Answers to questions

From David Pogue's email newsletter:

Why do the signal-strength bars on my cellphone change when I’m standing still?

The signal indicator isn’t a live depiction of your cell strength. The phone needs to send out a “ping” to the tower from time to time to figure out if it is still connected. You may be in a spot where you get full signal strength, then move to a dead spot, and the phone won’t know for a set interval (30 seconds or so, I believe) until it pings again and figures out the new strength. Thus, you stand there with 4 bars and then suddenly get 1 or 0. If it were a live update, the battery would drain a heck of a lot faster.
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Often the signal is being reflected off buildings and or terrain and that will give you varying signal strength. This may also explain why sometimes you can’t make a call even though you’ve got enough bars as reflected signals are weak anyway.

Why is the numeric keypad on a computer (7-8-9 at the top) upside-down from the numeric keypad on phones (1-2-3 on top)?

When 10-key touch-tone telephones were invented it was decided that folks accustomed to 10-key calculators would type in the numbers faster than the then-developed equipment could handle, so the numbers were inverted.
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The computer keypad is a legacy of the adding machine/calculator and is mostly used by bean counters, who are too old to learn new tricks. The phone keypad is a legacy from the rotary dial, with the 1 on top and 0 at bottom. The dial had the alphabet to contend with. No one wants to see that upside down.

Why aren’t elevator buttons double action? Press once to go to floor, press again to cancel. It would save all those “OOPS! — I hit the wrong button” moments.

I live in Korea — almost all the elevators are “one push on/second push off” style. Most in Japan, too. Much more sensible, and if that annoying kid who presses them all shows up, easy to fix. Though one time I had someone unpush my floor because they thought they had pushed it by mistake, and so I had a bit longer elevator ride. But over all, a definite plus.
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Because there are people who think punching a lit elevator button makes it come faster. Really. Drop in to my office.