Nibble-Wide Bidirectional Personal Computer Parallel Port Communication Interface
Original Publication Date: 1987-Aug-01
Included in the Prior Art Database: 2005-Feb-01
A technique is described whereby nibble-wide bidirectional communica- tions is provided to enable point-to-point communication between two IBM personal computers (PCs) for message and file transfers. No modifications are made to the existing PC parallel communication circuit cards. Four control lines going out and four control lines going in are provided as an interface to two PCs connected together by means of a cable, enabling the two interface cards to exchange nibble-wide (4 bits) data. The hardware interface along with the pseudo-code described herein, provide a method of implementing a disk operating system (DOS) extension which will copy files and facilitate the field upgrade of PCs with different disk drive formats, such as a 5.25" PC drive being able to exchange data with a 3.5" PC drive.