Epson DFX-8500 service manual Serial Interface, Optional Interface

DFX-8500

1.3.3		Serial Interface
‰￿	Synchronization :		Asynchronous
‰￿	Signal level (ELA-232D) :
„￿		MARK (logical 1) :	-3Vto-25V
„￿		SPACE (logical 0) :	+3Vto+25V
‰￿	Word length :
„￿		Start bit :	1 bit
„￿		Data bit :	8 bit
„￿		Parity bit :	Odd, Even, Non, of Ignore
„￿		Stop bit :	1 bit or more
‰￿	Baud rate :		2400, 4800, 9600 or 19200 bps
‰￿	Handshaking :		DTR signal or X-ON / X-OFF
„￿		DTR=MARK, X-OFF :	Indicates that the printer cannot receive data.
„￿		DTR=SPACE, X-ON :	Indicates that the printer is ready to receive data.
Note:	The DTR signal is MARK and X-OFF code (DC3, 13h) is transmitted when the rest of the
	input buffer becomes 256-byte. The DTR signal is SPACE and X-ON code (DC1, 11h) is
	transmitted when the rest of the input buffer is regained 256-byte.
‰￿	Error handling :		When parity error is detected, the received byte is changed to the
￿			"*" character code. Overrun error and framing error are ignored.
‰￿	Connector :		25 pin sub-miniature D-shell connector (female)
‰￿	Connector pin assignment and signals : Refer to Table 1-12.

Table 1-12. Signal and Connector Pin Assignment (EIA-232D)

Pin No.	Signal Name	In / Out*	Functional Description
2	TXD	Out	Transmit data.
20	DTR	Out	Indicates that the printer is ready to receive data or not.
11	REV	Out	Connected directly to the DTR signal.
4	RTS	Out	Request to send. always SPACE level when the printer is
			powered on. Pulled up to +12 V via 4.7K-ohm resistor.
3	RXD	In	Receive data
7	Signal GND	-	Signal GND
1	Chassis	-	Chassis GND
	GND
Other	NC	-	Not used. Not connected.

Note: * In/Out refers to the direction of signal flow from the printer’s point of view.

1.3.4 Optional Interface

Type-B and Type-B level 2 optional interfaces are available (Refer to Table 1-1.).

1-22 Rev. B