Epson SQ-2550 User Manual

Each of the three user-defined character modes (draft, Letter

Quality, and proportional) 

be used in combination with

most of your printer’s various print styles. For instance,

emphasized works with user-defined characters. The characters

you design are enhanced to give this printing effect.

Mixing the types of user-defined character sets is not permitted.

If, for example, you select draft and define some characters,

select proportional and define some more, the first

character definitions will be destroyed. Only one type of

character definition may be stored in RAM at 

time.

If you define characters in one mode, then switch to another

mode and select the user-defined character set, the command

will not be effective and 

character in ROM will printed.

The user-defined character definitions, however, remain

unaffected. If you switch back to the mode in which they were

defined, you can then select and print them.
Keep in mind that user-defined characters are stored in RAM,

which is not permanent. Whenever the printer power is turned

off, or the printer is initialized with the INIT signal, the

user-defined characters are lost. (Some computers do this each

time BASIC is loaded.) ESC @, however, does not destroy

user-defined characters.