Epson Scan 2500 service manual Scanner interfaces, IEEE1284.4 Protocol

EPSON Stylus Scan 2500 Revision A

IEEE1284.4 PROTOCOL

The packet protocol described by IEEE1284.4 standard allows a device to carry on multiple exchanges or conversations which contain data and/or control information with another device at the same time across a single point-to-point link. The protocol is not, however, a device control language. It does provide basic transport-level flow control and multiplexing services. The multiplexed logical channels are independent of each other and blocking of one has no effect on the others. The protocol operates over IEEE1284.

	Automatic Selection
	An initial state is compatible interface and starts IEEE1284.4
	communication when magic strings (1284.4 synchronous commands)
	are received.
	On
	An initial state is IEEE1284.4 communication and data that received it
	by the time it is able to take synchronization by magic string (1284.4
V	synchronous commands) is discarded.
	Off
	An initial state is compatible interface and never starts IEEE1284.4
	communication even if magic strings (1284.4 synchronous
	commands) are received.

1.5.2 Scanner interfaces

PARALLEL

1. Specification
Transmission mode	8 bit parallel, IEEE-1284 compatibility/nibble mode
Synchronization	Refer to the IEEE-1284 specification
Handshaking	Refer to the IEEE-1284 specification
Packet	Refer to the IEEE-1284 Standard for Data Delivery
	and Logical Channels for IEEE Std. 1284.4 Interface
	(Draft D1.50)
	Refer to the IEEE-1284 specification
Signal level	TTL compatible level (IEEE-1284 Level 1 device)
Data trans. timing	Refer to the IEEE-1284 specification

2.Connector pin assignment and signals Refer to the IEEE-1284 specification

3.Data transmission timing

Refer to the IEEE-1284 specification

Product Description Interfaces 21