dechanyu - A character encoding system (codeset) for Traditional Chinese
The DEC Hanyu (dechanyu) codeset consists of the following sets of characters: ASCII The first and second character planes of CNS11643-1986 Digital Taiwan Supplemental Character Set (DTSCS) User-defined characters
DEC Hanyu uses a combination of single-byte data, 2-byte data, and 4-byte
data to represent ASCII characters, symbols, or ideographic characters.
All ASCII characters are represented in the form of single-byte, 7-bit
data in DEC Hanyu; that is, the most significant bit (MSB) of a byte that
represents an ASCII character is always set off. Refer to
information about the ASCII character set.
Each plane of the CNS 11643-1986 character set is divided into 94 rows and each of these rows has 94 columns. The characters defined in plane 1 and plane 2 of CNS 11643-1986 are as follows:
|Character Plane||Character Type||Number of Characters|
|Frequently used characters||5401|
|2||Less frequently used characters||7650|
Note that the first two planes of the CNS11643-1986 character set are the same as those specified for the revised CNS11643-1992 character set.
In DEC Hanyu, each CNS 11643-1986 character is represented by two bytes, in conformance with the CNS 11643-1986 standard. The MSB of the first byte is always turned on while that of the second byte is on for the first character plane and off for the second character plane.
The first byte of CNS 11643-1986 encoding determines the row number of the character, while the second byte determines its column number. Code ranges for the two character planes are as follows: A1A1 to FEFE A121 to FE7E
The following formulas determine the value of a CNS 11643-1986 character in relation to its row and column numbers. For a CNS 11643-1986 Plane 1 character:
For example, if a character is positioned at the first column of the 36th row on CNS 11643 plane 1, its value is C4A1, which is calculated as follows:
1st byte = A0(hex) + 36 = C4(hex) 2nd byte = A0(hex) + 01 = A1(hex)
Similarly, if a character is positioned at the first column of the 36th row on CNS 11643 plane 2, its value is C421, which is calculated as follows:
1st byte = A0(hex) + 36 = C4(hex) 2nd byte = 20(hex) + 01 = 21(hex)
Currently, only the EDPC (Electronic Data Processing Centre) Recommended Character Set, which defines a total of 6319 characters (rows 1 to 68), is included in the Digital Taiwan Supplementary Character Set (DTSCS). In the revised CNS 11643-1992 standard, the 6319 characters in the EDPC Recommended Character Set are assigned to the third and fourth character planes as follows:
|EDPC Characters||Character Plane||Number of Characters|
|Part I||Plane 3||6148|
|Part II||Plane 4||171|
The characters defined in Plane 3 and Plane 4 of CNS 11643-1992 are as follows:
|Character Plane||Character Type||
Number of Characters
|3||Rarely-used characters (EDPC Part I)||6148|
|4||Used for residency system, ISO 2nd edition DIS 10646 Han characters, 171 EDPC Part II Characters||7298|
In DEC Hanyu, each DTSCS character is represented by a 4-byte value.
The first two bytes are the leading value, specifically C2CB, which is used
as a designator sequence for the DTSCS character set. The MSB of the third
and fourth bytes is set on for the EDPC Recommended Character Set.
In addition to the two Chinese character sets described in preceding sections, DEC Hanyu provides an area of 3587 positions for user-defined characters (UDC). The positions for UDC are those positions that are unused (but not reserved) code points on the first and second character planes of CNS 11643-1986.
The encoding for UDC is exactly the same as that for CNS11643-1986 except that the two sets of characters occupy different regions. Code ranges for UDC are as follows:
|Character Plane||Number of UDC||Code Range|
|1||145||FDCC to FEFE|
|1||2256||AAA1 to C1FE|
|2||1186||F245 to FE7E|
The following codeset converter pairs are available for converting Traditional Chinese characters between dechanyu and other encoding formats. Refer to iconv_intro(5) for an introduction to codeset conversion. For more information about the other codeset for which dechanyu is the input or output, see the reference page specified in the list item. big5_dechanyu, dechanyu_big5
The operating system provides both screen and printer fonts for DEC Hanyu characters.
The following bitmap fonts are grouped according to character set and family; they reflect various sizes and typefaces for 75dpi and 100dpi display devices:
CNS 11643-1986 Fonts (Hei family):
-adecw-hei-medium-r-normal--16-160-75-75-m-160-dec.cns11643.1986-2 -adecw-hei-medium-r-normal--24-240-75-75-m-240-dec.cns11643.1986-2 -adecw-hei-medium-r-normal--16-160-100-100-m-160-dec.cns11643.1986-2 -adecw-hei-medium-r-normal--24-240-100-100-m-240-dec.cns11643.1986-2
CNS 11643-1986 fonts (Screen family):
-adecw-screen-medium-r-normal--18-180-75-75-m-160-dec.cns11643.1986-2 -adecw-screen-medium-r-normal--24-240-75-75-m-240-dec.cns11643.1986-2 -adecw-screen-medium-r-normal--18-180-100-100-m-160-dec.cns11643.1986-2 -adecw-screen-medium-r-normal--24-240-100-100-m-240-dec.cns11643.1986-2 -adecw-screen-medium-r-normal--18-180-100-100-m-160-dec.cns11643.1986-UDC -adecw-screen-medium-r-normal--24-240-100-100-m-240-dec.cns11643.1986-UDC
CNS 11643-1986 fonts (Sung family):
-adecw-sung-medium-r-normal--24-240-75-75-m-240-dec.cns11643.1986-2 -adecw-sung-medium-r-normal--32-320-75-75-m-320-dec.cns11643.1986-2 -adecw-sung-medium-r-normal--24-240-100-100-m-240-dec.cns11643.1986-2 -adecw-sung-medium-r-normal--32-320-100-100-m-320-dec.cns11643.1986-2
DTSCS fonts (Hei family):
-adecw-hei-medium-r-normal--16-160-75-75-m-160-dec.dtscs.1990-2 -adecw-hei-medium-r-normal--24-240-75-75-m-240-dec.dtscs.1990-2 -adecw-hei-medium-r-normal--16-160-100-100-m-160-dec.dtscs.1990-2 -adecw-hei-medium-r-normal--24-240-100-100-m-240-dec.dtscs.1990-2
DTSCS fonts (Screen family):
-adecw-screen-medium-r-normal--18-180-75-75-m-160-dec.dtscs.1990-2 -adecw-screen-medium-r-normal--24-240-75-75-m-240-dec.dtscs.1990-2 -adecw-screen-medium-r-normal--18-180-100-100-m-160-dec.dtscs.1990-2 -adecw-screen-medium-r-normal--24-240-100-100-m-240-dec.dtscs.1990-2
DTSCS fonts (Sung family):
-adecw-sung-medium-r-normal--24-240-75-75-m-240-dec.dtscs.1990-2 -adecw-sung-medium-r-normal--32-320-75-75-m-320-dec.dtscs.1990-2 -adecw-sung-medium-r-normal--24-240-100-100-m-240-dec.dtscs.1990-2 -adecw-sung-medium-r-normal--32-320-100-100-m-320-dec.dtscs.1990-2
The operating system provides the following PostScript printer fonts for CNS 11643-1986 characters: Hei-Light-CNS11643 Sung-Light-CNS11643
Printer fonts for DTSCS characters are not available.
For general information on printing Asian language text, refer to
Others: ascii(5), big5(5), Chinese(5), dechanzi(5), eucTW(5), i18n_intro(5), i18n_printing(5), iconv_intro(5), l10n_intro(5), sbig5(5), telecode(5), Unicode(5)