I would like to take this opportunity to make a suggestion.  There
are many devices that use an up/down mechanism for setting parameters or
a round-robbin menu system in which one must keep pressing a selection button
until the desired selection appears.  These mechanisms are pure Hell for
users of the devices who happen to be blind.  Since thermostats, timers,
and countless other control systems exist in homes and businesses, there
is no telling when this problem will occur.  My suggestion is to have an
abnormal key sequence such as the simultaneous pressing of both the up and
down button or some other sequence to start the selection process at a
known point in the circle.  This might be accompanied by a beep or some
audible indication, if there is a sounder, but this feature would be very
cheap to implement and would allow a blind person to use the device by learning
the order of selections.

        I don't know how many modern devices are almost impossible to use
efficiently due to this type of control mechanism.  All I know is that it
shows up all the time and is an utter pain to deal with.

        There is a literary quote that goes something like "It isn't the
mountains in the distance, but that little grain of sand in your shoe that
can drive a person to madness."  That pretty well sums up the feeling about
the state of the art in control technology over the last 10 years or so.

Martin McCormick