Star Micronics TSP400 Series Programmer's Manual page 18

Starts the
STX-ETX mode.
Sends ENQ
Receives status byte.
NO
Is the data buffer
empty?
YES
Sends STX signal
Is an odd parity
check?
YES
(FF) H is set for the text
byte.
Acquires the exclusive OR of the content
of the text byte and the data to sent, then
it is used as the content of the test byte.
Transmits the data to
the printer.
NO
Is this the last data in
a block?
YES
NO
The test byte is set at (0)H.
Check byte:
Horizotal parity of the printer.
Test byte:
Horrizontal parity of the host
computer.
– 15 –
Sends an ENQ signal.
Receives status signal.
Receives a check byte.
Is the status an
error?
NO
Horizontal
parity check
Check byte =
test byte?
YES
Sends ETX
(Printing)
Ends the
STX-ETX mode.
Is there a data block in
the STX-ETX mode?
YES
YES
NO
Sends CAN
NO
RET