88-ACR KCS modification - test-drb@ccmp.vtda.org

26 Dec 2006

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Subject: 88-ACR KCS modification
   From: Grant Stockly <grant at stockly.com>
   Date: Mon, 25 Dec 2006 14:00:27 -0900
     To: cctalk at classiccmp.org

I'm trying to modify my 88-ACR to work with the KCS specification.

Does anyone know where the information on modifying the 88-ACR to 
read/wrote KCS audio is?

Also, I was wondering if anyone ever looked at this card?  The XR210 chip 
MITS used for demodulation of the FSK signal is capable of MODULATING 
too.  (with both mark and space frequencies).  Does anyone know why they 
would have used 5 ICs and a few opamps to do the modulation when they could 
have used the other half of a chip already present?

Grant  
Not possible.  The ACR is simple FSK and the KCS is redundent FM.

As to the latter question of component use... the ACR was intended as a 
modem (bell 103) and it's design was based on that.

Allison