Instruct: Classify the given review into positive or negative sentiment.
Query: interesting

I wanted a book with basic information about telephone circuits, especially older classic phones. This one touches on that but really has more information on related topics. There are several chapters on basic electronics repair. The writing style is clean, and easy to read. It is not overly technical and should be easily understood by anyone with even a minimal background in electronics. However, the drawings are not very good. Looks like someone is just learning a computer drawing program. It is disappointing that the classic phone is given a not very useful wiring diagram rather than a schematic. Diacs are shown in the circuits as a "loop length compensator" with no explanation how that works. Very confusing. On the whole though, I would recommend this book. Nice little section on using the oscilloscope.