IEEE Standard 1284.4

Standard for Data Delivery and Logical Channels for IEEE Std. 1284 Interfaces.

A Transport Protocol standard that may be used accross an IEEE Std. 1284-1994 parallel port interface, or any other suitable physical interface such as USB or IEEE 1394. This standard will provide a protocol to create and maintain multiple conversations accross a single parallel port link. Think of this as using the 1284 parallel port to communicate with a multifunction device having printer, scanner and fax capabilities. With this protocol multiple applications will have access to the individual functions without the knowledge of the other applications.

The starting point for this standard is the Hewlett-Packard standard for Multiple Logical Channels (HP Multiple Logical Channels protocol (MLC)). It should be noted that the goal of this committee is not to make a standard of the HP MLC specification, but to use the HP Multiple Logical Channels protocol (MLC) spec as a starting point from which to meet the objectives standard.

Patent Issues: Hewlett-Packard and Genoa Technology joinly own a patent which is the basis for IEEE 1284.4. They have agreed to offer a license for this patent free of charge. You may obtain a license online by going to http://www.gentech.com/1284/mlc.htm. Many thanks to Hewlett-Packard and Genoa Technology for making this available.

Technical reference manuals can be ordered from the IEEE standards association: http://www.ieee.org/

You can also download the 1284.4 draft from Lexmarks FTP site: ftp://ftp.lexmark.com/pub/ieee/1284.4/specification The latest draft is “Draft1284_4v4.pdf”. This is the final draft that is being sent to the IEEE. There are editorial changes to be made prior to its' release.

• HP Multiple Logical Channels protocol (MLC) HP Multiple Logical Channels Protocol. Superseded by this standard.
• IEEE Standard 1284 IEEE Standard Signaling Method for a Bidiretional Parallel Peripheral Interface for Personal Computers
• IEEE Standard 1284.1 Standard for Information Technology for Transport Independent Printer/Scanner Interface.
• IEEE Standard 1284.3 Standard for Interface and Protocol Extensions to IEEE Std. 1284 Compliant Peripheral and Host Adapter Ports.