POSIFLEX Business Machines PP3000 - Manual (Page 37)

Horizontal
parity check
RET
Ends the STX -
ETX mode
Starts the STX-
ETX mode
YES
NO
Is the
status an
error?
Check byte
= test byte?
Is there a
data block in the STX-
ETX mode?
Receives status
signal
Receives a check
byte
Sends ETX
Sends CAN
Sends an ENQ
signal
NO
NO
NO
NO
YES
YES
YES
YES
Is this
the last data in
a block ?
Transmits the data to
the printer
Acquires the exclusive OR of the
content of the test byte and the
data to send, then it is used as the
content of the test byte
Set test byte 00H
NO
YES
Set test byte FFH
Is it
odd parity
check?
Sends STX signal
Is the
data buffer
empty ?
Receives status
byte
Sends ENQ
PP3000 Series User’s Manual 4 - 13