SATO D512, D508 service manual 1 RS-232C Interface Signals, Pin Direction Signal Definition

SECTION 5: INTERFACE SPECIFICATIONS

5.4.1 RS-232C INTERFACE SIGNALS

Pin	Direction	Signal Definition
1	Reference	FG (Frame Ground)
2	To Host	TD (Transmit Data) -Data from the printer to the host computer. Sends X-On/X-Off
		characters or status data (Bi-Directional protocols).
3	To Printer	RD (Receive Data) -Data to the printer from the host computer.
4	To Host	RTS (Request to Send) -Used with Ready/Busy flow control to indicate an error
		condition. RTS is high and remains high unless the print head is open (in this case,
		RTS would return to the high state after the print head is closed and the printer is
		placed back on-line) or an error condition occurs during printing (e.g. Time Out
		error, label out).
5	To Printer	CTS (Clear to Send) -When this line is high, the printer assumes that data is ready
		to be transmitted. The printer will not receive data when this line is low. If this line is
		not being used, it should be tied high (to pin 4).
6	To Printer	DSR (Data Set Ready) -When this line is high, the printer will be ready to receive
		data. This line must be high before data is transmitted. If this line is not being used,
		it should be tied high (to pin 20).
7	Reference	SG (Signal Ground)
20	To Host	DTR (Data Terminal Ready) -This signal applies to Ready/Busy flow control. The
		printer is ready to receive data when this pin is high. It goes low when the printer is
		off-line, either manually or due to an error condition, and while printing in the Sin-
		gle Job Buffer mode. It will also go low when the data in the buffer reaches the Buf-
		fer Near Full level.

Cable Requirements

DB9	DB2	HOST INTERCONNECTION		PRINTER
	5
1	1	FG	1	FG (Frame Ground)
2	3	RD	2	TD (Transmit Data)
3	2	TD	3	RD (Receive Data)
8	5	CTS	4	RTS (Request to Send)
7	4	RTS	5	CTS (Clear to Send)
4	20	DTR	6	DSR (Data Set Ready)
6	6	DSR*	20	DTR (Data Terminal Ready)
5	7	SG	7	SG (Signal Ground)

*This connection at the host side of the interface would depend upon the pin that is being used as the Ready/Busy signal by the driving software. Typically, on a PC, it would be either CTS (pin 5) or DSR (pin 6) on a DB-25 connector.

Page 5-6 SATO D508/D512 Operator Manual