I recently posted a message about up/down scrolling displays and
how difficult many of todays systems were to use if one could not see the
display.  I had an amusing experience in the art of alternative I/O, once
that I will relate.

        I was given a memory tester that checks the DRAM used in the older
P.C/XT type mother boards.  The device has a ZIF socket on it and a
LED display that shows whether the chip is good, a 64 K RAM, or a 256 K
RAM.  I can't read the display so I needed to figure out what I was going to
do.  I could butcher it up and maybe connect the LED drivers to a PIC or
some other kind of processor and make a grand cluge out of it all, but
I had a major attack of laziness and a flash of inspiration.  I laid a portable
AM radio next to the tester, tuned to a quiet spot on the dial, and put
in a 64 K chip and pressed the button.  The EMI from the tester made a little
blerp on the radio.  Now, I tried a 256 K RAM.  It made a longer
double-blerp much like a British telephone ring.  Memory that was
misinserted or bad makes no sound at all except for a faint click as one
presses the button.  Problem solved.  I didn't even have to drill any holes.

Martin McCormick