Chapter 3 Printer Control Codes The MPS 1000 printer is easy to use, especially with commercial soft- ware that has print control features. This chapter explains some of the basics of printer control and communications to help you understand how your computer works with your printer. This information should also help you understand the terms used in your software and computer manuals. Because the MPS 1000 has both a Commodore mode and an IBM mode, it features two separate means of communicating with your com- puter. In its Commodore mode, the MPS 1000 is able to print Commo- dore letter and graphics characters in draft and NLQ fonts. In its IBM mode, your MPS 1000 has two character sets:
IBM Character/Graphic (CG) set 1 and CG set 2. These will all be explained in this and the next chapter. If you are an advanced user or a programmer, you may want to turn to Appendix B, which has a full summary of all the MPS 1000 com - mands. PETASCII and IBM Extension ASCII Codes When you write a document with a word processing program, you press keys with letters on them. When you send the document to a printer, it prints the letters on paper. The computer and the printer, however, do not use or understand letters of the alphabet. They func- tion by manipulating numbers. Therefore, when you press the A key, for example, the computer sends a number to its memory.
When the com- puter tells the printer to print that letter, it sends the number to the printer, which then convens the number to a pattern of pins that will fire to print the dots making up that letter. 31