HP FS-8000C manual Serial Interface, Interface voltage levels, Serial connector

Interface Signals

B.2 Serial Interface

B.2.1 Interface Signals

Table B-2below shows the pins and corresponding input and output signals of the RS-232C interface connector.

Pin	In or out	Signal	Description
1	—	FG	Frame Ground. This pin is connected directly to the
			printer frame.
2	Out	TXD	Transmit Data. This pin is used to output asynchronous
			data sent from the printer to the computer. This signal is
			often used in handshaking.
3	In	RXD	Receive Data. This pin is used to input serial asynchro-
			nous data sent from the computer to the printer.
4	Out	RTS	Request To Send. This output is always high (above 3
			volts).
5	In	CTS	Clear To Send. Not used.
6	In	DSR	Data Set Ready. Not used.
7	—	SG	Signal Ground. This pin is used to establish a common ref-
			erence level for the voltages of all signals other than
			Frame Ground.
20	Out	DTR	Data Terminal Ready . This pin is used to notify the status
			of the printer buffer (i.e., nearly full or nearly empty)
			when handshaking is used. The pin goes high (above 3
			volts) when the buffer is able to accept more data.

Table B-2

B.2.2 Interface voltage levels

The voltage levels of the interface signals conform to EIA RS-232C specifications. The voltage level of SPACE is 3 to 15 volts. The voltage level of MARK is -3 to -15 volts. Voltages between -3 and 3 volts are undefined.

B.2.3 Serial connector

The serial interface connector (RS-232C) is a DB-25S connector. Use a cable with a DB-25P connector or its equivalent for this connector.

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