IEC 62298-3:2005

IEC 62298-3 ®
Edition 1.0 2005-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Teleweb application –
Part 3: Superteletext profile
Application téléweb –
Partie 3: Profil supertélétexte

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IEC 62298-3 ®
Edition 1.0 2005-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Teleweb application –
Part 3: Superteletext profile
Application téléweb –
Partie 3: Profil supertélétexte

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XD
ICS 33.170; 35.240.99 ISBN 978-2-8322-0778-9

– 2 – 62298-3  IEC:2005
CONTENTS
FOREWORD . 4
INTRODUCTION . 6

1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviations . 8
3.1 Terms and definitions . 8
3.2 Abbreviations . 8
4 Display . 9
4.1 Colour representation . 9
4.2 Text representation . 10
4.3 Text placement . 12
4.4 Image representation . 13
4.5 4:3 and 16:9 aspect ratio displays . 13
5 URLs . 14
5.1 File naming . 15
5.2 Access through page number . 15
5.3 TeleWeb file reference scheme . 16
5.4 Teletext page reference scheme. 18
5.5 NexTView reference scheme . 19
5.6 Special function URLs . 20
6 Text and hypertext . 20
6.1 TeleWeb HTML file format . 20
6.2 Syntax of TeleWeb HTML tags . 22
6.3 Document structure elements . 24
6.4 Header section tags . 27
6.5 Paragraph formatting . 29
6.6 Character formatting . 32
6.7 Hypertext links . 36
6.8 Lists . 41
6.9 Tables . 44
6.10 Images . 50
6.11 Ticker text . 53
6.12 Exceptional ignored tags . 55
7 TeleWeb default style . 55
8 Image files. 55
8.1 GIF . 55
8.2 JPEG . 56
9 Content labelling . 56
9.1 Predefined themes and identifier coding . 56
9.2 Parental ratings . 56
10 Special data . 56
10.1 Service identification graphic . 56
10.2 Home page . 57
10.3 Default page . 57
10.4 Profile upgrade page . 57

62298-3  IEC:2005 – 3 –
10.5 ZLIB dictionary files . 57
11 Service-related attributes . 58
11.1 Name . 58
11.2 Information . 58
11.3 Language . 58
11.4 Transmission schedule . 58
12 File-related attributes . 59
12.1 General file attributes . 60
12.2 File content attributes . 61
12.3 Time- and date-related attributes . 62
12.4 Storage-related attributes . 63
12.5 Special function attributes . 63
13 Short and full TeleWeb service . 64
14 Individual addressing – Group addressing . 65

Annex A (informative)  HTML compatibility . 66
Annex B (normative)  Default colour palette specification . 69
Annex C (normative)  Table of predefined themes . 71
Annex D (informative)  TeleWeb document type definition (DTD) . 78
Annex E (informative)  TeleWeb default CSS2 style sheet . 87
Annex F (normative)  Font metrics . 90
Annex G (informative) TeleWeb Superteletext profile reference decoder . 95

Bibliography . 98

Table 1 – Default colour palette . 10
Table 2 – Font sizes . 11
Table 3 – File naming . 15
Table 4 – EPG parameters . 17
Table 5 – Profile parameter . 18
Table 6 – Special function URLs . 20
Table 7 – List of service-related attributes . 58
Table 8 – List of file-related attributes . 59
Table 9 – Rating scheme . 62
Table 10 – Filter attributes for nexTView references . 65
Table A.1 – HTML V3.2 tags not supported . 66
Table A.2 – HTML V3.2 attributes not supported . 67
Table A.3 − Browser specific tags supported . 67
Table A.4 – TeleWeb specific tags supported . 67
Table B.1 – Default colour palette specification. 69
Table C.1 – Predefined themes . 71

– 4 – 62298-3  IEC:2005
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TELEWEB APPLICATION –
Part 3: Superteletext profile
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62298-3 has been prepared by IEC technical committee 100:
Audio, video and multimedia systems and equipment.
This standard cancels and replaces IEC/PAS 62298 published in 2002.
This first edition constitutes a technical revision.
This bilingual version (2013-07) corresponds to the monolingual English version, published in
2005-05.
The text of this standard is based on the following documents:
FDIS Report on voting
100/924/FDIS 100/962/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.

62298-3  IEC:2005 – 5 –
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
IEC 62298 consists of the following parts, under the general title TeleWeb application:
Part 1: General description
Part 2: Delivery methods
Part 3: Superteletext profile
Part 4: Hyperteletext profile (in preparation)
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – 62298-3  IEC:2005
INTRODUCTION
The aim of TeleWeb is to deliver World Wide Web-style content to the living-room TV to give
the viewer an enhanced television experience. A TeleWeb service broadcasts data files
containing text and high-definition graphics to suitable decoders. The data transmitted can be
closely linked to events within the accompanying TV programs or can be more general in
nature to emulate a traditional, but higher definition, superteletext service. Different profiles
are defined.
It is intended that TV-based decoders can be implemented in a cost-effective manner without
recourse to the technology normally associated with personal computers. In part, this is
achieved by limiting the number of different types of multimedia data that can be used within a
service. By careful design of the user interface, decoder manufacturers will be able to offer
easy-to-use equipment for accessing TeleWeb services without requiring the consumer to be
computer-literate. In addition, they will be able to customize their products to differentiate
them from those of their competitors.
This standard specifies the TeleWeb Superteletext profile and focuses on the presentation
layer especially the implementation of TeleWeb HTML. It further defines graphical
requirements like colours and fonts and the content formats used.

62298-3  IEC:2005 – 7 –
TELEWEB APPLICATION –
Part 3: Superteletext profile
1 Scope
This part of IEC 62298 specifies the TeleWeb Superteletext profile that allows Web-style text
and graphics to be displayed on suitable decoders. A TeleWeb service comprises multimedia
data files whose format and attributes are defined by this specification. This specification
focuses on the presentation layer especially the implementation of TeleWeb HTML. It further
defines graphical requirements like colours and fonts and the used content formats. For
information regarding general information and the transport layer, refer to IEC 62298-1 and
IEC 62298-2.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 62297-1, Triggering messages for broadcast applications
ISO 639-2, Codes for the representation of names and languages – Part 2: Alpha-3 code
ISO 8601, Data elements and interchange formats – Information interchange –
Representation of dates and times
ISO 8859-1:1998, Information technology – 8-bit single-byte coded graphic character sets –
Part 1: Latin alphabet No. 1
ETSI TR 101 231, Television systems; Register of Country and Network Identification (CNI),
Video Programming System (VPS) codes and Application codes for Teletext based systems
ETSI EN 300 231, Television systems; Specification of the domestic video Program Delivery
Control (PDC) system
ETSI EN 300 468, Digital Video Broadcasting (DVB); Specification for Service Information (SI)
in DVB systems
ETSI EN 300 706, Enhanced Teletext Specification
ETSI EN 300 707, Electronic Program Guide (EPG); Protocol for a TV Guide using electronic
data transmission
– 8 – 62298-3  IEC:2005
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
button
part of the user interface that enables the viewer to select a page or trigger an event, etc. It
may not necessarily exist as a physical button on a remote control handset
3.1.2
CDATA
character data in an HTML document. Character entities and HTML mark-up is not recognized
3.1.3
conditional access (CA)
mechanism by which user access to service components can be restricted
3.1.4
PCDATA
Parsed character data in an HTML document. Character entities (numeric and named entities)
as well as HTML mark-up are recognized in the data
3.1.5
signed_integer
positive or negative integer value, in decimal notation. The first digit is preceded by a
mandatory plus (+) or minus (–) symbol with no white space between the symbol and the first
digit
3.1.6
text_string
sequence of displayable Latin-1 characters
3.1.7
unsigned_integer
integer value, in decimal notation, without a preceding plus (+) or minus (-) symbol
3.2 Abbreviations
ASCII American Standard Code for Information Interchange
CA Conditional Access
CDATA Character Data
CRC Cyclic Redundancy Check
DTD Document Type Definition
DVB Digital Video Broadcasting
ETS European Telecommunication Standard
GIF Graphics Interchange Format
HTML Hyper Text Mark-up Language
JFIF JPEG File Interchange Format
JPEG Joint Picture Experts Group
LSB Least Significant Bit
62298-3  IEC:2005 – 9 –
MJD Modified Julian Date
MSB Most Significant Bit
PCDATA Parsed Character Data between tags
RFC Request For Comments
URL Uniform Resource Locator
UTC Universal Time Coordinated
WWW World Wide Web
4 Display
This clause defines the minimum requirements of a TeleWeb display. They are applicable to
both editing stations and decoders.
4.1 Colour representation
4.1.1 General requirements
A decoder shall be able to display each pixel on the text/graphics, background image and
background colour planes in a different colour from a palette of at least 188 colours. Full
transparency and one-level semi-transparency to video shall also be supported.
A decoder may be implemented with either a true-colour store or an indexed colour system.
To accommodate the latter type of decoder and to define a palette for GIF images that do not
specify a palette themselves, a single 188 colour palette is defined in 4.1.5. As a minimum,
the text/graphics, background image and background colour planes shall be able to support
colours subjectively equivalent to these colours. Content can be authored using other colours,
but authors should be aware that some decoders may not be able to reproduce them exactly
and may map such a colour to the closest match in the pre-defined colour palette.
For authoring purposes the text/graphics, background image and background colour planes
shall support at least 188 colours on the screen at any one time. In practical terms, a decoder
is likely to be able to display at least 256 colours, giving the equipment manufacturers at least
68 colours for their user interface.
To get an optimal display, the content should be authored using the TeleWeb default colour
palette. The response of a decoder is not defined by this specification if the colours used are
not all taken from the pre-defined colour palette. Under these circumstances, colour dithering
or matching techniques may need to be applied and the response of decoders may differ.
4.1.2 Colour resolution
Each colour shall be defined by red, green and blue (RGB) components or by a colour
constant (see 6.2.5.1).
The authored content shall define colours as 24-bit values, i.e. 8 bits for each component in
the order R, G, B.
A decoder is required to have a colour resolution of at least 4 bits per component (12 bits
minimum overall).
4.1.3 Gamma
Decoders shall assume that all RGB values defined and invoked by authored content have
been gamma pre-corrected for the eye.

– 10 – 62298-3  IEC:2005
4.1.4 Transparency
Decoders are required to implement a minimum of three levels of transparency – opaque,
semi-transparency and completely transparent.
The colour palette is optimized for 30 % semi-transparency. Where the decoder cannot
implement the value of 30 % semi-transparency, it shall replace it with the nearest value of
semi-transparency it can implement. If the encoded value of transparency is in the range
between 10 % and 90 %, it shall not be approximated as either 0 % or 100 % transparency.
So, 9 % may be approximated as 0 % but 10 % shall be represented with a value in the range
10 % to 90 % such as 30 %. Similarly, 91 % may be approximated as 100 %.
4.1.5 Colour palette
The predefined set of 188 colours is shown in Table 1 and in Annex B. The colours chosen
have a perceptually uniform distribution over the colour space. A service provider may choose
to author content using only this set of colours.
As a minimum, a decoder shall support these colours up to its resolution limit. It is then the
responsibility of the decoder to map the colours defined within the authored content to their
closest approximation within the predefined set.
Table 1 – Default colour palette
Transparency Total number Quantization Quantization Quantization
level of entries levels for red levels for green levels for blue
0 % 135 5 levels: 9 levels: 3 levels:
(fully opaque) 0, 63, 127, 191, 255 0, 31, 63, 95, 127, 0, 127, 255
159, 191, 223, 255
0 % 4 4 additional grey-scale colours:
(fully opaque)
R = G = B = 42, 85, 170, 212
30 % 48 4 levels 6 levels: 2 levels:
0, 85, 170, 255 0, 51, 102, 153, 204, 0, 255
100 % 1 - - -
(fully transparent)
Decoder definable 68
NOTE Levels are quoted as decimal values in the range 0 to 255.

To allow these colours to be used to render a GIF image from which the colour palette
information has been omitted, it is necessary to assign a unique value to each colour, as
defined in Annex B.
4.2 Text representation
Text is rendered using one proportionally spaced font and one monospaced font, each in five
sizes and in two styles – plain and bold. Italics and bold italics styles are optional. The fonts
are not defined by this specification. Instead, the metrics of each character cell are defined for
all aforementioned sizes to ensure compatibility between equipment.
A service provider who wishes to ensure consistent displays shall author content using the
same metrics as implemented in decoders. Content shall be authored with kerning disabled.

62298-3  IEC:2005 – 11 –
4.2.1 Required sizes
Table 2 shows the supported font sizes for the proportional and monospaced font and the
assignment to the size attribute of the HTML font tag. The font and character metrics
including the width (advance) of all character cells for the proportional and the monospaced
font for the different font sizes are specified in Annex F.
Table 2 – Font sizes
HTML Font tag
Size
pixels
22 SIZE = 1 or 2
24 SIZE = 3
27 SIZE = 4
31 SIZE = 5
36 SIZE = 6 or 7
4.2.2 Bold and italic styles
If the font does not support the bold style, a bold version can be emulated by writing a second
instance of the required character with an offset by one pixel to the right of the normal
position. The bold style should be restricted to small parts of the text, for example, headings.
It should not be used for the whole text. The emulated bold style may not be acceptable for
certain characters especially for the small font sizes (for example, the double-quote character
or the characters with umlaut may be critical). In this case, the bold style should be avoided
for these characters.
For the proportional font, the width (advance) of a character cell containing a bold character
may be increased by a maximum of one pixel per character, as shown in Figure 1. Content
shall be authored with this extra pixel space in mind. For the monospaced font, the width of all
characters of a given font size is the same for all styles.
The implementation of the optional italic and bold italic style is left open. However, the
corresponding character cell width shall always be the same as for the plain and bold styles
respectively.
– 12 – 62298-3  IEC:2005
IEC  686/05
Figure 1 – Character metrics
4.2.3 Character repertoire
Decoders shall support the full ISO Latin-1 character set given in ISO 8859-1 and the EURO
sign character (Unicode 0×20AC). The EURO sign can be used by the name character entity
(&euro) or the numerical representations (#&X20AC or #&8364). If the character encoding of
the HTML file is different from ISO Latin-1 or the character is not defined in ISO Latin-1 and is
not the EURO sign the decoder shall display a replacement character represented by an
empty square with the size of a capital ‘V’.
NOTE The characters 0×00 to 0×1F and 0×7F to 0×9F are not defined by ISO Latin-1; thus, a replacement
character will be shown instead.
4.2.4 Default attributes
In the absence of any font, size, foreground colour or background information within the
authored content, a decoder is free to set its own default conditions. It is recommended that
the decoder follow the default style defined in Annex E.
4.3 Text placement
4.3.1 Text width
To ensure that text will flow identically on different decoders and authoring equipment,
regardless of the quality of the character rendering, simple algorithms are defined to deter-
mine vertical placement and when to wrap lines of text. The flow is considered identical if
lines and words break at the same character position. The calculations allow content creators
to provide sufficient space for their strings at authoring time. They make no demands on the
particular rendering system employed. The characters can be bit-map or vector fonts, aliased
or anti-aliased, etc. The calculations shall be applied in both authoring equipment and
decoders.
62298-3  IEC:2005 – 13 –
4.3.2 Text-width calculation
The width calculation is defined in terms of the bounding rectangle of each character as
defined within the font metrics shown in Figure 1. Any extra width due to bolding shall be
taken into account for the proportional font. The width of a text string is the sum of the
character widths. This calculation is carried out at pixel-resolution.
4.3.3 Line breaks
Once the text-width calculation defined in 4.3.1 produces a result that exceeds the space
available, the first word after a white space (but not a non-breaking space (0×A0)), a hyphen
(0×2D) or a soft hyphen (0×AD) that will not fit completely on the line shall be rendered on the
line below. This implies the equipment does not have to know or apply word-hyphenation
rules.
4.3.4 Vertical line spacing
The baseline of a font is determined by its ascent and descent metrics (see Figure 1). All
characters are vertically aligned to their baseline. The vertical space required for a line is the
sum of the largest ascent and the largest descent in that line plus the gap (external leading).
The gap (external leading) between lines is set to –1 for all fonts and all sizes.
4.4 Image representation
4.4.1 Format
A decoder is required to implement the full GIF specification [GIF], apart from the "plain-text"
extension. A transmitted file may include "plain text". In addition, the sequential baseline
JPEG image format is supported [HTML3.2][HTML4.0][XHTML1.0].
4.4.2 Animation
Animation and looping of GIF images are supported as described in [GIF] and [GIFabout]
respectively.
NOTE There is no minimum time specified for the display of one frame when animating or looping. This will
depend upon the processing power in the decoder and the complexity and size of the images. Different decoders
may show different response speeds. The size of an animated GIF image may be restricted by a code of practice.
4.4.3 Use on the background image plane
An image that is smaller than the background image plane should be tiled to fill the available
area.
A decoder is not required to reproduce animation on the background image plane. If multiple
frames are present in the designated file, the first frame should be displayed continuously.
4.5 4:3 and 16:9 aspect ratio displays
Content should be authored for a 4:3 display. Decoders with a screen aspect ratio of 16:9 can
choose to render the TeleWeb content so that its 4:3 aspect ratio is maintained. Thus, a circle
in an image should still appear as a circle.
The aspect ratio used to display the TeleWeb content is the responsibility of the decoder
manufacturers. The TeleWeb specification recommends the display of the content square
pixel in 4 by 3 but leaves other options open to the manufacturer. Displaying the content using
a 16:9 aspect ratio seems to be acceptable (IFA 2001).

– 14 – 62298-3  IEC:2005
The above is valid as long as there is no transparency to the video. In the latter case, the
content should be displayed in the aspect ratio of the displayed video to guarantee alignment
with the video. Displaying 4 by 3 TeleWeb content on top of 16:9 video can give nasty side-
effects (see Figure 2) . The broadcaster, aware of this set behaviour, can pre-compensate the
drawings and pictures on such transparent content in line with the broadcast video (for
example, broadcast an oval to have a circle displayed).
16 / 9 16 / 9
VIDEO VIDEO
TW content TW content
4:3 TeleWeb content correctly aligned on The same TeleWeb content incorrectly
the underlying video aligned on the underlying video

IEC  687/05
Figure 2 – Alignment of transparent content over video
5 URLs
A uniform resource locator (URL) is a compact textual notation for accessing information
within the TeleWeb system. The URLs within the TeleWeb system shall conform, except
where otherwise noted, to the syntax for Internet URLs as specified in [URI]. Note that the
URL character set is limited to the lower half of the ISO-Latin-1 character set as described in
ISO 8859-1. To ensure compatibility with other browsers, URLs shall encode character codes
in the upper half.
A URL consists of a scheme and a scheme specific part. All characters in a URL belong to the
ISO Latin 1 character set as described in ISO 8859-1.
scheme : scheme-specific-part
In a complete URL, the scheme is followed by a colon (':') and the string for the scheme
specific part. Superteletext profile decoders shall ignore schemes not listed in this clause
when such schemes appear in TeleWeb documents.
The scheme name is a string of characters. The only characters permitted in a scheme name
are the lower-case characters 'a' through 'z', the digits '0' through '9', and the characters plus,
hyphen, and full-stop, i.e. '+', '–', '.'. For robustness, software that interprets URLs (for
example, the TeleWeb decoder) shall map upper-case alphabetic characters to their
corresponding lower-case characters.
The scheme-specific-part is a string of safe characters. Safe characters have a printable
graphic representation in ISO Latin-1 as described in ISO 8859-1. Furthermore, the set of
safe characters is restricted to respect the reserved use of some punctuation characters.
The alphabetic characters are at positions 41 hex through 5A hex, 61 hex through 7A hex, C0
hex through D6 hex, D8 hex through F6 hex, and F8 through FF hex. Thus, only alphanumeric
characters, characters in the string "$-_.+!*'()," and scheme-specific key characters from the
string ";/?:@=&" may be used un-encoded within a URL. Any data character, on the other
hand, may be encoded. Encoded characters shall be recognized and decoded by software
that interprets URLs. A data character is one not used as punctuation by a scheme.
TW content
TW content
62298-3  IEC:2005 – 15 –
Data character encoding is the mapping of an 8-bit value to a 3-character sequence. The per
cent character, '%', indicates the start of the code. The next two characters are the
hexadecimal value of the encoded character. For example, a space is encoded as %20 since
a space has the code 32 decimal, which is 20 hexadecimal. A per cent data character is
encoded as %25 since the per cent sign is at position 37 decimal (or 25 hex). An incomplete
encoding sequence, for example, %F=, has no specified meaning.
5.1 File naming
A name attribute (12.1.2) shall be associated with each file. This attribute, a text string, shall
include both name and type (extension) elements, for example, "file1.html", where "file1" is
the name element and "html" is the type element. This name should be used to reference the
corresponding file in any hypertext links. The file type element for HTML (text) files shall be
either "htm" or "html". Table 3 specifies naming conventions for the file types processed by
TeleWeb.
Table 3 – File naming
Content type File-name extension MIME type
HTML .htm or .html text/html
GIF .gif image/gif
JPEG .jpg or .jpeg image/jpeg
ZLIB Dictionary .dic application/x-zlib-dic

A type attribute (see 12.1.1) shall be included with the file and shall indicate the type of the
file, for example, for HTML "text/html". If a type attribute is omitted or missing, a decoder
should attempt to determine the file type by inspecting the name attribute. In the event of a
conflict, the type attribute shall have priority. File names are not case-sensitive.
5.2 Access through page number
This subclause describes how pages can be accessed directly through page numbers.
The body of such file names is composed of digits only, for example, 123.htm, 4545.html,
911.htm and 4444.html.
A set maker shall provide a mechanism to select these files directly through digit entries. For
example, a file with the name ‘123.html’ can be reached directly by typing in the digits ‘1’, ‘2’
and ‘3’ on the remote control. The definition of the user interface is up to the set
manufacturers. They can provide numerical access through a special button, a menu item or
any other technique in line with their user interface.
The numerically named files shall be broadcast in the root directory of the TeleWeb content.
Numeric file names in subdirectories will not be accessible through this digit entry user
interfaces.
All numbers within one TeleWeb transmission shall fulfil the prefix condition, which defines
that a number should never be the prefix of another number. For example, 1234.html may not
exist in the same TeleWeb service as 1234567.html.
The length of the digit sequence is limited only by the maximum length of the file name.

– 16 – 62298-3  IEC:2005
5.3 TeleWeb file reference scheme
TeleWeb file reference URLs may be absolute or relative. An absolute URL specifies the
service name of the content provider, while a relative URL cannot. An absolute URL shall
specify a complete path to a resource, while a relative URL can specify a partial path.
5.3.1 Absolute URLs
An absolute TeleWeb URL has the form
tw : // service-name / path-name [ ?query ] [ # fragment ]
where all upper-case characters are considered equivalent to their lower-case forms and
where portions within brackets may be omitted.
The components are specified below:
tw is the scheme name, which identifies the scheme-specific part as a
TeleWeb URL.
// service-name identifies the name of the service (see 11.1).
/ path-name The path to the information, i.e. loosely the name of the file. Slashes
within the path-name identify hierarchical sections of the name, but do
not require a specific data structure within TeleWeb components,
though an analogy to a file system is possible. The slash ('/') is thus a
reserved character, and a data slash shall be encoded as %2F if
needed. Furthermore, the hierarchical section names . and . ("dot"
and "dot-dot") are reserved, and data with these names may be
specified with %2E and %2E %2E if needed. The dot-separator
preceding the file type e
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