Epson DFX-8500 service manual Parallel Interface Reverse channel

			GENERAL DESCRIPTION
1.3.2 Parallel Interface (Reverse channel)
‰￿	Data transmission mode:	IEEE-1284 nibble mode
‰￿	Connector type:	57-30360 (AMPHENOL) 36-pin plug or equivalent
‰￿	Synchronization:	No Info.
‰￿	Handshaking:	No info.
‰￿	Data transmission timing:	No info.
‰￿	Signal Level:	TTL-level compatible, IEEE-1284 level 1 device
‰￿	Extensibility request :	The printer responds to the extensibility request in the affirmative,
		when the request is 00h or 04h, which mean:
		00h : Request nibble mode of reverse channel transfer
	Device ID :	04h : Request device ID in nibble mode of reverse channel transfer
‰￿
		[00h][3Ah]
		MPG:EPSON;
		CMD:ESCP9,PRPII9,BDC;
		MDL:DFX-8500;
		CLS:PRINTER;

‰￿Connector pin assignments: Refer to Table 1-11.

Table 1-11. Signal and Connector Pin Assignment (Reverse channel)

Pin No.	Signal Name	I/O*	Description
1	/STROBE	IN	HostCIk: This signal is a strobe pulse used to read extension
			request values from the host computer during negotiation.
2-9	DATA 1-8	IN	The signals are data bits of extension request Values during
			negotiation. This printer supports following values:
			0000 0100: Request Device ID (by nibble mode sending)
			0000 0000: Request nibble mode
10	/ACKNLG	OUT	PtrCIk: Printer data sending clock.
11	BUSY	OUT	PtrBusy: Printer sending data bits 3 and 7 during data transfer to
			the host computer
12	PE	OUT	AckDataReq: Printer sending data bits 2 and 6 during data transfer
			to the host computer
13	SLCT	OUT	Xflag: Printer sending data bits 2 and 6 during data transfer to the
			host computer.
14	/AUTO-FEED	IN	HostBusy: This signal informs the printer of the host computer
			state. When the signal is HIGH, the host computer cannot accept
			data.
15	NC	-	Not used.
16	GND	-	Logic ground level
17	CHASSISGND	-	Connected to the printer chassis. The printer chassis GND and the
			signal GND are connected to each other.
18	NC	-	Not connected.
19-30	GND	-	Ground level for the twisted pair return signal.
31	/INIT	IN	nlnit: High level fixed
32	/ERROR	OUT	nDataAvaiI: Printer sending data bits 0 and 4 during data transfer to
			the host computer.
33	GND	-	Same as for ins19to30.
34	NC	-	Not used.
35	+5	-	Pulled up to +5V through 1.0K ohm resistor.
36	/SLCT IN	IN	1284Active: If this signal is set to HIGH, this printer active
			P1284(reverse mode).

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

Rev. B 1-21