The dot matrix for the 5224 Printer and 5225 Printer is an 8-row-by-9-column matrix. All 8 rows and 9 columns are printed regardless of CPI or LPI settings.
The vertical distance between dots is always 0.352 mm (0.014 inch) regardless of the LPI setting (LPI parameter on the CRTPRTF command). The LPI setting determines the space between lines, not the height of characters. At a setting of 9 lpi (2.82 mm or 0.111 inch for each line), there is no vertical space between lines if all rows of dots are used. However, the normal character set does not use the bottom row of dots (line 8) in the matrix, so that even at 9 lpi there is some space between lines. If you choose, use row 8 to define your own characters.
The horizontal distance between dots depends on the CPI setting. At 10 CPI, each column is spaced 0.262 mm (0.0111 inches) apart, giving each character 2.54 mm (0.1 inches). At 15 CPI, each column is spaced 0.188 mm (0.0074 inches) apart, giving each character 1.69 mm (0.0667 inches). The standard character set does not use columns 1 and 9 (to allow spacing between characters).
You can use columns 1 and 9 to define your own characters with one restriction: the 5224 Printer and 5225 Printer cannot print two adjacent horizontal dots. To print two adjacent horizontal dots (such as in a solid underline), the line must be printed twice. This can be done using a different set of code points on each pass, one to define the odd dots, and the other to define the even dots. Both passes occur during one output operation. If your program attempts to print two adjacent horizontal dots, no error message appears, but one of the dots is not printed. (The last position of dots in one character and the first position in the character to its right are considered adjacent dots.) There is no restriction on adjacent vertical dots.
On any one output operation, each code point represents a single eight-by-nine matrix. To print characters larger than this requires more than one eight-by-nine matrix, each one normally defined by a different code point. Overprinting is also required.
For example, to print a double-wide character, specify a code point for the left half of the character and another code point for the right half. Double-high characters require a code point for the top half of the character and another for the bottom half. On the first line, the top half of all characters are printed, and on the next line, the bottom half of all characters. You must specify lpi(9) on the CRTPRTF, CHGPRTF, or OVRPRTF command to avoid a space between the top and bottom halves. Using DDS, you can define two fields in one record format, one for the upper half and one for the lower half. Example 2 shows a character two wide by two high.