IBM TM7 - Manual (Page 137)

v Once characters are downloaded to the printer, they remain valid until
you redefine them. This is true even if power to the printer is removed.
v Before the characters are defined, the sector of the flash EPROM which
stores this data must be erased. (See “Erase Flash EPROM Sector” on
page 121.) Also, the character matrix for the code page must have
already been defined. (See Table 15 on page 123, MCT# 3, 4, and 5.)
v Flash EPROM sector 4 contains all user-defined code pages for the
thermal printhead. To redefine a code page, you must erase and
reprogram all of them.
v Flash EPROM sector 3 contains both user-defined code pages for the
impact printhead. To redefine a code page, you must erase and
reprogram both of them.
v Thermal height must be even.
v There is no way to redefine one character only. You must redefine a
whole code page.
v If the parameter s, n, or m is out of range, the command is discarded
and the remaining data is processed as print data.
v This command should be sent only when the data buffer is empty. See
the description of bit 6 in “Status Byte 2” on page 161.
v ASCII characters 0 through 31 are reserved for RS-232 functions and
cannot be defined.
Thermal Code Page
You define the character matrix for each code page with MCT #2, MCT #3, MCT
#23, and MCT #24 for thermal code pages 1, 2, 3, and 4, respectively. See
Table 15 on page 123.
The number of data bytes per character loaded is 2 × the character height. The
total number of data bytes for this command is 2 × the character height × (1+m−n).
Example: 10 wide × 20 high
updated March 18, 2002
Appendix C. RS-232 Programming Information 113