Rs-232C/Rs-422A Interface; Rs-232C Interface - Kyocera FS 3750 User Manual

C.2. RS-232C/RS-422A Interface
C.2.

RS-232C/RS-422A Interface

RS-232C interface

Interface Signals
The pins of the printer's RS-232C interface connector carry the signals listed in Table C.2. The table also
indicates whether each signal is incoming or outgoing with respect to the printer.
Table C.2. RS-232C Signal Pin Assignments
Pin In/out
1 –
2 Out
3 In
4 Out
5 In
6 In
7 –
20 Out
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.
DTR - Data Terminal Ready - (Pin 20)
This output is used as a buffer nearly-full handshake line. It is held high (above 3 volts) when the buffer can
accept more data.
RS-232C Interface Voltage Levels
The voltage levels of the interface signals conform to EIA RS-232C specifications. SPACE is from 3 volts to
15 volts. MARK is from -3 volts to -15 volts. Voltages between -3 volts and 3 volts are undefined.
C-4
Signal Description
FG Frame ground
TXD Transmit Data
RXD Receive Data
RTS Request To Send
CTS Clear To Send
DSR Data Set Ready
SG Signal Ground
DTR Data Terminal Ready