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From: landman%hanami@Sun.COM (Howard A. Landman)
Newsgroups: comp.windows.misc,comp.sys.next,comp.sys.mac
Subject: Re: wireless keyboard (was Re: replacing the desktop metaphor)
Keywords: desktop metaphor, graphical interfaces, computing environments
Message-ID: <83075@sun.uucp>
Date: 27 Dec 88 18:21:22 GMT
References: <4362@pitt.UUCP> <257@gloom.UUCP> <82702@sun.uucp> <8939@ut-emx.UUCP> <34173@think.UUCP>
Sender: news@sun.uucp
Reply-To: landman@sun.UUCP (Howard A. Landman)
Organization: Sun Microsystems, Mountain View
Lines: 30

>In article <8939@ut-emx.UUCP> osmigo@emx.UUCP (Ron Morgan) writes:
>>I don't know why a wireless keyboard would be far-fetched.

In article <34173@think.UUCP> barmar@kulla.think.com.UUCP (Barry Margolin) writes:
>Hardly far-fetched, since it was done in a commercial computer several
>years ago.  The original IBM PC Jr had a wireless keyboard that used
>infrared signals.  They eventually punted it because it didn't work
>too well.  Input would be missed because someone would walk between
>the keyboard and the PC, and it could get confusing with multiple
>machines in the same room.

>Wireless communication is pretty noisy and error prone.  It is well
>suited to low-bandwidth applications such as telegraphy, or less
>error-sensitive applications such as voice.  For applications such as
>terminal I/O integrity is important, so you would need an
>error-detecting protocol between the PC and the device.

Just because IBM's implementation failed to address the important issues
and was unreliable, is no reason to punt on the concept.  We already know
of systems that face the same kinds of difficulties and work fine.
Ethernet is one example, and even the old ALOHA packet-radio network
worked well enough.  Implementing this at keyboard bandwidths should be
childsplay.

If someone walking between keyboard and computer interrupts communication,
the keyboard should retry until the data is received.  Of course, to do that
it has to *know* whether the data was received or not!

	Howard A. Landman
	landman@hanami.sun.com