Citizen CL-E321 User Manual page 100

XON / XOFF Protocol
a Conditions for XON code output
Ÿ Communication is possible after the power is turned on.
Ÿ Scenario in which the receive buffer has less than 128 bytes available caus-
ing output of the XOFF code followed by the receive buffer then having at least
1,024 bytes available.
b Conditions for XOFF code output
Ÿ Scenario in which the receive buffer has less than 128 bytes available.
DTR Protocol
a Conditions when DTR signal state changes to Ready (High)
Scenario in which the receive buffer has at least 128 bytes available.
Note that once the receive buffer has less than 1,024 bytes available causing the
DTR signal to change to the Busy (Low) state, the DTR signal state remains in the
Busy (Low) state until the receive buffer has at least 1,024 bytes available.
b Conditions when DTR signal state changes to Busy (Low)
Scenario in which the receive buffer has less than 128 bytes available.
Receive buffer 16k bytes
XON
100
— —
XOFF
128 bytes
1024 bytes