Shift-control double-byte characters
When the IBM-host code scheme is used, the system uses shift-control characters to identify the beginning and end of a string of double-byte characters.
The shift-out (SO) character, hex 0E, indicates the beginning of a double-byte character string. The shift-in (SI) character, hex 0F, indicates the end of a double-byte character string. Figure 1. Placement of shift-out and shift-in characters
Each shift-control character occupies the same amount of space as one alphanumeric character. By contrast, double-byte characters occupy the same amount of space as two alphanumeric characters.
When double-byte characters are stored in a graphic field or a variable of graphic data type, there is no need to use shift control characters to surround the double-byte characters.