ISO/IEC JTC 1/SC 2/WG 2
PROPOSAL SUMMARY FORM TO ACCOMPANY SUBMISSIONS
1
FOR ADDITIONS TO THE REPERTOIRE OF ISO/IEC 10646
Please fill all the sections A, B and C below.
TPL2/06-268

PT

Please read Principles and Procedures Document (P & P) from http://www.dkuug.dk/JTC1/SC2/WG2/docs/principles.html forguidelines and details before filling this form.
Please ensure you are using the latest Form from http://www.dkuug.dk/JTC1/SC2/WG2/docs/summaryform.html .
See also http://www.dkuug.dk/JTC1/SC2/WG2/docs/roadmaps.html for latest Roadmaps.
HTUUTHHTUUTHHTUUTH

A. Administrative
1. Title:
Proposal to encode an EXTERNAL LINK SIGN in the BMP
Karl Pentzlin
2. Requester's name:Individual contribution
3. Requester type (Member body/Liaison/Individual contribution):
2006-08-01
4. Submission date:
5. Requester's reference (if applicable):
6. Choose one of the following:
Yes
This is a complete proposal:(or) More information will be provided later:
B. Technical – General
1. Choose one of the following:a. This proposal is for a new script (set of characters):
Proposed name of script:
Yesb. The proposal is for addition of character(s) to an existing block:
Miscellaneous Symbols
Name of the existing block:1
2. Number of characters in proposal:
3. Proposed category (select one from below - see section 2.2 of P&P document):
A-Contemporary
X B.1-Specialized (small collection)
B.2-Specialized (large collection)
C-Major extinct
D-Attested extinct
E-Minor extinct
F-Archaic Hieroglyphic or Ideographic
G-Obscure or questionable usage symbols
1
4. Proposed Level of Implementation (1, 2 or 3) (see Annex K in P&P document):
Yes
Is a rationale provided for the choice?
Contains no non-spacing characters.
If Yes, reference:Yes
5. Is a repertoire including character names provided?
a. If YES, are the names in accordance with the “character naming guidelines”
Yes
in Annex L of P&P document?
Yesb. Are the character shapes attached in a legible form suitable for review?
6. Who will provide the appropriate computerized font (ordered preference: True Type, or PostScript format) forThe author
publishing the standard?
If available now, identify source(s) for the font (include address, e-mail, ftp-site, etc.) and indicate the tools
http://www.europatastatur.de/material/ExternalLink.ttf
used:
7. References:
Noa. Are references (to other character sets, dictionaries, descriptive texts etc.) provided?
b. Are published examples of use (such as samples from newspapers, magazines, or other sources)Yesof proposed characters attached?
8. Special encoding issues:
Does the proposal address other aspects of character data processing (if applicable) such as input,
No
presentation, sorting, searching, indexing, transliteration etc. (if yes please enclose information)?
9. Additional Information:
Submitters are invited to provide any additional information about Properties of the proposed Character(s) or Scriptthat will assist in correct understanding of and correct linguistic processing of the proposed character(s) or script.
Examples of such properties are: Casing information, Numeric information, Currency information, Display behaviour
information such as line breaks, widths etc., Combining behaviour, Spacing behaviour, Directional behaviour, Default
Collation behaviour, relevance in Mark Up contexts, Compatibility equivalence and other Unicode normalizationrelated information. See the Unicode standard at http://www.unicode.org for such information on other scripts. Also
see http://www.unicode.org/Public/UNIDATA/UCD.html and associated Unicode Technical Reports for informationneeded for consideration by the Unicode Technical Committee for inclusion in the Unicode Standard.
HTU

HTU

1UTH

UTH

Form number: N3002-F (Original 1994-10-14; Revised 1995-01, 1995-04, 1996-04, 1996-08, 1999-03, 2001-05, 2001-09, 200311, 2005-01, 2005-09, 2005-10)
TPPT

C. Technical - Justification
No
1. Has this proposal for addition of character(s) been submitted before?
If YES explain
2. Has contact been made to members of the user community (for example: National Body,
Nouser groups of the script or characters, other experts, etc.)?
If YES, with whom?
If YES, available relevant documents:
3. Information on the user community for the proposed characters (for example:
Yessize, demographics, information technology use, or publishing use) is included?
All authors of web sites using external links
Reference:
Common4. The context of use for the proposed characters (type of use; common or rare)
Reference:
5. Are the proposed characters in current use by the user community?
Yes
Frequent use on the World Wide Web
If YES, where? Reference:
6. After giving due considerations to the principles in the P&P document must the proposed characters be entirelyYesin the BMP?
Yes
If YES, is a rationale provided?
Keeping it together with the other Miscellaneous Symbols
If YES, reference:
N/A
7. Should the proposed characters be kept together in a contiguous range (rather than being scattered)?
8. Can any of the proposed characters be considered a presentation form of an existing
Nocharacter or character sequence?
If YES, is a rationale for its inclusion provided?
If YES, reference:
9. Can any of the proposed characters be encoded using a composed character sequence of either
Noexisting characters or other proposed characters?
If YES, is a rationale for its inclusion provided?
If YES, reference:
10. Can any of the proposed character(s) be considered to be similar (in appearance or function)No
to an existing character?
If YES, is a rationale for its inclusion provided?
If YES, reference:No
11. Does the proposal include use of combining characters and/or use of composite sequences?
If YES, is a rationale for such use provided?
If YES, reference:
Is a list of composite sequences and their corresponding glyph images (graphic symbols) provided?
If YES, reference:
12. Does the proposal contain characters with any special properties such asNocontrol function or similar semantics?
If YES, describe in detail (include attachment if necessary)

13. Does the proposal contain any Ideographic compatibility character(s)?
If YES, is the equivalent corresponding unified ideographic character(s) identified?
If YES, reference:NoU+26xx

EXTERNAL LINK SIGN

I. Use and semantics of the proposed character
The proposed symbol marks external links within web pages (i.e. links which lead to another site,contrary to internal links which lead to another page within the same site or domain).
Such a marking is especially used where the marking of external links has legal implications(such as denying responsibility for the contents reached by the marked link), thus acting in asomewhat similar way as U+00A9 COPYRIGHT SIGN, U+00AE REGISTERED SIGN or U+2122
TRADE MARK SIGN (which also were the models for the chosen naming of the proposedsymbol).
As the information about legal facts or claims is an important part of the semantic field of themarking and therefore of the proposed symbol, the symbol is not a pure control symbol (denoting
only the external link at a technical level), unlike some other link symbols commonly found on web
pages as "previous" or "home". Therefore, it is not directly comparable in function to e.g. acarriage return or its symbols (U+000D, U+240D, U+2386, U+23CE).
It is used as a part of the descriptive text the user has to click (or consider) to call the link (mostly
as the first character of that text, sometime as the last character). Thus, it is used as a textual
character within the plain text which constitutes the link description.
As the symbol occurs only as part of a text (unlike e.g. the aforementioned "previous" or "home"symbols), it is no pure "icon" which carries its meaning by itself (like e.g. a traffic sign). It is an
integral part of the text which it denotes (the link description), like a TRADE MARK SIGN does notoccur without the text which it denotes (the trade mark name).
Thus, it is a character rather than an icon.
The designs shown below (see "specimens") all show a design which fits into the text, having aheight comparable to the ascent of the default font as long as the default font size in common
HTML viewers is used. The symbol is also commonly used within running text. This shows it isused like a character, and thus deserves to be encoded as a character, rather than to be
standardized as a graphical icon which cannot be assumed to fit universally into running text.
The proposed character is by no means to be considered as "the" external link sign, i.e to be anattempt to standardize a symbol for the "external link" functionality on web pages (or to benormative in any other way). Therefore, the addressed institution for standardizing it is not theW3C or a similar institution.
It is to be considered as "an" external link sign which is really found "in the wild" used as acharacter (as discussed above). Therefore the Unicode consortium is addressed to standardize it.
It is like encoding a script character without saying anything normative about the orthographies
using that script or telling anybody when or how to use it, yet giving it a name based on its
function (e.g. common phonetic value) rather than its shape.
In short: The "external link symbol" is proposed to be encoded because it is there, not tostandardize any use.

II. Appearance of the proposed character
In its essence, the EXTERNAL LINK SIGN symbol is a rectangle with an arrow starting from its
center, with the arrowhead outside. The rectangle usually has a gap, dent or sloping where thearrow crosses it.
The reference glyph above shows a single-stemmed arrow pointing diagonally upward ("northeast").
Glyph variants show a double-stemmed arrow (e.g. at Wikipedia) or an arrow pointing rightward(see specimens).
The proposed reference glyph is designed to be the "common denominator" of the glyphs found.

As it applies to Unicode characters generally, the reference glyph is in no way intended to betaken for a standardized icon or to be the best design in any font.
This is also the reason to not name the symbol after the appearance of its reference glyph, e.g.
something like "RECTANGLE WITH NORTH WEST POINTING ARROW", as it is appropriate fortechnical symbols like U+21B5 DOWNWARDS ARROW WITH CORNER LEFTWARDS.
As no specimens were found wthin right-to-left scripts, it only can be speculated (or left to future
font designers) whether the arrow would point leftward with such scripts or straight upward within
mixed direction environments. This is considered to be within the possible range of glyphvariation. It is not proposed to set the Bidi_Mirrored property to "yes", as the proposed symbol isneither paired punctuation nor a math operator (which are the types of characters currentlycovered by Bidi_Mirrored).

III. Properties of the proposed characterAll properties of the proposed character are proposed as the ones common to symbols.
Thus, the entry in UnicodeData.txt is proposed as:26xx;EXTERNAL LINK SIGN;So;0;ON;;;;;N;;;;;

IV. Contemporary marking of external links
As there exists no standardized character now, site authors use to create a little graphic which
they use for the external link symbol throughout their site. The existence of a standardized
character as proposed would free the site authors from having to reinvent the wheel for thatpurpose.
As site authors are free to design that symbol (in absence of any standard), some diverging
designs are found (see Appendix), but there is a clear evidence of an evolving convergence
towards a rectangle with an arrow pointing outward from it.
Sites which use an arbritrary design for an external link symbol use to explain it, while some sites
using a rectangle with an arrow pointing outward design do not in some cases, thus showing
more confidence in the understandability of the symbol.
This is evidence that a sufficiently universally recognized symbol has emerged.

V. Acknowledgements
Drafts of this proposal were discussed at the public Unicode E-mail list. Thanks to all participiants.
Many hints from there are incorporated into this proposal.

VI. SPECIMENS
1. Collected 2006-07-21 from:http://en.wikipedia.org/wiki/Unicode2. Collected 2006-07-21 from:http://www.heise.de/tp/r4/artikel/23/23144/1.html

Note: www.heise.de is the site of a German publisher, publishing e.g. the German computer
magazine "c’t".
The site authors also created a symbol for "internal link" (used in the specimen at the link
"Neue Affenmenschen"). As such a symbol is rarely found elsewhere (usually, internal links
are not marked with a special symbol), such a symbol is not proposed here.
3. Collected 2006-07-21 from:http://www.signographie.de/cms/front_content.php?idcat=1&idart=57

4. Collected 2006-07-21 from:http://hackage.haskell.org/trac/ghc

5. Collected 2006-07-21 from:http://investor.invescoperpetual.co.uk/invesco/default/page/literature/request/list_single_copy/
0,2879,32524157_34698815,00.html

VII. Appendix: Google image search for "external link icon"
A Google image search on 2006-07-30 yielded:

Of the 26 symbols found here (the last symbol in the first row is not counted [as it serves anotherpurpose], the duplicate in the second last row and the trademark in the last row also are not counted),
16 resemble (more or less) the "box with arrow pointing out of it" pattern. 7 other ones resemble a"circle or world with arrow pointing from it", "boxed arrow", or a simple "pointing symbol" pattern. Only
three follow a totally different pattern.