In article hM67g.1131$Zf3.73@trndny01, HFguy wrote:
Grimly Curmudgeon wrote:

I fully agree that in some conditions a Morse tone will get through where
voice is an unintelligble mush, if heard at all, but apart from prisoners
tapping out messages on pipes its days as an *essential* comms tool are
pretty much over.

How do you send Morse code by tapping on a pipe when all you can send is
a 'dit'?

They don't. They use a counting code where the alphabet is represented
as a 5x5 or 6x6 (for cyrillic) matrix and then they use a count for
row and column. It was described in Koestler's "Darkness at Noon", a novel
about the Stalinist Purges, but I've read that a 5x5 version is used in the
west. Unless you're a US Airman in a North Vietnamese POW prison, they
used Morse using a tap/scrape for dot/dash.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)