This circuit was obtained from an old Signalite documentation. Neon lamps are special types of the time. The operation occurs at low frequencies.
IDT ZSSC3230 Capacitive Sensor Signal Conditioner Available from Mouser Electronics stock, this IDT...
We found this transmitter circuit for different frequency ranges in a 1992 documentation. The...
This crystal configuration can be made with triggers of any logic. The frequency is given by the...