Epson EPL-N1200 Reference Manual page 230

Overview of the EJL commands
EJL commands must be sent immediately after the printer receives the
universal exit command; otherwise the printer returns to its currently
selected emulation mode.
Every EJL command starts with the string @EJL, which must be in
uppercase letters, although other commands can be both uppercase and
lowercase.
You must send the LF code at the end of an EJL command; only an LF
code terminates the EJL command. If the EJL command is not followed by
an LF code, the printer does not recognize it as an EJL command; it is then
printed as a character string in the currently selected printer emulation
mode.
If the printer emulation you attempt to switch to is not available, the
printer switches to the currently selected printer emulation mode.
Note:
If the emulation setting is set to Auto, the printer switches automatically
between emulation modes, depending on the recieved data. If a specific emulation
setting is selected, the printer switches to that mode.
EJL command summary
<ESC><SOH>
Description:
@EJL<WS>ENTER<WS>Option[<WS>]=
[<WS>]Value[<CR>]<LF>
Option (Value):
Description:
@EJL<WS>COMMENT<WS>comment strings[<CR>]<LF>
Description:
Exit current printer emulation and enter EJL mode
LANGUAGE (LJ4, EPSONGL2, PS*, ESCP2, FX, I239X)
*Available only when the appropriate option module
is installed.
Enter printer emulation from EJL mode
Enter comments
Command Summary
C-17