ISO 646-1973 Information technology — ISO 7-bit coded character set for information interchange [1 ed.]

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INTERNATIONAL STANDARD I S O 646 I N T E R N A T I O N A I O R G A N I Z A T I O N F O R S T A N D A R O I 7A T I O N • М Е Ж П У Н А Р О Л Н А Я О Р Г А Н И З А Ш И Я П О С Т А Н Л А Р Т И З А | | И И • O R G A N I S A T I O N I N T E R N A T I O N A IF

D E N O R M A II S A T I O N

7-b it c o d e d c h a r a c t e r s e t f o r i n f o r m a t i o n p r o c e s s i n g

interchange

First e d i t i o n - 1973-07-01

UDC 681.3.042 : 003.62

Ref. No. ISO 646-1973 (E)

Descriptors : data processing, data trasmission, character sets, coding, information interchange.

Price based on 13 pages

FOREWORD ISO (THE INTERNATIONAL ORGAI

O (N FOR STANDARDIZATION) IS AWORLDWIDE FEDERATION OF NATIONAL

STANDARDS INSTITUTES (ISO MEMBER BODIES). T H E WORK FO DEVELOPING INTERNATIONAL STANDARDS SI IO TECHNICAL COMMITTEES. EVERY MEMBER BODY INTERESTED N I ASUBJECT FOR CARRIED OUT THROUGH S WHC IH ATECHNC IAL COMMT ITEE HAS BEEN SET U P HAS T H E RG IHT O T EB REPRESENTED O N THA T COMMITTEE. I LIAISON WT IH ISO, ALSO TAKE INTERNATIONAL ORGANIZATIONS, GOVERNMENTAL AND NON GOVERNMENTAL, N PART N I THE WORK.

DRAFT INTERNATIONAL STANDARDS ADOPTED B Y THE TECHNICAL COMMITTEES ARE CIRCULATED O T THE MEMBER BODIES FOR APPROVAL BEFORE THEIR ACCEPTANCE AS INTERNATIONAL STANDARDS BY THE ISO COUNCIL INTERN

ONAL STANDARD SIO 646 W A S DRA WN U PY B TECHNC IAL COMMT ITEE ISOT / C 97, COMPUTERS A N D

O THEMEMBER BODIES N I APRIL 1972. INFORMATION PROCESSING, ANDCIRCULATEDT

Y THE MEMBER BODIES OF THE FOLLOWING COUNTRIES: T I HAS BEEN APPROVED B BELGIUM

IRELAND

SWEDEN

BRAZIL

ITALY

SWITZERLAND

CANADA CZECHOSLOVAKIA

JAPAN

NETHERLANDS

THAILAND UNITEDKINGDOM

DENMARK EGYPT, ARAB REP. O F FRANCE

PORTUGAL

U.S.A.

F SOUTH AFRICA. REP. O

GERMANY

SPAIN

U.S.S.R.

O N MEMBER B ODYEXPRESSED DS IAPPROVAL O F THE DOCUMENT.

© INTERNATIONAL ORGA

I SWITZERLANI PRINTED N

N I FOR STANDARDIZATION, 1973

INTERNATIONAL STANDARD

ISO 646-1973 (E)

7-bit c o d e d c h a r a c t e r s e t for i n f o r m a t i o n p r o c e s s i n g interchange

1 SCOPE

1.1

A N D F I E L D OF A P P L I C A T I O N

c h a r a c t e r s (control c h a r a c t e r s a n d g r a p h i c c h a r a c t e r s s u c h a s

1.7 The definitions of some control characters in this International Standard a s s u m e that data associated with them

letters, digits and symbols) with their coded representation.

is to b e p r o c e s s e d serially in a forward direction.

Most of these characters are mandatory and unchangeable,

Their effect when included in strings of data which are processed other than serially in a forward direction or included in data formatted for fixed record processing may have undesirable effects or may require additional special treatment

This International Standard contains a set of

128

but provision is made for some flexibility to accommodate s p e c i a l n a t i o n a l a n d other r e q u i r e m e n t s .

1.2 The need for graphics and controls in data processing and in d a t a t r a n s m i s s i o n h a s b e e n d e t e r m i n i n g t h i s c h a r a c t e r set.

taken

into

account

in

2 IMPLEMENTATION

1.3 This International Standard consists of a general tabie with a number of options, notes, a legend and explanatory notes.

It a l s o c o n t a i n s

a

s p e c i fi c

to e n s u r e that t h e control c h a r a c t e r s h a v e their d e s i r e d effect.

international

reference

version, guidance on the exercise of the options to define specific national versions and application oriented versions.

1.4 This character set is primarily intended for the interchange

of information among data processing systems and associated equipment, and within in m e s s a g e transmission

2.1 This character set should be regarded a s a basic alphabet in an abstract sense. Its practical use requires definitions of its implementation in various media. For example, this could include punched tapes, punched cards, magnetic tapes and transmission channels, thus permitting interchange of data to take place either indirectly by means of an intermediate recording in a physical medium, or by local electrical connection of various units (such a s input and output devices and computers) or by means of data transmission equipment.

systems.

1.5 This character set is applicable to all latin alphabets. 1.6 T h i s c h a r a c t e r s e t i n c l u d e s facitities for e x t e n s i o n w h e r e

2.2 The implementation of this coded character set in physical

media and for transmission, taking into account the need for error checking, is the subject of other ISO publications. (See Appendix Y.)

its 128 characters are insufficient for particular applications.

1

ISO 646-1973 (E)

3 B A S I C C O D E TA B L E TABLE 1 - B a s i c c o d e table

O 1

1

1

2 3

TC,

SP

0 0

0

DC,

TC,

DC,

TC,

DC,

(STX)

3 4

(ETX)

1

1

4 5

6 7

8

9 1

11

P

p

A 2

£( #)

3

a B

R

C

S

b

S

DC, $ ( a )

4

TC,

TC,

%

5

E

U

e

TC,

&

6

F

V

f

7

G

(ENQ) (NAK)

TC. 6 (ACK) 7

3

0

TC,

(EOT)

5

(DLE)

TC,

(SOH)

2

0

문등

1

b

NUL

2

1

1

b.

b

1

BEL

FE,

(BS)

(HT)

FE,

(LF), (VT),

(SYN) ТС

(ETB)

D

d

W

H

CAN

g h

EM

J

SUB ESC

+

K

Z

Z

k

(FF).

IS,

(FS)

L

1 3

FE, (CR).

IS,

M

m

1 4

SO

IS,

N

n

1 5

SI

1 2

W

(GS)

(RS)

IS,

(US)

3

3 3

DE L

ISO 646-1973 (E)

NOTES ABOUT TABLE 1

The f o r m a t effectors a r e i n t e n d e d for e q u i p m e n t in which horizontal a n d vertical m o v e m e n t s a r e effected separately. If e q u i p m e n t r e q u i r e s t h e action of CARRIAGE RETURN t o b e c o m b i n e d with a vertical m o v e m e n t , t h e f o r m a t effector f o rt h a t vertical m o v e m e n t

may be used to effect the combined movement. For example, if NEW LINE (symbol NL, equivalent to CR + LF) is required, FE! shall be used to represent it. This substitution requires agreement between the sender and the recipient of the data. The use of these combined functions may be restricted for international transmission on general switched telecommunication n e t w o r k s (telegraph a n d t e l e p h o n e networks).

2

T h e s y m b o l § is a s s i g n e d to position 2/3 a n d the s y m b o l $ is a s s i g n e d to position 2/4. In a situation w h e r e there is n o r e q u i r e m e n t

for the symbol § the symbol # (number sign) may be used in position 2/3. Where there is no requirement for the symbol $ the s y m b o la (currency sign) may be used in position 2/4. The chosen allocations of symbols to these positions for international information i n t e r c h a n g e s h a l b e a g r e e d b e t w e e n the i n t e r e s t e d parties. It s h o u l d b e n o t e d that, u n l e s s o t h e r w i s e a g r e e d b e t w e e n

sender and recipient, the symbols £, $ or a do not designate the currency of a specific country. National use positions. The allocations of characters to these positionsl i e s within the responsibility of national standardization bodies. These positions are primarily intended for alphabetextensions. If they are not required for that purpose, they may be used for symbols.

Positions 5/14, 6/0 and 7/14 are provided for the symbols UPWARD ARROW HEAD, GRAVE ACCENT and OVERLINE. However, these positions may be used for other graphical characters when it is necessary to have 8, 9 or 10 positions for national use. 6

Position 7/14 is used for the graphic character - (OVERLINE), the graphical representation of which may vary according to national u s e to r e p r e s e n t ~(TILDE) or a n o t h e r diacritical s i g n provided that there is n o risk of c o n f u s i o n with a n o t h e r g r a p h i c c h a r a c t e r i n c l u d e d i n t h e t a b l e .

6

The graphic characters in positions 2/2, 2/7, 2/12 and 5/14 have respectively the significance ofQUOTATION MARK, APOSTROPHE, COMMA a n d UPWARD ARROW HEAD. However, t h e s e c h a r a c t e r s take o n the s i g n i fi c a n c e of the diacritical s i g n s DIAERESIS ACUTE ACCENT, CEDILLA a n d CIRCUMFLEX ACCENT w h e n they are p r e c e d e d o r followed by the BACKSPACE c h a r a c t e r (0/8).

3

ISO 646-1973 (E)

4 LEGEND

4.1 C o n t r o l c h a r a c t e r s

4.2 G r a p h i c c h a r a c t e r s

Position in A b b r e v i a t i o n

Note

M e a n i n g

r

h

e c

o

d

e

P o s I t i o n i n

Graphic

N o t e

r

a

m

e

m a o l e

h

e c o d e t a o l e

S p a c e ( s e e 7.2)

210

Exclamation mark

211

0/8

Quotation mark. Diaeresis

212

1/8

Pound sign

213

Carriage Return

Number sign

213

Device Control

214

Delete

Dollar sign Currency sign

Data Link Escape

Percent sian

2/5

E n d of Medium

Ampersand

Enquiry

Apostrophe, acute accent

217

E n d of Tr a n s m i s s i o n

L e t t p a r e n t h e s i s

218

ACK

Acknowledge

BEL

Bell C a n c e l

Esca pe End of Transmission Block End of Text Format Effector Form Feed File Separator

(space)

214

R i g h t p a r e n t h e s i s

0/12

Group Separator

A S t e r I S K

2/10

P l u s s i a n

2111

Comma, Cedilla

2/12

H o h e n . M i n u s s i a n

2/13

Full s t o p (period)

2/14

Solidus

2/15 3/10

HorizontalTabulation Information Separator

SUB

r

S e m i - c o l o n

3 / 11

Line Feed

0/10

L e s st h a ns i a n

3/12

Negative Acknowledae

1/5

Equals sign

3/13

Null

0/0

C r e a t e r t h a n s i a n

3/14

Record Separator

1/14

Question mark

3/15

Shift-In

0/15

U p w a r d a r r o w h e a d (Circumflex accont'

5/14

Shift-Out

0 / 1 4

Shift-Out

5/15

Start o f Headina

0/1

Start of Heading

6/0

Space (see 7.2)

2/0

s p a c e [ s e a 7 21

7/14

S t a r t o f T e x t

0/2

Substitute Character

1/10

S y n c h r o n o u s Idle Transmission Control

Unit Separator Ve r t i c a l T a b u l a t i o n

4. 6

ISO 646-1973 (E)

5 E X P L A N ATO RY N O T E S

5.1 Numbering of the positions in Table 1 Within any one character the bits are identified by by, b,,

b...b,, where b, is the highest order, or most significant bit,

and b, is the lowest order, or least significant bit.

If desired, these may be given a numerical significance in the binary system, thus:

Bit identification: b,

b. b

b, b, b, b,

Significance:

32

8

64

16

2

1

w h i c h a r e different from t h e c h a r a c t e r s of t h e international

reference version may be assigned to the national use positions. When such assignments are made, the graphic characters shall have distinct forms and be given distinctive names which are not in conflict with any of the forms or the names of any of the graphic characters in the international r e f e r e n c e ve rsi on .

5.4 U n i q u e n e s s of c h a r a c t e r a l l o c a t i o n

In the table the columns and rows are identified by numbers written in binary and decimal notations. Any one position in the table may be identified either by its bit pattern, or by its column and row numbers. For instance, the position containing the digit 1 may be identified: by i t s b i t p a t t e r n in o r d e r of d e c r e a s i n g significance, i.e. 011 0001. -

Under the provision of Note 3 of Table 1, graphic characters

by its column a n d row n u m b e r s , i.e. 3/1.

A character allocated to a position in Table 1 may not be placed elsewhere in the table. For example, in the c a s e of position 2/3 the character not used cannot be placed elsewhere. In particular the POUND sign (€ can never be represented by the bit combination of position 2/4. 6 V E R S I O N S O F TA B L E 1

6.1 Ge ner al

The columnnumberis derived from bits b, b, and b giving

them weights of 4, 2 and 1 respectively. The row number is

6.1.1 In order to use Table 1 for information interchange, ti is

derived from bits b, by, b, and b, giving them weights of 8, 4,

affected by Notes (

2 a n d 1 r e s p e c t i v e l y.

necessary to exercise the options left open, i.e.

to 5 . A single character must be

a l l o c a t e d to e a c h of t h e p o s i t i o n s for w h i c h this f r e e d o m

exists or it must be declared to be unused. A code table completed in this way is called a "version".

5.2 Diacritical s i g n s In the 7-bit character set, some printing symbols may be d e s i g n e d to p e r m i t their u s e for t h e c o m p o s i t i o n of a c c e n t e d l e t t e r s w h e n n e c e s s a r y for g e n e r a l i n t e r c h a n g e of

information. A sequence of three characters, comprising a

6.1.2 The notes to Table 1, the explanatory notes and the legend apply in full to any version.

letter, "backspace" and one of these symbols, is neededfor this composition. The symbol is then regarded as a diacritical

6.2 International r e f e r e n c e v e r s i o n

s i g n . It s h o u l d b e n o t e d t h a t t h e s e s y m b o l s t a k e o n their

to u s e

diacritical significance when they are preceded or followed by o n e "backspace" character. For example the symbol

corresponding to the code combination 2/7 normally has the

significance of "apostrophe", but becomes the diacritical sign

"acute accent" when it precedes or follows a "backspace" c h a r a c t e r.

In order to increase efficiency, ti is possible to introduce accented

letters

(as

those

single

characters)

in

the

positions

marked by Note 3 in the code table. According to national requirements, these positions may contain special diacritical signs.

5.3 Names, m e a n i n g s a n d fonts of c h a r a c t e r s This International Standard assigns at least one name to denote each of the graphic characters displaved in Tables 1 and 2. The names chosen to denote graphic characters are intended to reflect their customary meanings. However, this International S t a n d a r d d o e s n o t d e fi n e a n d d o e s n o t restrict

This version is available for use when there is no requirement a

n a t i o n a l or

an

application-oriented

version.

In international information processing interchange t h e international r e f e r e n c e v e r s i o n ( Ta b l e 2) is a s s u m e d u n l e s s a

particular agreement exists between sender and recipient of

the data. The following characters are allocated to the

optional positions of Table 1:

Number sign

213

Currency sign

214

Commercial at

4/0

Left s q u a r e b r a c k e t

5 / 11

Reverse solidus

5/12

Right square bracket

5/13

Left c u r l y b r a c k e t

7111

Vertical line

7/12

Right curly b r a c k e t

7113

it s h o u l d b e n o t e d t h a t n o s u b s t i t u t i o n i s a l l o w e d w h e n u s i n g t h e i n t e r n a t i o n ar e f e r e n c e v e r s i o n

the meanings of graphic characters. In addition, it does not specify a particular style or font design for the graphic characters.

5

ISO 646-1973 (E)

TABLE 2 - I n t e r n a t i o n a l r e f e r e n c e v e r s i o n 1

1

.b

1

b

b

1

0

1

1

1

1

2 3

4 5

TC,

SP

@

6 7

b

NUL

1 0

0

(DLE)

TG,

DC,

(SOH)

2

TC,

(STX)

DC,

3

TC,

DC,

(ETX)

4

0

5 6

TC,

(EOT)

TC,

T C

(ENQ) ( N A K ) TO , TC.

흐음 음 음은

8

BEL

FE,

(BS)

FE

FE,

SUB

11

F E (VT)

ESC

1 2

FE, (FF)

IS,

(FS)

1 3

FE,

(CR)

15,

(GS)

1 4

SO

1S;

1 5

SI

Q

a

b

3

C

S

C

4

D

%

5

E

&

6

F

#

7

S

d

U

V

W

G

t

e

f

W

g

H

CAN

1 0

p

R

(ETB)

(HT)

P

B

2

ТС

9

(LF)

A

DC,

( A C K )(SYN)

7

6

1

EM

(RS)

IS,

(US)

J

Z

Z

K

+

k

M

N

m

Л

n

O DEL

I S O 6 4 6 - 1 9 7 3 (E)

6.3 National v e r s i o n s 6.3.1 The responsibility for defining national versions lies with the national standardization bodies. These bodies shall exercise

the

options

available

and

make

the

format effectors, any reference to printing devices s h o u l d b e i n t e r p r e t e d a s including d i s p l a y d e v i c e s .

required

The definitions of format effectors use the following

selection.

concept:

6.3.2 fI so required, more than one national version can be d e fi n e d within a c o u n t r y.

The different v e r s i o n s shall b e

a) a page is comp osed of a numb er of lines of

separately identified. In particular when for a given national use position, for example, 5/12 or 6/0, alternative characters

characters.

b) the characters forming a line occupy a number of positions called character positions.

are required, two different versions shall be identified, even fi they differ only by this single character.

c) t h e a c t i v e position is t h a t c h a r a c t e r position in w h i c h t h e c h a r a c t e r a b o u t to b e p r o c e s s e d w o u l d

6.3.3 If there is in a country no special demand for specific charact ers, it is strongly recomm ended that the charact ers of

appear, fi it were to be printed.

n o r m a l l y a d v a n c e s o n e c h a r a c t e r position a t a time.

t h e international r e f e r e n c e v e r s i o n b e a l l o c a t e d to t h e s a m e national u s e positions.

The format effector characters are: BS, CR, FF, HT, LF and VT (see also Note 1).

6.4 Application-oriented versions Within national or international industries, organizations or

DC

professional groups, application-oriented versions c a n b e

ancillary d e v i c e (or d e v i c e s c o n n e c t e d t o a

Publications.

7.1 General d e s i g n a t i o n s of control c h a r a c t e r s The general designation of control characters involves a specific class name followed by a subscript number.

data

proc essin g and/or telec omm unic ation syste m. Thes e control

characters

are

not

telecommunication systems. by the use of TCs.

7 FUNCTIONAL C H A R A C T E R I S T I C S R E L AT E D T O CONTROL CHARACTERS

Some definitions in this section are stated in general terms and more explicit definitions of use may be needed for specific implementation of the code table on recording media or on transmission channels. These more explicit definitions and the use of these characters are the subiect of other ISO

Device control characters C o n t r o l c h a r a c t e r s for t h e c o n t r o l of a l o c a l o r r e m o t e

used. They require precise agreement among the interested parties, who will have to exercise the options available and to make the required selection.

intended

to

control

This should be achieved

Certain preferred uses of the individual DCs are given in 7.2.

IS

Information s e p a r a t o r s Control c h a r a c t e r s t h a t a r e u s e d to s e p a r a t e a n d

qualify data logically. There are four such characters. They may be used either in hierarchical order or nonhierarchically. In the latter c a s e their specific meanings depend on their applications.

When they are used hierarchically, the ascending order is: US, RS, GS, FS. In this case, data normally delimited by a particular separator cannot be split by a higher order separator

They are defined a s follows: TC

The active position

Transmission control characters

but will be considered as delimited by any higher order s e p a r a t o r.

Control characters intended to control or facilitate t r a n s m i s s i o n of information over

telecommunication

networks

The use of

FE

7.2 Specific control characters Individual members of the classes of controls are sometimes

the

TC characters on the general

r e f e r r e d to b y their a b b r e v i a t e d c l a s s n a m e a n d a s u b s c r i p t

t e l e c o m m u n i c a t i o n n e t w o r k s is t h e s u b j e c t of other

number (for example, TC,) and sometimes by a specific

ISO publications.

name indicative of their use (for example, ENQ).

The transmission control characters are:

Different but related meanings may be associated with some of the control characters but in an interchange of data this

ACK, DLE, ENQ, EOT, ETB, ETX, NAK, SOH, STX a n d SYN.

normally r e q u i r e s a g r e e m e n t b e t w e e n t h e s e n d e r a n d t h e recipient.

Format effectors

ACK Acknowledge

Control characters mainly intended for the control of the layout and positioning of information on printing and/or display devices. In the definitions of specific

A t r a n s m i s s i o n control c h a r a c t e r

transmitted

by a

receiver a s an affirmative response to the sender

7

I S O 6 4 6 - 1 9 7 3 (E)

BELL

Bell A control c h a r a c t e r that is u s e d w h e n t h e r e is a n e e d

BS

E x a m p l e s of u s e of the d e v i c e contr ols:

to call for attention. It may control alarm or attention

1) One switching

devices.

2 ) Two

first o n e

Backspace

second one

A f o r m a t effector w h i c h m o v e s t h e a c t i v e position o n e

character position backwards on the s a m e line. CAN

indicating t h a t t h e d a t a p r e c e d i n g it is in error. A s a

general

particular

output

of this character must be defined for each application

input

a n d / o r b e t w e e n s e n d e r a n d recipient.

Carriage return

on-DO,

on-DO,

on-DC, on-DC,

off-DC,

on-DC, off-DC,

on-DC, off-DC,

off-DC

4 ) Input a n d o u t p u t s w i t c h i n g

result, this data is to be ignored. The specific meaning

CR

on-DC, on-DC,

on-DO,

3) Two dep end ent switchings

Cancel

A character, or the first character of a sequence,

on-DC, independent switchings

DEL

A format effector which moves the active position to

Delete A character used primarily to erase or obliterate an erroneous or unwanted character in punched tape. DEL characters may also serve to accomplish mediafill or time-fill. They may be inserted into or removed from a stream of data without affecting the information

t h e first c h a r a c t e r position o n t h e s a m e line.

Device controls

c o n t e n t of t h a t s t r e a m b u t t h e n t h e a d d i t i o n o r r e m o v a l

DC,

DC,

of these characters may affect the information layout and/or the control of equipment.

A d e v i c e control c h a r a c t e r w h i c h is primarily i n t e n d e d

for turning on or starting an ancillary device. If it is not required for this purpose, it may be used to restore a device to the basic mode of operation (see also DC, and DCs), or for any other device control function not provided by other DCs.

DLE

A t r a n s m i s s i o n control c h a r a c t e r w h i c h will c h a n g e t h e

meaning of a limited number of contiguously following characters. It is u s e d exclusively to provide

A device control character which is primarily intended

s u p p l e m e n t a r y d a t a t r a n s m i s s i o n control functions. Only g r a p h i c c h a r a c t e r s a n d t r a n s m i s s i o n control c h a r a c t e r s c a n b e u s e d in DLE s e q u e n c e s .

for turning on or starting an ancillary device. If it is not required for this purpose, it may be used to set a device to a special mode of operation (in which c a s e DC is used to restore the device to the basic mode), or

Data link e s c a p e

EM

for a n y other d e v i c e control function n o t p r o v i d e d by other D C s .

E n d of m e d i u m A control character that may be used to identify the

physical end of a medium, or the end of the used

DC,

of data recorded on a medium. The position of this character does not necessarily correspond to the physical end of the medium.

for turning off or stopping an ancillary device. This function may be a secondary level stop, for example wait, pause, stand-by or halt (in which c a s e DC, is used to restore normal operation). If it is not required for this purpose, it may be used for any other ancillary d e v i c e control function n o t p r o v i d e d by other D C s .

DC,

portion o f a m e d i u m , o r t h e e n d o f t h e w a n t e d portion

A device control character which is primarily intended

A device control character which is primarily intended for turning off, stopping or interrupting an ancillary device. If it is not required for this purpose, it may be used for any other device control function not provided by o t h e r D C s .

ENQ

Enquiry A transmission control character used a s a request for a response from a remote station - the response may include station identification and/or station status. When a "Who are you" function is required on the

general switched transmission network, the first use of E N Q after t h e c o n n e c t i o n is e s t a b l i s h e d shall h a v e t h e

meaning "Who are you" (station identification). Subsequent use of ENQ may, or may not, include the

function "Who are you" determined by agreement.

8

I S O 6 4 6 - 1 9 7 3 (E)

EOT

E n d of t r a n s m i s s i o n

LF

A t r a n s m i s s i o n control c h a r a c t e r u s e d to i n d i c a t e t h e c o n c l u s i o n of t h e t r a n s m i s s i o n of o n e or m o r e texts.

ESC

ETB

Escape

A format effector which advances the active position to the same character position of the next line.

NAK

Negative acknowledge

A control c h a r a c t e r w h i c h is u s e d to p r o v i d e additional

A t r a n s m i s s i o n control c h a r a c t e r t r a n s m i t t e d by a

control functions. It alters the meaning of a limited number of contiguously following bit combinations. The use of this character is specified in ISO 2022.

receiver as a negative response to the sender.

NUL

Null A control c h a r a c t e r u s e d to a c c o m p l i s h media-fill o r

End of transmission block

time-fill. NUL characters may be inserted into or removed from a stream of data without affecting the

A t r a n s m i s s i o n control c h a r a c t e r u s e d t o i n d i c a t e t h e e n d of a t r a n s m i s s i o n b l o c k of d a t a w h e r e d a t a is

information content of that stream, but then the

divided into such blocks for transmission purposes.

ETX

Line feed

addition or removal of these characters may affect the information layout and/or the control of equipment.

End of text A format effector which moves the active position to the first character position on the s a m e line.

SI

Shift-in A control c h a r a c t e r w h i c h is u s e d in c o n i u n c t i o n with

SHIFT-OUT and ESCAPE to extend the graphic FF

c h a r a c t e r s e t of t h e c o d e . It m a y r e i n s t a t e t h e s t a n d a r d

Form feed

mean ings of the bit comb inati ons which follow it. The effect of this character when using code extension techniques is described in ISO 2022

A f o r m a t e ff e c t o r w h i c h a d v a n c e s t h e a c t i v e position to t h e s a m e c h a r a c t e r position o n a p r e - d e t e r m i n e d line

of the next form or page. SO HT

Horizontal tabulation

Shift-out A control c h a r a c t e r w h i c h is u s e d in c o n j u n c t i o n with

A format effector which advances the active position to

SHIFT-IN and ESCAPE to extend the graphic

t h e n e x t p r e - d e t e r m i n e d c h a r a c t e r position o n t h e s a m e line.

character set of the code. It may alter the meaning of t h e bit c o m b i n a t i o n s of c o l u m n s 2 t o 7 w h i c h follow it

until a SHIFT-IN chara cter is reached. However, the

characters SPACE (2/0) and DELETE (7/15) are

Information s e p a r a t o r s

1S,

(US) A control character used to separate and qualify d a t a loqically. Its s p e c i fi c m e a n i n g h a s to b e d e fi n e d

for each application. If this character is used in hierarchical order a s specified in the general definition of IS, it delimits a data item called a UNIT.

IS,

unaffected by SHIFT-OUT. The effect of this character when using code extension techniques is described in ISO 202 2.

(RS) A control character used to separate and qualify data logically. Its specific meaning has to be defined for each application. If this character is used in hierarchical order a s specified in the general definition of IS, it delimits a data item called a RECORD.

SOH

Start of heading A transmission control character used a s the first character of a heading of an information message.

S P

Space

A character which advances the active position one c h a r a c t e r position o n t h e s a m e line.

This character is also regarded as a non-printing

IS,

IS,

(GS) A control character used to separate and qualify data logically. Its specific meaning has to be defined for each application. If this character is used in hierarchical order as specified in the general definition of IS, it delimits a data item called a GROUP. (FS) A control character used to separate and qualify data logically; its specific meaning has to be defined for each application. If this character is used in hierarchical order as specified in the general definition of IS, it delimits a data item called a FILE.

graphic.

STX

Start of text A transmission control character which precedes a text and which is used to terminate a heading

SUB

Substitute character A control c h a r a c t e r u s e d in t h e p l a c e of a c h a r a c t e r

that has been found to be invalid or in error. SUB is intended to b e introduced by automatic means.

9

I S O 6 4 6 - 1 9 7 3 (E)

SYN

S y n c h r o n o u s idle

A t r a n s m i s s i o n control c h a r a c t e r u s e d by a synchronous transmission system in the absence of a n y o t h e r c h a r a c t e r (idle c o n d i t i o n ) t o p r o v i d e a s i g n a l

from which synchronism may be achieved or retained between data terminal equipment.

10

VT

Ve r t i c a l t a b u l a t i o n A format effector w h i c h a d v a n c e s t h e a c t i v e position t o t h e s a m e c h a r a c t e r position o n t h e n e x t pred e t e r m i n e d line.

ISO 646-1973 (E)

APPENDIX Y

RELEVANT ISO PUBLICATIONS

ISO/R 961, Implementation ofthe 6 and 7-bit coded character sets on 7 track 12,7 mm (1/2 in) magnetic tape. ISO/R 962, Implementation of the 7-bit coded character set on 9 track 12,7 mm (1/2 in) magnetic tape. ISO/R 963, Guide for t h e definition o f 4-bit c h a r a c t e r s e t s d e r i v e d from t h e ISO 7 - b i tc o d e d c h a r a c t e r s e t for information p r o c e s s i n g interchange.

ISO/R 1113, Representation of 6 and 7-bit coded character sets on punched tape.

ISO/R 1155, The use of longitudinal parity to detect errors in information messages. ISO/R 1177, Character s t r u c t u r e for s t a r t / s t o p a n d s y n c h r o n o u s transmission.

ISO/R 1679, Representation ofISO 7-bit coded character set on 12-rowpunched cards. ISO/R 1745, Basic mode control procedures for data communication systems.

ISO 2022, Code extension techniques for use with the ISO 7-bit coded character set. ISO 2047, Graphical representations for the control characters of the ISO 7-bit coded character set.

11

ISO 646-1973 (E)

APPENDIX Z ISO R e c o m m e n d a t i o n R 6 4 6 - 1 9 6 7 c o n t a i n e d a t a b l e for a 6-bit c o d e d c h a r a c t e r set. This c h a r a c t e r s e t h a s b e e n

deleted from the present International Standard and is no more part of the standard. The corresponding table with the relevant Notes is reproduced in this Appendix for information only. 1 1

2 3

1 b

SP

0

3

Q

F,

(VT)

R

B

3

S D

T

4

(FF)

5

Fs

(CR)

5

E

U

6

SO

6

F

V

8 1

A

2

(LF)

SI

00

P

(HT)

2

0

N U L

F,

1 0

O

9

4

7

G

8

H

W X

9

10

J

1 1

K

1 2

(£)

1 3

1 4 1 5 12

Z

M

&

N

ESC O

ED L

ISO 646-1973 (E)

The controls CR and LF are intended for printer equipment which requires separate combinations to return the cariage and to feed For e q u i p m e n t which u s e s a single control for a c o m b i n e d c a r i a g e return a n d line feed operation,

- inthe 6-bit set table, the function F, wil havethe meaning of "New Line" (NL), F, wil then have themeaning of "Back-

space" (BS);

- in the 7-bit set table, the function FE, will have the meaning of "New Line" (NL). T h e s e s u b s t i t u t i o n s require a g r e e m e n t b e t w e e n t h e s e n d e r a n d t h e recipeint of t h e data.

The use of this function " L " is not allowed for international transmission on general telecommunication networks (Telex and Te l e p h o n e networks). 2

For international information interchange, $ a n d § s y m b o l s d o n o t d e s i g n a t e t h e c u r r e n c y of a given country. T h e u s e of t h e s e

symbols combined with other graphic symbols to designate national currencies may be the subject of other ISO recommendations.

3

Reserved for National Use. These positions are primarily intended for alphabetic extensions. If they are not required for that p u r p o s e , t h e y m a y b e u s e d for s y m b o l s a n d a r e c o m m e n d e d c h o i c e is s h o w n in p a r e n t h e s i s in s o m e c a s e s . S o m e restrictions a r e p l a c e d o n the u s e of t h e s e c h a r a c t e r s o n the g e n e r a l telecommunication n e t w o r k s for international transmission.

8

If 10 a n d 11 a s single c h a r a c t e r s a r e n e e d e d (for example, for Sterling c u r r e n c y subdivision), they s h o u l d take the place of

"colon" (:) and "semi-colon" (;) respectively. These substitutions require agreement between the sender and the recipient of the d a t a .

On the general telecommunication networks, the characters "colon"and "semi-colon" are the only ones authorized for international transmission. g

Either of the two sets of three symbols shown in these positions in the table may be chosen. The interpretation of the corresponding combinations requires agreement between the sender and the recipient of the data.

13