Kyocera FS-1050 Service Manual - Page 173

Serial interface signals The following table provides details for the signals used on the serial interface board. 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 8, 9) SDB (Pin 8, 10) DTR (Pin 20) Meaning 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 inverted differential data (RDA). This output is always held high (above 3 V). Unused. Unused. All signals can transmit between the printer and the host computer to send each signals with a signal ground. This output transmits asynchronous inverted form of differential data from the printer to the computer. This output carries asynchronous non-inverted form of differential data from the computer to the printer. 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. 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. RS-422A interface voltage levels The interface signal voltage levels for RS-422A conforms with the EIA RS-422A standards. The differential voltage ranges is from 200 mV to 6 V. FS-1050 C-9