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RXD
-
receives data from the Host. The interface ignores RX Data when DSR
is low.
TXD
-
when using XON/XOFF, Printer to Host, Clear to Send (CTS) must be
high to enable transmission. The Printer does not transmit any data
when RTS or CTS are high.
DTR
-
is set and remains 'HIGH' while the Printer power is ON and the
interface is operational.
GND
-
This pin is connected to the logic ground to provide a common
reference for the data and control signals.
DSR
-
The interface ignores received data unless DSR is 'HIGH'.
RTS
-
This signal is set, 'HIGH' at power ON. RTS. 'HIGH' tells the HOST
that the Printer is busy and cannot receive data.
CTS
-
The interface monitors this signal which must be. 'HIGH' for the
interface to transmit XON and XOFF where:
XON = DC1, Hexadecimal 11
XOFF = DC3, Hexadecimal 13.
6.2.3
Handshaking
This is either XON/XOFF or RTS/CTS with the Flow Control according to Setup.
A Buffer full treatment is performed according to Flow Control when the available
space is 10 bytes.
XON/XOFF
When this protocol is selected, the Printer sends XON to the Host
when it is able to receive data and XOFF to stop the data flow or
to indicate it is unable to receive any data.
RTS/CTS
When the Host wants to send data to the Printer, it must wait for
the Printer RTS line to go 'HIGH'. If RTS goes 'LOW', the Host
must stop transmission and wait for RTS 'HIGH' before sending
any data.
Specifications
6-3
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