Douglas Henke wrote:

CW is a modulation type. It is interesting in that it is the only form
of digital modulation which can be encoded and decoded by an
unassisted human in real-time. It is also interesting for a variety of
other reasons, such as historical importance, widespread adoption,
simplicity of equipment and readability in high-noise, weak-signal
environments.


The old rotary telephones were "Digital Modulation" in that they
opened the line to control the Stowager stepper relays, or crossbar
switching eguipment. If you were good at it you could dial numbers with
the hook switch.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida