Seiko Instruments DPU-30 - Manual (Page 26)

4-4
Data timing for hardware control
2. Xon/Xoff
control
The data transmission from a host computer is controlled through the exchange of Xon(11
16
)
command and Xoff(13
16
) command between the printer and the host computer.
When the data stored in the input buffer of the printer exceeds 4,046 bytes, the printer sends the
Xoff command to the host computer.
Upon the reception of the Xoff command, the host computer stops to send the data.
If the data stored in the input buffer of the printer falls below 3,995 bytes, the printer sends the
Xon command to the host computer.
Upon the reception of the Xon command, the host computer resumes sending the rest of the
data.
∗ When the printer fails (for example, paper-out), the printer sends the Xoff command to the
host computer.
And then, after the printer gets back to normal, the printer sends the Xon command to the
host computer.
Data timing for Xon/Xoff control
Buffer
4,046 bytes
or more
RTS
RxD
Print
Paper out
ON-LINE
OFF-LINE
Power ON
Buffer
3,995 bytes or less
RTS
RxD
RxD
Print
Paper out
ON-LINE
OFF-LINE
Power ON
Xon Xoff Xoff Xon Xon
Buffer
4,046 bytes
or more
Buffer
3,995 bytes or less