
Appendix C Host Computer Interface
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.
+5 V DC – (Pin 11)
This line is connected to the printer’s +5 V DC line (+5 V ±0.5 V, 250 mA [Parallel and Serial total] maximum, fused).
DTR – Data Terminal Ready – (Pin 20)
This output is used as a buffer
The voltage levels of the interface signals conform to EIA