Epson Printer Interface Cartridge Operation Manual page 46

Figure 7-7. Data numbers for one column
To calculate the data numbers for this column, note which dots are
used in the top group (the top eight positions) and add their values
together. Then go down to the middle group (the next 8 positions) and
add the values of any dots that are used there. Finally, look at the
bottom group (2 dot positions) and add together the values used there.
If no dots are used in a group, the data number for that group is
zero. All zeros must be entered in the DATA statements for the NLQ
definition programs.
Figure 7-8 shows you how to use the NLQ character definition with
a musical design. The figure shows the design drawn on a grid and the
data numbers printed at the top or bottom of each column.
41