the 810 was the first of the hand-held range
of anita calculators from sumlock comptometers and manufactured by
rockwell in 1973.
this is a fine example in almost perfect condition. the display is 8
digit led whose segments themselves appear to be made up of smaller dots.
it is very well constructed and palm sized. the form factor reminds me of
the fx-20 or the hp-25, a
size i find convenient.
the on switch doubles as a means to select power from an external
supply and the other switch selects rounding indicated by a rounded arc.
rounding is fixed to 2 decimal places for accounting purposes.
although pocket sized, this unit was clearly intended for use in
accounting because operationally it behaves like a desk calculator. that
is to say that add does not chain to multiply. so 2*3+1 is not 7. instead,
you press 2*3=+, 1+ and to subtract to press, for example, 3- rather than
-3. this is exactly how most desk calculators operate like the anita
811sl. a clue to this is the subtle colour shading of the plus and