This circuit monitors an old-style analog telephone line. We found it in the September 1991 issue of Radio Electronics magazine.
November 3, 2015 - Mouser Electronics, Inc. is now shipping the new Intel® Quark™ microcontroller...
We found this circuit in the March 1992 issue of Radio Electronics magazine. The circuit has a...
This circuit is from an old documentation but still current for assembly. Just use BC548 instead...