⎯ Code element G0 and code element G1 (in 8-bit mode only) are always invoked in the GL and GR areas of the code table respectively. Designated character sets for these code elements are immediately in use. Code elements G2 and G3 are not used.
⎯ The primary set of Control Characters shall always be designated as the C0 code element and this shall be invoked in the CL area of the code table. The C1 code element shall not be used.