ML720/721 Printer Handbook 49Chapter 4: Working with SoftwareThis chapter covers the fundamentals of setting up commercial software packages foruse with your printer. Be sure to read your software documentation carefully for moredetails.Basic TerminologyBefore we start, let’s examine a few terms with which you may not be familiar.Printer CommandsIf you’re using commercial software with an appropriate printer driver (see“Printer Drivers” below), the printer commands will normally be sent to theprinter by your software and you won’t even need to think about them.Printer commands are signals sent by your PC to the printer which guide and controlits operation. Printer commands tell the printer what character pitch to use, what fontto use, what margins to use, whether to use single or double spacing, when to en-gage/disengage double width or double height printing, etc.Printer commands can be sent in decimal, ASCII, or hexadecimal form. The values(decimal/ASCII/hexadecimal) for each type of command depend on which emula-tion is active (see Appendix C for a listing of printer commands for each emulation).With only a few exceptions, printer commands begin with the ESC character, decimal27 (hexadecimal 1B), which serves as signal to the printer that what follows is to beinterpreted as a command rather than just a string of characters. Some printer com-mands expect you supply a numerical value, representing tab stops, line spacing, etc.