You are correct, Sir!  (As Ed might say..)  It was a very different
arrangement I was thinking of..  On a normal keypad 2 keys are no
problem and 3 is always ambiguous because the 4th appears at the same
time..  Thanks for the correction.

Alan



Andrew Warren wrote:
> Alan:
>
> It's been my experience that ambiguity only occurs when THREE keys
> that form three corners of a rectangle are pressed, and that TWO keys
> are never a problem to read.
>
> Of course, this applies only to keypads that are scanned by row or
> column; were you talking about another keypad topology?
>
> -Andy