This voice scrambler and descrambler circuit was found in a Radio Electronics from July 1963. Transformers are common types at the time with impedances according to telephones and line.
Using transistors at the time, this circuit was found in a 1967 Ferranti documentation. The...
These circuits were found in Exar documentation from the 90s. The circuits use both a small...
Found in Radio Electronics, this circuit is intended to activate the lighting system of garages...