6-9
6.2.4 RS-232C protocol(1) X-ON/X-OFF system (see the figure)
This is a control system in which the data transmi ssion request
signal (X-ON (11H)code) and the data transmissionstop request
signal (X-OFF(13H) code) are output.
Requirementsof output of X-ON code:
• Whenthe power is switched to ON.
• Whenthe remaining buffer is 2K bytes or less, the X-OFF is
output, and the remainingbuf feris 4K bytes or more.
Requirementsof output of X-OFF code:
• Whenprinter error occurs.
• Whenthe remaining buffer is 2K bytes or less.
Note: Even if each code is ready for output, the same code cannot be
transmitted twice successively(except when the power is turnedon
or the printer is reset from the control panel).
Fig. Buffer in use
Receivebuffer = 32K bytes
2Kbyt es
4Kbyt es
X-OFF code output
X-ON code output
Receivingdata