IBM TM7 - Manual (Page 139)

v ASCII characters 0 through 31 are reserved for RS-232 functions and
cannot be defined.
v See Appendix E, “Proportional Fonts” on page 165 for suggestions about
how to implement proportional fonts.
Limitations:
The memory required for proportional fonts is much greater than the
memory that was required for user-defined fonts. Therefore, when code
page 1 (or 3) is set up as proportional, code page 2 (or 4) is not valid.
You cannot set up code page 2 or code page 4 as a proportional font.
To download the font:
1. Store the code page matrix as an MCT value. Use the command X'1B
4D x 55 wb' where:
x X'02' for thermal code page 1, X'17' for thermal code page 3
wb The number of bytes, which is also 1⁄8 the number of dots, in
the width of the widest character. The valid range is 2
≤wb≤4.
2. Erase the existing character set using the command X'1B 23 04'.
3. Use the Proportional Font command to download the font.
Example:
To define an A to code page 1 when wb is set to 02, enter the following:
X'1B260141410C16'
X'0F001F803FC070E06060C030C030C030C030C030C030'
X'C030FFF0FFF0C030C030C030C030C030C030C030'
X'C030000000000000000000000000000000000000000000'
This command specifies a character width of 12 dots (X'0C') and a
character height of 22 dots (X'16'). Following the width and height are 64
bytes that define the character. If, as in this case, the character is defined
before all 64 bytes have been used, the rest of the bytes are filled with X'0'
(see Figure 42 on page 116).
Note: If wb were set to 03, then the total number of data bytes would be
98 (3×32+2)
updated March 18, 2002
Appendix C. RS-232 Programming Information 115