Epson ActionPrinter 4000 User Manual page 116

User-defined Characters
Data numbers
The bits within each byte have values of 1,2,4,8,16,32,64, and 128.
In the vertical column of dots, the bits are arranged so that the most
significant bit (with a value of 128) is at the top of the column and
the least significant bit (with a value of 1) is at the bottom.
The next illustration shows how to use this method to calculate the
data numbers for the character in this example. On the left side of
the figure, the data numbers are calculated for the middle column.
The value of each byte is calculated by adding the values of the rows
in which dots appear. The right side of the figure shows the whole
character with the three data numbers for each column indicated at
the bottom.
This manual uses decimal numbers because the program examples
are written in BASIC and everyone is familiar with decimals. The
data you send to your printer, however, must be in the form (binary,
decimal, hexadecimal) that you can use with your programming
language.
4-20 Software and Graphics