Citizen Systems iDP-3550 - Manual (Page 77)

SI
[Function] Specifying the inverted character
[Code] <0F>H
[Outline] This command selects and prints the inverted characters. Enter it at the beginning of one
line. Otherwise, it will be invalid. Erect and inverted characters cannot be mixed in one line.
DC2
[Function] Canceling the Inverted character
[Code] <12>H
[Outline] This command deselects the inverted characters. Enter this command at the beginning of one
line.
LF
[Function] Printing and paper feed
[Code] <0A>H
[Outline] If the print buffer contains the data, this command will feed the line after printing. If not, the
command only feeds the line.