SATO M-8400RV Service Manual page 53


3-4 RS232C Serial Interface (Cont.)

Pin Assignments (Cont.)
PIN DIRECTION
4 To Host
5 To Printer
6 To Printer
7 Reference
20 To Host

Ready/Busy Flow Control
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SECTION 3 - Interface Specifications
RS232C Interface Signals
RTS (Request to Send) - Used with Ready/Busy flow control to
indicate an error condition. RTS is high and remains high unless the
print head is open, (in this case, RTS would return to the high state
after the print head is closed and the printer is placed back on-line)
or an error condition occurs during printing (e.g., ribbon out, label
out).
CTS (Clear to Send) - When this line is high, the printer assumes
that data is ready to be transmitted. The printer will not receive data
when this line is low. If this line is not being used, it should be tied
high (to pin 4).
DSR (Data Set Ready) - When this line is high, the printer will be
ready to receive data. This line must be high before data is
transmitted. If this line is not being used, it should be tied high (to
pin 20).
SG (Signal Ground).
DTR (Data Terminal Ready) - This signal applies to Ready/Busy
flow control. The printer is ready to receive data when this pin is
high. It goes low when the printer is off-line, either manually or due
to an error condition, and while printing in the Single Job Buffer
mode. It will also go low when the data in the buffer reaches the
Buffer Near Full level.
SATO M-8400RV Service Manual

SIGNAL DESCRIPTION
49
Rev C