This CW circuit was found in a Radio Amateur Today from the 890s. The CMOS circuit must be powered by an isolated source and has different dash and dot timings.
This sequential circuit with an optical coupler was found in a Popular Electronics from the 90s to...
This circuit is from 1967 General Electric documentation. It uses SUS which are not very common...
I found this circuit in an article in a 2003 publication. The circuit is an example of how to...