Epson 4500 - Manual (Page 131)

User-defined Characters
You have seen how to design a character by placing dots on a grid and
translating the dots to decimal equivalents. The last step in defining a
character is sending this information to your printer.
Sending Information to Your Printer
The printer loads characters in the print style (Letter Quality, draft, or
proportional) that the printer is currently using. It also records whether
italic, superscript, or subscript is turned on. This means that if you
want to print a character in italics, for example, you must have the
italic mode turned on when you define the character.
The command your printer uses to define characters is one of the most
complex in its repertoire. The format of the command is this:
ESC & 0 n1 n2 d0 d1 d2 data
The ESC & is simple enough. The 0 (which is ASCII code 0, not the
character zero in quotation marks) allows for future enhancements. At
this time, it is always ASCII 0.
You can define many characters with a single command. The values n1
and n2 are the ASCII codes of the first and last characters you are
defining. If you are defining only one character, n1 and n2 are the
same. You can use any codes between decimal 32 and 127 for n1 and
n2, but it is best not to define decimal 32, which is the code for a space.
Also, you can use letters in quotation marks instead of ASCII codes for
n1 and n2.
Note: Because user-defined characters require additional memory,
you must set DIP switch 2-5 to 1 KB (off) before downloading these
characters.
4-24 Software and Graphics