This type of answering machine was common at the time this circuit was published. Using two tape recorders, it was published in the June 1986 issue of Radio Electronics magazine.
This is a circuit published in the January 1962 Radio Electronics magazine. The circuit is for...
Taken from a 1967 RCA publication, this circuit maintains a low current in the battery when it is...
This simple pass-through circuit was obtained in an old documentation, but it is still up to date...