Serial Interface Connection; Rs-232C Interface Voltage Levels - Mita DP-2800 Service Manual

Serial interface connection

Detailed descriptions of the serial interface signals follow.
Signal
FG (Pin 1)
TxD (Pin 2)
RxD/RDA (Pin 3)
RTS (Pin 4)
CTS (Pin 5)/DSR (Pin 6)
SG (Pin 7)
SDA (Pin 89)
SDB (Pin 810)
+5 V DC (Pin 11)
DTR – Data Terminal
Ready (Pin 20)

RS-232C interface voltage levels

The voltage levels of the RS-232C signals conform to EIA RS-232C specifications. FALSE
is from 3 volts to 15 volts. TRUE is from -3 volts to -15 volts. Voltages between -3 volts and
3 volts are undefined. The voltage levels of the RS-422A signals are equivalent to those of
the RS-232C signals except the signals used for transmission and reception.
This pin is connected directly to the printer frame.
RS-232C only: This output carries asynchronous data
sent by the printer to the computer. It is used mainly in
handshaking protocols.
This input carries serial asynchronous data sent by the
computer to the printer. In RS-422A, this carries the
inversed differential data (RDA).
This output is always held high (above 3 V).
Unused.
All signals can transmit between the printer and the host
computer to send each signals with a signal ground.
This output transmits asynchronous inversed form of
differential data from the printer to the computer.
This output carries asynchronous non-inversed form of
differential data from the computercmputer to the printer.
This line is connected to the printer's +5 V DC line (+5 V
±0.5 V, 250 mA maximum [serial and parallel total],
fused).
This output is used as a buffer nearly-full handshake line.
It is held high (above 3 V) when the buffer can accept
more data.
Meaning
5A2
A-7