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.
MCP19124/5 Contains Independent Voltage and Current Control Loops Plus a Full Suite of...
This circuit is designed to control static loads fed by direct voltage. The circuit is from...
This circuit is from an American 1964 documentation. Transistors of the time are used, but modern...