像所有ucs平面那样，包含了256行，其中每行包含256个单元，字符仅仅按照BMP中的行和单元的八位元在单元中被编码。

This BMP, like all UCS planes, contains 256 rows each of 256 cells, and a character is coded at a cell by just the row and cell octets in the BMP.

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这种编码概念被称为UCS - 4；四个八位元用来表示指定组、平面、行和单元的每个字符。

This coding concept is called UCS-4; four octets of bits are used to represent each character specifying the group, plane, row and cell.

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