This circuit was found in a Poptronics of the 90's. The components can be changed to the desired frequency. The power supply must be symmetrical.
In critical applications of the RS-232 interface, the danger of induced voltages in the cables must...
The sensitive relay reed trigger transistors can be the BC548 and the diode can be the 1N4148. The...
We found this circuit in an old English documentation. The circuit can employ other gates and...