IBM-eucTW
The EUC for the Traditional Chinese language is an encoding consisting of characters that contain 1, 2 and 4 bytes. The EUC encoding is based on ISO2022, the Chinese National Standard (CNS) as defined by Taiwan, and multibyte character definitions unique to the manufacturer.
The current CNS defines 13,501 Chinese characters and 684 symbols. The IBM-eucTW is based upon a concept of 15 planes, each containing up to 8836 (94x94) characters. The encoding values of these characters range from 0xa1a1 to 0xfefe. Characters have presently been defined for only 4 of the planes, with the other planes being reserved for future expansion.
The 15 planes are mapped into the CS1 and CS2 of EUC, with the CS2 of EUC consisting of 14 planes. Specifically, the IBM-eucTW consists of the following character sets:
| Character set | Description |
|---|---|
| ISO646-IRV | 7-bit ASCII character set, Graphic Left. |
| CNS11643.1986-1 | Plane 1, containing 6085 characters (5401+684). This plane uses positions 0ax1a1-0xc2c1 and 0xc4a1-0xfdcb. |
| CNS11643.1986-2 | Plane 2, containing 7650 characters. This plane occupies positions 0x8ea2a1a1-0x8ea2f2c4. |
| CNS11643.1992-3 | Plane 4, containing 7298 characters. This plane occupies positions 0x8ea4a1a1-0x8ea4eedc. |
| IBM-udcTW | Plane 12, containing 6204 characters. This plane is reserved for the User Defined Characters (udc) areas. It occupies the positions 0x8eaca1a1-0x8ea2f2c4. |
| IBM-sbdTW | Plane 13, containing 325 characters. This plane is reserved for symbols unique to the manufacturer. It occupies positions 0xeada1a1-0x8eada4cb. |
Planes 3-11 are expected to occupy positions 0x8ea3xxxx to 0x8eabxxxx. Planes 14-15 are expected to occupy positions 0x8eaexxxx to 0x8eafxxxx.