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2
XON/XOFF protocol
(a) Conditions for sending XON
・
Communication is enabled after power is turned ON.
・
Residual capacity of the buffer is 1 K bytes or more after
sending XOFF code.
・
XOFF code is output due to error and printer returns to normal
conditions.
(b) Conditions for sending XOFF
・
Printer is in error.
・
Printer is in pause state.
・
Received buffer has less than 128 bytes available.
128 bytes
1K bytes
Reception buffer = 16K bytes
XON code transmission
XOFF code transmission
Reception data