US 4,286,319 AGranted

Expandable inter-computer communication system

AssigneeThe Singer Company

InventorsRobert J. Membrino, Raphael R. Some, Van A. Quinn

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Abstract

This disclosure describes a system for providing a communications channel between a master computer and a plurality of similar or dissimilar slave computers that may be separated by great distances. The foregoing system comprises a buffer unit and at least one computer linkage unit. The buffer unit acts as an interface between the master or control computer, the external hardware that is coupled to the master computer and a plurality of slave computers, and the one or more computer linkage units so that the buffer unit may act as an expandable direct memory access bus to a slave computer and provide communication with a plurality of peripheral systems. The computer linkage unit performs all of the remaining interface functions between the master computer and the plurality of slave computers that are coupled to the master computer. Additional computer linkage units together with additional slave computers may be connected to the original computer linkage unit permitting this system to be easily expandable without extensive modifications.

Claims20

Dependent claims

A expandable asynchronous parallel intercomputer communication system that provides a two-way communication signal channel between a master computer and a plurality of slave computers, and between said master computer and a plurality of peripheral units which are electrically and functionally compatible with said master computer, said master computer being separated from said plurality of slave computers and said plurality of peripheral units by varying transmission distances, said system comprising:

a. a buffer unit having at least three bidirectional channels so interconnected that signals received by said buffer unit on said first channel are provided to said second and third channels as described in this claim, and signals received by said buffer unit on said second and third channels are provided to said first channel as described in this claim, the first buffer unit bidirectional channel being electrically compatible with and coupled to said master computer and the second buffer unit bidirectional channel being coupled to at least one of said peripheral units, said second buffer unit bidirectional channel transmits electrical signals which are electrically and functionally identical to the signals that are transmitted on said first bidirectional channel so that the presence of said buffer unit does not affect the communications between said master computer and said plurality of peripheral units;
the third buffer unit bidirectional channel comprising a bidirectional differential channel which transmits signals that have been electrically altered by said buffer unit without functionally altering the meaning of said signals so that electrical characteristics of said signals are maintained over long transmission distances;
and
b. a first computer linkage unit for providing functional and electrical interface functions between said first slave computer and said buffer unit, said first computer linkage unit being coupled to said buffer unit at said third buffer unit bidirectional differential channel and coupled to said first slave computer so that said first computer linkage unit may maintain electrical and functional compatibility with said buffer unit and said first slave computer;
whereby said first slave computer, and said first computer linkage unit may be added to an existing computer communication system without modifying the existing system.

2 more elements

Apparatus for providing bidirectional communication between a first computer and a second computer, and between the first computer and a peripheral device, comprising:

first buffer means adapted to be connected between a first computer and a peripheral device for providing first computer signals from the first computer to the peripheral device in a noise reduced condition;
second buffer means adapted to be connected between the first computer and the peripheral device for providing received signals to the first computer in a noise reduced condition;
third buffer means operatively connected to said first buffer means to receive noise-reduced first computer signals therefrom for electrically altering at its input and de-altering at its output noise-reduced computer signals so that the electrical and functional characteristics of such signals can be maintained over substantial transmission distances;
first linkage means operatively connected to said third buffer means to receive noise-reduced first computer signals therefrom and adapted to be connected to a second computer, for interfacing signals to and from the second computer;
and
fourth buffer means operatively connected to said first linkage means to receive second computer signals therefrom, and operatively connected to said second buffer means, for electrically altering at its input and de-altering at its output received second computer signals so that the electrical and functional characteristics of such signals can be maintained over substantial transmission distances and are provided to said second buffer means, wherein said second buffer means provides signals received from the peripheral device and from said first linkage means to said first computer in a noise reduced condition.

3 more elements

Dependencies are inferred from the claim text.