This 2002 circuit uses many more electrical components than electronics. The keys are common, and the alarm is a common clock that has this feature.
The transistor of this remote preamp can be the BC549. We found this circuit in a 1976 technical...
Although it is a common configuration today, these circuits were taken from an old publication. The...
We found this circuit in a 1982 publication. This source allows an adjustment of the output...