Seiko FB-900 - Manual (Page 176)

● Serial interface
Upon reception of ETX(03)H, the printer sends ACK(06)H to the
computer to indicate that it is ready. If the printer is busy, it does
not send ACK to indicate that it is busy.
If the free area in the buffer is less than the CIN value when the
printer receives ETX, the printer does not send ACK
immediately. It sends ACK when the free area in the buffer
becomes greater than the CRN value. If the printer is in the
offline state, the printer sends ACK when the ONLINE key is
pressed and the printer becomes ready.
In the busy or offline state, the SRTS and DTR signals remain
ON. The printer sends ACK to the computer even if the CTS
input signal is OFF.
The interface does not analyze the (03)H code. Thus, the printer
sends ACK in response to (03)H received in an escape sequence
or graphic data sequence. The received (03)H code is sent to the
emulation as normal data.
The baud rate can be selected from the values shown below in the
extended setup mode:
38400BPS, 19200BPS, 9600BPS, 4800BPS,
2400BPS, 1200BPS, 600BPS, 300BPS,
The data frame has the following organization.
START BIT (1) + DATA BIT (7 or 8) + PARITY BIT (0 or 1) + STOP
BIT (1 or 2)
MARK: Logic "1" (-3 to -15 V)
SPACE: Logic "0" (+3 to +15 V)
7-11 — 7. Interface specifications —
ETX/ACK protocol
Baud rate
Serial data organization
Automatic serial/parallel selection
+3 +15V
-3 -15V START D1 D2 D3 D4 D5 D6 D7 D8 STOP
See page 3-49.
If #70 INTERFACE is set to AUTO in the EXTENDED SETUP MODE, the serial or parallel
interface is selected automatically.
In the initial condition, both the serial and parallel interfaces are ready. When data is input
through either interface, printing is done through that interface. In printing, the other interface is
in the busy state. If data is input through the busy interface, the data is ignored.
If no data is input to the first interface, both interfaces are reset to the initial ready state.