UCS-2

In the 2-octet form of UCS, UCS-2, the first octet of a character representation gives the row number and the second one gives the cell number. Those 65,536 (256 rows x 256 cells) characters' positions are represented by UCS-2 belong to plane 0 of group 0, which is also called the Basic Multilingual Plane, BMP. However, a designated surrogate area in the BMP is not meant for character assignment directly. Instead, code points in this area are used through the definition of surrogate pairs to represent characters in plane 1 to 16 of Group 0.