Citizen Systems iDP-3550 - Manual (Page 91)

CAN
[Function] Canceling the print data
[Code] <18>H
[Outline] This command clears the input buffer and print buffer. In the STX-EXT mode of the serial
interface printer, the command clears the data in the data buffer and ends the STX-ETX
mode.
DC3
[Function] Setting the deselect mode
[Code] <13>H
[Outline] If the printer receives <DC3>, it will ignore the subsequent data. The Deselect mode is
cancelled by <DC1>.
DC1
[Function] Setting the select mode
[Code] <11H>
[Outline] If the printer receives this command, it will save the subsequent data in the input buffer.