Star Micronics NP-IO manual Eighth bit controls

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H The seven bit dilemma

Some computers (not the IBM-PC fortunately!) don’t have the capability to send eight bits on their parallel interface, but can only send seven bits. This would make it impossible for these computers to use this printer’s block graphics characters and special symbols if our engineers hadn’t thought of a solution.

(All of these characters have ASCII codes greater than 127 which means that the eighth bit must be on to use them.) The solution lies in the three control codes given in the following table:

Table 5-3

Eighth bit controls

~1

Accept the eighth bit “as is” from cESCj ,,#,,

nBlock graphics characters and special symbols

Besides the upper and lower case letters and symbols that we are by now familiar with, your printer has a whole different set of characters that are for special uses. These characters include block graphics for drawing forms and graphs, and special sym- bols for mathematical, engineering and professional uses. The special characters are included in two character sets.. The character set you normally use with IBM mode is called character set #l. The special characters are printed out when you send ASCII codes 160-255 to the printer.

Your printer also offers character set #2 which is almost the same as character set #l except for the addition of ASCII codes

3--6,20,21,26, and 128-159. Character set #2 is selected with (ESC)“G”; to go back to character set #l, use (ESC“7”.

You can also specify the power-on default character set by set- ting DIP switch l-4 on for character set #l and off for character set #2. The following program will print out all of the graphics characters available: