This circuit is from the 80's, using an integrated of the time. The circuit serves as a reference, as this type of dialing is no longer used today.
This Intersil circuit was found in a 1980s documentation. Operational are of the time, but current...
New Low-Power PIC24 “GA7” Microcontroller Family Now Available CHANDLER, Ariz., Dec. 12, 2016 — The...
This circuit was found in a 1976 NASA manual, making use of components of the time. The transistor...