowest
that operates at numbered G-set in which that character has been
receiving implementation
b) A
allocated.
ISO/IEC 4873 level 3 may treat as an error the reception
of any single shift control function which attempts to
Requirement 41:
invoke an empty cell of a code table into GL.
A sending implementation shall not send any byte that
GO is permanently invoked into GL. This applies whatever
a>
represents an empty code table position.
registered coded character set is designated as GO. GO is never
it has a default designation or is
designated as the empty set -
This implies that LSO is never used - see b) A receiving implementation may treat as an error the
designated as IR 6.
reception of any byte that represents an empty code table
requirement 2 9.
position.
Requirement 35:
into GL.
GO is permanently invoked
13 The Characters SPACE and DEL
CO and Cl are permanently invoked into CL and CR respectively.
ISO/IEC 4873 makes available and always codes SPACE as
This applies whatever registered control sets are designated as
02/00 and DEL as 07/l 5.
SPACE is included in ISO/IEC 8859-l
CO and Cl respectively.
but DEL is not. This is a basic discrepancy.
Requirement 36:
DEL was originally used to erase or obliterate an erroneous or
unwanted character in punched tape. DEL may be used for
CO and Cl are permanently invoked into CL and CR
media-fill or time-fill. DEL characters may be inserted into, or
respectively.
removed from, a data stream without affecting the information
content of that stream, but such action may affect the information
By default Gl is initially invoked into GR and the use of a Gl
layout and/or control of equipment.
function automatically invokes Gl into GR
designation
irrespective of the current shift status.
The use of DEL is considered obsolete in modem data
communications in the context of the user data part of application
Requirement 37:
layer protocols. There is no requirement for its use in application
profiles and its use is therefore considered outside of scope by
By default, Gl is initially invoked into GR.
this part of ISO/IEC ISP 12070.
-
Requirement 38:
Requirement 42:
designation escape sequence invokes Gl into
The use of a Gl
a) A sending implementation shall not use code 07/15 to
GR.
represent the character DEL in user data.
b) A receiving implementation may treat as an error the
reception of the character DEL (coded as 0705) in user
12 Character coding
data.
Requirement 39:
The character coding that shall be used is defined in the code
14 ASN.l type GeneralString
tables registered in the IS0 International Register of Coded
Character Sets to be Used with Escape Sequences.
The provisions of clauses 3 to 9 apply to this string type apart
from those relating specifically to non-ASN.l string types. In
Where a particular implementation requires that every
addition, it should be noted that the ISO/IEC 8824 default for GO
character should have a unique coded representation, then
designation and invocation is IR 2 (the IRV of IS0 646 1983).
requireme
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