SATO CL412E service manual Ready/Busy Flow Control, Signal Description

Section 3. Interface Specifications

			RS232C Interface Signals
PIN	DIRECTION			SIGNAL DESCRIPTION
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 protocol).
3	To Printer	RD (Receive Data) - Data to the printer from the host computer.
		RTS (Request to Send) - Used with Ready/Busy flow control to
		indicate an error condition. RTS is high and remains high unless the
4	To Host	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. label out).
		CTS (Clear to Send) - When this line is high, the printer assumes
5	To Printer	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).
		DSR (Data Set Ready) - When this line is high, the printer will be
6	To Printer	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)
		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
20	To Host	goes low when the printer is off-line either manually or due to an
		error condition, and while printing in the Single Job Buffer mode. It
		will also go low when the data in the buffer reaches the Buffer Near
		Full level.

Ready/Busy Flow Control

Ready/Busy is the hardware flow control for the serial interface on the CL408e/CL412e printers. By raising/lowering the voltage level on Pin 20 of the RS232 port, the printer notifies the host when it is ready to receive data. Pin 4 (RTS) and pin 20 (DTR) are the important signals on the printer for this method of flow control. The host must be capable of supporting this flow control method for it to function properly.

Page 3-8 SATO CL408e/CL412e Service Manual

PN 9001078 Rev. B