P1284.3 Scope
This standard, IEEE P1284.3, defines system extensions consistent with the
implementation and functionality of IEEE Std 1284-1994. These functions
include:
- Multi-port expansion architectures
- Multiplexor
- Daisy Chain
- Application and Device Driver Programming Interface architecture that can
be supported across various operating systems.
- Data link layer services for supporting IEEE Std 1284-1994 parallel
ports.
P1284.3 Purpose
In March 1994, IEEE Std 1284-1994 was formally approved. IEEE Std 1284-1994
(hereafter referred to as Std 1284) specifies all the required mechanical,
electrical, and timing characteristics for a high-speed, bi-directional
parallel port for printers and other peripherals. While these parameters
define the physical environment and protocol requirements for an
operational Std 1284 port, there is a need to standardize a
number of extensions and operating system interfaces to help facilitate
operation across various system platforms and operating environments.
ftp://ftp.lexmark.com/pub/ieee/1284.3/d400.pdf
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P1284.4 Scope
The packet protocol described by this standard allows a device to carry on
multiple, concurrent exchanges of data and/or control information with
another device across a single point-to-point
link. The protocol is not a device control language. The protocol provides
basic transport-level flow control and multiplexing services. The
multiplexed information exchanges are independent and
blocking of one has no effect on any other. The protocol shall operate over
IEEE 1284-1994 interfaces and may operate over other point-to-point
interfaces.
P1284.4 Purpose
IEEE Standard 1284-1994 defines and describes an updated PC parallel
interface by adding multiple modes of operation which provide for higher
speed, bi-directional communication
between devices. The IEEE 1284-1994 standard does not provide anything
beyond a physical protocol. The 1284.4 standard specifies a point-to-point
protocol with one or more layers above
the physical interface and below the application. These layers take on the
functions and characteristics of the transport and session layers of the
OSI model.
ftp://ftp.lexmark.com/pub/ieee/1284.4/specification/draft170.pdf
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IEEE Std 1284.1-1997 is available from the IEEE at 1-800-678-4333 or
1-732-981-0600
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