IBM 3164 ASCII Manual page 163

Chapter 5. Programming considerations
Using the Select Character Set command to select the character set
5-76
The display station supports two 94-graphic-character spaces addressable by
line codes (21 through 7E). These two spaces are known as GO and G1.
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The host program can allocate two of the following character sets to GO and
G1 atatime:
• U.S. ASCII characters
• Special graphics
• Alternate characters.
The arrangement of the character sets in GO and G1 spaces is controlled
independently for the inbound and outbound operations.
In the inbound operation, the Select Character Set
GO/G1
responses and
SI/SO control characters are sent to the host as required when the character
set is changed in relation to the Shift key operation.
In the case of the outbound operation, the Select Character Set (SCS)
GO/G1
commands are used to assign the character set to
GO/G1.
By using the Select Character Set
GO/G1 commands and the SI/SO control
characters, the host can display any character stored in the above two
character sets. You can enter any character from the keyboard by using the
appropriate shift (Alt Chr, Line Draw, and Shift) key.
In addition, each page can use the independent
GO/G1;
that is, the SCS
GO/G1 commands and the SI/SO control characters are effective only in the
outbound active page. For details on the SCS GO/G1 commands and
responses, refer to the summary table of commands and responses earlier in
this chapter.
The method of selecting the two active spaces GO and G1 depends on the
Word Length option you are presently using; the 7 bit or the 8 bit word
length. The following tables illustrate how this works for the 7 bit and the 8
bit word length inbound and outbound operations.
(