David G. Nagel wrote:
Actually the Code that Sam developed is completely unlike the code we
use on radio. What is tested for is the "International Morse Code"
Sam's code was click based and radio is beep based.

Sam's original equipment used ink and scrolling paper to
record the dots and dashes because he didn't think an
ordinary human being could distinguish between the sound
of the dots and the sound of the dashes. He was wrong.
Human operators quickly discovered that they could distinguish
the difference between the down clicks and up clicks and
therefore distinguish the dots from the dashes.

It is true that Sam's "American" Morse was different from
"International" Morse in about a dozen characters but both
used dots and dashes. Still, more characters were alike
than were different.

The term "lid" may have originated from newbie Morse operators
laying a lid on top of the relay receiver to make it easier to
distinguish the dots from the dashes.
--
73, Cecil http://www.qsl.net/w5dxp