Star Micronics RS232 manual X-ON/X-OFF mode

SERIAL

4-5-2. X-ON/X-OFF mode

This mode is accessed when DIP switch 1-6 is set to OFF.

	X–OFF	X–OFF
X–ON	X–OFF X–OFF X–ON	X–OFF X–OFF X–ON

TXD

RXD Data

Printing

PAPER OUT signal

ON

ON LINE indicator OFF

Power ON

Data Data

Paper out	Load paper and press
	the ON LINE switch (Star mode).

Immediately after power on (provided that no error occurs), the printer informs the host that it is ready to receive data by outputting the X-ON signal (control code DC1; value = 11H) over the TXD line. If necessary the printer repeats the signal every three seconds until the host begins sending text data over the RXD line.

When the printer’s remaining buffer space falls to *256 bytes or less, the printer begins to output X-OFF signals (DC3, value = 13H) over the TXD line. The host responds by halting the data transfer. Note that the printer remains capable of receiving data until the buffer becomes full.

Available buffer space increases as the printer prints the buffered data. When the printer has cleared all but the last *256 bytes of data, it again outputs the X-ON signal.

	Data buffer full Nearly full	Nearly empty		Empty
	*256 bytes		*256 bytes
	remaining
Printer outputs				Pinter outputs
X-OFF.				X-ON.

* 16 bytes when the buffer size is set to 45 bytes

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