telecode(5) — Macro Packages and Conventions

NAME

telecode − A character encoding system (codeset) for Traditional Chinese

DESCRIPTION

The Telecode codeset (called Mitac Telex in early versions of the operating system) consists of 2 character planes. Each character plane has 8836 character positions. In plane 1, standard characters occupy positions 0001 to 8045; the remaining 791 positions are for user-defined characters. In plane 2, standard characters occupy positions 0001 to 8489; the remaining 346 positions are for user-defined characters. Telecode uses 2-byte values to represent characters on both planes.

Plane 1 Character Encoding

To differentiate plane 1 code from plane 2 code, the most significant bit (MSB) is set on in both bytes of a plane 1 character code. The following formula calculates the value of a plane 1 character from its position on the plane:

1st byte = M + 161
2nd byte = N + 161 − M x 94

In this formula, N is the position of the character and M = N / 94.

For example, if a character is at position 2502 on plane 1, its encoding value is BBDB, which is calculated as follows:

N = 2502, M = 2502/94 = 26
1st byte = 26 + 161 = 187
2nd byte = 2502 + 161 - 26 x 94 = 219

Plane 2 Character Encoding

To differentiate plane 2 code from plane 1 code, the MSB of the first byte is set on and that of the second byte is set off for each plane 2 character code. The following formula calculates the value of a plane 2 character from its position:

1st byte = M + 161
2nd byte = N + 33 − M x 94

In this formula, N is the position of the character on the plane and M = N / 94.

For example, if a character is at position 2502 on plane 2, its encoding value is BB5B, which is calculated as follows:

N = 2502, M = 2502/94 = 26
1st byte = 26 + 161 = 187
2nd byte = 2502 + 33 - 26 x 94 = 91

Font Support for Telecode

The operating system supports Telecode only through conversion to another codeset. For information on codeset conversion, refer to iconv_intro(5).

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