Epson C82315 - Manual (Page 18)

For example, you could define user-defined string 1 to be the command string to
turn on bold printing, as used in the example in the previous section. Then,
instead of inserting the &% 1B 45&% command in your text, you would insert only
&%U1.
INTERFACE SETUP COMMANDS
You send these commands in a similar manner to command-pass-thru, but the
commands are used to make interface settings instead of being sent on to the
printer. These interface settings control printing regardless of the printer model
connected.
The format of the interface setup commands is as follows:
&%Z##,P
The 8%Z indicates that an interface setup command follows. The ## is a two-digit
number, indicating the number of the command. The P is the parameter of the
command: the length of the parameter varies by command.
A table of commands and parameters, as well as a short description of each
follows.
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