C.2.
C.2. RS-232C/RS-422A Interface
RS-232C interface
Interface Signals
The pins of the printer's
Table C.2. RS-232C Signal Pin Assignments
Pin | In/out | Signal | Description |
1 | - | FG | Frame ground |
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2 | Out | TXD | Transmit Data |
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3 | In | RXD | Receive Data |
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4 | Out | RTS | Request To Send |
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5 | In | CTS | Clear To Send |
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6 | In | DSR | Data Set Ready |
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7 | - | SG | Signal Ground |
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20 | Out | DTR | Data Terminal Ready |
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Brief descriptions of the signals follow.
FG - Frame Ground - (Pin 1)
This pin is connected directly to the printer frame.
TXD - Transmit Data - (Pin 2)
This output carries asynchronous data sent by the printer to the computer. It is used mainly in handshaking protocols.
RXD - Receive Data - (Pin 3)
This input carries serial asynchronous data sent by the computer to the printer.
RTS - Request To Send - (Pin 4)
This output is always held high (above 3 volts).
CTS - Clear To Send - (Pin 5)
DSR - Data Set Ready - (Pin 6)
Unused.
SG - Signal Ground - (Pin 7)
All signals can transmit between the printer and the host computer to send each signals with a signal ground.