AMT Datasouth Accel-7350 Service Manual page 15

Printer Input Signals
RXD Receive Data
A serial data line that consists of a start bit, data bits, (party bit), and stop bit. The
configuration of the data length (7 or 8 bits), parity and stop bit are set in the
setup mode from the control panel. RXD signal level is determined as "0" when
"high" and as "1" when "low".
CTS Clear To Send
This signal is ignored.
Printer Output Signals
TXD Transmit Data
A Serial output data line that sends XON, XOFF, ACK, and ID sequence. This signal
is sent regardless of whether CTS and DSR is "high" or "low". The format of the
data is the same as the received data.
TXD signal level is determined as "0" when "high" and as "1" when "low".
RTS Request To Send
Always held in the ON ("space" or "high") state.
DTR Data Terminal Ready
This signal represents the busy state of the printer. When signal is "low", it indicates
that the printer is busy and therefore data cannot be sent to the printer.
When this signal is "high", it indicates that the printer is ready and thereby data can
be sent to the printer. In the case of the XON/XOFF protocol, this signal is always
"high".
Signal Signals "HIGH" (ON, SPACE = Logic "0"):
"LOW" (OFF, MARK = Logic "1") :
Handshake Protocol
DTR (READY/BUSY) Protocol
A protocol that indicates the printer state with the signal line DTR (terminal
No.20). When the printer is in the ready state, the signal line is high (+12V).
When the printer is in the busy state or in the offline state, the signal line is low
(-12V). When the printer is in the busy state and in the offline state, the host
must not send data to the printer. However, the printer will accept data from the
host when busy is indicated until the buffer is filled.
Power ON state After the power is turned on and the initialization of the printer
is completed, DTR is set "high".
+3 through +15V
-3 through -15V
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