Path: utzoo!utgpu!watserv1!watmath!att!pacbell!pacbell.com!mips!sjsca4!poffen
From: poffen@sj.ate.slb.com (Russ Poffenberger)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: PC (XT) keyboard & XT/286 m/b
Message-ID: <1990Sep4.191514.2883@sj.ate.slb.com>
Date: 4 Sep 90 19:15:14 GMT
References: <25345.26d502c6@kuhub.cc.ukans.edu> <1990Aug24.194929.25595@mcs.anl.gov>
Reply-To: poffen@sj.ate.slb.com (Russ Poffenberger)
Organization: Schlumberger Technologies, San Jose, CA.
Lines: 44

In article <1990Aug24.194929.25595@mcs.anl.gov> winans@sirius.mcs.anl.gov (John Winans) writes:
>In article <25345.26d502c6@kuhub.cc.ukans.edu>,
>michal@kuhub.cc.ukans.edu (Merlin The Magician) writes:
>|> Is there any way to get an 84-Key Keyboard to work with an AT
>|>Motherbaord ? Before you answer, here is the scenario:
>|> I own a True Blue XT/286 Box with True Blue 101 AT Style Keyboard.
>|>It all works well. For reasons not to obvious, I would like to
>|>get this box to work with a True Blue 84 PC (yes!) keyboard. 
>|> When the system boots with the PC keyboard plugged in, an error
>|>message is displayed (System Options not set, F1 to continue) and
>|>an annoying repetative beep is heard, which cannot be made to go away.
>|> IBM local dealer says the two keyboards use a diffrent scan and you
>|>CANNOT use an XT (PC) keyboard on an AT m/b. But then the rep also
>|>flatly denied the existance of an IBM XT/286. 
>
>A different "scan" huh??  I always thought the word was protocol.  Mr. IBM 
>local dealer is correct in that it is different, but "scan" is the term I'd
>expect from a car salesoid...
>
>(insert your favorite flame here)
>
>The keyboards are not interchangable.  They communicate with the computer
>with a serial protocol a whole lot like that of the "COM" ports.  Except
>there is a different number of bits used on them.  If U want to know more
>about it, there is a nice discussion of how they work in one of the 1990
>issues of "Circuit Cellar" (I think it was around April).
>
>I would think that if one exists, one of the Digi-key/Jameco type places 
>(that advertise in the back of BYTE) would probably have one.
>

You are correct in that the keyboards use a different protocol, and in many
cases (True Blue IBM equipment anyway), they are not interchangeable. Some
clones can accept either, some clone keyboards can run with either protocol.

However, you analogy to the "com" port is a little lacking. Whereas the "com"
ports are asynchronous, the keyboard uses a synchronous (separate clock signal)
protocol.


Russ Poffenberger               DOMAIN: poffen@sj.ate.slb.com
Schlumberger Technologies       UUCP:   {uunet,decwrl,amdahl}!sjsca4!poffen
1601 Technology Drive		CIS:	72401,276
San Jose, Ca. 95110             (408)437-5254