Fw: Deck of IBM PLAYING CARDS GOES FOR $325

[Chuck Guzis]

On 12/18/2005 at 10:37 PM William Maddox wrote:

>I recall reading that the Cray-1 used balanced logic circuits, in which 
>a complementary pair of a signal and its complement were always 
>generated, and each fed a terminated transmission line.  The idea was 
>that the machine drew essentially constant current regardless of its
>logic state.  Perhaps this placed constraints on the chips that could be 
>used, as most MSI functions are not implemented in such a perfectly 
>symmetric fashion.

LVDS uses the same scheme of being differential throughout and even ECL
uses differential outputs (even if only one of them is actually brought out
to a pin).  CML goes back to the 60's.  

Cheers,
Chuck