Ieee 1284.4 Protocol - Epson Stylus Color 980 Service Manual

EPSON Stylus Color 980

1.3.7.1 IEEE 1284.4 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:
IEEE1284.4 is enabled as initial state. Data sent before the magic
string (1284.4 synchronous commands) is discarded.
OFF:
IEEE1284.4 is disabled and IEEE1284.4 synchronous commands
are ignored. Compatible interface is the initial state.
Product Description Interface
Revision A
28