Browse Prior Art Database

Infrared Local Area Network Disclosure Number: IPCOM000120084D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 3 page(s) / 101K

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Related People

McLean, JG: AUTHOR [+4]


This article describes an implementation of local area networks (LANs) with the use of infrared (IR) links.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Infrared Local Area Network

      This article describes an implementation of local area
networks (LANs) with the use of infrared (IR) links.

      In the concept disclosed herein, a home or office complex has
built into one or more walls of each room, an infrared transceiver
unit.  All units connect via wires to a central hub, which receives
IR signal input from any room and directs it, perhaps "intelligently"
based upon information in the incoming signal, to one, several, or
all other units.  A wireless LAN could be implemented to provide
communication between personal computers (PCs), printers, lab
equipment, etc.  The entire assembly could be made part of a modular
office wall section.

      By using standard LAN techniques (random retry, token passing,
etc.) and using the IR network as a simple transmission medium,
hardware complexity is minimized.  The basic building block of the IR
LAN is a simple IR omnidirectional repeater.  Referring to the block
diagram of Fig. 1, it is illustrated that a signal received in any
room is replicated in every room; it is up to the LAN software to
sort it out.  In this implementation the IR network is a true LAN
medium.  Unlike other LAN media, intelligence can be added to the IR

      Room-addressing at the hub can be added, thus taking some of
the performance load from the LAN software.  LAN performance could be
improved through the use of a multiplexer, to resolve the case of
signals inbound from more than one source at once, eliminating retry
delays. Adding even more addressing capability would allow a digital
PBX (CBX) approach which can accommodate and route simultaneous
signals from multiple sources to multiple targets, like a smart
cross- point switch.

      The IR LAN allows a number of IR linked devices to communicate
between rooms of a house or an office.  The IR links allow the
devices to communicate without the need for communication cables
between devices.  The cables are all inside of the walls which