Star Micronics Line Thermal Printer Specifications page 7

3) General description of operations in the XON/XOFF mode
This mode is set when DIPSW #1 to #3 are turned OFF. This mode notifies the host of the XON (DC1) data when the
printer can receive data and the XOFF (DC3) data when the printer cannot receive data, using the TXD signals.
This functions so that XON outputs only 1 byte when the printer shifts from OFFLINE (printer busy) to ONLINE (printer
ready) and; XOFF outputs 1 byte when the printer shifts from ONLINE (printer ready) to OFFLINE (printer busy) .
XON
TXD
RXD
Printing
Out of
paper
signal
Power ON
If there is no error after turning the power ON, XON (control code name: DC1; Hexadecimal name: 11H) is output by the
TXD signal line. After the host computer receives the XON, it sends the data text to the RXD signal line. XOFF (DC 3;
13H) is output when the empty space in the data buffer is a maximum of 256 bytes. The host computer stops sending
data text when it receives the XOFF, however, the printer is capable of receiving data at that time for the amount of
empty space in the data buffer. Data exceeding the amount of empty space is discarded. As the empty space in the
data buffer increases through printing, XON is output when the data in the buffer is a maximum of 256 bytes.
4) Buffer full/Buffer full cancel in the XON/XOFF mode
Full
Buffer Empty area: 256 bytes
XOFF Output
Printer Setting Conditions
Memory switch B-4 = 0
Memory switch B-4 = 1
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STAR Line Mode Command Specifications
XOFF
DATA
Near Full
XOFF outputs only 1 byte when the empty area is a maximum of 256
bytes. XON outputs 1 byte when the data in the buffer is a maximum
of 256 bytes.
XOFF output for every 1 byte of data received, when the empty area
is a maximum of 256 bytes. XON output when the data in the buffer is
a maximum of 256 bytes.
1-3
XON XOFF
DATA
No paper
Near Empty
Reception data: 256 bytes
XON Output
Explanation of Operations
XON
DATA
ON-LINE Recovery
Empty